[patch V2 07/31] PCI/MSI: Protect MSI operations

[Thomas Gleixner <tglx@xxxxxxxxxxxxx>]

To prepare for dynamic extension of MSI-X vectors, protect the MSI
operations for MSI and MSI-X. This requires to move the invocation of
irq_create_affinity_masks() out of the descriptor lock section to avoid
reverse lock ordering vs. CPU hotplug lock as some callers of the PCI/MSI
allocation interfaces already hold it.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
---
 drivers/pci/msi/irqdomain.c |    4 -
 drivers/pci/msi/msi.c       |  120 ++++++++++++++++++++++++++------------------
 2 files changed, 73 insertions(+), 51 deletions(-)

--- a/drivers/pci/msi/irqdomain.c
+++ b/drivers/pci/msi/irqdomain.c
@@ -14,7 +14,7 @@ int pci_msi_setup_msi_irqs(struct pci_de
 
        domain = dev_get_msi_domain(&dev->dev);
        if (domain && irq_domain_is_hierarchy(domain))
-               return msi_domain_alloc_irqs(domain, &dev->dev, nvec);
+               return msi_domain_alloc_irqs_descs_locked(domain, &dev->dev, 
nvec);
 
        return pci_msi_legacy_setup_msi_irqs(dev, nvec, type);
 }
@@ -25,7 +25,7 @@ void pci_msi_teardown_msi_irqs(struct pc
 
        domain = dev_get_msi_domain(&dev->dev);
        if (domain && irq_domain_is_hierarchy(domain))
-               msi_domain_free_irqs(domain, &dev->dev);
+               msi_domain_free_irqs_descs_locked(domain, &dev->dev);
        else
                pci_msi_legacy_teardown_msi_irqs(dev);
 }
--- a/drivers/pci/msi/msi.c
+++ b/drivers/pci/msi/msi.c
@@ -322,11 +322,13 @@ static void __pci_restore_msix_state(str
 
        write_msg = arch_restore_msi_irqs(dev);
 
+       msi_lock_descs(&dev->dev);
        for_each_pci_msi_entry(entry, dev) {
                if (write_msg)
                        __pci_write_msi_msg(entry, &entry->msg);
                pci_msix_write_vector_ctrl(entry, entry->pci.msix_ctrl);
        }
+       msi_unlock_descs(&dev->dev);
 
        pci_msix_clear_and_set_ctrl(dev, PCI_MSIX_FLAGS_MASKALL, 0);
 }
@@ -339,20 +341,16 @@ void pci_restore_msi_state(struct pci_de
 EXPORT_SYMBOL_GPL(pci_restore_msi_state);
 
 static struct msi_desc *
-msi_setup_entry(struct pci_dev *dev, int nvec, struct irq_affinity *affd)
+msi_setup_entry(struct pci_dev *dev, int nvec, struct irq_affinity_desc *masks)
 {
-       struct irq_affinity_desc *masks = NULL;
        struct msi_desc *entry;
        unsigned long prop;
        u16 control;
 
-       if (affd)
-               masks = irq_create_affinity_masks(nvec, affd);
-
        /* MSI Entry Initialization */
        entry = alloc_msi_entry(&dev->dev, nvec, masks);
        if (!entry)
-               goto out;
+               return NULL;
 
        pci_read_config_word(dev, dev->msi_cap + PCI_MSI_FLAGS, &control);
        /* Lies, damned lies, and MSIs */
@@ -379,8 +377,7 @@ msi_setup_entry(struct pci_dev *dev, int
        if (entry->pci.msi_attrib.is_64)
                prop |= MSI_PROP_64BIT;
        msi_device_set_properties(&dev->dev, prop);
-out:
-       kfree(masks);
+
        return entry;
 }
 
@@ -416,14 +413,21 @@ static int msi_verify_entries(struct pci
 static int msi_capability_init(struct pci_dev *dev, int nvec,
                               struct irq_affinity *affd)
 {
+       struct irq_affinity_desc *masks = NULL;
        struct msi_desc *entry;
        int ret;
 
        pci_msi_set_enable(dev, 0);     /* Disable MSI during set up */
 
-       entry = msi_setup_entry(dev, nvec, affd);
-       if (!entry)
-               return -ENOMEM;
+       if (affd)
+               masks = irq_create_affinity_masks(nvec, affd);
+
+       msi_lock_descs(&dev->dev);
+       entry = msi_setup_entry(dev, nvec, masks);
+       if (!entry) {
+               ret = -ENOMEM;
+               goto unlock;
+       }
 
        /* All MSIs are unmasked by default; mask them all */
        pci_msi_mask(entry, msi_multi_mask(entry));
@@ -446,11 +450,14 @@ static int msi_capability_init(struct pc
 
        pcibios_free_irq(dev);
        dev->irq = entry->irq;
-       return 0;
+       goto unlock;
 
 err:
        pci_msi_unmask(entry, msi_multi_mask(entry));
        free_msi_irqs(dev);
+unlock:
+       msi_unlock_descs(&dev->dev);
+       kfree(masks);
        return ret;
 }
 
