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Subject[PATCH 1/5] msi: Simplify msi sanity checks by adding with generic irq code.
Date
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@xmission.com>
---
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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