!1287 scsi: virtio_scsi: limit number of hw queues by nr_cpu_ids

From: @did-you-collect-the-wool-today 
Reviewed-by: @yuzenghui, @Lostwayzxc 
Signed-off-by: @Lostwayzxc

kernel.spec

@@ -32,7 +32,7 @@
 
 Name:	 kernel
 Version: 4.19.90
-Release: %{hulkrelease}.0237
+Release: %{hulkrelease}.0238
 Summary: Linux Kernel
 License: GPLv2
 URL:	 http://www.kernel.org/
@@ -836,6 +836,9 @@ fi
 %endif
 
 %changelog
+* Thu Nov 9 2023 Kunkun Jiang <jiangkunkun@huawei.com> - 4.19.90-2311.1.0.0238
+- scsi: virtio_scsi: limit number of hw queues by nr_cpu_ids
+
 * Tue Nov 7 2023 YaQiang Chen <chenyaqiang@huawei.com> - 4.19.90-2311.1.0.0237
 - spec: fix the problem that patches are not packaged in src.rpm
 

patches/0117-scsi-virtio_scsi-limit-number-of-hw-queues-by-nr_cpu.patch

@@ -0,0 +1,52 @@
+From 0e50e0bfb9bef1d26243038f0714db65a2c0e9a5 Mon Sep 17 00:00:00 2001
+From: Dongli Zhang <dongli.zhang@oracle.com>
+Date: Wed, 27 Mar 2019 18:36:35 +0800
+Subject: [PATCH] scsi: virtio_scsi: limit number of hw queues by nr_cpu_ids
+
+mainline inclusion
+from mainline-v5.1-rc2
+commit 1978f30a87732d4d9072a20abeded9fe17884f1b
+category: bugfix
+bugzilla: https://gitee.com/openeuler/kernel/issues/I8F6P4
+CVE: NA
+
+Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=1978f30a87732d4d9072a20abeded9fe17884f1b
+
+-----------------------------------
+
+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>
+---
+ drivers/scsi/virtio_scsi.c | 1 +
+ 1 file changed, 1 insertion(+)
+
+diff --git a/drivers/scsi/virtio_scsi.c b/drivers/scsi/virtio_scsi.c
+index 8118c06f491b..ba84514b662a 100644
+--- a/drivers/scsi/virtio_scsi.c
++++ b/drivers/scsi/virtio_scsi.c
+@@ -858,6 +858,7 @@ static int virtscsi_probe(struct virtio_device *vdev)
+ 
+ 	/* 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;
+ 
+-- 
+2.27.0
+

series.conf

@@ -117,3 +117,4 @@ patches/0113-perf-auxtrace-arm-Refactor-event-list-iteration-in-a.patch
 patches/0114-perf-auxtrace-arm64-Add-support-for-HiSilicon-PCIe-T.patch
 patches/0115-perf-auxtrace-arm64-Add-support-for-parsing-HiSilico.patch
 patches/0116-Fix-the-header-file-location-error-and-adjust-the-fu.patch
+patches/0117-scsi-virtio_scsi-limit-number-of-hw-queues-by-nr_cpu.patch