[PATCH] aio: avoid extra aio_{read,write} call when ki_left == 0

Recently aio_p{read,write} changed to perform retries internally rather
than returning -EIOCBRETRY.  This inadvertantly resulted in always calling
aio_{read,write} with ki_left at 0 which would in turn immediately return
0.  Harmless, but we can avoid this call by checking in the caller.

Signed-off-by: Zach Brown <zach.brown@oracle.com>
Signed-off-by: Benjamin LaHaise <bcrl@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 2 insertions, 2 deletions

diff --git a/fs/aio.c b/fs/aio.c
index 9edc0e4a1219..d6b1551342b7 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -1347,7 +1347,7 @@ static ssize_t aio_pread(struct kiocb *iocb)
                  * regular files we retry till we complete the entire read or
                  * find that we can't read any more data (e.g short reads).
                  */
-        } while (ret > 0 &&
+        } while (ret > 0 && iocb->ki_left > 0 &&
                  !S_ISFIFO(inode->i_mode) && !S_ISSOCK(inode->i_mode));
 
         /* This means we must have transferred all that we could */
@@ -1371,7 +1371,7 @@ static ssize_t aio_pwrite(struct kiocb *iocb)
                         iocb->ki_buf += ret;
                         iocb->ki_left -= ret;
                 }
-        } while (ret > 0);
+        } while (ret > 0 && iocb->ki_left > 0);
 
         if ((ret == 0) || (iocb->ki_left == 0))
                 ret = iocb->ki_nbytes - iocb->ki_left;