msi: Kill msi_lookup_irq

The function msi_lookup_irq was horrible.  As a side effect of running
it changed dev->irq, and then the callers would need to change it
back.  In addition it does a global scan through all of the irqs,
which seems to be the sole justification of the msi_lock.

To remove the neede for msi_lookup_irq I added first_msi_irq to struct
pci_dev.  Then depending on the context I replaced msi_lookup_irq with
dev->first_msi_irq, dev->msi_enabled, or dev->msix_enabled.

msi_enabled and msix_enabled were already present in pci_dev for other
reasons.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

2 files changed, 62 insertions, 90 deletions

diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
index 067ae9917fd6..b945470bef18 100644
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -272,28 +272,6 @@ void disable_msi_mode(struct pci_dev *dev, int pos, int type)
         pci_intx(dev, 1);  /* enable intx */
 }
 
-static int msi_lookup_irq(struct pci_dev *dev, int type)
-{
-        int irq;
-        unsigned long flags;
-
-        spin_lock_irqsave(&msi_lock, flags);
-        for (irq = 0; irq < NR_IRQS; irq++) {
-                if (!msi_desc[irq] || msi_desc[irq]->dev != dev ||
-                        msi_desc[irq]->msi_attrib.type != type ||
-                        msi_desc[irq]->msi_attrib.default_irq != dev->irq)
-                        continue;
-                spin_unlock_irqrestore(&msi_lock, flags);
-                /* This pre-assigned MSI irq for this device
-                   already exists. Override dev->irq with this irq */
-                dev->irq = irq;
-                return 0;
-        }
-        spin_unlock_irqrestore(&msi_lock, flags);
-
-        return -EACCES;
-}
-
 #ifdef CONFIG_PM
 static int __pci_save_msi_state(struct pci_dev *dev)
 {
@@ -364,11 +342,13 @@ static void __pci_restore_msi_state(struct pci_dev *dev)
 static int __pci_save_msix_state(struct pci_dev *dev)
 {
         int pos;
-        int temp;
         int irq, head, tail = 0;
         u16 control;
         struct pci_cap_saved_state *save_state;
 
+        if (!dev->msix_enabled)
+                return 0;
+
         pos = pci_find_capability(dev, PCI_CAP_ID_MSIX);
         if (pos <= 0 || dev->no_msi)
                 return 0;
@@ -386,13 +366,7 @@ static int __pci_save_msix_state(struct pci_dev *dev)
         *((u16 *)&save_state->data[0]) = control;
 
         /* save the table */
-        temp = dev->irq;
-        if (msi_lookup_irq(dev, PCI_CAP_ID_MSIX)) {
-                kfree(save_state);
-                return -EINVAL;
-        }
-
-        irq = head = dev->irq;
+        irq = head = dev->first_msi_irq;
         while (head != tail) {
                 struct msi_desc *entry;
 
@@ -402,7 +376,6 @@ static int __pci_save_msix_state(struct pci_dev *dev)
                 tail = msi_desc[irq]->link.tail;
                 irq = tail;
         }
-        dev->irq = temp;
 
         save_state->cap_nr = PCI_CAP_ID_MSIX;
         pci_add_saved_cap(dev, save_state);
@@ -428,9 +401,11 @@ static void __pci_restore_msix_state(struct pci_dev *dev)
         int pos;
         int irq, head, tail = 0;
         struct msi_desc *entry;
-        int temp;
         struct pci_cap_saved_state *save_state;
 
+        if (!dev->msix_enabled)
+                return;
+
         save_state = pci_find_saved_cap(dev, PCI_CAP_ID_MSIX);
         if (!save_state)
                 return;
@@ -443,10 +418,7 @@ static void __pci_restore_msix_state(struct pci_dev *dev)
                 return;
 
         /* route the table */
-        temp = dev->irq;
-        if (msi_lookup_irq(dev, PCI_CAP_ID_MSIX))
-                return;
-        irq = head = dev->irq;
+        irq = head = dev->first_msi_irq;
         while (head != tail) {
                 entry = msi_desc[irq];
                 write_msi_msg(irq, &entry->msg_save);
@@ -454,7 +426,6 @@ static void __pci_restore_msix_state(struct pci_dev *dev)
                 tail = msi_desc[irq]->link.tail;
                 irq = tail;
         }
-        dev->irq = temp;
 
         pci_write_config_word(dev, msi_control_reg(pos), save);
         enable_msi_mode(dev, pos, PCI_CAP_ID_MSIX);
@@ -524,6 +495,7 @@ static int msi_capability_init(struct pci_dev *dev)
                 return status;
         }
 
+        dev->first_msi_irq = irq;
         attach_msi_entry(entry, irq);
         /* Set MSI enabled bits  */
         enable_msi_mode(dev, pos, PCI_CAP_ID_MSI);
@@ -620,6 +592,7 @@ static int msix_capability_init(struct pci_dev *dev,
                         avail = -EBUSY;
                 return avail;
         }
+        dev->first_msi_irq = entries[0].vector;
         /* Set MSI-X enabled bits */
         enable_msi_mode(dev, pos, PCI_CAP_ID_MSIX);
 
