X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=block%2Fll_rw_blk.c;h=3b927be038501f178577da45ebb447c6dc27b90f;hb=d89a9bda14204547f966ed1510a269a44c0b7f5d;hp=d8616e6ebd92bfbd21087aab4b93959492a3d821;hpb=abbeb88d00bef294ce661a9229c1dc31be064545;p=linux-2.6

diff --git a/block/ll_rw_blk.c b/block/ll_rw_blk.c
index d8616e6ebd..3b927be038 100644
--- a/block/ll_rw_blk.c
+++ b/block/ll_rw_blk.c
@@ -791,7 +791,6 @@ static int __blk_free_tags(struct blk_queue_tag *bqt)
 	retval = atomic_dec_and_test(&bqt->refcnt);
 	if (retval) {
 		BUG_ON(bqt->busy);
-		BUG_ON(!list_empty(&bqt->busy_list));
 
 		kfree(bqt->tag_index);
 		bqt->tag_index = NULL;
@@ -903,7 +902,6 @@ static struct blk_queue_tag *__blk_queue_init_tags(struct request_queue *q,
 	if (init_tag_map(q, tags, depth))
 		goto fail;
 
-	INIT_LIST_HEAD(&tags->busy_list);
 	tags->busy = 0;
 	atomic_set(&tags->refcnt, 1);
 	return tags;
@@ -954,6 +952,7 @@ int blk_queue_init_tags(struct request_queue *q, int depth,
 	 */
 	q->queue_tags = tags;
 	q->queue_flags |= (1 << QUEUE_FLAG_QUEUED);
+	INIT_LIST_HEAD(&q->tag_busy_list);
 	return 0;
 fail:
 	kfree(tags);
@@ -1057,18 +1056,16 @@ void blk_queue_end_tag(struct request_queue *q, struct request *rq)
 
 	bqt->tag_index[tag] = NULL;
 
-	/*
-	 * We use test_and_clear_bit's memory ordering properties here.
-	 * The tag_map bit acts as a lock for tag_index[bit], so we need
-	 * a barrer before clearing the bit (precisely: release semantics).
-	 * Could use clear_bit_unlock when it is merged.
-	 */
-	if (unlikely(!test_and_clear_bit(tag, bqt->tag_map))) {
+	if (unlikely(!test_bit(tag, bqt->tag_map))) {
 		printk(KERN_ERR "%s: attempt to clear non-busy tag (%d)\n",
 		       __FUNCTION__, tag);
 		return;
 	}
-
+	/*
+	 * The tag_map bit acts as a lock for tag_index[bit], so we need
+	 * unlock memory barrier semantics.
+	 */
+	clear_bit_unlock(tag, bqt->tag_map);
 	bqt->busy--;
 }
 
@@ -1114,17 +1111,17 @@ int blk_queue_start_tag(struct request_queue *q, struct request *rq)
 		if (tag >= bqt->max_depth)
 			return 1;
 
-	} while (test_and_set_bit(tag, bqt->tag_map));
+	} while (test_and_set_bit_lock(tag, bqt->tag_map));
 	/*
-	 * We rely on test_and_set_bit providing lock memory ordering semantics
-	 * (could use test_and_set_bit_lock when it is merged).
+	 * We need lock ordering semantics given by test_and_set_bit_lock.
+	 * See blk_queue_end_tag for details.
 	 */
 
 	rq->cmd_flags |= REQ_QUEUED;
 	rq->tag = tag;
 	bqt->tag_index[tag] = rq;
 	blkdev_dequeue_request(rq);
-	list_add(&rq->queuelist, &bqt->busy_list);
+	list_add(&rq->queuelist, &q->tag_busy_list);
 	bqt->busy++;
 	return 0;
 }
@@ -1145,24 +1142,10 @@ EXPORT_SYMBOL(blk_queue_start_tag);
  **/
 void blk_queue_invalidate_tags(struct request_queue *q)
 {
-	struct blk_queue_tag *bqt = q->queue_tags;
 	struct list_head *tmp, *n;
-	struct request *rq;
 
-	list_for_each_safe(tmp, n, &bqt->busy_list) {
-		rq = list_entry_rq(tmp);
-
-		if (rq->tag == -1) {
-			printk(KERN_ERR
-			       "%s: bad tag found on list\n", __FUNCTION__);
-			list_del_init(&rq->queuelist);
-			rq->cmd_flags &= ~REQ_QUEUED;
-		} else
-			blk_queue_end_tag(q, rq);
-
-		rq->cmd_flags &= ~REQ_STARTED;
-		__elv_add_request(q, rq, ELEVATOR_INSERT_BACK, 0);
-	}
+	list_for_each_safe(tmp, n, &q->tag_busy_list)
+		blk_requeue_request(q, list_entry_rq(tmp));
 }
 
 EXPORT_SYMBOL(blk_queue_invalidate_tags);
@@ -1373,7 +1356,7 @@ new_segment:
 	} /* segments in rq */
 
 	if (sg)
-		__sg_mark_end(sg);
+		sg_mark_end(sg);
 
 	return nsegs;
 }
@@ -1638,15 +1621,7 @@ static void blk_backing_dev_unplug(struct backing_dev_info *bdi,
 {
 	struct request_queue *q = bdi->unplug_io_data;
 
-	/*
-	 * devices don't necessarily have an ->unplug_fn defined
-	 */
-	if (q->unplug_fn) {
-		blk_add_trace_pdu_int(q, BLK_TA_UNPLUG_IO, NULL,
-					q->rq.count[READ] + q->rq.count[WRITE]);
-
-		q->unplug_fn(q);
-	}
+	blk_unplug(q);
 }
 
 static void blk_unplug_work(struct work_struct *work)
@@ -1670,6 +1645,20 @@ static void blk_unplug_timeout(unsigned long data)
 	kblockd_schedule_work(&q->unplug_work);
 }
 
+void blk_unplug(struct request_queue *q)
+{
+	/*
+	 * devices don't necessarily have an ->unplug_fn defined
+	 */
+	if (q->unplug_fn) {
+		blk_add_trace_pdu_int(q, BLK_TA_UNPLUG_IO, NULL,
+					q->rq.count[READ] + q->rq.count[WRITE]);
+
+		q->unplug_fn(q);
+	}
+}
+EXPORT_SYMBOL(blk_unplug);
+
 /**
  * blk_start_queue - restart a previously stopped queue
  * @q:    The &struct request_queue in question
@@ -3225,6 +3214,7 @@ static inline void __generic_make_request(struct bio *bio)
 	sector_t old_sector;
 	int ret, nr_sectors = bio_sectors(bio);
 	dev_t old_dev;
+	int err = -EIO;
 
 	might_sleep();
 
@@ -3252,7 +3242,7 @@ static inline void __generic_make_request(struct bio *bio)
 				bdevname(bio->bi_bdev, b),
 				(long long) bio->bi_sector);
 end_io:
-			bio_endio(bio, -EIO);
+			bio_endio(bio, err);
 			break;
 		}
 
@@ -3287,6 +3277,10 @@ end_io:
 
 		if (bio_check_eod(bio, nr_sectors))
 			goto end_io;
+		if (bio_empty_barrier(bio) && !q->prepare_flush_fn) {
+			err = -EOPNOTSUPP;
+			goto end_io;
+		}
 
 		ret = q->make_request_fn(q, bio);
 	} while (ret);