From ebff6d5c91195d37e33b7bbfb36c6cc0119aa06f Mon Sep 17 00:00:00 2001 From: Ming Lei Date: Tue, 5 May 2015 19:49:54 +0800 Subject: [PATCH 1/2] block: loop: convert to per-device workqueue Documentation/workqueue.txt: If there is dependency among multiple work items used during memory reclaim, they should be queued to separate wq each with WQ_MEM_RECLAIM. Loop devices can be stacked, so we have to convert to per-device workqueue. One example is Fedora live CD. Fixes: b5dd2f6047ca108001328aac0e8588edd15f1778 Cc: stable@vger.kernel.org (v4.0) Cc: Justin M. Forbes Signed-off-by: Ming Lei Acked-by: Tejun Heo Signed-off-by: Jens Axboe --- drivers/block/loop.c | 30 ++++++++++++++---------------- drivers/block/loop.h | 1 + 2 files changed, 15 insertions(+), 16 deletions(-) diff --git a/drivers/block/loop.c b/drivers/block/loop.c index d7173cb..9786aa3 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -86,8 +86,6 @@ static DEFINE_MUTEX(loop_index_mutex); static int max_part; static int part_shift; -static struct workqueue_struct *loop_wq; - static int transfer_xor(struct loop_device *lo, int cmd, struct page *raw_page, unsigned raw_off, struct page *loop_page, unsigned loop_off, @@ -725,6 +723,12 @@ static int loop_set_fd(struct loop_device *lo, fmode_t mode, size = get_loop_size(lo, file); if ((loff_t)(sector_t)size != size) goto out_putf; + error = -ENOMEM; + lo->wq = alloc_workqueue("kloopd%d", + WQ_MEM_RECLAIM | WQ_HIGHPRI | WQ_UNBOUND, 0, + lo->lo_number); + if (!lo->wq) + goto out_putf; error = 0; @@ -872,6 +876,8 @@ static int loop_clr_fd(struct loop_device *lo) lo->lo_flags = 0; if (!part_shift) lo->lo_disk->flags |= GENHD_FL_NO_PART_SCAN; + destroy_workqueue(lo->wq); + lo->wq = NULL; mutex_unlock(&lo->lo_ctl_mutex); /* * Need not hold lo_ctl_mutex to fput backing file. @@ -1425,9 +1431,13 @@ static int loop_queue_rq(struct blk_mq_hw_ctx *hctx, const struct blk_mq_queue_data *bd) { struct loop_cmd *cmd = blk_mq_rq_to_pdu(bd->rq); + struct loop_device *lo = cmd->rq->q->queuedata; blk_mq_start_request(bd->rq); + if (lo->lo_state != Lo_bound) + return -EIO; + if (cmd->rq->cmd_flags & REQ_WRITE) { struct loop_device *lo = cmd->rq->q->queuedata; bool need_sched = true; @@ -1441,9 +1451,9 @@ static int loop_queue_rq(struct blk_mq_hw_ctx *hctx, spin_unlock_irq(&lo->lo_lock); if (need_sched) - queue_work(loop_wq, &lo->write_work); + queue_work(lo->wq, &lo->write_work); } else { - queue_work(loop_wq, &cmd->read_work); + queue_work(lo->wq, &cmd->read_work); } return BLK_MQ_RQ_QUEUE_OK; @@ -1455,9 +1465,6 @@ static void loop_handle_cmd(struct loop_cmd *cmd) struct loop_device *lo = cmd->rq->q->queuedata; int ret = -EIO; - if (lo->lo_state != Lo_bound) - goto failed; - if (write && (lo->lo_flags & LO_FLAGS_READ_ONLY)) goto failed; @@ -1806,13 +1813,6 @@ static int __init loop_init(void) goto misc_out; } - loop_wq = alloc_workqueue("kloopd", - WQ_MEM_RECLAIM | WQ_HIGHPRI | WQ_UNBOUND, 0); - if (!loop_wq) { - err = -ENOMEM; - goto misc_out; - } - blk_register_region(MKDEV(LOOP_MAJOR, 0), range, THIS_MODULE, loop_probe, NULL, NULL); @@ -1850,8 +1850,6 @@ static void __exit loop_exit(void) blk_unregister_region(MKDEV(LOOP_MAJOR, 0), range); unregister_blkdev(LOOP_MAJOR, "loop"); - destroy_workqueue(loop_wq); - misc_deregister(&loop_misc); } diff --git a/drivers/block/loop.h b/drivers/block/loop.h index 301c27f..49564ed 100644 --- a/drivers/block/loop.h +++ b/drivers/block/loop.h @@ -54,6 +54,7 @@ struct loop_device { gfp_t old_gfp_mask; spinlock_t lo_lock; + struct workqueue_struct *wq; struct list_head write_cmd_head; struct work_struct write_work; bool write_started; -- 2.4.5