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Commit 0ceb3314 authored by Dmitriy Monakhov's avatar Dmitriy Monakhov Committed by Linus Torvalds
Browse files

mm: move common segment checks to separate helper function 



[akpm@linux-foundation.org: cleanup]
Signed-off-by: default avatarMonakhov Dmitriy <dmonakhov@openvz.org>
Cc: Christoph Hellwig <hch@lst.de>
Acked-by: default avatarAnton Altaparmakov <aia21@cam.ac.uk>
Acked-by: default avatarDavid Chinner <dgc@sgi.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent b46b8f19

fs/ntfs/file.c

+3 −18
Original line number Diff line number Diff line
@@ -2129,28 +2129,13 @@ static ssize_t ntfs_file_aio_write_nolock(struct kiocb *iocb, 
	struct address_space *mapping = file->f_mapping;

	struct inode *inode = mapping->host;

	loff_t pos;

	unsigned long seg;

	size_t count;		/* after file limit checks */

	ssize_t written, err;



	count = 0;

	for (seg = 0; seg < nr_segs; seg++) {

		const struct iovec *iv = &iov[seg];

		/*

		 * If any segment has a negative length, or the cumulative

		 * length ever wraps negative then return -EINVAL.

		 */

		count += iv->iov_len;

		if (unlikely((ssize_t)(count|iv->iov_len) < 0))

			return -EINVAL;

		if (access_ok(VERIFY_READ, iv->iov_base, iv->iov_len))

			continue;

		if (!seg)

			return -EFAULT;

		nr_segs = seg;

		count -= iv->iov_len;	/* This segment is no good */

		break;

	}

	err = generic_segment_checks(iov, &nr_segs, &count, VERIFY_READ);

	if (err)

		return err;

	pos = *ppos;

	vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);

	/* We can write back this queue in page reclaim. */

fs/xfs/linux-2.6/xfs_lrw.c

+3 −19
Original line number Diff line number Diff line
@@ -639,7 +639,6 @@ xfs_write( 
	xfs_fsize_t		isize, new_size;

	xfs_iocore_t		*io;

	bhv_vnode_t		*vp;

	unsigned long		seg;

	int			iolock;

	int			eventsent = 0;

	bhv_vrwlock_t		locktype;
@@ -652,24 +651,9 @@ xfs_write( 
	vp = BHV_TO_VNODE(bdp);

	xip = XFS_BHVTOI(bdp);



	for (seg = 0; seg < segs; seg++) {

		const struct iovec *iv = &iovp[seg];



		/*

		 * If any segment has a negative length, or the cumulative

		 * length ever wraps negative then return -EINVAL.

		 */

		ocount += iv->iov_len;

		if (unlikely((ssize_t)(ocount|iv->iov_len) < 0))

			return -EINVAL;

		if (access_ok(VERIFY_READ, iv->iov_base, iv->iov_len))

			continue;

		if (seg == 0)

			return -EFAULT;

		segs = seg;

		ocount -= iv->iov_len;  /* This segment is no good */

		break;

	}

	error = generic_segment_checks(iovp, &segs, &ocount, VERIFY_READ);

	if (error)

		return error;



	count = ocount;

	pos = *offset;

include/linux/fs.h

+2 −0
Original line number Diff line number Diff line
@@ -1735,6 +1735,8 @@ extern ssize_t generic_file_sendfile(struct file *, loff_t *, size_t, read_actor 
extern void do_generic_mapping_read(struct address_space *mapping,

				    struct file_ra_state *, struct file *,

				    loff_t *, read_descriptor_t *, read_actor_t);

extern int generic_segment_checks(const struct iovec *iov,

		unsigned long *nr_segs, size_t *count, int access_flags);



/* fs/splice.c */

extern ssize_t generic_file_splice_read(struct file *, loff_t *,

mm/filemap.c

+45 −37
Original line number Diff line number Diff line
@@ -1110,6 +1110,45 @@ int file_read_actor(read_descriptor_t *desc, struct page *page, 
	return size;

}



/*

 * Performs necessary checks before doing a write

 * @iov:	io vector request

 * @nr_segs:	number of segments in the iovec

 * @count:	number of bytes to write

 * @access_flags: type of access: %VERIFY_READ or %VERIFY_WRITE

 *

 * Adjust number of segments and amount of bytes to write (nr_segs should be

 * properly initialized first). Returns appropriate error code that caller

 * should return or zero in case that write should be allowed.

 */

int generic_segment_checks(const struct iovec *iov,

			unsigned long *nr_segs, size_t *count, int access_flags)

{

	unsigned long   seg;

	size_t cnt = 0;

	for (seg = 0; seg < *nr_segs; seg++) {

		const struct iovec *iv = &iov[seg];



		/*

		 * If any segment has a negative length, or the cumulative

		 * length ever wraps negative then return -EINVAL.

		 */

		cnt += iv->iov_len;

		if (unlikely((ssize_t)(cnt|iv->iov_len) < 0))

			return -EINVAL;

		if (access_ok(access_flags, iv->iov_base, iv->iov_len))

			continue;

		if (seg == 0)

			return -EFAULT;

		*nr_segs = seg;

		cnt -= iv->iov_len;	/* This segment is no good */

		break;

	}

	*count = cnt;

	return 0;

}

EXPORT_SYMBOL(generic_segment_checks);



/**

 * generic_file_aio_read - generic filesystem read routine

 * @iocb:	kernel I/O control block
@@ -1131,24 +1170,9 @@ generic_file_aio_read(struct kiocb *iocb, const struct iovec *iov, 
	loff_t *ppos = &iocb->ki_pos;



	count = 0;

	for (seg = 0; seg < nr_segs; seg++) {

		const struct iovec *iv = &iov[seg];



		/*

		 * If any segment has a negative length, or the cumulative

		 * length ever wraps negative then return -EINVAL.

		 */

		count += iv->iov_len;

		if (unlikely((ssize_t)(count|iv->iov_len) < 0))

			return -EINVAL;

		if (access_ok(VERIFY_WRITE, iv->iov_base, iv->iov_len))

			continue;

		if (seg == 0)

			return -EFAULT;

		nr_segs = seg;

		count -= iv->iov_len;	/* This segment is no good */

		break;

	}

	retval = generic_segment_checks(iov, &nr_segs, &count, VERIFY_WRITE);

	if (retval)

		return retval;



	/* coalesce the iovecs and go direct-to-BIO for O_DIRECT */

	if (filp->f_flags & O_DIRECT) {
@@ -2218,30 +2242,14 @@ __generic_file_aio_write_nolock(struct kiocb *iocb, const struct iovec *iov, 
	size_t ocount;		/* original count */

	size_t count;		/* after file limit checks */

	struct inode 	*inode = mapping->host;

	unsigned long	seg;

	loff_t		pos;

	ssize_t		written;

	ssize_t		err;



	ocount = 0;

	for (seg = 0; seg < nr_segs; seg++) {

		const struct iovec *iv = &iov[seg];



		/*

		 * If any segment has a negative length, or the cumulative

		 * length ever wraps negative then return -EINVAL.

		 */

		ocount += iv->iov_len;

		if (unlikely((ssize_t)(ocount|iv->iov_len) < 0))

			return -EINVAL;

		if (access_ok(VERIFY_READ, iv->iov_base, iv->iov_len))

			continue;

		if (seg == 0)

			return -EFAULT;

		nr_segs = seg;

		ocount -= iv->iov_len;	/* This segment is no good */

		break;

	}

	err = generic_segment_checks(iov, &nr_segs, &ocount, VERIFY_READ);

	if (err)

		return err;



	count = ocount;

	pos = *ppos;