I propose the following change to the sn/kernel arch SN IRQ handling.
The central issue here is that the current unidirectional list implementation in sn_irq_info does not easily allow sn_irq_info struct removals when PCI devices are hotplug removed from the system.
After input from a few others I changed my approach in the patch. Please reconsider it for submission to the community.
P.
# This is a BitKeeper generated diff -Nru style patch.
#
# ChangeSet
# 2005/03/15 20:21:28-05:00 [EMAIL PROTECTED]
# intr.h, irq.c, io_init.c, pcidev.h:
# sn IRQ modifications required for PCI Hotplug
#
# include/asm-ia64/sn/intr.h
# 2005/03/15 20:19:06-05:00 [EMAIL PROTECTED] +5 -0
# sn IRQ modifications required for PCI Hotplug
#
# arch/ia64/sn/kernel/irq.c
# 2005/03/15 20:17:45-05:00 [EMAIL PROTECTED] +93 -57
# sn IRQ modifications required for PCI Hotplug
#
# arch/ia64/sn/kernel/io_init.c
# 2005/03/15 20:17:36-05:00 [EMAIL PROTECTED] +14 -7
# sn IRQ modifications required for PCI Hotplug
#
# arch/ia64/sn/include/pci/pcidev.h
# 2005/03/15 20:17:08-05:00 [EMAIL PROTECTED] +1 -1
# sn IRQ modifications required for PCI Hotplug
#
diff -Nru a/arch/ia64/sn/include/pci/pcidev.h
b/arch/ia64/sn/include/pci/pcidev.h
--- a/arch/ia64/sn/include/pci/pcidev.h 2005-03-15 20:23:19 -05:00
+++ b/arch/ia64/sn/include/pci/pcidev.h 2005-03-15 20:23:19 -05:00
@@ -10,7 +10,7 @@
#include <linux/pci.h>
-extern struct sn_irq_info **sn_irq;
+extern struct list_head **sn_irq_lh;
#define SN_PCIDEV_INFO(pci_dev) \
((struct pcidev_info *)(pci_dev)->sysdata)
diff -Nru a/arch/ia64/sn/kernel/io_init.c b/arch/ia64/sn/kernel/io_init.c
--- a/arch/ia64/sn/kernel/io_init.c 2005-03-15 20:23:19 -05:00
+++ b/arch/ia64/sn/kernel/io_init.c 2005-03-15 20:23:19 -05:00
@@ -343,10 +343,18 @@
*/
ia64_max_iommu_merge_mask = ~PAGE_MASK;
sn_fixup_ionodes();
- sn_irq = kmalloc(sizeof(struct sn_irq_info *) * NR_IRQS, GFP_KERNEL);
- if (sn_irq <= 0)
- BUG(); /* Canno afford to run out of memory. */
- memset(sn_irq, 0, sizeof(struct sn_irq_info *) * NR_IRQS);
+
+ sn_irq_lh = kmalloc(sizeof(struct list_head *) * NR_IRQS, GFP_KERNEL);
+ if (!sn_irq_lh)
+ BUG();
+
+ for (i = 0; i < NR_IRQS; i++) {
+ sn_irq_lh[i] = kmalloc(sizeof(struct list_head), GFP_KERNEL);
+ if (!sn_irq_lh[i])
+ BUG();
+
+ INIT_LIST_HEAD(sn_irq_lh[i]);
+ }
sn_init_cpei_timer();
@@ -365,9 +373,8 @@
*/
while ((pci_dev =
- pci_find_device(PCI_ANY_ID, PCI_ANY_ID, pci_dev)) != NULL) {
- sn_pci_fixup_slot(pci_dev);
- }
+ pci_find_device(PCI_ANY_ID, PCI_ANY_ID, pci_dev)) != NULL)
+ sn_pci_fixup_slot(pci_dev);
sn_ioif_inited = 1; /* sn I/O infrastructure now initialized */
