rt_device_write/read return data type as rt_ssize_t

rt_ssize_t can give negative error code, which follows the unix style correctly

55 files changed, 151 insertions, 151 deletions

diff --git a/components/drivers/audio/audio.c b/components/drivers/audio/audio.c
index edef7d0eeb..2907b10ba0 100644
--- a/components/drivers/audio/audio.c
+++ b/components/drivers/audio/audio.c
@@ -357,7 +357,7 @@ static rt_err_t _audio_dev_close(struct rt_device *dev)
     return RT_EOK;
 }
 
-static rt_size_t _audio_dev_read(struct rt_device *dev, rt_off_t pos, void *buffer, rt_size_t size)
+static rt_ssize_t _audio_dev_read(struct rt_device *dev, rt_off_t pos, void *buffer, rt_size_t size)
 {
     struct rt_audio_device *audio;
     RT_ASSERT(dev != RT_NULL);
@@ -369,7 +369,7 @@ static rt_size_t _audio_dev_read(struct rt_device *dev, rt_off_t pos, void *buff
     return rt_device_read(RT_DEVICE(&audio->record->pipe), pos, buffer, size);
 }
 
-static rt_size_t _audio_dev_write(struct rt_device *dev, rt_off_t pos, const void *buffer, rt_size_t size)
+static rt_ssize_t _audio_dev_write(struct rt_device *dev, rt_off_t pos, const void *buffer, rt_size_t size)
 {
 
     struct rt_audio_device *audio;
diff --git a/components/drivers/audio/audio_pipe.c b/components/drivers/audio/audio_pipe.c
index 35a3faf73f..4c8aa288b1 100644
--- a/components/drivers/audio/audio_pipe.c
+++ b/components/drivers/audio/audio_pipe.c
@@ -32,7 +32,7 @@ static void _rt_pipe_resume_writer(struct rt_audio_pipe *pipe)
     }
 }
 
-static rt_size_t rt_pipe_read(rt_device_t dev,
+static rt_ssize_t rt_pipe_read(rt_device_t dev,
                               rt_off_t    pos,
                               void       *buffer,
                               rt_size_t   size)
@@ -114,7 +114,7 @@ static void _rt_pipe_resume_reader(struct rt_audio_pipe *pipe)
     }
 }
 
-static rt_size_t rt_pipe_write(rt_device_t dev,
+static rt_ssize_t rt_pipe_write(rt_device_t dev,
                                rt_off_t    pos,
                                const void *buffer,
                                rt_size_t   size)
diff --git a/components/drivers/can/can.c b/components/drivers/can/can.c
index a3d81f6081..53bc2ba45a 100644
--- a/components/drivers/can/can.c
+++ b/components/drivers/can/can.c
@@ -438,7 +438,7 @@ static rt_err_t rt_can_close(struct rt_device *dev)
     return RT_EOK;
 }
 
-static rt_size_t rt_can_read(struct rt_device *dev,
+static rt_ssize_t rt_can_read(struct rt_device *dev,
                              rt_off_t          pos,
                              void             *buffer,
                              rt_size_t         size)
@@ -458,7 +458,7 @@ static rt_size_t rt_can_read(struct rt_device *dev,
     return 0;
 }
 
-static rt_size_t rt_can_write(struct rt_device *dev,
+static rt_ssize_t rt_can_write(struct rt_device *dev,
                               rt_off_t          pos,
                               const void       *buffer,
                               rt_size_t         size)
diff --git a/components/drivers/hwtimer/hwtimer.c b/components/drivers/hwtimer/hwtimer.c
index 189ef7df49..f8e1a35275 100644
--- a/components/drivers/hwtimer/hwtimer.c
+++ b/components/drivers/hwtimer/hwtimer.c
@@ -143,7 +143,7 @@ static rt_err_t rt_hwtimer_close(struct rt_device *dev)
     return result;
 }
 
-static rt_size_t rt_hwtimer_read(struct rt_device *dev, rt_off_t pos, void *buffer, rt_size_t size)
+static rt_ssize_t rt_hwtimer_read(struct rt_device *dev, rt_off_t pos, void *buffer, rt_size_t size)
 {
     rt_hwtimer_t *timer;
     rt_hwtimerval_t tv;
@@ -175,7 +175,7 @@ static rt_size_t rt_hwtimer_read(struct rt_device *dev, rt_off_t pos, void *buff
     return size;
 }
 
-static rt_size_t rt_hwtimer_write(struct rt_device *dev, rt_off_t pos, const void *buffer, rt_size_t size)
+static rt_ssize_t rt_hwtimer_write(struct rt_device *dev, rt_off_t pos, const void *buffer, rt_size_t size)
 {
     rt_base_t level;
     rt_uint32_t t;
diff --git a/components/drivers/i2c/i2c-bit-ops.c b/components/drivers/i2c/i2c-bit-ops.c
index ee6acd886d..5446184558 100644
--- a/components/drivers/i2c/i2c-bit-ops.c
+++ b/components/drivers/i2c/i2c-bit-ops.c
@@ -186,7 +186,7 @@ static rt_int32_t i2c_readb(struct rt_i2c_bus_device *bus)
     return data;
 }
 
-static rt_size_t i2c_send_bytes(struct rt_i2c_bus_device *bus,
+static rt_ssize_t i2c_send_bytes(struct rt_i2c_bus_device *bus,
                                 struct rt_i2c_msg        *msg)
 {
     rt_int32_t ret;
@@ -240,7 +240,7 @@ static rt_err_t i2c_send_ack_or_nack(struct rt_i2c_bus_device *bus, int ack)
     return RT_EOK;
 }
 
-static rt_size_t i2c_recv_bytes(struct rt_i2c_bus_device *bus,
+static rt_ssize_t i2c_recv_bytes(struct rt_i2c_bus_device *bus,
                                 struct rt_i2c_msg        *msg)
 {
     rt_int32_t val;
@@ -366,7 +366,7 @@ static rt_err_t i2c_bit_send_address(struct rt_i2c_bus_device *bus,
     return RT_EOK;
 }
 
-static rt_size_t i2c_bit_xfer(struct rt_i2c_bus_device *bus,
+static rt_ssize_t i2c_bit_xfer(struct rt_i2c_bus_device *bus,
                               struct rt_i2c_msg         msgs[],
                               rt_uint32_t               num)
 {
diff --git a/components/drivers/i2c/i2c_dev.c b/components/drivers/i2c/i2c_dev.c
index 4e2ca8924f..ffd24f95b5 100644
--- a/components/drivers/i2c/i2c_dev.c
+++ b/components/drivers/i2c/i2c_dev.c
@@ -20,7 +20,7 @@
 #endif
 #include <rtdbg.h>
 
-static rt_size_t i2c_bus_device_read(rt_device_t dev,
+static rt_ssize_t i2c_bus_device_read(rt_device_t dev,
                                      rt_off_t    pos,
                                      void       *buffer,
                                      rt_size_t   count)
@@ -40,7 +40,7 @@ static rt_size_t i2c_bus_device_read(rt_device_t dev,
     return rt_i2c_master_recv(bus, addr, flags, (rt_uint8_t *)buffer, count);
 }
 
-static rt_size_t i2c_bus_device_write(rt_device_t dev,
+static rt_ssize_t i2c_bus_device_write(rt_device_t dev,
                                       rt_off_t    pos,
                                       const void *buffer,
                                       rt_size_t   count)
diff --git a/components/drivers/include/drivers/audio.h b/components/drivers/include/drivers/audio.h
index d9a7388678..79856a37a8 100644
--- a/components/drivers/include/drivers/audio.h
+++ b/components/drivers/include/drivers/audio.h
@@ -105,7 +105,7 @@ struct rt_audio_ops
     rt_err_t (*init)(struct rt_audio_device *audio);
     rt_err_t (*start)(struct rt_audio_device *audio, int stream);
     rt_err_t (*stop)(struct rt_audio_device *audio, int stream);
-    rt_size_t (*transmit)(struct rt_audio_device *audio, const void *writeBuf, void *readBuf, rt_size_t size);
+    rt_ssize_t (*transmit)(struct rt_audio_device *audio, const void *writeBuf, void *readBuf, rt_size_t size);
     /* get page size of codec or private buffer's info */
     void (*buffer_info)(struct rt_audio_device *audio, struct rt_audio_buf_info *info);
 };
diff --git a/components/drivers/include/drivers/i2c.h b/components/drivers/include/drivers/i2c.h
index 308c344294..3186f13414 100644
--- a/components/drivers/include/drivers/i2c.h
+++ b/components/drivers/include/drivers/i2c.h
@@ -38,10 +38,10 @@ struct rt_i2c_bus_device;
 
 struct rt_i2c_bus_device_ops
 {
-    rt_size_t (*master_xfer)(struct rt_i2c_bus_device *bus,
+    rt_ssize_t (*master_xfer)(struct rt_i2c_bus_device *bus,
                              struct rt_i2c_msg msgs[],
                              rt_uint32_t num);
-    rt_size_t (*slave_xfer)(struct rt_i2c_bus_device *bus,
+    rt_ssize_t (*slave_xfer)(struct rt_i2c_bus_device *bus,
                             struct rt_i2c_msg msgs[],
                             rt_uint32_t num);
     rt_err_t (*i2c_bus_control)(struct rt_i2c_bus_device *bus,
diff --git a/components/drivers/include/drivers/serial.h b/components/drivers/include/drivers/serial.h
index b4c6fb4a7a..e7432b1e1d 100644
--- a/components/drivers/include/drivers/serial.h
+++ b/components/drivers/include/drivers/serial.h
@@ -167,7 +167,7 @@ struct rt_uart_ops
     int (*putc)(struct rt_serial_device *serial, char c);
     int (*getc)(struct rt_serial_device *serial);
 
