MSI: Use a list instead of the custom link structure

The msi descriptors are linked together with what looks a lot like
a linked list, but isn't a struct list_head list. Make it one.

The only complication is that previously we walked a list of irqs, and
got the descriptor for each with get_irq_msi(). Now we have a list of
descriptors and need to get the irq out of it, so it needs to be in the
actual struct msi_desc. We use 0 to indicate no irq is setup.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

5 files changed, 33 insertions, 46 deletions

diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
index 5902c00f4fce..434c7182d926 100644
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -218,7 +218,8 @@ static struct msi_desc* alloc_msi_entry(void)
         if (!entry)
                 return NULL;
 
-        entry->link.tail = entry->link.head = 0;        /* single message */
+        INIT_LIST_HEAD(&entry->list);
+        entry->irq = 0;
         entry->dev = NULL;
 
         return entry;
@@ -253,7 +254,6 @@ static void __pci_restore_msi_state(struct pci_dev *dev)
 static void __pci_restore_msix_state(struct pci_dev *dev)
 {
         int pos;
-        int irq, head, tail = 0;
         struct msi_desc *entry;
         u16 control;
 
@@ -263,18 +263,14 @@ static void __pci_restore_msix_state(struct pci_dev *dev)
         /* route the table */
         pci_intx(dev, 0);               /* disable intx */
         msix_set_enable(dev, 0);
-        irq = head = dev->first_msi_irq;
-        entry = get_irq_msi(irq);
-        pos = entry->msi_attrib.pos;
-        while (head != tail) {
-                entry = get_irq_msi(irq);
-                write_msi_msg(irq, &entry->msg);
-                msi_set_mask_bit(irq, entry->msi_attrib.masked);
 
-                tail = entry->link.tail;
-                irq = tail;
+        list_for_each_entry(entry, &dev->msi_list, list) {
+                write_msi_msg(entry->irq, &entry->msg);
+                msi_set_mask_bit(entry->irq, entry->msi_attrib.masked);
         }
 
+        entry = get_irq_msi(dev->first_msi_irq);
+        pos = entry->msi_attrib.pos;
         pci_read_config_word(dev, pos + PCI_MSIX_FLAGS, &control);
         control &= ~PCI_MSIX_FLAGS_MASKALL;
         control |= PCI_MSIX_FLAGS_ENABLE;
@@ -343,8 +339,8 @@ static int msi_capability_init(struct pci_dev *dev)
                 kfree(entry);
                 return irq;
         }
-        entry->link.head = irq;
-        entry->link.tail = irq;
+        entry->irq = irq;
+        list_add(&entry->list, &dev->msi_list);
         dev->first_msi_irq = irq;
         set_irq_msi(irq, entry);
 
@@ -370,8 +366,8 @@ static int msi_capability_init(struct pci_dev *dev)
 static int msix_capability_init(struct pci_dev *dev,
                                 struct msix_entry *entries, int nvec)
 {
-        struct msi_desc *head = NULL, *tail = NULL, *entry = NULL;
-        int irq, pos, i, j, nr_entries, temp = 0;
+        struct msi_desc *entry;
+        int irq, pos, i, j, nr_entries;
         unsigned long phys_addr;
         u32 table_offset;
         u16 control;
@@ -416,19 +412,9 @@ static int msix_capability_init(struct pci_dev *dev,
                         kfree(entry);
                         break;
                 }
+                entry->irq = irq;
                 entries[i].vector = irq;
-                if (!head) {
-                        entry->link.head = irq;
-                        entry->link.tail = irq;
-                        head = entry;
-                } else {
-                        entry->link.head = temp;
-                        entry->link.tail = tail->link.tail;
-                        tail->link.tail = irq;
-                        head->link.head = irq;
-                }
-                temp = irq;
-                tail = entry;
+                list_add(&entry->list, &dev->msi_list);
 
                 set_irq_msi(irq, entry);
         }
@@ -557,7 +543,7 @@ EXPORT_SYMBOL(pci_disable_msi);
 static int msi_free_irq(struct pci_dev* dev, int irq)
 {
         struct msi_desc *entry;
-        int head, entry_nr, type;
+        int entry_nr, type;
         void __iomem *base;
 