@@ -477,23 +484,18 @@ static void __iomem *msix_map_region(str
 
 static int msix_setup_entries(struct pci_dev *dev, void __iomem *base,
                              struct msix_entry *entries, int nvec,
-                             struct irq_affinity *affd)
+                             struct irq_affinity_desc *masks)
 {
-       struct irq_affinity_desc *curmsk, *masks = NULL;
+       int i, vec_count = pci_msix_vec_count(dev);
+       struct irq_affinity_desc *curmsk;
        struct msi_desc *entry;
        void __iomem *addr;
-       int ret, i;
-       int vec_count = pci_msix_vec_count(dev);
-
-       if (affd)
-               masks = irq_create_affinity_masks(nvec, affd);
 
        for (i = 0, curmsk = masks; i < nvec; i++) {
                entry = alloc_msi_entry(&dev->dev, 1, curmsk);
                if (!entry) {
                        /* No enough memory. Don't try again */
-                       ret = -ENOMEM;
-                       goto out;
+                       return -ENOMEM;
                }
 
                entry->pci.msi_attrib.is_msix   = 1;
@@ -522,10 +524,7 @@ static int msix_setup_entries(struct pci
                        curmsk++;
        }
        msi_device_set_properties(&dev->dev, MSI_PROP_PCI_MSIX | 
MSI_PROP_64BIT);
-       ret = 0;
-out:
-       kfree(masks);
-       return ret;
+       return 0;
 }
 
 static void msix_update_entries(struct pci_dev *dev, struct msix_entry 
*entries)
@@ -552,6 +551,41 @@ static void msix_mask_all(void __iomem *
                writel(ctrl, base + PCI_MSIX_ENTRY_VECTOR_CTRL);
 }
 
+static int msix_setup_interrupts(struct pci_dev *dev, void __iomem *base,
+                                struct msix_entry *entries, int nvec,
+                                struct irq_affinity *affd)
+{
+       struct irq_affinity_desc *masks = NULL;
+       int ret;
+
+       if (affd)
+               masks = irq_create_affinity_masks(nvec, affd);
+
+       msi_lock_descs(&dev->dev);
+       ret = msix_setup_entries(dev, base, entries, nvec, masks);
+       if (ret)
+               goto out_free;
+
+       ret = pci_msi_setup_msi_irqs(dev, nvec, PCI_CAP_ID_MSIX);
+       if (ret)
+               goto out_free;
+
+       /* Check if all MSI entries honor device restrictions */
+       ret = msi_verify_entries(dev);
+       if (ret)
+               goto out_free;
+
+       msix_update_entries(dev, entries);
+       goto out_unlock;
+
+out_free:
+       free_msi_irqs(dev);
+out_unlock:
+       msi_unlock_descs(&dev->dev);
+       kfree(masks);
+       return ret;
+}
+
 /**
  * msix_capability_init - configure device's MSI-X capability
  * @dev: pointer to the pci_dev data structure of MSI-X device function
@@ -592,20 +626,9 @@ static int msix_capability_init(struct p
        /* Ensure that all table entries are masked. */
        msix_mask_all(base, tsize);
 
-       ret = msix_setup_entries(dev, base, entries, nvec, affd);
+       ret = msix_setup_interrupts(dev, base, entries, nvec, affd);
        if (ret)
-               goto out_free;
-
-       ret = pci_msi_setup_msi_irqs(dev, nvec, PCI_CAP_ID_MSIX);
-       if (ret)
-               goto out_free;
-
-       /* Check if all MSI entries honor device restrictions */
-       ret = msi_verify_entries(dev);
-       if (ret)
-               goto out_free;
-
-       msix_update_entries(dev, entries);
+               goto out_disable;
 
        /* Set MSI-X enabled bits and unmask the function */
        pci_intx_for_msi(dev, 0);
@@ -615,12 +638,8 @@ static int msix_capability_init(struct p
        pcibios_free_irq(dev);
        return 0;
 
-out_free:
-       free_msi_irqs(dev);
-
 out_disable:
        pci_msix_clear_and_set_ctrl(dev, PCI_MSIX_FLAGS_ENABLE, 0);
-
        return ret;
 }
 
@@ -725,8 +744,10 @@ void pci_disable_msi(struct pci_dev *dev
        if (!pci_msi_enable || !dev || !dev->msi_enabled)
                return;
 
+       msi_lock_descs(&dev->dev);
        pci_msi_shutdown(dev);
        free_msi_irqs(dev);
+       msi_unlock_descs(&dev->dev);
 }
 EXPORT_SYMBOL(pci_disable_msi);
 
@@ -812,8 +833,10 @@ void pci_disable_msix(struct pci_dev *de
        if (!pci_msi_enable || !dev || !dev->msix_enabled)
                return;
 
+       msi_lock_descs(&dev->dev);
        pci_msix_shutdown(dev);
        free_msi_irqs(dev);
+       msi_unlock_descs(&dev->dev);
 }
 EXPORT_SYMBOL(pci_disable_msix);
 
@@ -874,7 +897,6 @@ int pci_enable_msi(struct pci_dev *dev)
 
        if (!rc)
                rc = __pci_enable_msi_range(dev, 1, 1, NULL);
-
        return rc < 0 ? rc : 0;
 }
 EXPORT_SYMBOL(pci_enable_msi);
@@ -961,11 +983,7 @@ int pci_alloc_irq_vectors_affinity(struc
                                   struct irq_affinity *affd)
 {
        struct irq_affinity msi_default_affd = {0};
-       int ret = msi_setup_device_data(&dev->dev);
-       int nvecs = -ENOSPC;
-
-       if (ret)
-               return ret;
+       int ret, nvecs;
 
        if (flags & PCI_IRQ_AFFINITY) {
                if (!affd)
@@ -975,6 +993,10 @@ int pci_alloc_irq_vectors_affinity(struc
                        affd = NULL;
        }
 
+       ret = msi_setup_device_data(&dev->dev);
+       if (ret)
+               return ret;
+
        if (flags & PCI_IRQ_MSIX) {
                nvecs = __pci_enable_msix_range(dev, NULL, min_vecs, max_vecs,
                                                affd, flags);
@@ -1003,7 +1025,7 @@ int pci_alloc_irq_vectors_affinity(struc
                }
        }
 
-       return nvecs;
+       return -ENOSPC;
 }
 EXPORT_SYMBOL(pci_alloc_irq_vectors_affinity);