mm/page_io.c: fix polled swap page in

swap_readpage() wants to do polling to bring in pages if asked to, but
it doesn't mark the bio as being polled.  Additionally, the looping
around the blk_poll() check isn't correct - if we get a zero return, we
should call io_schedule(), we can't just assume that the bio has
completed.  The regular bio->bi_private check should be used for that.

Link: http://lkml.kernel.org/r/e15243a8-2cdf-c32c-ecee-f289377c8ef9@kernel.dk
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/page_io.c b/mm/page_io.c
index d975fa3..2e8019d 100644 (file)
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -401,6 +401,8 @@ int swap_readpage(struct page *page, bool synchronous)
        get_task_struct(current);
        bio->bi_private = current;
        bio_set_op_attrs(bio, REQ_OP_READ, 0);
+       if (synchronous)
+               bio->bi_opf |= REQ_HIPRI;
        count_vm_event(PSWPIN);
        bio_get(bio);
        qc = submit_bio(bio);
@@ -410,7 +412,7 @@ int swap_readpage(struct page *page, bool synchronous)
                        break;
 
                if (!blk_poll(disk->queue, qc, true))
-                       break;
+                       io_schedule();
        }
        __set_current_state(TASK_RUNNING);
        bio_put(bio);