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kill generic_segment_checks()

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all callers of ->aio_read() and ->aio_write() have iov/nr_segs already
checked - generic_segment_checks() done after that is just an odd way
to spell iov_length().

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro
2014-03-04 15:24:06 -05:00
parent 0ae5e4d370
commit cb66a7a1f1
10 changed files with 16 additions and 104 deletions
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53
mm/filemap.c
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@ -1663,45 +1663,6 @@ out:
return written ? written : error;
}
/*
* 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
@ -1717,15 +1678,12 @@ generic_file_aio_read(struct kiocb *iocb, const struct iovec *iov,
unsigned long nr_segs, loff_t pos)
{
struct file *filp = iocb->ki_filp;
ssize_t retval;
ssize_t retval = 0;
size_t count;
loff_t *ppos = &iocb->ki_pos;
struct iov_iter i;
count = 0;
retval = generic_segment_checks(iov, &nr_segs, &count, VERIFY_WRITE);
if (retval)
return retval;
count = iov_length(iov, nr_segs);
iov_iter_init(&i, iov, nr_segs, count, 0);
/* coalesce the iovecs and go direct-to-BIO for O_DIRECT */
@ -2615,12 +2573,7 @@ ssize_t __generic_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
ssize_t status;
struct iov_iter from;
ocount = 0;
err = generic_segment_checks(iov, &nr_segs, &ocount, VERIFY_READ);
if (err)
return err;
count = ocount;
count = ocount = iov_length(iov, nr_segs);
/* We can write back this queue in page reclaim */
current->backing_dev_info = mapping->backing_dev_info;