diff -Nru a/arch/ia64/sn/kernel/irq.c b/arch/ia64/sn/kernel/irq.c
--- a/arch/ia64/sn/kernel/irq.c 2005-03-15 20:23:19 -05:00
+++ b/arch/ia64/sn/kernel/irq.c 2005-03-15 20:23:19 -05:00
@@ -9,6 +9,7 @@
*/
#include <linux/irq.h>
+#include <linux/spinlock.h>
#include <asm/sn/intr.h>
#include <asm/sn/addrs.h>
#include <asm/sn/arch.h>
@@ -25,7 +26,8 @@
extern int sn_force_interrupt_flag;
extern int sn_ioif_inited;
-struct sn_irq_info **sn_irq;
+struct list_head **sn_irq_lh;
+static spinlock_t sn_irq_info_lock = SPIN_LOCK_UNLOCKED; /* non-IRQ lock */
static inline uint64_t sn_intr_alloc(nasid_t local_nasid, int local_widget,
u64 sn_irq_info,
@@ -126,13 +128,13 @@
force_interrupt(irq);
}
+static void sn_irq_info_free(struct rcu_head *head);
+
static void sn_set_affinity_irq(unsigned int irq, cpumask_t mask)
{
- struct sn_irq_info *sn_irq_info = sn_irq[irq];
+ struct sn_irq_info *sn_irq_info, *sn_irq_info_safe;
struct sn_irq_info *tmp_sn_irq_info;
int cpuid, cpuphys;
- nasid_t t_nasid; /* nasid to target */
- int t_slice; /* slice to target */
/* allocate a temp sn_irq_info struct to get new target info */
tmp_sn_irq_info = kmalloc(sizeof(*tmp_sn_irq_info), GFP_KERNEL);
@@ -141,56 +143,61 @@
cpuid = first_cpu(mask);
cpuphys = cpu_physical_id(cpuid);
- t_nasid = cpuid_to_nasid(cpuid);
- t_slice = cpuid_to_slice(cpuid);
- while (sn_irq_info) {
- int status;
- int local_widget;
- uint64_t bridge = (uint64_t) sn_irq_info->irq_bridge;
- nasid_t local_nasid = NASID_GET(bridge);
+ list_for_each_entry_safe(sn_irq_info, sn_irq_info_safe,
+ sn_irq_lh[irq], list) {
+ uint64_t bridge;
+ int local_widget, status;
+ nasid_t local_nasid;
+ struct sn_irq_info *tmp_irq_info;
+
+ tmp_irq_info = kmalloc(sizeof(struct sn_irq_info), GFP_ATOMIC);
+ if (tmp_irq_info == NULL)
+ break;
+ memcpy(tmp_irq_info, sn_irq_info, sizeof(struct sn_irq_info));
+ bridge = (uint64_t) tmp_irq_info->irq_bridge;
if (!bridge)
- break; /* irq is not a device interrupt */
+ break; /* irq is not a device interrupt */
+
+ local_nasid = NASID_GET(bridge);
if (local_nasid & 1)
local_widget = TIO_SWIN_WIDGETNUM(bridge);
else
local_widget = SWIN_WIDGETNUM(bridge);
- /* Free the old PROM sn_irq_info structure */
- sn_intr_free(local_nasid, local_widget, sn_irq_info);
+ /* Free the old PROM tmp_irq_info structure */
+ sn_intr_free(local_nasid, local_widget, tmp_irq_info);
+ /* Update kernels tmp_irq_info with new target info */
+ unregister_intr_pda(tmp_irq_info);
- /* allocate a new PROM sn_irq_info struct */
+ /* allocate a new PROM tmp_irq_info struct */
status = sn_intr_alloc(local_nasid, local_widget,
- __pa(tmp_sn_irq_info), irq, t_nasid,
- t_slice);
