fs/block_dev.c: fix iov_shorten() criteria in blkdev_aio_read()

blkdev_aio_read() test 'size' to see if it is equal or greater than the
target count we request(iocb->ki_left).  If so there is no need to call
iov_shorten() to reduce number of segments and the iovec's length.  So the
judgement should be changed to 'if (size < iocb->ki_left)' instead.

Signed-off-by: Jianpeng Ma <majianpeng@gmail.com>
Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 1 insertions, 1 deletions

diff --git a/fs/block_dev.c b/fs/block_dev.c
index aea605c98ba6..dc7f9836fb5e 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -1558,7 +1558,7 @@ static ssize_t blkdev_aio_read(struct kiocb *iocb, const struct iovec *iov,
                 return 0;
 
         size -= pos;
-        if (size < INT_MAX)
+        if (size < iocb->ki_left)
                 nr_segs = iov_shorten((struct iovec *)iov, nr_segs, size);
         return generic_file_aio_read(iocb, iov, nr_segs, pos);
 }