-    rt_size_t (*dma_transmit)(struct rt_serial_device *serial, rt_uint8_t *buf, rt_size_t size, int direction);
+    rt_ssize_t (*dma_transmit)(struct rt_serial_device *serial, rt_uint8_t *buf, rt_size_t size, int direction);
 };
 
 void rt_hw_serial_isr(struct rt_serial_device *serial, int event);
diff --git a/components/drivers/ipc/pipe.c b/components/drivers/ipc/pipe.c
index 7567a73482..ccb953bc23 100644
--- a/components/drivers/ipc/pipe.c
+++ b/components/drivers/ipc/pipe.c
@@ -462,7 +462,7 @@ rt_err_t rt_pipe_close(rt_device_t device)
  * @return   Return the length of data read.
  *           When the return value is 0, it means the pipe device handle is empty or the count is 0.
  */
-rt_size_t rt_pipe_read(rt_device_t device, rt_off_t pos, void *buffer, rt_size_t count)
+rt_ssize_t rt_pipe_read(rt_device_t device, rt_off_t pos, void *buffer, rt_size_t count)
 {
     uint8_t *pbuf;
     rt_size_t read_bytes = 0;
@@ -510,7 +510,7 @@ rt_size_t rt_pipe_read(rt_device_t device, rt_off_t pos, void *buffer, rt_size_t
  * @return   Return the length of data written.
  *           When the return value is 0, it means the pipe device handle is empty or the count is 0.
  */
-rt_size_t rt_pipe_write(rt_device_t device, rt_off_t pos, const void *buffer, rt_size_t count)
+rt_ssize_t rt_pipe_write(rt_device_t device, rt_off_t pos, const void *buffer, rt_size_t count)
 {
     uint8_t *pbuf;
     rt_size_t write_bytes = 0;
diff --git a/components/drivers/misc/adc.c b/components/drivers/misc/adc.c
index a85be09fe9..29dbb86f96 100644
--- a/components/drivers/misc/adc.c
+++ b/components/drivers/misc/adc.c
@@ -20,7 +20,7 @@
 #define DBG_LVL DBG_INFO
 #include <rtdbg.h>
 
-static rt_size_t _adc_read(rt_device_t dev, rt_off_t pos, void *buffer, rt_size_t size)
+static rt_ssize_t _adc_read(rt_device_t dev, rt_off_t pos, void *buffer, rt_size_t size)
 {
     rt_err_t result = RT_EOK;
     rt_size_t i;
diff --git a/components/drivers/misc/dac.c b/components/drivers/misc/dac.c
index c1176cc36c..788eac851b 100644
--- a/components/drivers/misc/dac.c
+++ b/components/drivers/misc/dac.c
@@ -17,7 +17,7 @@
 #define DBG_LVL DBG_INFO
 #include <rtdbg.h>
 
-static rt_size_t _dac_write(rt_device_t dev, rt_off_t pos, const void *buffer, rt_size_t size)
+static rt_ssize_t _dac_write(rt_device_t dev, rt_off_t pos, const void *buffer, rt_size_t size)
 {
     rt_err_t result = RT_EOK;
     rt_size_t i;
diff --git a/components/drivers/misc/pin.c b/components/drivers/misc/pin.c
index 91913dccfd..a5a5addafe 100644
--- a/components/drivers/misc/pin.c
+++ b/components/drivers/misc/pin.c
@@ -13,7 +13,7 @@
 #include <drivers/pin.h>
 
 static struct rt_device_pin _hw_pin;
-static rt_size_t _pin_read(rt_device_t dev, rt_off_t pos, void *buffer, rt_size_t size)
+static rt_ssize_t _pin_read(rt_device_t dev, rt_off_t pos, void *buffer, rt_size_t size)
 {
     struct rt_device_pin_status *status;
     struct rt_device_pin *pin = (struct rt_device_pin *)dev;
@@ -29,7 +29,7 @@ static rt_size_t _pin_read(rt_device_t dev, rt_off_t pos, void *buffer, rt_size_
     return size;
 }
 
-static rt_size_t _pin_write(rt_device_t dev, rt_off_t pos, const void *buffer, rt_size_t size)
+static rt_ssize_t _pin_write(rt_device_t dev, rt_off_t pos, const void *buffer, rt_size_t size)
 {
     struct rt_device_pin_status *status;
     struct rt_device_pin *pin = (struct rt_device_pin *)dev;
diff --git a/components/drivers/misc/pulse_encoder.c b/components/drivers/misc/pulse_encoder.c
index d5efcef8e7..39bf3de2f3 100644
--- a/components/drivers/misc/pulse_encoder.c
+++ b/components/drivers/misc/pulse_encoder.c
@@ -55,7 +55,7 @@ static rt_err_t rt_pulse_encoder_close(struct rt_device *dev)
     }
 }
 
-static rt_size_t rt_pulse_encoder_read(struct rt_device *dev, rt_off_t pos, void *buffer, rt_size_t size)
+static rt_ssize_t rt_pulse_encoder_read(struct rt_device *dev, rt_off_t pos, void *buffer, rt_size_t size)
 {
     struct rt_pulse_encoder_device *pulse_encoder;
 
diff --git a/components/drivers/misc/rt_drv_pwm.c b/components/drivers/misc/rt_drv_pwm.c
index 7cc01e4e1a..25b45f9d43 100644
--- a/components/drivers/misc/rt_drv_pwm.c
+++ b/components/drivers/misc/rt_drv_pwm.c
@@ -43,7 +43,7 @@ pos: channel
 void *buffer: rt_uint32_t pulse[size]
 size : number of pulse, only set to sizeof(rt_uint32_t).
 */
-static rt_size_t _pwm_read(rt_device_t dev, rt_off_t pos, void *buffer, rt_size_t size)
+static rt_ssize_t _pwm_read(rt_device_t dev, rt_off_t pos, void *buffer, rt_size_t size)
 {
     rt_err_t result = RT_EOK;
     struct rt_device_pwm *pwm = (struct rt_device_pwm *)dev;
@@ -71,7 +71,7 @@ pos: channel
 void *buffer: rt_uint32_t pulse[size]
 size : number of pulse, only set to sizeof(rt_uint32_t).
 */
-static rt_size_t _pwm_write(rt_device_t dev, rt_off_t pos, const void *buffer, rt_size_t size)
+static rt_ssize_t _pwm_write(rt_device_t dev, rt_off_t pos, const void *buffer, rt_size_t size)
 {
     rt_err_t result = RT_EOK;
     struct rt_device_pwm *pwm = (struct rt_device_pwm *)dev;
diff --git a/components/drivers/misc/rt_inputcapture.c b/components/drivers/misc/rt_inputcapture.c
index c7a9edaaf6..067aeef2df 100644
--- a/components/drivers/misc/rt_inputcapture.c
+++ b/components/drivers/misc/rt_inputcapture.c
@@ -81,7 +81,7 @@ static rt_err_t rt_inputcapture_close(struct rt_device *dev)
     return ret;
 }
 
-static rt_size_t rt_inputcapture_read(struct rt_device *dev,
+static rt_ssize_t rt_inputcapture_read(struct rt_device *dev,
                                  rt_off_t          pos,
                                  void             *buffer,
                                  rt_size_t         size)
diff --git a/components/drivers/misc/rt_null.c b/components/drivers/misc/rt_null.c
index 3e4cf6f3da..bc329ab50e 100644
--- a/components/drivers/misc/rt_null.c
+++ b/components/drivers/misc/rt_null.c
@@ -12,12 +12,12 @@
 
 static struct rt_device null_dev;
 
-static rt_size_t null_read    (rt_device_t dev, rt_off_t pos, void *buffer, rt_size_t size)
+static rt_ssize_t null_read    (rt_device_t dev, rt_off_t pos, void *buffer, rt_size_t size)
 {
     return 0;
 }
 
-static rt_size_t null_write   (rt_device_t dev, rt_off_t pos, const void *buffer, rt_size_t size)
+static rt_ssize_t null_write   (rt_device_t dev, rt_off_t pos, const void *buffer, rt_size_t size)
 {
     return size;
 }
diff --git a/components/drivers/misc/rt_random.c b/components/drivers/misc/rt_random.c
index 1ea0480b7c..9b52918ae9 100644
--- a/components/drivers/misc/rt_random.c
+++ b/components/drivers/misc/rt_random.c
@@ -19,7 +19,7 @@ static rt_uint16_t calc_random(void)
     return (seed >> 16) & 0x7FFF;   /* return bits 16~30 */
 }
 
-static rt_size_t random_read(rt_device_t dev, rt_off_t pos, void *buffer, rt_size_t size)
+static rt_ssize_t random_read(rt_device_t dev, rt_off_t pos, void *buffer, rt_size_t size)
 {
     rt_uint16_t rand = calc_random();
     ssize_t ret = sizeof(rand);
@@ -27,7 +27,7 @@ static rt_size_t random_read(rt_device_t dev, rt_off_t pos, void *buffer, rt_siz
     return ret;
 }
 
-static rt_size_t random_write(rt_device_t dev, rt_off_t pos, const void *buffer, rt_size_t size)
+static rt_ssize_t random_write(rt_device_t dev, rt_off_t pos, const void *buffer, rt_size_t size)
 {
     ssize_t ret = sizeof(seed);
     rt_memcpy(&seed, buffer, ret);
@@ -93,7 +93,7 @@ static rt_uint16_t calc_urandom(void)
     return (useed >> 16) & 0x7FFF;   /* return bits 16~30 */
 }
 
-static rt_size_t random_uread(rt_device_t dev, rt_off_t pos, void *buffer, rt_size_t size)
+static rt_ssize_t random_uread(rt_device_t dev, rt_off_t pos, void *buffer, rt_size_t size)
 {
     rt_uint16_t rand = calc_urandom();
     ssize_t ret = sizeof(rand);
@@ -101,7 +101,7 @@ static rt_size_t random_uread(rt_device_t dev, rt_off_t pos, void *buffer, rt_si
     return ret;
 }
 
