Patch "PCI/MSI: Ignore affinity if pre/post vector count is more than min_vecs" has been added to the 4.12-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    PCI/MSI: Ignore affinity if pre/post vector count is more than min_vecs

to the 4.12-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     pci-msi-ignore-affinity-if-pre-post-vector-count-is-more-than-min_vecs.patch
and it can be found in the queue-4.12 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 6f9a22bc5775d231ab8fbe2c2f3c88e45e3e7c28 Mon Sep 17 00:00:00 2001
From: Michael Hernandez <michael.hernandez@cavium.com>
Date: Thu, 18 May 2017 10:47:47 -0700
Subject: PCI/MSI: Ignore affinity if pre/post vector count is more than min_vecs

From: Michael Hernandez <michael.hernandez@cavium.com>

commit 6f9a22bc5775d231ab8fbe2c2f3c88e45e3e7c28 upstream.

min_vecs is the minimum amount of vectors needed to operate in MSI-X mode
which may just include the vectors that don't need affinity.

Disabling affinity settings causes the qla2xxx driver scsi_add_host() to fail
when blk_mq is enabled as the blk_mq_pci_map_queues() expects affinity masks
on each vector.

Fixes: dfef358bd1be ("PCI/MSI: Don't apply affinity if there aren't enough vectors left")
Signed-off-by: Michael Hernandez <michael.hernandez@cavium.com>
Signed-off-by: Himanshu Madhani <himanshu.madhani@cavium.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/pci/msi.c         |   14 ++------------
 include/linux/interrupt.h |    4 ++--
 kernel/irq/affinity.c     |   13 ++++++++++++-
 3 files changed, 16 insertions(+), 15 deletions(-)

--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -1058,7 +1058,7 @@ static int __pci_enable_msi_range(struct
 
 	for (;;) {
 		if (affd) {
-			nvec = irq_calc_affinity_vectors(nvec, affd);
+			nvec = irq_calc_affinity_vectors(minvec, nvec, affd);
 			if (nvec < minvec)
 				return -ENOSPC;
 		}
@@ -1097,7 +1097,7 @@ static int __pci_enable_msix_range(struc
 
 	for (;;) {
 		if (affd) {
-			nvec = irq_calc_affinity_vectors(nvec, affd);
+			nvec = irq_calc_affinity_vectors(minvec, nvec, affd);
 			if (nvec < minvec)
 				return -ENOSPC;
 		}
@@ -1165,16 +1165,6 @@ int pci_alloc_irq_vectors_affinity(struc
 	if (flags & PCI_IRQ_AFFINITY) {
 		if (!affd)
 			affd = &msi_default_affd;
-
-		if (affd->pre_vectors + affd->post_vectors > min_vecs)
-			return -EINVAL;
-
-		/*
-		 * If there aren't any vectors left after applying the pre/post
-		 * vectors don't bother with assigning affinity.
-		 */
-		if (affd->pre_vectors + affd->post_vectors == min_vecs)
-			affd = NULL;
 	} else {
 		if (WARN_ON(affd))
 			affd = NULL;
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -291,7 +291,7 @@ extern int
 irq_set_affinity_notifier(unsigned int irq, struct irq_affinity_notify *notify);
 
 struct cpumask *irq_create_affinity_masks(int nvec, const struct irq_affinity *affd);
-int irq_calc_affinity_vectors(int maxvec, const struct irq_affinity *affd);
+int irq_calc_affinity_vectors(int minvec, int maxvec, const struct irq_affinity *affd);
 
 #else /* CONFIG_SMP */
 
@@ -331,7 +331,7 @@ irq_create_affinity_masks(int nvec, cons
 }
 
 static inline int
-irq_calc_affinity_vectors(int maxvec, const struct irq_affinity *affd)
+irq_calc_affinity_vectors(int minvec, int maxvec, const struct irq_affinity *affd)
 {
 	return maxvec;
 }
--- a/kernel/irq/affinity.c
+++ b/kernel/irq/affinity.c
@@ -66,6 +66,13 @@ irq_create_affinity_masks(int nvecs, con
 	struct cpumask *masks;
 	cpumask_var_t nmsk;
 
+	/*
+	 * If there aren't any vectors left after applying the pre/post
+	 * vectors don't bother with assigning affinity.
+	 */
+	if (!affv)
+		return NULL;
+
 	if (!zalloc_cpumask_var(&nmsk, GFP_KERNEL))
 		return NULL;
 
@@ -140,15 +147,19 @@ out:
 
 /**
  * irq_calc_affinity_vectors - Calculate the optimal number of vectors
+ * @minvec:	The minimum number of vectors available
  * @maxvec:	The maximum number of vectors available
  * @affd:	Description of the affinity requirements
  */
-int irq_calc_affinity_vectors(int maxvec, const struct irq_affinity *affd)
+int irq_calc_affinity_vectors(int minvec, int maxvec, const struct irq_affinity *affd)
 {
 	int resv = affd->pre_vectors + affd->post_vectors;
 	int vecs = maxvec - resv;
 	int cpus;
 
+	if (resv > minvec)
+		return 0;
+
 	/* Stabilize the cpumasks */
 	get_online_cpus();
 	cpus = cpumask_weight(cpu_online_mask);


Patches currently in stable-queue which might be from michael.hernandez@cavium.com are

queue-4.12/pci-msi-ignore-affinity-if-pre-post-vector-count-is-more-than-min_vecs.patch