@@ -667,13 +640,11 @@ int pci_msi_supported(struct pci_dev * dev)
  **/
 int pci_enable_msi(struct pci_dev* dev)
 {
-        int pos, temp, status;
+        int pos, status;
 
         if (pci_msi_supported(dev) < 0)
                 return -EINVAL;
 
-        temp = dev->irq;
-
         status = msi_init();
         if (status < 0)
                 return status;
@@ -682,15 +653,14 @@ int pci_enable_msi(struct pci_dev* dev)
         if (!pos)
                 return -EINVAL;
 
-        WARN_ON(!msi_lookup_irq(dev, PCI_CAP_ID_MSI));
+        WARN_ON(!!dev->msi_enabled);
 
         /* Check whether driver already requested for MSI-X irqs */
         pos = pci_find_capability(dev, PCI_CAP_ID_MSIX);
-        if (pos > 0 && !msi_lookup_irq(dev, PCI_CAP_ID_MSIX)) {
+        if (pos > 0 && dev->msix_enabled) {
                         printk(KERN_INFO "PCI: %s: Can't enable MSI.  "
-                               "Device already has MSI-X irq assigned\n",
+                               "Device already has MSI-X enabled\n",
                                pci_name(dev));
-                        dev->irq = temp;
                         return -EINVAL;
         }
         status = msi_capability_init(dev);
@@ -709,6 +679,9 @@ void pci_disable_msi(struct pci_dev* dev)
         if (!dev)
                 return;
 
+        if (!dev->msi_enabled)
+                return;
+
         pos = pci_find_capability(dev, PCI_CAP_ID_MSI);
         if (!pos)
                 return;
@@ -717,28 +690,30 @@ void pci_disable_msi(struct pci_dev* dev)
         if (!(control & PCI_MSI_FLAGS_ENABLE))
                 return;
 
+
         disable_msi_mode(dev, pos, PCI_CAP_ID_MSI);
 
         spin_lock_irqsave(&msi_lock, flags);
-        entry = msi_desc[dev->irq];
+        entry = msi_desc[dev->first_msi_irq];
         if (!entry || !entry->dev || entry->msi_attrib.type != PCI_CAP_ID_MSI) {
                 spin_unlock_irqrestore(&msi_lock, flags);
                 return;
         }
-        if (irq_has_action(dev->irq)) {
+        if (irq_has_action(dev->first_msi_irq)) {
                 spin_unlock_irqrestore(&msi_lock, flags);
                 printk(KERN_WARNING "PCI: %s: pci_disable_msi() called without "
                        "free_irq() on MSI irq %d\n",
-                       pci_name(dev), dev->irq);
-                BUG_ON(irq_has_action(dev->irq));
+                       pci_name(dev), dev->first_msi_irq);
+                BUG_ON(irq_has_action(dev->first_msi_irq));
         } else {
                 default_irq = entry->msi_attrib.default_irq;
                 spin_unlock_irqrestore(&msi_lock, flags);
-                msi_free_irq(dev, dev->irq);
+                msi_free_irq(dev, dev->first_msi_irq);
 
                 /* Restore dev->irq to its default pin-assertion irq */
                 dev->irq = default_irq;
         }
+        dev->first_msi_irq = 0;
 }
 
 static int msi_free_irq(struct pci_dev* dev, int irq)
@@ -797,7 +772,7 @@ static int msi_free_irq(struct pci_dev* dev, int irq)
 int pci_enable_msix(struct pci_dev* dev, struct msix_entry *entries, int nvec)
 {
         int status, pos, nr_entries;
-        int i, j, temp;
+        int i, j;
         u16 control;
 
         if (!entries || pci_msi_supported(dev) < 0)
@@ -825,16 +800,14 @@ int pci_enable_msix(struct pci_dev* dev, struct msix_entry *entries, int nvec)
                                 return -EINVAL; /* duplicate entry */
                 }
         }
-        temp = dev->irq;
-        WARN_ON(!msi_lookup_irq(dev, PCI_CAP_ID_MSIX));
+        WARN_ON(!!dev->msix_enabled);
 
         /* Check whether driver already requested for MSI irq */
         if (pci_find_capability(dev, PCI_CAP_ID_MSI) > 0 &&
-                !msi_lookup_irq(dev, PCI_CAP_ID_MSI)) {
+                dev->msi_enabled) {
                 printk(KERN_INFO "PCI: %s: Can't enable MSI-X.  "
                        "Device already has an MSI irq assigned\n",
                        pci_name(dev));
-                dev->irq = temp;
                 return -EINVAL;
         }
         status = msix_capability_init(dev, entries, nvec);
@@ -843,7 +816,9 @@ int pci_enable_msix(struct pci_dev* dev, struct msix_entry *entries, int nvec)
 
 void pci_disable_msix(struct pci_dev* dev)
 {
-        int pos, temp;
+        int irq, head, tail = 0, warning = 0;
+        unsigned long flags;
+        int pos;
         u16 control;
 
         if (!pci_msi_enable)
@@ -851,6 +826,9 @@ void pci_disable_msix(struct pci_dev* dev)
         if (!dev)
                 return;
 
