[PATCH 1/5] msi: Simplify msi sanity checks by adding with generic irq code.

From: Eric W. Biederman
Date: Wed Sep 27 2006 - 16:34:00 EST


Currently msi.c is doing sanity checks that make certain before
an irq is destroyed it has no more users.

By adding irq_has_action I can perform the test is a generic way, instead
of relying on a msi specific data structure.

By performing the core check in dynamic_irq_cleanup I ensure every user
of dynamic irqs has a test present and we don't free resources that are
in use.

In msi.c this allows me to kill the attrib.state member of msi_desc and
all of the assciated code to maintain it.

To keep from freeing data structures when irq cleanup code is called to
soon changing dyanamic_irq_cleanup is insufficient because there are
msi specific data structures that are also not safe to free.

Signed-off-by: Eric W. Biederman <ebiederm@xxxxxxxxxxxx>
---
drivers/pci/msi.c | 43 ++++++++-----------------------------------
drivers/pci/msi.h | 2 +-
include/linux/irq.h | 7 +++++++
kernel/irq/chip.c | 7 +++++++
4 files changed, 23 insertions(+), 36 deletions(-)

diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
index da2c6c2..e3ba396 100644
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -188,18 +188,6 @@ static void unmask_MSI_irq(unsigned int

static unsigned int startup_msi_irq_wo_maskbit(unsigned int irq)
{
- struct msi_desc *entry;
- unsigned long flags;
-
- spin_lock_irqsave(&msi_lock, flags);
- entry = msi_desc[irq];
- if (!entry || !entry->dev) {
- spin_unlock_irqrestore(&msi_lock, flags);
- return 0;
- }
- entry->msi_attrib.state = 1; /* Mark it active */
- spin_unlock_irqrestore(&msi_lock, flags);
-
return 0; /* never anything pending */
}

@@ -212,14 +200,6 @@ static unsigned int startup_msi_irq_w_ma

static void shutdown_msi_irq(unsigned int irq)
{
- struct msi_desc *entry;
- unsigned long flags;
-
- spin_lock_irqsave(&msi_lock, flags);
- entry = msi_desc[irq];
- if (entry && entry->dev)
- entry->msi_attrib.state = 0; /* Mark it not active */
- spin_unlock_irqrestore(&msi_lock, flags);
}

static void end_msi_irq_wo_maskbit(unsigned int irq)
@@ -671,7 +651,6 @@ static int msi_capability_init(struct pc
entry->link.head = irq;
entry->link.tail = irq;
entry->msi_attrib.type = PCI_CAP_ID_MSI;
- entry->msi_attrib.state = 0; /* Mark it not active */
entry->msi_attrib.is_64 = is_64bit_address(control);
entry->msi_attrib.entry_nr = 0;
entry->msi_attrib.maskbit = is_mask_bit_support(control);
@@ -744,7 +723,6 @@ static int msix_capability_init(struct p
j = entries[i].entry;
entries[i].vector = irq;
entry->msi_attrib.type = PCI_CAP_ID_MSIX;
- entry->msi_attrib.state = 0; /* Mark it not active */
entry->msi_attrib.is_64 = 1;
entry->msi_attrib.entry_nr = j;
entry->msi_attrib.maskbit = 1;
@@ -897,12 +875,12 @@ void pci_disable_msi(struct pci_dev* dev
spin_unlock_irqrestore(&msi_lock, flags);
return;
}
- if (entry->msi_attrib.state) {
+ if (irq_has_action(dev->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(entry->msi_attrib.state > 0);
+ BUG_ON(irq_has_action(dev->irq));
} else {
default_irq = entry->msi_attrib.default_irq;
spin_unlock_irqrestore(&msi_lock, flags);
@@ -1035,17 +1013,16 @@ void pci_disable_msix(struct pci_dev* de

