From: Nitzan Carmi Date: Mon, 9 Apr 2018 14:50:26 +0000 (+0300) Subject: nvme: Avoid flush dependency in delete controller flow X-Git-Tag: for-linus-20180616~111^2~1^2^2~2 X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=4317228ad9b86f094d70c951f9210a8a9b2816be;p=linux-block.git nvme: Avoid flush dependency in delete controller flow The nvme_delete_ctrl() function queues a work item on a MEM_RECLAIM queue (nvme_delete_wq), which eventually calls cleanup_srcu_struct(), which in turn flushes a delayed work from an !MEM_RECLAIM queue. This is unsafe as we might trigger deadlocks under severe memory pressure. Since we don't ever invoke call_srcu(), it is safe to use the shiny new _quiesced() version of srcu cleanup, thus avoiding that flush dependency. This commit makes that change. Signed-off-by: Nitzan Carmi Signed-off-by: Paul E. McKenney Reviewed-by: Max Gurtovoy Tested-by: Nicholas Piggin --- diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c index 9df4f71e58ca..c3cea8a29843 100644 --- a/drivers/nvme/host/core.c +++ b/drivers/nvme/host/core.c @@ -349,7 +349,7 @@ static void nvme_free_ns_head(struct kref *ref) nvme_mpath_remove_disk(head); ida_simple_remove(&head->subsys->ns_ida, head->instance); list_del_init(&head->entry); - cleanup_srcu_struct(&head->srcu); + cleanup_srcu_struct_quiesced(&head->srcu); kfree(head); }