-static rt_size_t random_uwrite(rt_device_t dev, rt_off_t pos, const void *buffer, rt_size_t size)
+static rt_ssize_t random_uwrite(rt_device_t dev, rt_off_t pos, const void *buffer, rt_size_t size)
 {
     ssize_t ret = sizeof(useed);
     rt_memcpy(&useed, buffer, ret);
diff --git a/components/drivers/misc/rt_zero.c b/components/drivers/misc/rt_zero.c
index f2657a2360..08df5cb3aa 100644
--- a/components/drivers/misc/rt_zero.c
+++ b/components/drivers/misc/rt_zero.c
@@ -12,13 +12,13 @@
 
 static struct rt_device zero_dev;
 
-static rt_size_t zero_read    (rt_device_t dev, rt_off_t pos, void *buffer, rt_size_t size)
+static rt_ssize_t zero_read    (rt_device_t dev, rt_off_t pos, void *buffer, rt_size_t size)
 {
     rt_memset(buffer, 0, size);
     return size;
 }
 
-static rt_size_t zero_write   (rt_device_t dev, rt_off_t pos, const void *buffer, rt_size_t size)
+static rt_ssize_t zero_write   (rt_device_t dev, rt_off_t pos, const void *buffer, rt_size_t size)
 {
     return size;
 }
diff --git a/components/drivers/mtd/mtd_nand.c b/components/drivers/mtd/mtd_nand.c
index 6ca56f9a6d..9c3397dfdd 100644
--- a/components/drivers/mtd/mtd_nand.c
+++ b/components/drivers/mtd/mtd_nand.c
@@ -34,7 +34,7 @@ static rt_err_t _mtd_close(rt_device_t dev)
     return RT_EOK;
 }
 
-static rt_size_t _mtd_read(rt_device_t dev,
+static rt_ssize_t _mtd_read(rt_device_t dev,
                            rt_off_t    pos,
                            void       *buffer,
                            rt_size_t   size)
@@ -42,7 +42,7 @@ static rt_size_t _mtd_read(rt_device_t dev,
     return size;
 }
 
-static rt_size_t _mtd_write(rt_device_t dev,
+static rt_ssize_t _mtd_write(rt_device_t dev,
                             rt_off_t    pos,
                             const void *buffer,
                             rt_size_t   size)
diff --git a/components/drivers/mtd/mtd_nor.c b/components/drivers/mtd/mtd_nor.c
index af3b50e42f..6824190475 100644
--- a/components/drivers/mtd/mtd_nor.c
+++ b/components/drivers/mtd/mtd_nor.c
@@ -30,7 +30,7 @@ static rt_err_t _mtd_close(rt_device_t dev)
     return RT_EOK;
 }
 
-static rt_size_t _mtd_read(rt_device_t dev,
+static rt_ssize_t _mtd_read(rt_device_t dev,
                            rt_off_t    pos,
                            void       *buffer,
                            rt_size_t   size)
@@ -38,7 +38,7 @@ static rt_size_t _mtd_read(rt_device_t dev,
     return size;
 }
 
-static rt_size_t _mtd_write(rt_device_t dev,
+static rt_ssize_t _mtd_write(rt_device_t dev,
                             rt_off_t    pos,
                             const void *buffer,
                             rt_size_t   size)
diff --git a/components/drivers/phy/phy.c b/components/drivers/phy/phy.c
index ef47a91d7c..317b24ebfc 100644
--- a/components/drivers/phy/phy.c
+++ b/components/drivers/phy/phy.c
@@ -18,13 +18,13 @@
 #include <rtdbg.h>
 
 
-static rt_size_t phy_device_read(rt_device_t dev, rt_off_t pos, void *buffer, rt_size_t count)
+static rt_ssize_t phy_device_read(rt_device_t dev, rt_off_t pos, void *buffer, rt_size_t count)
 {
     struct rt_phy_device *phy = (struct rt_phy_device *)dev->user_data;
     struct rt_phy_msg *msg = (struct rt_phy_msg *)buffer;
     return phy->bus->ops->read(phy->bus, phy->addr, msg->reg, &(msg->value), 4);
 }
-static rt_size_t phy_device_write(rt_device_t dev, rt_off_t pos, const void *buffer, rt_size_t count)
+static rt_ssize_t phy_device_write(rt_device_t dev, rt_off_t pos, const void *buffer, rt_size_t count)
 {
     struct rt_phy_device *phy = (struct rt_phy_device *)dev->user_data;
     struct rt_phy_msg *msg = (struct rt_phy_msg *)buffer;
diff --git a/components/drivers/pm/pm.c b/components/drivers/pm/pm.c
index 0c6dcf065d..f70333090c 100644
--- a/components/drivers/pm/pm.c
+++ b/components/drivers/pm/pm.c
@@ -845,7 +845,7 @@ void rt_pm_default_set(rt_uint8_t sleep_mode)
 /**
  * RT-Thread device interface for PM device
  */
-static rt_size_t _rt_pm_device_read(rt_device_t dev,
+static rt_ssize_t _rt_pm_device_read(rt_device_t dev,
                                     rt_off_t    pos,
                                     void       *buffer,
                                     rt_size_t   size)
@@ -868,7 +868,7 @@ static rt_size_t _rt_pm_device_read(rt_device_t dev,
     return length;
 }
 
-static rt_size_t _rt_pm_device_write(rt_device_t dev,
+static rt_ssize_t _rt_pm_device_write(rt_device_t dev,
                                      rt_off_t    pos,
                                      const void *buffer,
                                      rt_size_t   size)
diff --git a/components/drivers/sdio/block_dev.c b/components/drivers/sdio/block_dev.c
index 59eb56cdcd..0025e7f08a 100644
--- a/components/drivers/sdio/block_dev.c
+++ b/components/drivers/sdio/block_dev.c
@@ -280,7 +280,7 @@ static rt_err_t rt_mmcsd_control(rt_device_t dev, int cmd, void *args)
     return RT_EOK;
 }
 
-static rt_size_t rt_mmcsd_read(rt_device_t dev,
+static rt_ssize_t rt_mmcsd_read(rt_device_t dev,
                                rt_off_t    pos,
                                void       *buffer,
                                rt_size_t   size)
@@ -321,7 +321,7 @@ static rt_size_t rt_mmcsd_read(rt_device_t dev,
     return size - remain_size;
 }
 
-static rt_size_t rt_mmcsd_write(rt_device_t dev,
+static rt_ssize_t rt_mmcsd_write(rt_device_t dev,
                                 rt_off_t    pos,
                                 const void *buffer,
                                 rt_size_t   size)
diff --git a/components/drivers/sensor/sensor.c b/components/drivers/sensor/sensor.c
index 40e4b46037..8835c10bac 100644
--- a/components/drivers/sensor/sensor.c
+++ b/components/drivers/sensor/sensor.c
@@ -284,7 +284,7 @@ __exit:
     return RT_EOK;
 }
 
-static rt_size_t _sensor_read(rt_device_t dev, rt_off_t pos, void *buf, rt_size_t len)
+static rt_ssize_t _sensor_read(rt_device_t dev, rt_off_t pos, void *buf, rt_size_t len)
 {
     rt_sensor_t sensor = (rt_sensor_t)dev;
     rt_size_t result = 0;
diff --git a/components/drivers/serial/serial.c b/components/drivers/serial/serial.c
index d667d70efd..06b519166c 100644
--- a/components/drivers/serial/serial.c
+++ b/components/drivers/serial/serial.c
@@ -381,7 +381,7 @@ static void _serial_check_buffer_size(void)
 }
 
 #if defined(RT_USING_POSIX_STDIO) || defined(RT_SERIAL_USING_DMA)
-static rt_size_t _serial_fifo_calc_recved_len(struct rt_serial_device *serial)
+static rt_ssize_t _serial_fifo_calc_recved_len(struct rt_serial_device *serial)
 {
     struct rt_serial_rx_fifo *rx_fifo = (struct rt_serial_rx_fifo *) serial->serial_rx;
 
@@ -413,7 +413,7 @@ static rt_size_t _serial_fifo_calc_recved_len(struct rt_serial_device *serial)
  *
  * @return length
  */
-static rt_size_t rt_dma_calc_recved_len(struct rt_serial_device *serial)
+static rt_ssize_t rt_dma_calc_recved_len(struct rt_serial_device *serial)
 {
     return _serial_fifo_calc_recved_len(serial);
 }
@@ -850,7 +850,7 @@ static rt_err_t rt_serial_close(struct rt_device *dev)
     return RT_EOK;
 }
 
-static rt_size_t rt_serial_read(struct rt_device *dev,
+static rt_ssize_t rt_serial_read(struct rt_device *dev,
                                 rt_off_t          pos,
                                 void             *buffer,
                                 rt_size_t         size)
@@ -876,7 +876,7 @@ static rt_size_t rt_serial_read(struct rt_device *dev,
     return _serial_poll_rx(serial, (rt_uint8_t *)buffer, size);
 }
 
-static rt_size_t rt_serial_write(struct rt_device *dev,
+static rt_ssize_t rt_serial_write(struct rt_device *dev,
                                  rt_off_t          pos,
                                  const void       *buffer,
                                  rt_size_t         size)
diff --git a/components/drivers/serial/serial_v2.c b/components/drivers/serial/serial_v2.c
index a6e4e22def..9e809048bd 100644
--- a/components/drivers/serial/serial_v2.c
+++ b/components/drivers/serial/serial_v2.c
@@ -194,7 +194,7 @@ const static struct dfs_file_ops _serial_fops =
 };
 #endif /* RT_USING_POSIX_STDIO */
 
-static rt_size_t rt_serial_get_linear_buffer(struct rt_ringbuffer       *rb,
+static rt_ssize_t rt_serial_get_linear_buffer(struct rt_ringbuffer       *rb,
                                                     rt_uint8_t         **ptr)
 {
     rt_size_t size;
@@ -220,7 +220,7 @@ static rt_size_t rt_serial_get_linear_buffer(struct rt_ringbuffer       *rb,
     return rb->buffer_size - rb->read_index;
 }
 
-static rt_size_t rt_serial_update_read_index(struct rt_ringbuffer    *rb,
+static rt_ssize_t rt_serial_update_read_index(struct rt_ringbuffer    *rb,
                                                     rt_uint16_t       read_index)
 {
     rt_size_t size;
@@ -253,7 +253,7 @@ static rt_size_t rt_serial_update_read_index(struct rt_ringbuffer    *rb,
     return read_index;
 }
 
