5.4-stable patches

added patches:
	nvme-mpath-replace-direct_make_request-with-generic_make_request.patch

diff --git a/queue-5.4/nvme-mpath-replace-direct_make_request-with-generic_make_request.patch b/queue-5.4/nvme-mpath-replace-direct_make_request-with-generic_make_request.patch
new file mode 100644 (file)
index 0000000..1b8d397
--- /dev/null
+++ b/queue-5.4/nvme-mpath-replace-direct_make_request-with-generic_make_request.patch
@@ -0,0 +1,82 @@
+From sagi@grimberg.me  Fri Apr  9 11:33:14 2021
+From: Sagi Grimberg <sagi@grimberg.me>
+Date: Fri,  2 Apr 2021 13:08:41 -0700
+Subject: nvme-mpath: replace direct_make_request with generic_make_request
+To: <stable@vger.kernel.org>
+Cc: Christoph Hellwig <hch@lst.de>, Keith Busch <kbusch@kernel.org>, linux-nvme@lists.infradead.org
+Message-ID: <20210402200841.347696-1-sagi@grimberg.me>
+
+From: Sagi Grimberg <sagi@grimberg.me>
+
+The below patches caused a regression in a multipath setup:
+Fixes: 9f98772ba307 ("nvme-rdma: fix controller reset hang during traffic")
+Fixes: 2875b0aecabe ("nvme-tcp: fix controller reset hang during traffic")
+
+These patches on their own are correct because they fixed a controller reset
+regression.
+
+When we reset/teardown a controller, we must freeze and quiesce the namespaces
+request queues to make sure that we safely stop inflight I/O submissions.
+Freeze is mandatory because if our hctx map changed between reconnects,
+blk_mq_update_nr_hw_queues will immediately attempt to freeze the queue, and
+if it still has pending submissions (that are still quiesced) it will hang.
+This is what the above patches fixed.
+
+However, by freezing the namespaces request queues, and only unfreezing them
+when we successfully reconnect, inflight submissions that are running
+concurrently can now block grabbing the nshead srcu until either we successfully
+reconnect or ctrl_loss_tmo expired (or the user explicitly disconnected).
+
+This caused a deadlock [1] when a different controller (different path on the
+same subsystem) became live (i.e. optimized/non-optimized). This is because
+nvme_mpath_set_live needs to synchronize the nshead srcu before requeueing I/O
+in order to make sure that current_path is visible to future (re)submisions.
+However the srcu lock is taken by a blocked submission on a frozen request
+queue, and we have a deadlock.
+
+In recent kernels (v5.9+) direct_make_request was replaced by submit_bio_noacct
+which does not have this issue because it bio_list will be active when
+nvme-mpath calls submit_bio_noacct on the bottom device (because it was
+populated when submit_bio was triggered on it.
+
+Hence, we need to fix all the kernels that were before submit_bio_noacct was
+introduced.
+
+[1]:
+Workqueue: nvme-wq nvme_tcp_reconnect_ctrl_work [nvme_tcp]
+Call Trace:
+ __schedule+0x293/0x730
+ schedule+0x33/0xa0
+ schedule_timeout+0x1d3/0x2f0
+ wait_for_completion+0xba/0x140
+ __synchronize_srcu.part.21+0x91/0xc0
+ synchronize_srcu_expedited+0x27/0x30
+ synchronize_srcu+0xce/0xe0
+ nvme_mpath_set_live+0x64/0x130 [nvme_core]
+ nvme_update_ns_ana_state+0x2c/0x30 [nvme_core]
+ nvme_update_ana_state+0xcd/0xe0 [nvme_core]
+ nvme_parse_ana_log+0xa1/0x180 [nvme_core]
+ nvme_read_ana_log+0x76/0x100 [nvme_core]
+ nvme_mpath_init+0x122/0x180 [nvme_core]
+ nvme_init_identify+0x80e/0xe20 [nvme_core]
+ nvme_tcp_setup_ctrl+0x359/0x660 [nvme_tcp]
+ nvme_tcp_reconnect_ctrl_work+0x24/0x70 [nvme_tcp]
+
+Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ drivers/nvme/host/multipath.c |    2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+--- a/drivers/nvme/host/multipath.c
++++ b/drivers/nvme/host/multipath.c
+@@ -330,7 +330,7 @@ static blk_qc_t nvme_ns_head_make_reques
+               trace_block_bio_remap(bio->bi_disk->queue, bio,
+                                     disk_devt(ns->head->disk),
+                                     bio->bi_iter.bi_sector);
+-              ret = direct_make_request(bio);
++              ret = generic_make_request(bio);
+       } else if (nvme_available_path(head)) {
+               dev_warn_ratelimited(dev, "no usable path - requeuing I/O\n");
+ 

diff --git a/queue-5.4/series b/queue-5.4/series
index ba389a891d0fe95defc58be89f3d69b23d398891..05c5945c12bdb5aef471659c8adcf7fa160210e0 100644 (file)
--- a/queue-5.4/series
+++ b/queue-5.4/series
@@ -18,3 +18,4 @@ cifs-revalidate-mapping-when-we-open-files-for-smb1-.patch
 cifs-silently-ignore-unknown-oplock-break-handle.patch
 bpf-x86-validate-computation-of-branch-displacements-for-x86-64.patch
 bpf-x86-validate-computation-of-branch-displacements-for-x86-32.patch
+nvme-mpath-replace-direct_make_request-with-generic_make_request.patch