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