+ __pa(tmp_irq_info), irq,
+ cpuid_to_nasid(cpuid),
+ cpuid_to_slice(cpuid));
+
+ /* SAL call failed */
+ if (status)
+ break;
- if (status == 0) {
- /* Update kernels sn_irq_info with new target info */
- unregister_intr_pda(sn_irq_info);
- sn_irq_info->irq_cpuid = cpuid;
- sn_irq_info->irq_nasid = t_nasid;
- sn_irq_info->irq_slice = t_slice;
- sn_irq_info->irq_xtalkaddr =
- tmp_sn_irq_info->irq_xtalkaddr;
- sn_irq_info->irq_cookie = tmp_sn_irq_info->irq_cookie;
- register_intr_pda(sn_irq_info);
+ tmp_irq_info->irq_cpuid = cpuid;
+ register_intr_pda(tmp_irq_info);
- if (IS_PCI_BRIDGE_ASIC(sn_irq_info->irq_bridge_type)) {
- pcibr_change_devices_irq(sn_irq_info);
- }
+ if (IS_PCI_BRIDGE_ASIC(tmp_irq_info->irq_bridge_type)) {
+ pcibr_change_devices_irq(tmp_irq_info);
+ }
- sn_irq_info = sn_irq_info->irq_next;
+ spin_lock(&sn_irq_info_lock);
+ list_replace_rcu(&sn_irq_info->list, &tmp_irq_info->list);
+ spin_unlock(&sn_irq_info_lock);
+ call_rcu(&sn_irq_info->rcu, sn_irq_info_free);
#ifdef CONFIG_SMP
- set_irq_affinity_info((irq & 0xff), cpuphys, 0);
+ set_irq_affinity_info((irq & 0xff), cpuphys, 0);
#endif
- } else {
- break; /* snp_affinity failed the intr_alloc */
- }
}
- kfree(tmp_sn_irq_info);
}
struct hw_interrupt_type irq_type_sn = {
@@ -242,20 +249,19 @@
struct sn_irq_info *tmp_irq_info;
int i, foundmatch;
+ rcu_read_lock();
if (pdacpu(cpu)->sn_last_irq == irq) {
foundmatch = 0;
for (i = pdacpu(cpu)->sn_last_irq - 1; i; i--) {
- tmp_irq_info = sn_irq[i];
- while (tmp_irq_info) {
+ list_for_each_entry_rcu(tmp_irq_info, sn_irq_lh[i],
list) {
if (tmp_irq_info->irq_cpuid == cpu) {
foundmatch++;
break;
}
- tmp_irq_info = tmp_irq_info->irq_next;
}
- if (foundmatch) {
+
+ if (foundmatch)
break;
- }
}
pdacpu(cpu)->sn_last_irq = i;
}
@@ -263,20 +269,19 @@
if (pdacpu(cpu)->sn_first_irq == irq) {
foundmatch = 0;
for (i = pdacpu(cpu)->sn_first_irq + 1; i < NR_IRQS; i++) {
- tmp_irq_info = sn_irq[i];
- while (tmp_irq_info) {
+ list_for_each_entry_rcu(tmp_irq_info, sn_irq_lh[i],
list) {
if (tmp_irq_info->irq_cpuid == cpu) {
foundmatch++;
break;
}
- tmp_irq_info = tmp_irq_info->irq_next;
}
- if (foundmatch) {
+
+ if (foundmatch)
break;
- }
}
pdacpu(cpu)->sn_first_irq = ((i == NR_IRQS) ? 0 : i);
}
+ rcu_read_unlock();
}
struct sn_irq_info *sn_irq_alloc(nasid_t local_nasid, int local_widget, int
irq,
@@ -303,6 +308,15 @@
}
}
+static void sn_irq_info_free(struct rcu_head *head)
+{
+ struct sn_irq_info *sn_irq_info = container_of(head,
+ struct sn_irq_info, rcu);
+
+ kfree(sn_irq_info);
+}
+
+
void sn_irq_free(struct sn_irq_info *sn_irq_info)
{
uint64_t bridge = (uint64_t) sn_irq_info->irq_bridge;
