History

genirq/msi: Make interrupt allocation less convoluted

There is no real reason to do several loops over the MSI descriptors instead of just doing one loop. In case of an error everything is undone anyway so it does not matter whether it's a partial or a full rollback.

Thomas Gleixner committed 4 years ago

Commit ef8dd011 parent a80713f3 files · +69 −67Browse files

Unified · Split

3 files
  1. .clang-format +0 −1
  2. include/linux/msi.h +0 −6
  3. kernel/irq/msi.c +69 −60
.clang-format+0−1
@@ -216,7 +216,6 @@ ForEachMacros: · 215 unmodified lines
216216 - 'for_each_migratetype_order'
217217 - 'for_each_msi_entry'
218218 - 'for_each_msi_entry_safe'
219− - 'for_each_msi_vector'
220219 - 'for_each_net'
221220 - 'for_each_net_continue_reverse'
222221 - 'for_each_netdev'
include/linux/msi.h+0−6
@@ -206,12 +206,6 @@ struct msi_desc *msi_next_desc(struct device *dev, enum msi_desc_filter filter); · 205 unmodified lines
206206 list_for_each_entry((desc), dev_to_msi_list((dev)), list)
207207 #define for_each_msi_entry_safe(desc, tmp, dev) \
208208 list_for_each_entry_safe((desc), (tmp), dev_to_msi_list((dev)), list)
209−#define for_each_msi_vector(desc, __irq, dev) \
210− for_each_msi_entry((desc), (dev)) \
211− if ((desc)->irq) \
212− for (__irq = (desc)->irq; \
213− __irq < ((desc)->irq + (desc)->nvec_used); \
214− __irq++)
215209
216210 #ifdef CONFIG_IRQ_MSI_IOMMU
217211 static inline const void *msi_desc_get_iommu_cookie(struct msi_desc *desc)
kernel/irq/msi.c+69−60
@@ -828,23 +828,74 @@ static int msi_handle_pci_fail(struct irq_domain *domain, struct msi_desc *desc, · 827 unmodified lines
828828 return allocated ? allocated : -ENOSPC;
829829 }
830830
831+#define VIRQ_CAN_RESERVE 0x01
832+#define VIRQ_ACTIVATE 0x02
833+#define VIRQ_NOMASK_QUIRK 0x04
834+
835+static int msi_init_virq(struct irq_domain *domain, int virq, unsigned int vflags)
836+{
837+ struct irq_data *irqd = irq_domain_get_irq_data(domain, virq);
838+ int ret;
839+
840+ if (!(vflags & VIRQ_CAN_RESERVE)) {
841+ irqd_clr_can_reserve(irqd);
842+ if (vflags & VIRQ_NOMASK_QUIRK)
843+ irqd_set_msi_nomask_quirk(irqd);
844+ }
845+
846+ if (!(vflags & VIRQ_ACTIVATE))
847+ return 0;
848+
849+ ret = irq_domain_activate_irq(irqd, vflags & VIRQ_CAN_RESERVE);
850+ if (ret)
851+ return ret;
852+ /*
853+ * If the interrupt uses reservation mode, clear the activated bit
854+ * so request_irq() will assign the final vector.
855+ */
856+ if (vflags & VIRQ_CAN_RESERVE)
857+ irqd_clr_activated(irqd);
858+ return 0;
859+}
860+
831861 int __msi_domain_alloc_irqs(struct irq_domain *domain, struct device *dev,
832862 int nvec)
833863 {
834864 struct msi_domain_info *info = domain->host_data;
835865 struct msi_domain_ops *ops = info->ops;
836− struct irq_data *irq_data;
837− struct msi_desc *desc;
838866 msi_alloc_info_t arg = { };
867+ unsigned int vflags = 0;
868+ struct msi_desc *desc;
839869 int allocated = 0;
840870 int i, ret, virq;
841− bool can_reserve;
842871
843872 ret = msi_domain_prepare_irqs(domain, dev, nvec, &arg);
844873 if (ret)
845874 return ret;
846875
847− for_each_msi_entry(desc, dev) {
876+ /*
877+ * This flag is set by the PCI layer as we need to activate
878+ * the MSI entries before the PCI layer enables MSI in the
879+ * card. Otherwise the card latches a random msi message.
880+ */
881+ if (info->flags & MSI_FLAG_ACTIVATE_EARLY)
882+ vflags |= VIRQ_ACTIVATE;
883+
884+ /*
885+ * Interrupt can use a reserved vector and will not occupy