-static rt_size_t rt_serial_update_write_index(struct rt_ringbuffer  *rb,
+static rt_ssize_t rt_serial_update_write_index(struct rt_ringbuffer  *rb,
                                                      rt_uint16_t     write_size)
 {
     rt_uint16_t size;
@@ -386,7 +386,7 @@ rt_size_t _serial_poll_tx(struct rt_device           *dev,
   * @param size Receive data buffer length.
   * @return Return the final length of data received.
   */
-static rt_size_t _serial_fifo_rx(struct rt_device        *dev,
+static rt_ssize_t _serial_fifo_rx(struct rt_device        *dev,
                                         rt_off_t          pos,
                                         void             *buffer,
                                         rt_size_t         size)
@@ -448,7 +448,7 @@ static rt_size_t _serial_fifo_rx(struct rt_device        *dev,
   * @param size Transmit data buffer length.
   * @return Return the final length of data transmit.
   */
-static rt_size_t _serial_fifo_tx_blocking_nbuf(struct rt_device        *dev,
+static rt_ssize_t _serial_fifo_tx_blocking_nbuf(struct rt_device        *dev,
                                                       rt_off_t          pos,
                                                 const void             *buffer,
                                                       rt_size_t         size)
@@ -495,7 +495,7 @@ static rt_size_t _serial_fifo_tx_blocking_nbuf(struct rt_device        *dev,
   * @param size Transmit data buffer length.
   * @return Return the final length of data transmit.
   */
-static rt_size_t _serial_fifo_tx_blocking_buf(struct rt_device        *dev,
+static rt_ssize_t _serial_fifo_tx_blocking_buf(struct rt_device        *dev,
                                                      rt_off_t          pos,
                                                const void             *buffer,
                                                     rt_size_t          size)
@@ -555,7 +555,7 @@ static rt_size_t _serial_fifo_tx_blocking_buf(struct rt_device        *dev,
   * @param size Transmit data buffer length.
   * @return Return the final length of data transmit.
   */
-static rt_size_t _serial_fifo_tx_nonblocking(struct rt_device        *dev,
+static rt_ssize_t _serial_fifo_tx_nonblocking(struct rt_device        *dev,
                                                     rt_off_t          pos,
                                               const void             *buffer,
                                                     rt_size_t         size)
@@ -1372,7 +1372,7 @@ static rt_err_t rt_serial_control(struct rt_device *dev,
 }
 
 #ifdef RT_USING_DEVICE_OPS
-static rt_size_t rt_serial_read(struct rt_device *dev,
+static rt_ssize_t rt_serial_read(struct rt_device *dev,
                                 rt_off_t          pos,
                                 void             *buffer,
                                 rt_size_t         size)
@@ -1393,7 +1393,7 @@ static rt_size_t rt_serial_read(struct rt_device *dev,
 }
 
 
-static rt_size_t rt_serial_write(struct rt_device *dev,
+static rt_ssize_t rt_serial_write(struct rt_device *dev,
                                  rt_off_t          pos,
                                  const void       *buffer,
                                  rt_size_t         size)
diff --git a/components/drivers/spi/enc28j60.c b/components/drivers/spi/enc28j60.c
index 361db776f6..f3c3ecb30b 100644
--- a/components/drivers/spi/enc28j60.c
+++ b/components/drivers/spi/enc28j60.c
@@ -381,14 +381,14 @@ static rt_err_t enc28j60_close(rt_device_t dev)
 }
 
 /* Read */
-static rt_size_t enc28j60_read(rt_device_t dev, rt_off_t pos, void *buffer, rt_size_t size)
+static rt_ssize_t enc28j60_read(rt_device_t dev, rt_off_t pos, void *buffer, rt_size_t size)
 {
     rt_set_errno(-RT_ENOSYS);
     return RT_EOK;
 }
 
 /* Write */
-static rt_size_t enc28j60_write(rt_device_t dev, rt_off_t pos, const void *buffer, rt_size_t size)
+static rt_ssize_t enc28j60_write(rt_device_t dev, rt_off_t pos, const void *buffer, rt_size_t size)
 {
     rt_set_errno(-RT_ENOSYS);
     return 0;
diff --git a/components/drivers/spi/spi_dev.c b/components/drivers/spi/spi_dev.c
index 4b21466b0d..2d63fbcfbb 100644
--- a/components/drivers/spi/spi_dev.c
+++ b/components/drivers/spi/spi_dev.c
@@ -11,7 +11,7 @@
 #include <drivers/spi.h>
 
 /* SPI bus device interface, compatible with RT-Thread 0.3.x/1.0.x */
-static rt_size_t _spi_bus_device_read(rt_device_t dev,
+static rt_ssize_t _spi_bus_device_read(rt_device_t dev,
                                       rt_off_t    pos,
                                       void       *buffer,
                                       rt_size_t   size)
@@ -25,7 +25,7 @@ static rt_size_t _spi_bus_device_read(rt_device_t dev,
     return rt_spi_transfer(bus->owner, RT_NULL, buffer, size);
 }
 
-static rt_size_t _spi_bus_device_write(rt_device_t dev,
+static rt_ssize_t _spi_bus_device_write(rt_device_t dev,
                                        rt_off_t    pos,
                                        const void *buffer,
                                        rt_size_t   size)
@@ -77,7 +77,7 @@ rt_err_t rt_spi_bus_device_init(struct rt_spi_bus *bus, const char *name)
 }
 
 /* SPI Dev device interface, compatible with RT-Thread 0.3.x/1.0.x */
-static rt_size_t _spidev_device_read(rt_device_t dev,
+static rt_ssize_t _spidev_device_read(rt_device_t dev,
                                      rt_off_t    pos,
                                      void       *buffer,
                                      rt_size_t   size)
@@ -91,7 +91,7 @@ static rt_size_t _spidev_device_read(rt_device_t dev,
     return rt_spi_transfer(device, RT_NULL, buffer, size);
 }
 
-static rt_size_t _spidev_device_write(rt_device_t dev,
+static rt_ssize_t _spidev_device_write(rt_device_t dev,
                                       rt_off_t    pos,
                                       const void *buffer,
                                       rt_size_t   size)
diff --git a/components/drivers/spi/spi_flash_sfud.c b/components/drivers/spi/spi_flash_sfud.c
index 30bc77a57d..83f8537c72 100644
--- a/components/drivers/spi/spi_flash_sfud.c
+++ b/components/drivers/spi/spi_flash_sfud.c
@@ -86,7 +86,7 @@ static rt_err_t rt_sfud_control(rt_device_t dev, int cmd, void *args) {
 }
 
 
-static rt_size_t rt_sfud_read(rt_device_t dev, rt_off_t pos, void* buffer, rt_size_t size) {
+static rt_ssize_t rt_sfud_read(rt_device_t dev, rt_off_t pos, void* buffer, rt_size_t size) {
     struct spi_flash_device *rtt_dev = (struct spi_flash_device *) (dev->user_data);
     sfud_flash *sfud_dev = (sfud_flash *) (rtt_dev->user_data);
 
@@ -104,7 +104,7 @@ static rt_size_t rt_sfud_read(rt_device_t dev, rt_off_t pos, void* buffer, rt_si
     }
 }
 
-static rt_size_t rt_sfud_write(rt_device_t dev, rt_off_t pos, const void* buffer, rt_size_t size) {
+static rt_ssize_t rt_sfud_write(rt_device_t dev, rt_off_t pos, const void* buffer, rt_size_t size) {
     struct spi_flash_device *rtt_dev = (struct spi_flash_device *) (dev->user_data);
     sfud_flash *sfud_dev = (sfud_flash *) (rtt_dev->user_data);
 
diff --git a/components/drivers/spi/spi_msd.c b/components/drivers/spi/spi_msd.c
index 6bd0501694..dce2a7c8b0 100644
--- a/components/drivers/spi/spi_msd.c
+++ b/components/drivers/spi/spi_msd.c
@@ -43,10 +43,10 @@ static rt_err_t _wait_ready(struct rt_spi_device *device);
 static rt_err_t  rt_msd_init(rt_device_t dev);
 static rt_err_t  rt_msd_open(rt_device_t dev, rt_uint16_t oflag);
 static rt_err_t  rt_msd_close(rt_device_t dev);
-static rt_size_t rt_msd_write(rt_device_t dev, rt_off_t pos, const void *buffer, rt_size_t size);
-static rt_size_t rt_msd_read(rt_device_t dev, rt_off_t pos, void *buffer, rt_size_t size);
-static rt_size_t rt_msd_sdhc_read(rt_device_t dev, rt_off_t pos, void *buffer, rt_size_t size);
-static rt_size_t rt_msd_sdhc_write(rt_device_t dev, rt_off_t pos, const void *buffer, rt_size_t size);
+static rt_ssize_t rt_msd_write(rt_device_t dev, rt_off_t pos, const void *buffer, rt_size_t size);
+static rt_ssize_t rt_msd_read(rt_device_t dev, rt_off_t pos, void *buffer, rt_size_t size);
+static rt_ssize_t rt_msd_sdhc_read(rt_device_t dev, rt_off_t pos, void *buffer, rt_size_t size);
+static rt_ssize_t rt_msd_sdhc_write(rt_device_t dev, rt_off_t pos, const void *buffer, rt_size_t size);
 static rt_err_t rt_msd_control(rt_device_t dev, int cmd, void *args);
 
 static rt_err_t MSD_take_owner(struct rt_spi_device *spi_device)
@@ -1209,7 +1209,7 @@ static rt_err_t rt_msd_close(rt_device_t dev)
     return RT_EOK;
 }
 