@@ -329,26 +343,46 @@
sn_irq_info->irq_pciioinfo = SN_PCIDEV_INFO(pci_dev);
/* link it into the sn_irq[irq] list */
- sn_irq_info->irq_next = sn_irq[sn_irq_info->irq_irq];
- sn_irq[sn_irq_info->irq_irq] = sn_irq_info;
+
+ spin_lock(&sn_irq_info_lock);
+ list_add_rcu(&sn_irq_info->list, sn_irq_lh[sn_irq_info->irq_irq]);
+ spin_unlock(&sn_irq_info_lock);
(void)register_intr_pda(sn_irq_info);
}
+void sn_irq_unfixup(struct pci_dev *pci_dev)
+{
+ struct sn_irq_info *sn_irq_info;
+
+ /* Only cleanup IRQ stuff if this device has a host bus context */
+ if (!SN_PCIDEV_BUSSOFT(pci_dev))
+ return;
+
+ sn_irq_info = SN_PCIDEV_INFO(pci_dev)->pdi_sn_irq_info;
+
+ unregister_intr_pda(sn_irq_info);
+ spin_lock(&sn_irq_info_lock);
+ list_del_rcu(&sn_irq_info->list);
+ spin_unlock(&sn_irq_info_lock);
+ call_rcu(&sn_irq_info->rcu, sn_irq_info_free);
+}
+
static void force_interrupt(int irq)
{
struct sn_irq_info *sn_irq_info;
if (!sn_ioif_inited)
return;
- sn_irq_info = sn_irq[irq];
- while (sn_irq_info) {
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(sn_irq_info, sn_irq_lh[irq], list)
+ {
if (IS_PCI_BRIDGE_ASIC(sn_irq_info->irq_bridge_type) &&
- (sn_irq_info->irq_bridge != NULL)) {
- pcibr_force_interrupt(sn_irq_info);
- }
- sn_irq_info = sn_irq_info->irq_next;
+ (sn_irq_info->irq_bridge != NULL))
+ pcibr_force_interrupt(sn_irq_info);
}
+ rcu_read_unlock();
}
/*
@@ -413,19 +447,21 @@
void sn_lb_int_war_check(void)
{
+ struct sn_irq_info *sn_irq_info;
int i;
if (!sn_ioif_inited || pda->sn_first_irq == 0)
return;
+
+ rcu_read_lock();
for (i = pda->sn_first_irq; i <= pda->sn_last_irq; i++) {
- struct sn_irq_info *sn_irq_info = sn_irq[i];
- while (sn_irq_info) {
+ list_for_each_entry_rcu(sn_irq_info, sn_irq_lh[i], list) {
/* Only call for PCI bridges that are fully
initialized. */
if (IS_PCI_BRIDGE_ASIC(sn_irq_info->irq_bridge_type) &&
(sn_irq_info->irq_bridge != NULL)) {
sn_check_intr(i, sn_irq_info);
}
- sn_irq_info = sn_irq_info->irq_next;
}
}
+ rcu_read_unlock();
}
diff -Nru a/include/asm-ia64/sn/intr.h b/include/asm-ia64/sn/intr.h
--- a/include/asm-ia64/sn/intr.h 2005-03-15 20:23:19 -05:00
+++ b/include/asm-ia64/sn/intr.h 2005-03-15 20:23:19 -05:00
@@ -9,6 +9,8 @@
#ifndef _ASM_IA64_SN_INTR_H
#define _ASM_IA64_SN_INTR_H
+#include <linux/rcupdate.h>
+
#define SGI_UART_VECTOR (0xe9)
#define SGI_PCIBR_ERROR (0x33)
@@ -47,6 +49,9 @@
int irq_cookie; /* unique cookie */
int irq_flags; /* flags */
int irq_share_cnt; /* num devices sharing IRQ */
+ struct list_head list; /* list of sn_irq_info structs */
+ struct rcu_head rcu; /* rcu callback list */
+
};
extern void sn_send_IPI_phys(int, long, int, int);
