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-rw-r--r--kernels/linux-libre-knock/0001-block-loop-convert-to-per-device-workqueue.patch133
1 files changed, 133 insertions, 0 deletions
diff --git a/kernels/linux-libre-knock/0001-block-loop-convert-to-per-device-workqueue.patch b/kernels/linux-libre-knock/0001-block-loop-convert-to-per-device-workqueue.patch
new file mode 100644
index 000000000..3b426c7b4
--- /dev/null
+++ b/kernels/linux-libre-knock/0001-block-loop-convert-to-per-device-workqueue.patch
@@ -0,0 +1,133 @@
+From ebcacf05168d9791d39c5434164c64b9ef937171 Mon Sep 17 00:00:00 2001
+From: Ming Lei <ming.lei@canonical.com>
+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 <jforbes@fedoraproject.org>
+Signed-off-by: Ming Lei <ming.lei@canonical.com>
+Acked-by: Tejun Heo <tj@kernel.org>
+Signed-off-by: Jens Axboe <axboe@fb.com>
+---
+ 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 d1f168b..fec06d5 100644
+--- a/drivers/block/loop.c
++++ b/drivers/block/loop.c
+@@ -85,8 +85,6 @@ static DEFINE_MUTEX(loop_index_mutex);
+ static int max_part;
+ static int part_shift;
+
+-static struct workqueue_struct *loop_wq;
+-
+ /*
+ * Transfer functions
+ */
+@@ -777,6 +775,12 @@ 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;
+
+@@ -924,6 +928,8 @@ 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.
+@@ -1477,9 +1483,13 @@ 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;
+@@ -1493,9 +1503,9 @@ 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;
+@@ -1507,9 +1517,6 @@ 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;
+
+@@ -1858,13 +1865,6 @@ 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);
+
+@@ -1902,8 +1902,6 @@ 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
+