PCI/MSI: Sanitize MSI-X checks

There is no point in doing the same sanity checks over and over in a loop
during MSI-X enablement. Put them in front of the loop and return early
when they fail.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://lore.kernel.org/r/20221111122015.516946468@linutronix.de

diff --git a/drivers/pci/msi/msi.c b/drivers/pci/msi/msi.c
index 380e65155b931ae6b687343af15352928767cfad..794ec97c5b7053246fb6d4ca1666a1aad7a87721 100644 (file)
--- a/drivers/pci/msi/msi.c
+++ b/drivers/pci/msi/msi.c
@@ -721,47 +721,31 @@ out_disable:
        return ret;
 }
 
-static int __pci_enable_msix(struct pci_dev *dev, struct msix_entry *entries,
-                            int nvec, struct irq_affinity *affd, int flags)
+static bool pci_msix_validate_entries(struct msix_entry *entries, int nvec, int hwsize)
 {
-       int nr_entries;
        int i, j;
 
-       if (!pci_msi_supported(dev, nvec) || dev->current_state != PCI_D0)
-               return -EINVAL;
+       if (!entries)
+               return true;
 
-       nr_entries = pci_msix_vec_count(dev);
-       if (nr_entries < 0)
-               return nr_entries;
-       if (nvec > nr_entries && !(flags & PCI_IRQ_VIRTUAL))
-               return nr_entries;
+       for (i = 0; i < nvec; i++) {
+               /* Entry within hardware limit? */
+               if (entries[i].entry >= hwsize)
+                       return false;
 
-       if (entries) {
-               /* Check for any invalid entries */
-               for (i = 0; i < nvec; i++) {
-                       if (entries[i].entry >= nr_entries)
-                               return -EINVAL;         /* invalid entry */
-                       for (j = i + 1; j < nvec; j++) {
-                               if (entries[i].entry == entries[j].entry)
-                                       return -EINVAL; /* duplicate entry */
-                       }
+               /* Check for duplicate entries */
+               for (j = i + 1; j < nvec; j++) {
+                       if (entries[i].entry == entries[j].entry)
+                               return false;
                }
        }
-
-       /* Check whether driver already requested for MSI IRQ */
-       if (dev->msi_enabled) {
-               pci_info(dev, "can't enable MSI-X (MSI IRQ already assigned)\n");
-               return -EINVAL;
-       }
-       return msix_capability_init(dev, entries, nvec, affd);
+       return true;
 }
 
-int __pci_enable_msix_range(struct pci_dev *dev,
-                           struct msix_entry *entries, int minvec,
-                           int maxvec, struct irq_affinity *affd,
-                           int flags)
+int __pci_enable_msix_range(struct pci_dev *dev, struct msix_entry *entries, int minvec,
+                           int maxvec, struct irq_affinity *affd, int flags)
 {
-       int rc, nvec = maxvec;
+       int hwsize, rc, nvec = maxvec;
 
        if (maxvec < minvec)
                return -ERANGE;
@@ -774,6 +758,23 @@ int __pci_enable_msix_range(struct pci_dev *dev,
        if (WARN_ON_ONCE(dev->msix_enabled))
                return -EINVAL;
 
+       if (!pci_msi_supported(dev, nvec) || dev->current_state != PCI_D0)
+               return -EINVAL;
+
+       hwsize = pci_msix_vec_count(dev);
+       if (hwsize < 0)
+               return hwsize;
+
+       if (!pci_msix_validate_entries(entries, nvec, hwsize))
+               return -EINVAL;
+
+       /* PCI_IRQ_VIRTUAL is a horrible hack! */
+       if (nvec > hwsize && !(flags & PCI_IRQ_VIRTUAL))
+               nvec = hwsize;
+
+       if (nvec < minvec)
+               return -ENOSPC;
+
        rc = pci_setup_msi_context(dev);
        if (rc)
                return rc;
@@ -785,7 +786,7 @@ int __pci_enable_msix_range(struct pci_dev *dev,
                                return -ENOSPC;
                }
 
-               rc = __pci_enable_msix(dev, entries, nvec, affd, flags);
+               rc = msix_capability_init(dev, entries, nvec, affd);
                if (rc == 0)
                        return nvec;