-static rt_size_t rt_msd_read(rt_device_t dev, rt_off_t pos, void *buffer, rt_size_t size)
+static rt_ssize_t rt_msd_read(rt_device_t dev, rt_off_t pos, void *buffer, rt_size_t size)
 {
     struct msd_device *msd = (struct msd_device *)dev;
     uint8_t response[MSD_RESPONSE_MAX_LEN];
@@ -1285,7 +1285,7 @@ _exit:
     return size;
 }
 
-static rt_size_t rt_msd_sdhc_read(rt_device_t dev, rt_off_t pos, void *buffer, rt_size_t size)
+static rt_ssize_t rt_msd_sdhc_read(rt_device_t dev, rt_off_t pos, void *buffer, rt_size_t size)
 {
     struct msd_device *msd = (struct msd_device *)dev;
     uint8_t response[MSD_RESPONSE_MAX_LEN];
@@ -1361,7 +1361,7 @@ _exit:
     return size;
 }
 
-static rt_size_t rt_msd_write(rt_device_t dev, rt_off_t pos, const void *buffer, rt_size_t size)
+static rt_ssize_t rt_msd_write(rt_device_t dev, rt_off_t pos, const void *buffer, rt_size_t size)
 {
     struct msd_device *msd = (struct msd_device *)dev;
     uint8_t response[MSD_RESPONSE_MAX_LEN];
@@ -1481,7 +1481,7 @@ _exit:
     return size;
 }
 
-static rt_size_t rt_msd_sdhc_write(rt_device_t dev, rt_off_t pos, const void *buffer, rt_size_t size)
+static rt_ssize_t rt_msd_sdhc_write(rt_device_t dev, rt_off_t pos, const void *buffer, rt_size_t size)
 {
     struct msd_device *msd = (struct msd_device *)dev;
     uint8_t response[MSD_RESPONSE_MAX_LEN];
diff --git a/components/drivers/spi/spi_wifi_rw009.c b/components/drivers/spi/spi_wifi_rw009.c
index 39388f10c4..6cbe8dbaa9 100644
--- a/components/drivers/spi/spi_wifi_rw009.c
+++ b/components/drivers/spi/spi_wifi_rw009.c
@@ -504,13 +504,13 @@ static rt_err_t rw009_wifi_close(rt_device_t dev)
     return RT_EOK;
 }
 
-static rt_size_t rw009_wifi_read(rt_device_t dev, rt_off_t pos, void *buffer, rt_size_t size)
+static rt_ssize_t rw009_wifi_read(rt_device_t dev, rt_off_t pos, void *buffer, rt_size_t size)
 {
     rt_set_errno(-RT_ENOSYS);
     return 0;
 }
 
-static rt_size_t rw009_wifi_write(rt_device_t dev, rt_off_t pos, const void *buffer, rt_size_t size)
+static rt_ssize_t rw009_wifi_write(rt_device_t dev, rt_off_t pos, const void *buffer, rt_size_t size)
 {
     rt_set_errno(-RT_ENOSYS);
     return 0;
diff --git a/components/drivers/touch/touch.c b/components/drivers/touch/touch.c
index 6f5b73a7cb..e15ebf5b05 100644
--- a/components/drivers/touch/touch.c
+++ b/components/drivers/touch/touch.c
@@ -122,7 +122,7 @@ static rt_err_t rt_touch_close(rt_device_t dev)
     return RT_EOK;
 }
 
-static rt_size_t rt_touch_read(rt_device_t dev, rt_off_t pos, void *buf, rt_size_t len)
+static rt_ssize_t rt_touch_read(rt_device_t dev, rt_off_t pos, void *buf, rt_size_t len)
 {
     rt_touch_t touch;
     rt_size_t result = 0;
diff --git a/components/drivers/tty/console.c b/components/drivers/tty/console.c
index dfab484f2e..01349635b4 100644
--- a/components/drivers/tty/console.c
+++ b/components/drivers/tty/console.c
@@ -197,7 +197,7 @@ static rt_err_t rt_console_close(struct rt_device *dev)
     return result;
 }
 
-static rt_size_t rt_console_read(struct rt_device *dev,
+static rt_ssize_t rt_console_read(struct rt_device *dev,
         rt_off_t          pos,
         void             *buffer,
         rt_size_t         size)
@@ -206,7 +206,7 @@ static rt_size_t rt_console_read(struct rt_device *dev,
     return len;
 }
 
-static rt_size_t rt_console_write(struct rt_device *dev,
+static rt_ssize_t rt_console_write(struct rt_device *dev,
         rt_off_t          pos,
         const void       *buffer,
         rt_size_t         size)
diff --git a/components/drivers/tty/pty.c b/components/drivers/tty/pty.c
index 34b366f399..46a241a715 100644
--- a/components/drivers/tty/pty.c
+++ b/components/drivers/tty/pty.c
@@ -123,7 +123,7 @@ static rt_err_t pty_device_close(struct rt_device *dev)
     return result;
 }
 
-static rt_size_t pty_device_read(struct rt_device *dev,
+static rt_ssize_t pty_device_read(struct rt_device *dev,
         rt_off_t          pos,
         void             *buffer,
         rt_size_t         size)
@@ -133,7 +133,7 @@ static rt_size_t pty_device_read(struct rt_device *dev,
     return len;
 }
 
-static rt_size_t pty_device_write(struct rt_device *dev,
+static rt_ssize_t pty_device_write(struct rt_device *dev,
         rt_off_t          pos,
         const void       *buffer,
         rt_size_t         size)
diff --git a/components/drivers/usb/usbdevice/class/cdc_vcom.c b/components/drivers/usb/usbdevice/class/cdc_vcom.c
index 89d03caf88..29d3e25174 100644
--- a/components/drivers/usb/usbdevice/class/cdc_vcom.c
+++ b/components/drivers/usb/usbdevice/class/cdc_vcom.c
@@ -721,7 +721,7 @@ static int _vcom_getc(struct rt_serial_device *serial)
     return result;
 }
 
-static rt_size_t _vcom_rb_block_put(struct vcom *data, const rt_uint8_t *buf, rt_size_t size)
+static rt_ssize_t _vcom_rb_block_put(struct vcom *data, const rt_uint8_t *buf, rt_size_t size)
 {
     rt_base_t level;
     rt_size_t   put_len = 0;
@@ -751,7 +751,7 @@ static rt_size_t _vcom_rb_block_put(struct vcom *data, const rt_uint8_t *buf, rt
     return size;
 }
 
-static rt_size_t _vcom_tx(struct rt_serial_device *serial, rt_uint8_t *buf, rt_size_t size, int direction)
+static rt_ssize_t _vcom_tx(struct rt_serial_device *serial, rt_uint8_t *buf, rt_size_t size, int direction)
 {
     struct ufunction *func;
     struct vcom *data;
diff --git a/components/drivers/usb/usbdevice/class/ecm.c b/components/drivers/usb/usbdevice/class/ecm.c
index 4f41c00531..f821a9969e 100644
--- a/components/drivers/usb/usbdevice/class/ecm.c
+++ b/components/drivers/usb/usbdevice/class/ecm.c
@@ -324,13 +324,13 @@ static rt_err_t rt_ecm_eth_close(rt_device_t dev)
     return RT_EOK;
 }
 
-static rt_size_t rt_ecm_eth_read(rt_device_t dev, rt_off_t pos, void* buffer, rt_size_t size)
+static rt_ssize_t rt_ecm_eth_read(rt_device_t dev, rt_off_t pos, void* buffer, rt_size_t size)
 {
     rt_set_errno(-RT_ENOSYS);
     return 0;
 }
 
-static rt_size_t rt_ecm_eth_write (rt_device_t dev, rt_off_t pos, const void* buffer, rt_size_t size)
+static rt_ssize_t rt_ecm_eth_write (rt_device_t dev, rt_off_t pos, const void* buffer, rt_size_t size)
 {
     rt_set_errno(-RT_ENOSYS);
     return 0;
diff --git a/components/drivers/usb/usbdevice/class/hid.c b/components/drivers/usb/usbdevice/class/hid.c
index a95e1d82e5..d2bb05ed24 100644
--- a/components/drivers/usb/usbdevice/class/hid.c
+++ b/components/drivers/usb/usbdevice/class/hid.c
@@ -594,7 +594,7 @@ static rt_err_t _hid_descriptor_config(uhid_comm_desc_t hid, rt_uint8_t cintf_nr
 
     return RT_EOK;
 }
-static rt_size_t _hid_write(rt_device_t dev, rt_off_t pos, const void *buffer, rt_size_t size)
+static rt_ssize_t _hid_write(rt_device_t dev, rt_off_t pos, const void *buffer, rt_size_t size)
 {
     struct hid_s *hiddev = (struct hid_s *)dev;
     struct hid_report report;
diff --git a/components/drivers/usb/usbdevice/class/mstorage.c b/components/drivers/usb/usbdevice/class/mstorage.c
index b8f21a29df..96a1299890 100644
--- a/components/drivers/usb/usbdevice/class/mstorage.c
+++ b/components/drivers/usb/usbdevice/class/mstorage.c
@@ -44,7 +44,7 @@ typedef enum
     DIR_NONE,
 }CB_DIR;
 
-typedef rt_size_t (*cbw_handler)(ufunction_t func, ustorage_cbw_t cbw);
+typedef rt_ssize_t (*cbw_handler)(ufunction_t func, ustorage_cbw_t cbw);
 
 struct scsi_cmd
 {
@@ -168,17 +168,17 @@ const static char* _ustring[] =
     "Interface",
 };
 
