4.19-stable patches

added patches:
	blk-mq-punt-failed-direct-issue-to-dispatch-list.patch

diff --git a/queue-4.19/blk-mq-punt-failed-direct-issue-to-dispatch-list.patch b/queue-4.19/blk-mq-punt-failed-direct-issue-to-dispatch-list.patch
new file mode 100644 (file)
index 0000000..adf054e
--- /dev/null
+++ b/queue-4.19/blk-mq-punt-failed-direct-issue-to-dispatch-list.patch
@@ -0,0 +1,124 @@
+From c616cbee97aed4bc6178f148a7240206dcdb85a6 Mon Sep 17 00:00:00 2001
+From: Jens Axboe <axboe@kernel.dk>
+Date: Thu, 6 Dec 2018 22:17:44 -0700
+Subject: blk-mq: punt failed direct issue to dispatch list
+
+From: Jens Axboe <axboe@kernel.dk>
+
+commit c616cbee97aed4bc6178f148a7240206dcdb85a6 upstream.
+
+After the direct dispatch corruption fix, we permanently disallow direct
+dispatch of non read/write requests. This works fine off the normal IO
+path, as they will be retried like any other failed direct dispatch
+request. But for the blk_insert_cloned_request() that only DM uses to
+bypass the bottom level scheduler, we always first attempt direct
+dispatch. For some types of requests, that's now a permanent failure,
+and no amount of retrying will make that succeed. This results in a
+livelock.
+
+Instead of making special cases for what we can direct issue, and now
+having to deal with DM solving the livelock while still retaining a BUSY
+condition feedback loop, always just add a request that has been through
+->queue_rq() to the hardware queue dispatch list. These are safe to use
+as no merging can take place there. Additionally, if requests do have
+prepped data from drivers, we aren't dependent on them not sharing space
+in the request structure to safely add them to the IO scheduler lists.
+
+This basically reverts ffe81d45322c and is based on a patch from Ming,
+but with the list insert case covered as well.
+
+Fixes: ffe81d45322c ("blk-mq: fix corruption with direct issue")
+Cc: stable@vger.kernel.org
+Suggested-by: Ming Lei <ming.lei@redhat.com>
+Reported-by: Bart Van Assche <bvanassche@acm.org>
+Tested-by: Ming Lei <ming.lei@redhat.com>
+Acked-by: Mike Snitzer <snitzer@redhat.com>
+Signed-off-by: Jens Axboe <axboe@kernel.dk>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ block/blk-mq.c |   33 +++++----------------------------
+ 1 file changed, 5 insertions(+), 28 deletions(-)
+
+--- a/block/blk-mq.c
++++ b/block/blk-mq.c
+@@ -1698,15 +1698,6 @@ static blk_status_t __blk_mq_issue_direc
+               break;
+       case BLK_STS_RESOURCE:
+       case BLK_STS_DEV_RESOURCE:
+-              /*
+-               * If direct dispatch fails, we cannot allow any merging on
+-               * this IO. Drivers (like SCSI) may have set up permanent state
+-               * for this request, like SG tables and mappings, and if we
+-               * merge to it later on then we'll still only do IO to the
+-               * original part.
+-               */
+-              rq->cmd_flags |= REQ_NOMERGE;
+-
+               blk_mq_update_dispatch_busy(hctx, true);
+               __blk_mq_requeue_request(rq);
+               break;
+@@ -1719,18 +1710,6 @@ static blk_status_t __blk_mq_issue_direc
+       return ret;
+ }
+ 
+-/*
+- * Don't allow direct dispatch of anything but regular reads/writes,
+- * as some of the other commands can potentially share request space
+- * with data we need for the IO scheduler. If we attempt a direct dispatch
+- * on those and fail, we can't safely add it to the scheduler afterwards
+- * without potentially overwriting data that the driver has already written.
+- */
+-static bool blk_rq_can_direct_dispatch(struct request *rq)
+-{
+-      return req_op(rq) == REQ_OP_READ || req_op(rq) == REQ_OP_WRITE;
+-}
+-
+ static blk_status_t __blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx,
+                                               struct request *rq,
+                                               blk_qc_t *cookie,
+@@ -1752,7 +1731,7 @@ static blk_status_t __blk_mq_try_issue_d
+               goto insert;
+       }
+ 
+-      if (!blk_rq_can_direct_dispatch(rq) || (q->elevator && !bypass_insert))
++      if (q->elevator && !bypass_insert)
+               goto insert;
+ 
+       if (!blk_mq_get_dispatch_budget(hctx))
+@@ -1768,7 +1747,7 @@ insert:
+       if (bypass_insert)
+               return BLK_STS_RESOURCE;
+ 
+-      blk_mq_sched_insert_request(rq, false, run_queue, false);
++      blk_mq_request_bypass_insert(rq, run_queue);
+       return BLK_STS_OK;
+ }
+ 
+@@ -1784,7 +1763,7 @@ static void blk_mq_try_issue_directly(st
+ 
+       ret = __blk_mq_try_issue_directly(hctx, rq, cookie, false);
+       if (ret == BLK_STS_RESOURCE || ret == BLK_STS_DEV_RESOURCE)
+-              blk_mq_sched_insert_request(rq, false, true, false);
++              blk_mq_request_bypass_insert(rq, true);
+       else if (ret != BLK_STS_OK)
+               blk_mq_end_request(rq, ret);
+ 
+@@ -1814,15 +1793,13 @@ void blk_mq_try_issue_list_directly(stru
+               struct request *rq = list_first_entry(list, struct request,
+                               queuelist);
+ 
+-              if (!blk_rq_can_direct_dispatch(rq))
+-                      break;
+-
+               list_del_init(&rq->queuelist);
+               ret = blk_mq_request_issue_directly(rq);
+               if (ret != BLK_STS_OK) {
+                       if (ret == BLK_STS_RESOURCE ||
+                                       ret == BLK_STS_DEV_RESOURCE) {
+-                              list_add(&rq->queuelist, list);
++                              blk_mq_request_bypass_insert(rq,
++                                                      list_empty(list));
+                               break;
+                       }
+                       blk_mq_end_request(rq, ret);

diff --git a/queue-4.19/series b/queue-4.19/series
index 28b6bcd4ab2732518d6fad86059ae0a51719d422..c1bb9675d7ec76278f9fe0759f1f1676f70ec706 100644 (file)
--- a/queue-4.19/series
+++ b/queue-4.19/series
@@ -38,3 +38,4 @@ btrfs-tree-checker-don-t-check-max-block-group-size-as-current-max-chunk-size-li
 arc-change-defconfig-defaults-to-arcv2.patch
 arc-add-support-of-nfsv3-acl.patch
 tipc-use-destination-length-for-copy-string.patch
+blk-mq-punt-failed-direct-issue-to-dispatch-list.patch