Merge branch 'for-3.1/drivers' of git://git.kernel.dk/linux-block

* 'for-3.1/drivers' of git://git.kernel.dk/linux-block:
  cciss: do not attempt to read from a write-only register
  xen/blkback: Add module alias for autoloading
  xen/blkback: Don't let in-flight requests defer pending ones.
  bsg: fix address space warning from sparse
  bsg: remove unnecessary conditional expressions
  bsg: fix bsg_poll() to return POLLOUT properly

1 files changed, 20 insertions, 17 deletions

diff --git a/drivers/block/xen-blkback/blkback.c b/drivers/block/xen-blkback/blkback.c
index 5cf2993a8338..2330a9ad5e95 100644
--- a/drivers/block/xen-blkback/blkback.c
+++ b/drivers/block/xen-blkback/blkback.c
@@ -458,7 +458,8 @@ static void end_block_io_op(struct bio *bio, int error)
  * (which has the sectors we want, number of them, grant references, etc),
  * and transmute  it to the block API to hand it over to the proper block disk.
  */
-static int do_block_io_op(struct xen_blkif *blkif)
+static int
+__do_block_io_op(struct xen_blkif *blkif)
 {
 	union blkif_back_rings *blk_rings = &blkif->blk_rings;
 	struct blkif_request req;
@@ -515,6 +516,23 @@ static int do_block_io_op(struct xen_blkif *blkif)
 	return more_to_do;
 }
 
+static int
+do_block_io_op(struct xen_blkif *blkif)
+{
+	union blkif_back_rings *blk_rings = &blkif->blk_rings;
+	int more_to_do;
+
+	do {
+		more_to_do = __do_block_io_op(blkif);
+		if (more_to_do)
+			break;
+
+		RING_FINAL_CHECK_FOR_REQUESTS(&blk_rings->common, more_to_do);
+	} while (more_to_do);
+
+	return more_to_do;
+}
+
 /*
  * Transmutation of the 'struct blkif_request' to a proper 'struct bio'
  * and call the 'submit_bio' to pass it to the underlying storage.
@@ -700,7 +718,6 @@ static void make_response(struct xen_blkif *blkif, u64 id,
 	struct blkif_response  resp;
 	unsigned long     flags;
 	union blkif_back_rings *blk_rings = &blkif->blk_rings;
-	int more_to_do = 0;
 	int notify;
 
 	resp.id        = id;
@@ -727,22 +744,7 @@ static void make_response(struct xen_blkif *blkif, u64 id,
 	}
 	blk_rings->common.rsp_prod_pvt++;
 	RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&blk_rings->common, notify);
-	if (blk_rings->common.rsp_prod_pvt == blk_rings->common.req_cons) {
-		/*
-		 * Tail check for pending requests. Allows frontend to avoid
-		 * notifications if requests are already in flight (lower
-		 * overheads and promotes batching).
-		 */
-		RING_FINAL_CHECK_FOR_REQUESTS(&blk_rings->common, more_to_do);
-
-	} else if (RING_HAS_UNCONSUMED_REQUESTS(&blk_rings->common)) {
-		more_to_do = 1;
-	}
-
 	spin_unlock_irqrestore(&blkif->blk_ring_lock, flags);
-
-	if (more_to_do)
-		blkif_notify_work(blkif);
 	if (notify)
 		notify_remote_via_irq(blkif->irq);
 }
@@ -824,3 +826,4 @@ static int __init xen_blkif_init(void)
 module_init(xen_blkif_init);
 
 MODULE_LICENSE("Dual BSD/GPL");
+MODULE_ALIAS("xen-backend:vbd");