-static rt_size_t _test_unit_ready(ufunction_t func, ustorage_cbw_t cbw);
-static rt_size_t _request_sense(ufunction_t func, ustorage_cbw_t cbw);
-static rt_size_t _inquiry_cmd(ufunction_t func, ustorage_cbw_t cbw);
-static rt_size_t _allow_removal(ufunction_t func, ustorage_cbw_t cbw);
-static rt_size_t _start_stop(ufunction_t func, ustorage_cbw_t cbw);
-static rt_size_t _mode_sense_6(ufunction_t func, ustorage_cbw_t cbw);
-static rt_size_t _read_capacities(ufunction_t func, ustorage_cbw_t cbw);
-static rt_size_t _read_capacity(ufunction_t func, ustorage_cbw_t cbw);
-static rt_size_t _read_10(ufunction_t func, ustorage_cbw_t cbw);
-static rt_size_t _write_10(ufunction_t func, ustorage_cbw_t cbw);
-static rt_size_t _verify_10(ufunction_t func, ustorage_cbw_t cbw);
+static rt_ssize_t _test_unit_ready(ufunction_t func, ustorage_cbw_t cbw);
+static rt_ssize_t _request_sense(ufunction_t func, ustorage_cbw_t cbw);
+static rt_ssize_t _inquiry_cmd(ufunction_t func, ustorage_cbw_t cbw);
+static rt_ssize_t _allow_removal(ufunction_t func, ustorage_cbw_t cbw);
+static rt_ssize_t _start_stop(ufunction_t func, ustorage_cbw_t cbw);
+static rt_ssize_t _mode_sense_6(ufunction_t func, ustorage_cbw_t cbw);
+static rt_ssize_t _read_capacities(ufunction_t func, ustorage_cbw_t cbw);
+static rt_ssize_t _read_capacity(ufunction_t func, ustorage_cbw_t cbw);
+static rt_ssize_t _read_10(ufunction_t func, ustorage_cbw_t cbw);
+static rt_ssize_t _write_10(ufunction_t func, ustorage_cbw_t cbw);
+static rt_ssize_t _verify_10(ufunction_t func, ustorage_cbw_t cbw);
 
 rt_align(4)
 static struct scsi_cmd cmd_data[] =
@@ -212,7 +212,7 @@ static void _send_status(ufunction_t func)
     data->status = STAT_CSW;
 }
 
-static rt_size_t _test_unit_ready(ufunction_t func, ustorage_cbw_t cbw)
+static rt_ssize_t _test_unit_ready(ufunction_t func, ustorage_cbw_t cbw)
 {
     struct mstorage *data;
 
@@ -227,7 +227,7 @@ static rt_size_t _test_unit_ready(ufunction_t func, ustorage_cbw_t cbw)
     return 0;
 }
 
-static rt_size_t _allow_removal(ufunction_t func, ustorage_cbw_t cbw)
+static rt_ssize_t _allow_removal(ufunction_t func, ustorage_cbw_t cbw)
 {
     struct mstorage *data;
 
@@ -251,7 +251,7 @@ static rt_size_t _allow_removal(ufunction_t func, ustorage_cbw_t cbw)
  * @return RT_EOK on successful.
  */
 
-static rt_size_t _inquiry_cmd(ufunction_t func, ustorage_cbw_t cbw)
+static rt_ssize_t _inquiry_cmd(ufunction_t func, ustorage_cbw_t cbw)
 {
     struct mstorage *data;
     rt_uint8_t *buf;
@@ -290,7 +290,7 @@ static rt_size_t _inquiry_cmd(ufunction_t func, ustorage_cbw_t cbw)
  *
  * @return RT_EOK on successful.
  */
-static rt_size_t _request_sense(ufunction_t func, ustorage_cbw_t cbw)
+static rt_ssize_t _request_sense(ufunction_t func, ustorage_cbw_t cbw)
 {
     struct mstorage *data;
     struct request_sense_data *buf;
@@ -333,7 +333,7 @@ static rt_size_t _request_sense(ufunction_t func, ustorage_cbw_t cbw)
  *
  * @return RT_EOK on successful.
  */
-static rt_size_t _mode_sense_6(ufunction_t func, ustorage_cbw_t cbw)
+static rt_ssize_t _mode_sense_6(ufunction_t func, ustorage_cbw_t cbw)
 {
     struct mstorage *data;
     rt_uint8_t *buf;
@@ -369,7 +369,7 @@ static rt_size_t _mode_sense_6(ufunction_t func, ustorage_cbw_t cbw)
  *
  * @return RT_EOK on successful.
  */
-static rt_size_t _read_capacities(ufunction_t func, ustorage_cbw_t cbw)
+static rt_ssize_t _read_capacities(ufunction_t func, ustorage_cbw_t cbw)
 {
     struct mstorage *data;
     rt_uint8_t *buf;
@@ -414,7 +414,7 @@ static rt_size_t _read_capacities(ufunction_t func, ustorage_cbw_t cbw)
  *
  * @return RT_EOK on successful.
  */
-static rt_size_t _read_capacity(ufunction_t func, ustorage_cbw_t cbw)
+static rt_ssize_t _read_capacity(ufunction_t func, ustorage_cbw_t cbw)
 {
     struct mstorage *data;
 
@@ -459,7 +459,7 @@ static rt_size_t _read_capacity(ufunction_t func, ustorage_cbw_t cbw)
  *
  * @return RT_EOK on successful.
  */
-static rt_size_t _read_10(ufunction_t func, ustorage_cbw_t cbw)
+static rt_ssize_t _read_10(ufunction_t func, ustorage_cbw_t cbw)
 {
     struct mstorage *data;
     rt_size_t size;
@@ -499,7 +499,7 @@ static rt_size_t _read_10(ufunction_t func, ustorage_cbw_t cbw)
  *
  * @return RT_EOK on successful.
  */
-static rt_size_t _write_10(ufunction_t func, ustorage_cbw_t cbw)
+static rt_ssize_t _write_10(ufunction_t func, ustorage_cbw_t cbw)
 {
     struct mstorage *data;
 
@@ -536,7 +536,7 @@ static rt_size_t _write_10(ufunction_t func, ustorage_cbw_t cbw)
  *
  * @return RT_EOK on successful.
  */
-static rt_size_t _verify_10(ufunction_t func, ustorage_cbw_t cbw)
+static rt_ssize_t _verify_10(ufunction_t func, ustorage_cbw_t cbw)
 {
     struct mstorage *data;
 
@@ -551,7 +551,7 @@ static rt_size_t _verify_10(ufunction_t func, ustorage_cbw_t cbw)
     return 0;
 }
 
-static rt_size_t _start_stop(ufunction_t func,
+static rt_ssize_t _start_stop(ufunction_t func,
     ustorage_cbw_t cbw)
 {
     struct mstorage *data;
@@ -795,7 +795,7 @@ static rt_bool_t _cbw_verify(ufunction_t func, struct scsi_cmd* cmd,
     return RT_TRUE;
 }
 
-static rt_size_t _cbw_handler(ufunction_t func, struct scsi_cmd* cmd,
+static rt_ssize_t _cbw_handler(ufunction_t func, struct scsi_cmd* cmd,
     ustorage_cbw_t cbw)
 {
     struct mstorage *data;
diff --git a/components/drivers/usb/usbdevice/class/rndis.c b/components/drivers/usb/usbdevice/class/rndis.c
index 425ff62ee1..449957db2e 100644
--- a/components/drivers/usb/usbdevice/class/rndis.c
+++ b/components/drivers/usb/usbdevice/class/rndis.c
@@ -1083,13 +1083,13 @@ static rt_err_t rt_rndis_eth_close(rt_device_t dev)
     return RT_EOK;
 }
 
-static rt_size_t rt_rndis_eth_read(rt_device_t dev, rt_off_t pos, void* buffer, rt_size_t size)
+static rt_ssize_t rt_rndis_eth_read(rt_device_t dev, rt_off_t pos, void* buffer, rt_size_t size)
 {
     rt_set_errno(-RT_ENOSYS);
     return 0;
 }
 
-static rt_size_t rt_rndis_eth_write (rt_device_t dev, rt_off_t pos, const void* buffer, rt_size_t size)
+static rt_ssize_t rt_rndis_eth_write (rt_device_t dev, rt_off_t pos, const void* buffer, rt_size_t size)
 {
     rt_set_errno(-RT_ENOSYS);
     return 0;
diff --git a/components/drivers/usb/usbdevice/class/winusb.c b/components/drivers/usb/usbdevice/class/winusb.c
index 4e534399be..cf72ce8d84 100644
--- a/components/drivers/usb/usbdevice/class/winusb.c
+++ b/components/drivers/usb/usbdevice/class/winusb.c
@@ -227,7 +227,7 @@ static rt_err_t _winusb_descriptor_config(winusb_desc_t winusb, rt_uint8_t cintf
     return RT_EOK;
 }
 
-static rt_size_t win_usb_read(rt_device_t dev, rt_off_t pos, void *buffer, rt_size_t size)
+static rt_ssize_t win_usb_read(rt_device_t dev, rt_off_t pos, void *buffer, rt_size_t size)
 {
     if(((ufunction_t)dev->user_data)->device->state != USB_STATE_CONFIGURED)
     {
@@ -241,7 +241,7 @@ static rt_size_t win_usb_read(rt_device_t dev, rt_off_t pos, void *buffer, rt_si
     rt_usbd_io_request(((ufunction_t)dev->user_data)->device,winusb_device->ep_out,&winusb_device->ep_out->request);
     return size;
 }
-static rt_size_t win_usb_write(rt_device_t dev, rt_off_t pos, const void *buffer, rt_size_t size)
+static rt_ssize_t win_usb_write(rt_device_t dev, rt_off_t pos, const void *buffer, rt_size_t size)
 {
     if(((ufunction_t)dev->user_data)->device->state != USB_STATE_CONFIGURED)
     {
diff --git a/components/drivers/usb/usbdevice/core/usbdevice_core.c b/components/drivers/usb/usbdevice/core/usbdevice_core.c
index 58d7170012..03f231dcef 100644
--- a/components/drivers/usb/usbdevice/core/usbdevice_core.c
+++ b/components/drivers/usb/usbdevice/core/usbdevice_core.c
@@ -19,8 +19,8 @@
 
 static rt_list_t device_list;
 
-static rt_size_t rt_usbd_ep_write(udevice_t device, uep_t ep, void *buffer, rt_size_t size);
-static rt_size_t rt_usbd_ep_read_prepare(udevice_t device, uep_t ep, void *buffer, rt_size_t size);
+static rt_ssize_t rt_usbd_ep_write(udevice_t device, uep_t ep, void *buffer, rt_size_t size);
+static rt_ssize_t rt_usbd_ep_read_prepare(udevice_t device, uep_t ep, void *buffer, rt_size_t size);
 static rt_err_t rt_usbd_ep_assign(udevice_t device, uep_t ep);
 rt_err_t rt_usbd_ep_unassign(udevice_t device, uep_t ep);
 