temp = dev->irq;
if (!msi_lookup_irq(dev, PCI_CAP_ID_MSIX)) {
- int state, irq, head, tail = 0, warning = 0;
+ 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);
- state = msi_desc[irq]->msi_attrib.state;
tail = msi_desc[irq]->link.tail;
spin_unlock_irqrestore(&msi_lock, flags);
- if (state)
+ if (irq_has_action(irq))
warning = 1;
else if (irq != head) /* Release MSI-X irq */
msi_free_irq(dev, irq);
@@ -1072,7 +1049,7 @@ void pci_disable_msix(struct pci_dev* de
**/
void msi_remove_pci_irq_vectors(struct pci_dev* dev)
{
- int state, pos, temp;
+ int pos, temp;
unsigned long flags;

if (!pci_msi_enable || !dev)
@@ -1081,14 +1058,11 @@ void msi_remove_pci_irq_vectors(struct p
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)) {
- spin_lock_irqsave(&msi_lock, flags);
- state = msi_desc[dev->irq]->msi_attrib.state;
- spin_unlock_irqrestore(&msi_lock, flags);
- if (state) {
+ if (irq_has_action(dev->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(state > 0);
+ BUG_ON(irq_has_action(dev->irq));
} else /* Release MSI irq assigned to this device */
msi_free_irq(dev, dev->irq);
dev->irq = temp; /* Restore IOAPIC IRQ */
@@ -1101,11 +1075,10 @@ void msi_remove_pci_irq_vectors(struct p
irq = head = dev->irq;
while (head != tail) {
spin_lock_irqsave(&msi_lock, flags);
- state = msi_desc[irq]->msi_attrib.state;
tail = msi_desc[irq]->link.tail;
base = msi_desc[irq]->mask_base;
spin_unlock_irqrestore(&msi_lock, flags);
- if (state)
+ if (irq_has_action(irq))
warning = 1;
else if (irq != head) /* Release MSI-X irq */
msi_free_irq(dev, irq);
diff --git a/drivers/pci/msi.h b/drivers/pci/msi.h
index 435d05a..77823bf 100644
--- a/drivers/pci/msi.h
+++ b/drivers/pci/msi.h
@@ -53,7 +53,7 @@ struct msi_desc {
struct {
__u8 type : 5; /* {0: unused, 5h:MSI, 11h:MSI-X} */
__u8 maskbit : 1; /* mask-pending bit supported ? */
- __u8 state : 1; /* {0: free, 1: busy} */
+ __u8 unused : 1;
__u8 is_64 : 1; /* Address size: 0=32bit 1=64bit */
__u8 pos; /* Location of the msi capability */
__u16 entry_nr; /* specific enabled entry */
diff --git a/include/linux/irq.h b/include/linux/irq.h
index ee8a5ea..86b65ed 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -373,6 +373,13 @@ set_irq_chained_handler(unsigned int irq
extern int create_irq(void);
extern void destroy_irq(unsigned int irq);

+/* Test to see if a driver has successfully requested an irq */
+static inline int irq_has_action(unsigned int irq)
+{
+ struct irq_desc *desc = irq_desc + irq;
+ return desc->action != NULL;
+}
+
/* Dynamic irq helper functions */
extern void dynamic_irq_init(unsigned int irq);
extern void dynamic_irq_cleanup(unsigned int irq);
diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
index e128b7d..2253898 100644
--- a/kernel/irq/chip.c
+++ b/kernel/irq/chip.c
@@ -151,6 +151,13 @@ void dynamic_irq_cleanup(unsigned int ir

desc = irq_desc + irq;
spin_lock_irqsave(&desc->lock, flags);
+ if (desc->action) {
+ spin_unlock_irqrestore(&desc->lock, flags);
+ printk(KERN_ERR "Destroying IRQ%d without calling free_irq\n",
+ irq);
+ WARN_ON(1);
+ return;
+ }
desc->handle_irq = handle_bad_irq;
desc->chip = &no_irq_chip;
spin_unlock_irqrestore(&desc->lock, flags);
--
1.4.2.rc3.g7e18e-dirty

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