[IDE] Use the block layer deferred softirq request completion

This patch makes IDE use the new blk_complete_request() interface.
There's still room for improvement, as __ide_end_request() really
could drop the lock after getting HWGROUP->rq (why does it need to
hold it in the first place? If ->rq access isn't serialized, we are
screwed anyways).

Signed-off-by: Jens Axboe <axboe@suse.de>

2 files changed, 37 insertions, 7 deletions

diff --git a/drivers/ide/ide-io.c b/drivers/ide/ide-io.c
index b5dc6df8e67d..dea2d4dcc698 100644
--- a/drivers/ide/ide-io.c
+++ b/drivers/ide/ide-io.c
@@ -55,9 +55,22 @@
 #include <asm/io.h>
 #include <asm/bitops.h>
 
+void ide_softirq_done(struct request *rq)
+{
+        request_queue_t *q = rq->q;
+
+        add_disk_randomness(rq->rq_disk);
+        end_that_request_chunk(rq, rq->errors, rq->data_len);
+
+        spin_lock_irq(q->queue_lock);
+        end_that_request_last(rq, rq->errors);
+        spin_unlock_irq(q->queue_lock);
+}
+
 int __ide_end_request(ide_drive_t *drive, struct request *rq, int uptodate,
                       int nr_sectors)
 {
+        unsigned int nbytes;
         int ret = 1;
 
         BUG_ON(!(rq->flags & REQ_STARTED));
@@ -81,17 +94,28 @@ int __ide_end_request(ide_drive_t *drive, struct request *rq, int uptodate,
                 HWGROUP(drive)->hwif->ide_dma_on(drive);
         }
 
-        if (!end_that_request_first(rq, uptodate, nr_sectors)) {
-                add_disk_randomness(rq->rq_disk);
-
-                if (blk_rq_tagged(rq))
-                        blk_queue_end_tag(drive->queue, rq);
-
+        /*
+         * For partial completions (or non fs/pc requests), use the regular
+         * direct completion path.
+         */
+        nbytes = nr_sectors << 9;
+        if (rq_all_done(rq, nbytes)) {
+                rq->errors = uptodate;
+                rq->data_len = nbytes;
                 blkdev_dequeue_request(rq);
                 HWGROUP(drive)->rq = NULL;
-                end_that_request_last(rq, uptodate);
+                blk_complete_request(rq);
                 ret = 0;
+        } else {
+                if (!end_that_request_first(rq, uptodate, nr_sectors)) {
+                        add_disk_randomness(rq->rq_disk);
+                        blkdev_dequeue_request(rq);
+                        HWGROUP(drive)->rq = NULL;
+                        end_that_request_last(rq, uptodate);
+                        ret = 0;
+                }
         }
+
         return ret;
 }
 EXPORT_SYMBOL(__ide_end_request);
@@ -113,6 +137,10 @@ int ide_end_request (ide_drive_t *drive, int uptodate, int nr_sectors)
         unsigned long flags;
         int ret = 1;
 
+        /*
+         * room for locking improvements here, the calls below don't
+         * need the queue lock held at all
+         */
         spin_lock_irqsave(&ide_lock, flags);
         rq = HWGROUP(drive)->rq;
 
diff --git a/drivers/ide/ide-probe.c b/drivers/ide/ide-probe.c
index 02167a5b751d..1ddaa71a8f45 100644
--- a/drivers/ide/ide-probe.c
+++ b/drivers/ide/ide-probe.c
@@ -1011,6 +1011,8 @@ static int ide_init_queue(ide_drive_t *drive)
         blk_queue_max_hw_segments(q, max_sg_entries);
         blk_queue_max_phys_segments(q, max_sg_entries);
 
+        blk_queue_softirq_done(q, ide_softirq_done);
+
         /* assign drive queue */
         drive->queue = q;