@@ -962,7 +962,7 @@ static rt_err_t _stop_notify(udevice_t device)
     return RT_EOK;
 }
 
-static rt_size_t rt_usbd_ep_write(udevice_t device, uep_t ep, void *buffer, rt_size_t size)
+static rt_ssize_t rt_usbd_ep_write(udevice_t device, uep_t ep, void *buffer, rt_size_t size)
 {
     rt_uint16_t maxpacket;
 
@@ -988,7 +988,7 @@ static rt_size_t rt_usbd_ep_write(udevice_t device, uep_t ep, void *buffer, rt_s
     return size;
 }
 
-static rt_size_t rt_usbd_ep_read_prepare(udevice_t device, uep_t ep, void *buffer, rt_size_t size)
+static rt_ssize_t rt_usbd_ep_read_prepare(udevice_t device, uep_t ep, void *buffer, rt_size_t size)
 {
     RT_ASSERT(device != RT_NULL);
     RT_ASSERT(device->dcd != RT_NULL);
diff --git a/components/drivers/usb/usbhost/class/adk.c b/components/drivers/usb/usbhost/class/adk.c
index 492a2f9bb7..3475214789 100644
--- a/components/drivers/usb/usbhost/class/adk.c
+++ b/components/drivers/usb/usbhost/class/adk.c
@@ -149,7 +149,7 @@ static rt_err_t rt_usbh_adk_start(struct uintf* intf)
  *
  * @return the error code, RT_EOK on successfully.
 */
-static rt_size_t rt_usbh_adk_read(rt_device_t device, rt_off_t pos, void* buffer,
+static rt_ssize_t rt_usbh_adk_read(rt_device_t device, rt_off_t pos, void* buffer,
     rt_size_t size)
 {
     uadk_t adk;
@@ -177,7 +177,7 @@ static rt_size_t rt_usbh_adk_read(rt_device_t device, rt_off_t pos, void* buffer
  *
  * @return the error code, RT_EOK on successfully.
 */
-static rt_size_t rt_usbh_adk_write (rt_device_t device, rt_off_t pos, const void* buffer,
+static rt_ssize_t rt_usbh_adk_write (rt_device_t device, rt_off_t pos, const void* buffer,
     rt_size_t size)
 {
     uadk_t adk;
diff --git a/components/drivers/usb/usbhost/class/udisk.c b/components/drivers/usb/usbhost/class/udisk.c
index 8be311e657..ee0129b487 100644
--- a/components/drivers/usb/usbhost/class/udisk.c
+++ b/components/drivers/usb/usbhost/class/udisk.c
@@ -64,7 +64,7 @@ static rt_err_t rt_udisk_init(rt_device_t dev)
  *
  * @return the actually read size on successful, otherwise negative returned.
  */
-static rt_size_t rt_udisk_read(rt_device_t dev, rt_off_t pos, void* buffer,
+static rt_ssize_t rt_udisk_read(rt_device_t dev, rt_off_t pos, void* buffer,
     rt_size_t size)
 {
     rt_err_t ret;
@@ -102,7 +102,7 @@ static rt_size_t rt_udisk_read(rt_device_t dev, rt_off_t pos, void* buffer,
  *
  * @return the actually written size on successful, otherwise negative returned.
  */
-static rt_size_t rt_udisk_write (rt_device_t dev, rt_off_t pos, const void* buffer,
+static rt_ssize_t rt_udisk_write (rt_device_t dev, rt_off_t pos, const void* buffer,
     rt_size_t size)
 {
     rt_err_t ret;
diff --git a/components/drivers/virtio/virtio_blk.c b/components/drivers/virtio/virtio_blk.c
index a568a7008a..41e03e39d4 100644
--- a/components/drivers/virtio/virtio_blk.c
+++ b/components/drivers/virtio/virtio_blk.c
@@ -82,14 +82,14 @@ static void virtio_blk_rw(struct virtio_blk_device *virtio_blk_dev, rt_off_t pos
 #endif
 }
 
-static rt_size_t virtio_blk_read(rt_device_t dev, rt_off_t pos, void *buffer, rt_size_t count)
+static rt_ssize_t virtio_blk_read(rt_device_t dev, rt_off_t pos, void *buffer, rt_size_t count)
 {
     virtio_blk_rw((struct virtio_blk_device *)dev, pos, buffer, count, VIRTIO_BLK_T_IN);
 
     return count;
 }
 
-static rt_size_t virtio_blk_write(rt_device_t dev, rt_off_t pos, const void *buffer, rt_size_t count)
+static rt_ssize_t virtio_blk_write(rt_device_t dev, rt_off_t pos, const void *buffer, rt_size_t count)
 {
     virtio_blk_rw((struct virtio_blk_device *)dev, pos, (void *)buffer, count, VIRTIO_BLK_T_OUT);
 
diff --git a/components/drivers/virtio/virtio_console.c b/components/drivers/virtio/virtio_console.c
index 7f1a9b8af5..ac6c821853 100644
--- a/components/drivers/virtio/virtio_console.c
+++ b/components/drivers/virtio/virtio_console.c
@@ -78,8 +78,8 @@ static void virtio_console_send_ctrl(struct virtio_console_device *virtio_consol
 static rt_err_t virtio_console_port_init(rt_device_t dev);
 static rt_err_t virtio_console_port_open(rt_device_t dev, rt_uint16_t oflag);
 static rt_err_t virtio_console_port_close(rt_device_t dev);
-static rt_size_t virtio_console_port_read(rt_device_t dev, rt_off_t pos, void *buffer, rt_size_t size);
-static rt_size_t virtio_console_port_write(rt_device_t dev, rt_off_t pos, const void *buffer, rt_size_t size);
+static rt_ssize_t virtio_console_port_read(rt_device_t dev, rt_off_t pos, void *buffer, rt_size_t size);
+static rt_ssize_t virtio_console_port_write(rt_device_t dev, rt_off_t pos, const void *buffer, rt_size_t size);
 static rt_err_t virtio_console_port_control(rt_device_t dev, int cmd, void *args);
 
 #ifdef RT_USING_DEVICE_OPS
@@ -295,7 +295,7 @@ static rt_err_t virtio_console_port_close(rt_device_t dev)
     return RT_EOK;
 }
 
-static rt_size_t virtio_console_port_read(rt_device_t dev, rt_off_t pos, void *buffer, rt_size_t size)
+static rt_ssize_t virtio_console_port_read(rt_device_t dev, rt_off_t pos, void *buffer, rt_size_t size)
 {
     rt_off_t i = 0;
     rt_uint16_t id;
@@ -346,7 +346,7 @@ static rt_size_t virtio_console_port_read(rt_device_t dev, rt_off_t pos, void *b
     return size;
 }
 
-static rt_size_t virtio_console_port_write(rt_device_t dev, rt_off_t pos, const void *buffer, rt_size_t size)
+static rt_ssize_t virtio_console_port_write(rt_device_t dev, rt_off_t pos, const void *buffer, rt_size_t size)
 {
     char ch = 0;
     rt_off_t i = 0;
diff --git a/components/drivers/virtio/virtio_gpu.c b/components/drivers/virtio/virtio_gpu.c
index 67ce28a876..a9836d9b7a 100644
--- a/components/drivers/virtio/virtio_gpu.c
+++ b/components/drivers/virtio/virtio_gpu.c
@@ -448,7 +448,7 @@ static rt_err_t virtio_gpu_init(rt_device_t dev)
     return status;
 }
 
-static rt_size_t virtio_gpu_read(rt_device_t dev, rt_off_t pos, void *buffer, rt_size_t size)
+static rt_ssize_t virtio_gpu_read(rt_device_t dev, rt_off_t pos, void *buffer, rt_size_t size)
 {
     struct virtio_gpu_device *virtio_gpu_dev = (struct virtio_gpu_device *)dev;
 
@@ -466,7 +466,7 @@ static rt_size_t virtio_gpu_read(rt_device_t dev, rt_off_t pos, void *buffer, rt
     return size;
 }
 
-static rt_size_t virtio_gpu_write(rt_device_t dev, rt_off_t pos, const void *buffer, rt_size_t size)
+static rt_ssize_t virtio_gpu_write(rt_device_t dev, rt_off_t pos, const void *buffer, rt_size_t size)
 {
     struct virtio_gpu_device *virtio_gpu_dev = (struct virtio_gpu_device *)dev;
 
diff --git a/components/drivers/virtio/virtio_input.c b/components/drivers/virtio/virtio_input.c
index 8de3d9c83f..41ecd6bb83 100644
--- a/components/drivers/virtio/virtio_input.c
+++ b/components/drivers/virtio/virtio_input.c
@@ -24,7 +24,7 @@ static void _set_bit(rt_uint32_t nr, volatile rt_ubase_t *addr)
     *p  |= mask;
 }
 
-static rt_size_t virtio_input_cfg_select(struct virtio_input_device *virtio_input_dev,
+static rt_ssize_t virtio_input_cfg_select(struct virtio_input_device *virtio_input_dev,
         rt_uint8_t select, rt_uint8_t subsel)
 {
     struct virtio_input_config *config = virtio_input_dev->config;
@@ -139,7 +139,7 @@ static rt_err_t virtio_input_init(rt_device_t dev)
     return RT_EOK;
 }
 
-static rt_size_t virtio_input_read(rt_device_t dev, rt_off_t pos, void *buffer, rt_size_t size)
+static rt_ssize_t virtio_input_read(rt_device_t dev, rt_off_t pos, void *buffer, rt_size_t size)
 {
     struct virtio_input_device *virtio_input_dev = (struct virtio_input_device *)dev;
 
@@ -157,7 +157,7 @@ static rt_size_t virtio_input_read(rt_device_t dev, rt_off_t pos, void *buffer,
     return size;
 }
 
