From 124d6db07c3bd0bdb57ba0e22ff4e5b87e7cb32e Mon Sep 17 00:00:00 2001 From: Josef Bacik Date: Wed, 1 Feb 2017 16:11:11 -0500 Subject: [PATCH] nbd: use our own workqueue for recv threads Since we are in the memory reclaim path we need our recv work to be on a workqueue that has WQ_MEM_RECLAIM set so we can avoid deadlocks. Also set WQ_HIGHPRI since we are in the completion path for IO. Signed-off-by: Josef Bacik Signed-off-by: Jens Axboe --- drivers/block/nbd.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c index 58296e4427b0..94e76579622d 100644 --- a/drivers/block/nbd.c +++ b/drivers/block/nbd.c @@ -91,6 +91,7 @@ static struct dentry *nbd_dbg_dir; static unsigned int nbds_max = 16; static struct nbd_device *nbd_dev; static int max_part; +static struct workqueue_struct *recv_workqueue; static inline struct device *nbd_to_dev(struct nbd_device *nbd) { @@ -781,7 +782,7 @@ static int __nbd_ioctl(struct block_device *bdev, struct nbd_device *nbd, INIT_WORK(&args[i].work, recv_work); args[i].nbd = nbd; args[i].index = i; - queue_work(system_long_wq, &args[i].work); + queue_work(recv_workqueue, &args[i].work); } wait_event_interruptible(nbd->recv_wq, atomic_read(&nbd->recv_threads) == 0); @@ -1030,10 +1031,16 @@ static int __init nbd_init(void) if (nbds_max > 1UL << (MINORBITS - part_shift)) return -EINVAL; + recv_workqueue = alloc_workqueue("knbd-recv", + WQ_MEM_RECLAIM | WQ_HIGHPRI, 0); + if (!recv_workqueue) + return -ENOMEM; nbd_dev = kcalloc(nbds_max, sizeof(*nbd_dev), GFP_KERNEL); - if (!nbd_dev) + if (!nbd_dev) { + destroy_workqueue(recv_workqueue); return -ENOMEM; + } for (i = 0; i < nbds_max; i++) { struct request_queue *q; @@ -1113,6 +1120,7 @@ out: put_disk(nbd_dev[i].disk); } kfree(nbd_dev); + destroy_workqueue(recv_workqueue); return err; } @@ -1132,6 +1140,7 @@ static void __exit nbd_cleanup(void) put_disk(disk); } } + destroy_workqueue(recv_workqueue); unregister_blkdev(NBD_MAJOR, "nbd"); kfree(nbd_dev); printk(KERN_INFO "nbd: unregistered device at major %d\n", NBD_MAJOR);