+        if (!dev->msix_enabled)
+                return;
+
         pos = pci_find_capability(dev, PCI_CAP_ID_MSIX);
         if (!pos)
                 return;
@@ -861,31 +839,25 @@ void pci_disable_msix(struct pci_dev* dev)
 
         disable_msi_mode(dev, pos, PCI_CAP_ID_MSIX);
 
-        temp = dev->irq;
-        if (!msi_lookup_irq(dev, PCI_CAP_ID_MSIX)) {
-                int irq, head, tail = 0, warning = 0;
-                unsigned long flags;
-
-                irq = head = dev->irq;
-                dev->irq = temp;                        /* Restore pin IRQ */
-                while (head != tail) {
-                        spin_lock_irqsave(&msi_lock, flags);
-                        tail = msi_desc[irq]->link.tail;
-                        spin_unlock_irqrestore(&msi_lock, flags);
-                        if (irq_has_action(irq))
-                                warning = 1;
-                        else if (irq != head)   /* Release MSI-X irq */
-                                msi_free_irq(dev, irq);
-                        irq = tail;
-                }
-                msi_free_irq(dev, irq);
-                if (warning) {
-                        printk(KERN_WARNING "PCI: %s: pci_disable_msix() called without "
-                               "free_irq() on all MSI-X irqs\n",
-                               pci_name(dev));
-                        BUG_ON(warning > 0);
-                }
+        irq = head = dev->first_msi_irq;
+        while (head != tail) {
+                spin_lock_irqsave(&msi_lock, flags);
+                tail = msi_desc[irq]->link.tail;
+                spin_unlock_irqrestore(&msi_lock, flags);
+                if (irq_has_action(irq))
+                        warning = 1;
+                else if (irq != head)   /* Release MSI-X irq */
+                        msi_free_irq(dev, irq);
+                irq = tail;
+        }
+        msi_free_irq(dev, irq);
+        if (warning) {
+                printk(KERN_WARNING "PCI: %s: pci_disable_msix() called without "
+                        "free_irq() on all MSI-X irqs\n",
+                        pci_name(dev));
+                BUG_ON(warning > 0);
         }
+        dev->first_msi_irq = 0;
 }
 
 /**
@@ -899,30 +871,28 @@ void pci_disable_msix(struct pci_dev* dev)
  **/
 void msi_remove_pci_irq_vectors(struct pci_dev* dev)
 {
-        int pos, temp;
+        int pos;
         unsigned long flags;
 
         if (!pci_msi_enable || !dev)
                 return;
 
-        temp = dev->irq;                /* Save IOAPIC IRQ */
         pos = pci_find_capability(dev, PCI_CAP_ID_MSI);
-        if (pos > 0 && !msi_lookup_irq(dev, PCI_CAP_ID_MSI)) {
-                if (irq_has_action(dev->irq)) {
+        if (pos > 0 && dev->msi_enabled) {
+                if (irq_has_action(dev->first_msi_irq)) {
                         printk(KERN_WARNING "PCI: %s: msi_remove_pci_irq_vectors() "
                                "called without free_irq() on MSI irq %d\n",
-                               pci_name(dev), dev->irq);
-                        BUG_ON(irq_has_action(dev->irq));
+                               pci_name(dev), dev->first_msi_irq);
+                        BUG_ON(irq_has_action(dev->first_msi_irq));
                 } else /* Release MSI irq assigned to this device */
-                        msi_free_irq(dev, dev->irq);
-                dev->irq = temp;                /* Restore IOAPIC IRQ */
+                        msi_free_irq(dev, dev->first_msi_irq);
         }
         pos = pci_find_capability(dev, PCI_CAP_ID_MSIX);
-        if (pos > 0 && !msi_lookup_irq(dev, PCI_CAP_ID_MSIX)) {
+        if (pos > 0 && dev->msix_enabled) {
                 int irq, head, tail = 0, warning = 0;
                 void __iomem *base = NULL;
 
-                irq = head = dev->irq;
+                irq = head = dev->first_msi_irq;
                 while (head != tail) {
                         spin_lock_irqsave(&msi_lock, flags);
                         tail = msi_desc[irq]->link.tail;
@@ -942,7 +912,6 @@ void msi_remove_pci_irq_vectors(struct pci_dev* dev)
                                pci_name(dev));
                         BUG_ON(warning > 0);
                 }
-                dev->irq = temp;                /* Restore IOAPIC IRQ */
         }
 }
 
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 29765e2b1e0a..1507f8cc45fd 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -174,6 +174,9 @@ struct pci_dev {
         struct bin_attribute *rom_attr; /* attribute descriptor for sysfs ROM entry */
         int rom_attr_enabled;           /* has display of the rom attribute been enabled? */
         struct bin_attribute *res_attr[DEVICE_COUNT_RESOURCE]; /* sysfs file for resources */
+#ifdef CONFIG_PCI_MSI
+        unsigned int first_msi_irq;
+#endif
 };
 
 #define pci_dev_g(n) list_entry(n, struct pci_dev, global_list)