-static rt_size_t virtio_input_write(rt_device_t dev, rt_off_t pos, const void *buffer, rt_size_t size)
+static rt_ssize_t virtio_input_write(rt_device_t dev, rt_off_t pos, const void *buffer, rt_size_t size)
 {
     struct virtio_input_device *virtio_input_dev = (struct virtio_input_device *)dev;
 
diff --git a/components/fal/src/fal_rtt.c b/components/fal/src/fal_rtt.c
index 3473bc233a..a40832f31c 100644
--- a/components/fal/src/fal_rtt.c
+++ b/components/fal/src/fal_rtt.c
@@ -75,7 +75,7 @@ static rt_err_t blk_dev_control(rt_device_t dev, rt_uint8_t cmd, void *args)
     return RT_EOK;
 }
 
-static rt_size_t blk_dev_read(rt_device_t dev, rt_off_t pos, void* buffer, rt_size_t size)
+static rt_ssize_t blk_dev_read(rt_device_t dev, rt_off_t pos, void* buffer, rt_size_t size)
 {
     int ret = 0;
     struct fal_blk_device *part = (struct fal_blk_device*) dev;
@@ -96,7 +96,7 @@ static rt_size_t blk_dev_read(rt_device_t dev, rt_off_t pos, void* buffer, rt_si
     return ret;
 }
 
-static rt_size_t blk_dev_write(rt_device_t dev, rt_off_t pos, const void* buffer, rt_size_t size)
+static rt_ssize_t blk_dev_write(rt_device_t dev, rt_off_t pos, const void* buffer, rt_size_t size)
 {
     int ret = 0;
     struct fal_blk_device *part;
@@ -212,7 +212,7 @@ struct fal_mtd_nor_device
     const struct fal_partition     *fal_part;
 };
 
-static rt_size_t mtd_nor_dev_read(struct rt_mtd_nor_device* device, rt_off_t offset, rt_uint8_t* data, rt_uint32_t length)
+static rt_ssize_t mtd_nor_dev_read(struct rt_mtd_nor_device* device, rt_off_t offset, rt_uint8_t* data, rt_uint32_t length)
 {
     int ret = 0;
     struct fal_mtd_nor_device *part = (struct fal_mtd_nor_device*) device;
@@ -233,7 +233,7 @@ static rt_size_t mtd_nor_dev_read(struct rt_mtd_nor_device* device, rt_off_t off
     return ret;
 }
 
-static rt_size_t mtd_nor_dev_write(struct rt_mtd_nor_device* device, rt_off_t offset, const rt_uint8_t* data, rt_uint32_t length)
+static rt_ssize_t mtd_nor_dev_write(struct rt_mtd_nor_device* device, rt_off_t offset, const rt_uint8_t* data, rt_uint32_t length)
 {
     int ret = 0;
     struct fal_mtd_nor_device *part;
@@ -343,7 +343,7 @@ struct fal_char_device
 };
 
 /* RT-Thread device interface */
-static rt_size_t char_dev_read(rt_device_t dev, rt_off_t pos, void *buffer, rt_size_t size)
+static rt_ssize_t char_dev_read(rt_device_t dev, rt_off_t pos, void *buffer, rt_size_t size)
 {
     int ret = 0;
     struct fal_char_device *part = (struct fal_char_device *) dev;
@@ -361,7 +361,7 @@ static rt_size_t char_dev_read(rt_device_t dev, rt_off_t pos, void *buffer, rt_s
     return ret;
 }
 
-static rt_size_t char_dev_write(rt_device_t dev, rt_off_t pos, const void *buffer, rt_size_t size)
+static rt_ssize_t char_dev_write(rt_device_t dev, rt_off_t pos, const void *buffer, rt_size_t size)
 {
     int ret = 0;
     struct fal_char_device *part;
diff --git a/components/lwp/lwp_syscall.c b/components/lwp/lwp_syscall.c
index 85e641e395..5a2d0d4263 100644
--- a/components/lwp/lwp_syscall.c
+++ b/components/lwp/lwp_syscall.c
@@ -2675,12 +2675,12 @@ rt_err_t sys_device_close(rt_device_t dev)
     return rt_device_close(dev);
 }
 
-rt_size_t sys_device_read(rt_device_t dev, rt_off_t pos, void *buffer, rt_size_t size)
+rt_ssize_t sys_device_read(rt_device_t dev, rt_off_t pos, void *buffer, rt_size_t size)
 {
     return rt_device_read(dev, pos, buffer, size);
 }
 
-rt_size_t sys_device_write(rt_device_t dev, rt_off_t pos, const void *buffer, rt_size_t size)
+rt_ssize_t sys_device_write(rt_device_t dev, rt_off_t pos, const void *buffer, rt_size_t size)
 {
     return rt_device_write(dev, pos, buffer, size);
 }
diff --git a/components/utilities/rt-link/src/rtlink.c b/components/utilities/rt-link/src/rtlink.c
index e4aa08824d..48d91fc94b 100644
--- a/components/utilities/rt-link/src/rtlink.c
+++ b/components/utilities/rt-link/src/rtlink.c
@@ -208,7 +208,7 @@ static void rt_link_service_send_finish(rt_link_err_e err)
     }
 }
 
-static rt_size_t frame_send(struct rt_link_frame *frame)
+static rt_ssize_t frame_send(struct rt_link_frame *frame)
 {
     rt_size_t length = 0;
     rt_uint8_t *data = RT_NULL;
diff --git a/components/utilities/rt-link/src/rtlink_dev.c b/components/utilities/rt-link/src/rtlink_dev.c
index f15294fc4d..24c45585ea 100644
--- a/components/utilities/rt-link/src/rtlink_dev.c
+++ b/components/utilities/rt-link/src/rtlink_dev.c
@@ -265,7 +265,7 @@ rt_err_t  rt_link_dev_close(rt_device_t dev)
     return rt_link_service_detach(&rtlink->service);
 }
 
-rt_size_t rt_link_dev_read(rt_device_t dev, rt_off_t pos, void *buffer, rt_size_t size)
+rt_ssize_t rt_link_dev_read(rt_device_t dev, rt_off_t pos, void *buffer, rt_size_t size)
 {
     RT_ASSERT(dev != RT_NULL);
     RT_ASSERT(buffer != RT_NULL);
@@ -305,7 +305,7 @@ rt_size_t rt_link_dev_read(rt_device_t dev, rt_off_t pos, void *buffer, rt_size_
     return read_len;
 }
 
-rt_size_t rt_link_dev_write(rt_device_t dev, rt_off_t pos, const void *buffer, rt_size_t size)
+rt_ssize_t rt_link_dev_write(rt_device_t dev, rt_off_t pos, const void *buffer, rt_size_t size)
 {
     RT_ASSERT(dev != RT_NULL);
     RT_ASSERT(buffer != RT_NULL);
diff --git a/components/utilities/rt-link/src/rtlink_hw.c b/components/utilities/rt-link/src/rtlink_hw.c
index 4a56ea4893..847100912e 100644
--- a/components/utilities/rt-link/src/rtlink_hw.c
+++ b/components/utilities/rt-link/src/rtlink_hw.c
@@ -45,7 +45,7 @@ struct rt_link_receive_buffer *rt_link_hw_buffer_init(void *parameter)
     return rx_buffer;
 }
 
-static rt_size_t rt_link_hw_buffer_write(void *data, rt_size_t count)
+static rt_ssize_t rt_link_hw_buffer_write(void *data, rt_size_t count)
 {
     rt_size_t surplus = 0;
     if (rx_buffer == RT_NULL)
diff --git a/components/utilities/ymodem/ymodem.c b/components/utilities/ymodem/ymodem.c
index efbb70defd..f554d81f98 100644
--- a/components/utilities/ymodem/ymodem.c
+++ b/components/utilities/ymodem/ymodem.c
@@ -121,7 +121,7 @@ static enum rym_code _rym_read_code(
 }
 
 /* the caller should at least alloc _RYM_STX_PKG_SZ buffer */
-static rt_size_t _rym_read_data(
+static rt_ssize_t _rym_read_data(
     struct rym_ctx *ctx,
     rt_size_t len)
 {
@@ -180,13 +180,13 @@ static rt_err_t _rym_send_packet(
     return RT_EOK;
 }
 
-static rt_size_t _rym_putchar(struct rym_ctx *ctx, rt_uint8_t code)
+static rt_ssize_t _rym_putchar(struct rym_ctx *ctx, rt_uint8_t code)
 {
     rt_device_write(ctx->dev, 0, &code, sizeof(code));
     return 1;
 }
 
-static rt_size_t _rym_getchar(struct rym_ctx *ctx)
+static rt_ssize_t _rym_getchar(struct rym_ctx *ctx)
 {
     rt_uint8_t getc_ack;
 
diff --git a/components/vbus/vbus_chnx.c b/components/vbus/vbus_chnx.c
index 1014369cc2..d9bb3e4d46 100644
--- a/components/vbus/vbus_chnx.c
+++ b/components/vbus/vbus_chnx.c
@@ -62,7 +62,7 @@ static rt_err_t _close(rt_device_t dev)
     return RT_EOK;
 }
 
-static rt_size_t _read(rt_device_t dev, rt_off_t pos, void *buffer, rt_size_t size)
+static rt_ssize_t _read(rt_device_t dev, rt_off_t pos, void *buffer, rt_size_t size)
 {
     rt_size_t outsz = 0;
     struct rt_vbus_dev *vdev = dev->user_data;
@@ -126,7 +126,7 @@ static rt_size_t _read(rt_device_t dev, rt_off_t pos, void *buffer, rt_size_t si
     }
 }
 
-static rt_size_t _write(rt_device_t dev, rt_off_t pos, const void *buffer, rt_size_t size)
+static rt_ssize_t _write(rt_device_t dev, rt_off_t pos, const void *buffer, rt_size_t size)
 {
     rt_err_t err;
     struct rt_vbus_dev *vdev = dev->user_data;