Commit 6f9a22bc authored by Michael Hernandez's avatar Michael Hernandez Committed by Bjorn Helgaas
Browse files

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



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: dfef358b ("PCI/MSI: Don't apply affinity if there aren't enough vectors left")
Signed-off-by: default avatarMichael Hernandez <michael.hernandez@cavium.com>
Signed-off-by: default avatarHimanshu Madhani <himanshu.madhani@cavium.com>
Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Cc: stable@vger.kernel.org	# v4.10+
parent 2ea659a9

drivers/pci/msi.c

+2 −12
Original line number Diff line number Diff line
@@ -1058,7 +1058,7 @@ static int __pci_enable_msi_range(struct pci_dev *dev, int minvec, int maxvec, 


	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(struct pci_dev *dev, 


	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(struct pci_dev *dev, unsigned int min_vecs, 
	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;

include/linux/interrupt.h

+2 −2
Original line number Diff line number Diff line
@@ -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, const struct irq_affinity *affd) 
}



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;

}

kernel/irq/affinity.c

+12 −1
Original line number Diff line number Diff line
@@ -66,6 +66,13 @@ irq_create_affinity_masks(int nvecs, const struct irq_affinity *affd) 
	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);

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