4.14-stable patches

added patches:
	scsi-virtio_scsi-limit-number-of-hw-queues-by-nr_cpu_ids.patch

diff --git a/queue-4.14/scsi-virtio_scsi-limit-number-of-hw-queues-by-nr_cpu_ids.patch b/queue-4.14/scsi-virtio_scsi-limit-number-of-hw-queues-by-nr_cpu_ids.patch
new file mode 100644 (file)
index 0000000..074a0d3
--- /dev/null
+++ b/queue-4.14/scsi-virtio_scsi-limit-number-of-hw-queues-by-nr_cpu_ids.patch
@@ -0,0 +1,41 @@
+From 1978f30a87732d4d9072a20abeded9fe17884f1b Mon Sep 17 00:00:00 2001
+From: Dongli Zhang <dongli.zhang@oracle.com>
+Date: Wed, 27 Mar 2019 18:36:35 +0800
+Subject: scsi: virtio_scsi: limit number of hw queues by nr_cpu_ids
+
+From: Dongli Zhang <dongli.zhang@oracle.com>
+
+commit 1978f30a87732d4d9072a20abeded9fe17884f1b upstream.
+
+When tag_set->nr_maps is 1, the block layer limits the number of hw queues
+by nr_cpu_ids. No matter how many hw queues are used by virtio-scsi, as it
+has (tag_set->nr_maps == 1), it can use at most nr_cpu_ids hw queues.
+
+In addition, specifically for pci scenario, when the 'num_queues' specified
+by qemu is more than maxcpus, virtio-scsi would not be able to allocate
+more than maxcpus vectors in order to have a vector for each queue. As a
+result, it falls back into MSI-X with one vector for config and one shared
+for queues.
+
+Considering above reasons, this patch limits the number of hw queues used
+by virtio-scsi by nr_cpu_ids.
+
+Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
+Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com>
+Signed-off-by: Jens Axboe <axboe@kernel.dk>
+Signed-off-by: Kunkun Jiang <jiangkunkun@huawei.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ drivers/scsi/virtio_scsi.c |    1 +
+ 1 file changed, 1 insertion(+)
+
+--- a/drivers/scsi/virtio_scsi.c
++++ b/drivers/scsi/virtio_scsi.c
+@@ -891,6 +891,7 @@ static int virtscsi_probe(struct virtio_
+ 
+       /* We need to know how many queues before we allocate. */
+       num_queues = virtscsi_config_get(vdev, num_queues) ? : 1;
++      num_queues = min_t(unsigned int, nr_cpu_ids, num_queues);
+ 
+       num_targets = virtscsi_config_get(vdev, max_target) + 1;
+ 

diff --git a/queue-4.14/series b/queue-4.14/series
index 3b3297b1ff644026627bb89c10cadac978e0b5b5..4ab61e978b435163763913ac250a083867fb2516 100644 (file)
--- a/queue-4.14/series
+++ b/queue-4.14/series
@@ -53,3 +53,4 @@ ext4-apply-umask-if-acl-support-is-disabled.patch
 ext4-correct-offset-of-gdb-backup-in-non-meta_bg-group-to-update_backups.patch
 ext4-correct-return-value-of-ext4_convert_meta_bg.patch
 ext4-remove-gdb-backup-copy-for-meta-bg-in-setup_new_flex_group_blocks.patch
+scsi-virtio_scsi-limit-number-of-hw-queues-by-nr_cpu_ids.patch