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Subject[PATCH 08/17] serial2002: switch serial2002_tty_write to kernel_{read/write}
Date
Instead of playing games with the address limit.  This also gains
us proper usage of the write counter, time stamp updates and kvec
validation.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
drivers/staging/comedi/drivers/serial2002.c | 24 +++++-------------------
1 file changed, 5 insertions(+), 19 deletions(-)

diff --git a/drivers/staging/comedi/drivers/serial2002.c b/drivers/staging/comedi/drivers/serial2002.c
index 0d33e520f635..cc18e25103ca 100644
--- a/drivers/staging/comedi/drivers/serial2002.c
+++ b/drivers/staging/comedi/drivers/serial2002.c
@@ -106,16 +106,8 @@ static long serial2002_tty_ioctl(struct file *f, unsigned int op,

static int serial2002_tty_write(struct file *f, unsigned char *buf, int count)
{
- const char __user *p = (__force const char __user *)buf;
- int result;
- loff_t offset = 0;
- mm_segment_t oldfs;
-
- oldfs = get_fs();
- set_fs(KERNEL_DS);
- result = __vfs_write(f, p, count, &offset);
- set_fs(oldfs);
- return result;
+ loff_t pos = 0;
+ return kernel_write(f, buf, count, &pos);
}

static void serial2002_tty_read_poll_wait(struct file *f, int timeout)
@@ -148,19 +140,14 @@ static int serial2002_tty_read(struct file *f, int timeout)
{
unsigned char ch;
int result;
+ loff_t pos = 0;

result = -1;
if (!IS_ERR(f)) {
- mm_segment_t oldfs;
- char __user *p = (__force char __user *)&ch;
- loff_t offset = 0;
-
- oldfs = get_fs();
- set_fs(KERNEL_DS);
if (f->f_op->poll) {
serial2002_tty_read_poll_wait(f, timeout);

- if (__vfs_read(f, p, 1, &offset) == 1)
+ if (kernel_read(f, &ch, 1, &pos) == 1)
result = ch;
} else {
/* Device does not support poll, busy wait */
@@ -171,14 +158,13 @@ static int serial2002_tty_read(struct file *f, int timeout)
if (retries >= timeout)
break;

- if (__vfs_read(f, p, 1, &offset) == 1) {
+ if (kernel_read(f, &ch, 1, &pos) == 1) {
result = ch;
break;
}
usleep_range(100, 1000);
}
}
- set_fs(oldfs);
}
return result;
}
--
2.11.0
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