Commit 81238b2c authored by Christoph Hellwig's avatar Christoph Hellwig
Browse files

fs: implement kernel_write using __kernel_write 



Consolidate the two in-kernel write helpers to make upcoming changes
easier.  The only difference are the missing call to rw_verify_area
in kernel_write, and an access_ok check that doesn't make sense for
kernel buffers to start with.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
parent a01ac27b

fs/read_write.c

+9 −8
Original line number Diff line number Diff line
@@ -499,6 +499,7 @@ static ssize_t __vfs_write(struct file *file, const char __user *p, 
		return -EINVAL;

}



/* caller is responsible for file_start_write/file_end_write */

ssize_t __kernel_write(struct file *file, const void *buf, size_t count, loff_t *pos)

{

	mm_segment_t old_fs;
@@ -528,16 +529,16 @@ ssize_t __kernel_write(struct file *file, const void *buf, size_t count, loff_t 
ssize_t kernel_write(struct file *file, const void *buf, size_t count,

			    loff_t *pos)

{

	mm_segment_t old_fs;

	ssize_t res;

	ssize_t ret;



	old_fs = get_fs();

	set_fs(KERNEL_DS);

	/* The cast to a user pointer is valid due to the set_fs() */

	res = vfs_write(file, (__force const char __user *)buf, count, pos);

	set_fs(old_fs);

	ret = rw_verify_area(WRITE, file, pos, count);

	if (ret)

		return ret;



	return res;

	file_start_write(file);

	ret =  __kernel_write(file, buf, count, pos);

	file_end_write(file);

	return ret;

}

EXPORT_SYMBOL(kernel_write);

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