886+ * a real device vector until the interrupt is requested.
887+ */
888+ if (msi_check_reservation_mode(domain, info, dev)) {
889+ vflags |= VIRQ_CAN_RESERVE;
890+ /*
891+ * MSI affinity setting requires a special quirk (X86) when
892+ * reservation mode is active.
893+ */
894+ if (domain->flags & IRQ_DOMAIN_MSI_NOMASK_QUIRK)
895+ vflags |= VIRQ_NOMASK_QUIRK;
896+ }
897+
898+ msi_for_each_desc(desc, dev, MSI_DESC_NOTASSOCIATED) {
848899 ops->set_desc(&arg, desc);
849900
850901 virq = __irq_domain_alloc_irqs(domain, -1, desc->nvec_used,
@@ -856,49 +907,12 @@ int __msi_domain_alloc_irqs(struct irq_domain *domain, struct device *dev, · 5 unmodified lines
856907 for (i = 0; i < desc->nvec_used; i++) {
857908 irq_set_msi_desc_off(virq, i, desc);
858909 irq_debugfs_copy_devname(virq + i, dev);
910+ ret = msi_init_virq(domain, virq + i, vflags);
911+ if (ret)
912+ return ret;
859913 }
860914 allocated++;
861915 }
862−
863− can_reserve = msi_check_reservation_mode(domain, info, dev);
864−
865− /*
866− * This flag is set by the PCI layer as we need to activate
867− * the MSI entries before the PCI layer enables MSI in the
868− * card. Otherwise the card latches a random msi message.
869− */
870− if (!(info->flags & MSI_FLAG_ACTIVATE_EARLY))
871− goto skip_activate;
872−
873− for_each_msi_vector(desc, i, dev) {
874− if (desc->irq == i) {
875− virq = desc->irq;
876− dev_dbg(dev, "irq [%d-%d] for MSI\n",
877− virq, virq + desc->nvec_used - 1);
878− }
879−
880− irq_data = irq_domain_get_irq_data(domain, i);
881− if (!can_reserve) {
882− irqd_clr_can_reserve(irq_data);
883− if (domain->flags & IRQ_DOMAIN_MSI_NOMASK_QUIRK)
884− irqd_set_msi_nomask_quirk(irq_data);
885− }
886− ret = irq_domain_activate_irq(irq_data, can_reserve);
887− if (ret)
888− return ret;
889− }
890−
891−skip_activate:
892− /*
893− * If these interrupts use reservation mode, clear the activated bit
894− * so request_irq() will assign the final vector.
895− */
896− if (can_reserve) {
897− for_each_msi_vector(desc, i, dev) {
898− irq_data = irq_domain_get_irq_data(domain, i);
899− irqd_clr_activated(irq_data);
900− }
901− }
902916 return 0;
903917 }
904918
@@ -976,26 +990,21 @@ int msi_domain_alloc_irqs(struct irq_domain *domain, struct device *dev, int nve · 71 unmodified lines
976990
977991 void __msi_domain_free_irqs(struct irq_domain *domain, struct device *dev)
978992 {
979− struct irq_data *irq_data;
993+ struct irq_data *irqd;
980994 struct msi_desc *desc;
981995 int i;
982996
983− for_each_msi_vector(desc, i, dev) {
984− irq_data = irq_domain_get_irq_data(domain, i);
985− if (irqd_is_activated(irq_data))
986− irq_domain_deactivate_irq(irq_data);
987− }
988−
989− for_each_msi_entry(desc, dev) {
990− /*
991− * We might have failed to allocate an MSI early
992− * enough that there is no IRQ associated to this
993− * entry. If that's the case, don't do anything.
994− */
995− if (desc->irq) {
996− irq_domain_free_irqs(desc->irq, desc->nvec_used);
997− desc->irq = 0;
997+ /* Only handle MSI entries which have an interrupt associated */
998+ msi_for_each_desc(desc, dev, MSI_DESC_ASSOCIATED) {
999+ /* Make sure all interrupts are deactivated */
1000+ for (i = 0; i < desc->nvec_used; i++) {
1001+ irqd = irq_domain_get_irq_data(domain, desc->irq + i);
1002+ if (irqd && irqd_is_activated(irqd))
1003+ irq_domain_deactivate_irq(irqd);
9981004 }
1005+
1006+ irq_domain_free_irqs(desc->irq, desc->nvec_used);
1007+ desc->irq = 0;
9991008 }
10001009 }
10011010