         BUG_ON(irq_has_action(irq));
@@ -568,10 +554,8 @@ static int msi_free_irq(struct pci_dev* dev, int irq)
         }
         type = entry->msi_attrib.type;
         entry_nr = entry->msi_attrib.entry_nr;
-        head = entry->link.head;
         base = entry->mask_base;
-        get_irq_msi(entry->link.head)->link.tail = entry->link.tail;
-        get_irq_msi(entry->link.tail)->link.head = entry->link.head;
+        list_del(&entry->list);
 
         arch_teardown_msi_irq(irq);
         kfree(entry);
@@ -580,7 +564,7 @@ static int msi_free_irq(struct pci_dev* dev, int irq)
                 writel(1, base + entry_nr * PCI_MSIX_ENTRY_SIZE +
                         PCI_MSIX_ENTRY_VECTOR_CTRL_OFFSET);
 
-                if (head == irq)
+                if (list_empty(&dev->msi_list))
                         iounmap(base);
         }
 
@@ -646,17 +630,10 @@ EXPORT_SYMBOL(pci_enable_msix);
 
 static void msix_free_all_irqs(struct pci_dev *dev)
 {
-        int irq, head, tail = 0;
-
-        irq = head = dev->first_msi_irq;
-        while (head != tail) {
-                tail = get_irq_msi(irq)->link.tail;
+        struct msi_desc *entry;
 
-                if (irq != head)
-                        msi_free_irq(dev, irq);
-                irq = tail;
-        }
-        msi_free_irq(dev, irq);
+        list_for_each_entry(entry, &dev->msi_list, list)
+                msi_free_irq(dev, entry->irq);
         dev->first_msi_irq = 0;
 }
 
@@ -699,6 +676,11 @@ void pci_no_msi(void)
         pci_msi_enable = 0;
 }
 
+void pci_msi_init_pci_dev(struct pci_dev *dev)
+{
+        INIT_LIST_HEAD(&dev->msi_list);
+}
+
 
 /* Arch hooks */
 
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 62ea04c8af64..3fec13d3add7 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -47,8 +47,10 @@ extern unsigned int pci_pm_d3_delay;
 
 #ifdef CONFIG_PCI_MSI
 void pci_no_msi(void);
+extern void pci_msi_init_pci_dev(struct pci_dev *dev);
 #else
 static inline void pci_no_msi(void) { }
+static inline void pci_msi_init_pci_dev(struct pci_dev *dev) { }
 #endif
 
 #if defined(CONFIG_PCI_MSI) && defined(CONFIG_PM)
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index c659f8ae441a..e48fcf089621 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -857,6 +857,8 @@ struct pci_dev *alloc_pci_dev(void)
         INIT_LIST_HEAD(&dev->global_list);
         INIT_LIST_HEAD(&dev->bus_list);
 
+        pci_msi_init_pci_dev(dev);
+
         return dev;
 }
 EXPORT_SYMBOL(alloc_pci_dev);
diff --git a/include/linux/msi.h b/include/linux/msi.h
index d2a200048b22..931e013f1db5 100644
--- a/include/linux/msi.h
+++ b/include/linux/msi.h
@@ -1,6 +1,8 @@
 #ifndef LINUX_MSI_H
 #define LINUX_MSI_H
 
+#include <linux/list.h>
+
 struct msi_msg {
         u32     address_lo;     /* low 32 bits of msi message address */
         u32     address_hi;     /* high 32 bits of msi message address */
@@ -24,10 +26,8 @@ struct msi_desc {
                 unsigned default_irq;   /* default pre-assigned irq       */
         }msi_attrib;
 
-        struct {
-                __u16   head;
-                __u16   tail;
-        }link;
+        unsigned int irq;
+        struct list_head list;
 
         void __iomem *mask_base;
         struct pci_dev *dev;
diff --git a/include/linux/pci.h b/include/linux/pci.h
index c02074785d40..d43097dc8672 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -190,6 +190,7 @@ struct pci_dev {
         struct bin_attribute *res_attr[DEVICE_COUNT_RESOURCE]; /* sysfs file for resources */
 #ifdef CONFIG_PCI_MSI
         unsigned int first_msi_irq;
+        struct list_head msi_list;
 #endif
 };