projects / packages / kernel.git / blame
| Commit | Line | Data |
|---|---|---|
| 0283c5ee AM |
1 | commit 6eca9004dfcb274a502438a591df5b197690afb1 |
| 2 | Author: Jens Axboe <jens.axboe@oracle.com> | |
| 3 | Date: Thu Oct 25 10:14:47 2007 +0200 | |
| 4 | ||
| 5 | [BLOCK] Fix bad sharing of tag busy list on queues with shared tag maps | |
| 6 | ||
| 7 | For the locking to work, only the tag map and tag bit map may be shared | |
| 8 | (incidentally, I was just explaining this to Nick yesterday, but I | |
| 9 | apparently didn't review the code well enough myself). But we also share | |
| 10 | the busy list! The busy_list must be queue private, or we need a | |
| 11 | block_queue_tag covering lock as well. | |
| 12 | ||
| 13 | So we have to move the busy_list to the queue. This'll work fine, and | |
| 14 | it'll actually also fix a problem with blk_queue_invalidate_tags() which | |
| 15 | will invalidate tags across all shared queues. This is a bit confusing, | |
| 16 | the low level driver should call it for each queue seperately since | |
| 17 | otherwise you cannot kill tags on just a single queue for eg a hard | |
| 18 | drive that stops responding. Since the function has no callers | |
| 19 | currently, it's not an issue. | |
| 20 | ||
| 21 | Signed-off-by: Jens Axboe <jens.axboe@oracle.com> | |
| 22 | ||
| 23 | diff --git a/block/ll_rw_blk.c b/block/ll_rw_blk.c | |
| 24 | index a8a1810..56f2646 100644 | |
| 25 | --- a/block/ll_rw_blk.c | |
| 26 | +++ b/block/ll_rw_blk.c | |
| 27 | @@ -791,7 +791,6 @@ static int __blk_free_tags(struct blk_queue_tag *bqt) | |
| 28 | retval = atomic_dec_and_test(&bqt->refcnt); | |
| 29 | if (retval) { | |
| 30 | BUG_ON(bqt->busy); | |
| 31 | - BUG_ON(!list_empty(&bqt->busy_list)); | |
| 32 | ||
| 33 | kfree(bqt->tag_index); | |
| 34 | bqt->tag_index = NULL; | |
| 35 | @@ -903,7 +902,6 @@ static struct blk_queue_tag *__blk_queue_init_tags(struct request_queue *q, | |
| 36 | if (init_tag_map(q, tags, depth)) | |
| 37 | goto fail; | |
| 38 | ||
| 39 | - INIT_LIST_HEAD(&tags->busy_list); | |
| 40 | tags->busy = 0; | |
| 41 | atomic_set(&tags->refcnt, 1); | |
| 42 | return tags; | |
| 43 | @@ -954,6 +952,7 @@ int blk_queue_init_tags(struct request_queue *q, int depth, | |
| 44 | */ | |
| 45 | q->queue_tags = tags; | |
| 46 | q->queue_flags |= (1 << QUEUE_FLAG_QUEUED); | |
| 47 | + INIT_LIST_HEAD(&q->tag_busy_list); | |
| 48 | return 0; | |
| 49 | fail: | |
| 50 | kfree(tags); | |
| 51 | @@ -1122,7 +1121,7 @@ int blk_queue_start_tag(struct request_queue *q, struct request *rq) | |
| 52 | rq->tag = tag; | |
| 53 | bqt->tag_index[tag] = rq; | |
| 54 | blkdev_dequeue_request(rq); | |
| 55 | - list_add(&rq->queuelist, &bqt->busy_list); | |
| 56 | + list_add(&rq->queuelist, &q->tag_busy_list); | |
| 57 | bqt->busy++; | |
| 58 | return 0; | |
| 59 | } | |
| 60 | @@ -1143,11 +1142,10 @@ EXPORT_SYMBOL(blk_queue_start_tag); | |
| 61 | **/ | |
| 62 | void blk_queue_invalidate_tags(struct request_queue *q) | |
| 63 | { | |
| 64 | - struct blk_queue_tag *bqt = q->queue_tags; | |
| 65 | struct list_head *tmp, *n; | |
| 66 | struct request *rq; | |
| 67 | ||
| 68 | - list_for_each_safe(tmp, n, &bqt->busy_list) { | |
| 69 | + list_for_each_safe(tmp, n, &q->tag_busy_list) { | |
| 70 | rq = list_entry_rq(tmp); | |
| 71 | ||
| 72 | if (rq->tag == -1) { | |
| 73 | diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h | |
| 74 | index bbf906a..8396db2 100644 | |
| 75 | --- a/include/linux/blkdev.h | |
| 76 | +++ b/include/linux/blkdev.h | |
| 77 | @@ -341,7 +341,6 @@ enum blk_queue_state { | |
| 78 | struct blk_queue_tag { | |
| 79 | struct request **tag_index; /* map of busy tags */ | |
| 80 | unsigned long *tag_map; /* bit map of free/busy tags */ | |
| 81 | - struct list_head busy_list; /* fifo list of busy tags */ | |
| 82 | int busy; /* current depth */ | |
| 83 | int max_depth; /* what we will send to device */ | |
| 84 | int real_max_depth; /* what the array can hold */ | |
| 85 | @@ -435,6 +434,7 @@ struct request_queue | |
| 86 | unsigned int dma_alignment; | |
| 87 | ||
| 88 | struct blk_queue_tag *queue_tags; | |
| 89 | + struct list_head tag_busy_list; | |
| 90 | ||
| 91 | unsigned int nr_sorted; | |
| 92 | unsigned int in_flight; |