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mm: move common segment checks to separate helper function

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[[email protected]: cleanup]
Signed-off-by: Monakhov Dmitriy <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Acked-by: Anton Altaparmakov <[email protected]>
Acked-by: David Chinner <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
This commit is contained in:
Dmitriy Monakhov 2007-05-08 00:23:02 -07:00 • committed by Linus Torvalds
commit 0ceb331433
4 changed files with 53 additions and 74 deletions
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82
mm/filemap.c
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@ -1110,6 +1110,45 @@ success:
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;