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Subject[PATCH] Linux1394 (r893)
SMP folks will hate me for this one. This fixes a deadlock during
add_host.


Index: drivers/ieee1394/highlevel.c
===================================================================
--- linux/drivers/ieee1394/highlevel.c (revision 893)
+++ linux/drivers/ieee1394/highlevel.c (working copy)
@@ -48,20 +48,22 @@
static struct hpsb_address_serve dummy_zero_addr, dummy_max_addr;


-/* Internal usage. Must be called with hl_drivers_lock held */
static struct hl_host_info *hl_get_hostinfo(struct hpsb_highlevel *hl,
struct hpsb_host *host)
{
- struct hl_host_info *hi;
+ struct hl_host_info *hi = NULL;
struct list_head *lh;

+ read_lock(&hl->host_info_lock);
list_for_each (lh, &hl->host_info_list) {
hi = list_entry(lh, struct hl_host_info, list);
if (hi->host == host)
- return hi;
+ break;
+ hi = NULL;
}
+ read_unlock(&hl->host_info_lock);

- return NULL;
+ return hi;
}


@@ -69,16 +71,12 @@
* hpsb_create_hostinfo. */
void *hpsb_get_hostinfo(struct hpsb_highlevel *hl, struct hpsb_host *host)
{
- struct hl_host_info *hi;
- void *data = NULL;
+ struct hl_host_info *hi = hl_get_hostinfo(hl, host);

- read_lock(&hl_drivers_lock);
- hi = hl_get_hostinfo(hl, host);
if (hi)
- data = hi->data;
- read_unlock(&hl_drivers_lock);
+ return hi->data;

- return data;
+ return NULL;
}


@@ -88,10 +86,9 @@
{
struct hl_host_info *hi;
void *data;
+ unsigned long flags;

- read_lock(&hl_drivers_lock);
hi = hl_get_hostinfo(hl, host);
- read_unlock(&hl_drivers_lock);
if (hi) {
HPSB_ERR("%s called hpsb_create_hostinfo when hostinfo already exists",
hl->name);
@@ -112,9 +109,9 @@

hi->host = host;

- write_lock_irq(&hl_drivers_lock);
+ write_lock_irqsave(&hl->host_info_lock, flags);
list_add_tail(&hi->list, &hl->host_info_list);
- write_unlock_irq(&hl_drivers_lock);
+ write_unlock_irqrestore(&hl->host_info_lock, flags);

return data;
}
@@ -124,23 +121,20 @@
void *data)
{
struct hl_host_info *hi;
- int ret = -EINVAL;

- write_lock_irq(&hl_drivers_lock);
hi = hl_get_hostinfo(hl, host);
if (hi) {
if (!hi->size && !hi->data) {
hi->data = data;
- ret = 0;
+ return 0;
} else
HPSB_ERR("%s called hpsb_set_hostinfo when hostinfo already has data",
hl->name);
} else
HPSB_ERR("%s called hpsb_set_hostinfo when no hostinfo exists",
hl->name);
- write_unlock_irq(&hl_drivers_lock);

- return ret;
+ return -EINVAL;
}


@@ -148,13 +142,14 @@
{
struct hl_host_info *hi;

- write_lock_irq(&hl_drivers_lock);
hi = hl_get_hostinfo(hl, host);
if (hi) {
+ unsigned long flags;
+ write_lock_irqsave(&hl->host_info_lock, flags);
list_del(&hi->list);
+ write_unlock_irqrestore(&hl->host_info_lock, flags);
kfree(hi);
}
- write_unlock_irq(&hl_drivers_lock);

return;
}
@@ -164,11 +159,9 @@
{
struct hl_host_info *hi;

- write_lock(&hl_drivers_lock);
hi = hl_get_hostinfo(hl, host);
if (hi)
hi->key = key;
- write_unlock(&hl_drivers_lock);

return;
}
@@ -177,15 +170,12 @@
unsigned long hpsb_get_hostinfo_key(struct hpsb_highlevel *hl, struct hpsb_host *host)
{
struct hl_host_info *hi;
- unsigned long key = 0;

- read_lock(&hl_drivers_lock);
hi = hl_get_hostinfo(hl, host);
if (hi)
- key = hi->key;
- read_unlock(&hl_drivers_lock);
+ return hi->key;

- return key;
+ return 0;
}


@@ -195,7 +185,7 @@
struct hl_host_info *hi;
void *data = NULL;

- read_lock(&hl_drivers_lock);
+ read_lock(&hl->host_info_lock);
list_for_each (lh, &hl->host_info_list) {
hi = list_entry(lh, struct hl_host_info, list);
if (hi->key == key) {
@@ -203,7 +193,7 @@
break;
}
}
- read_unlock(&hl_drivers_lock);
+ read_unlock(&hl->host_info_lock);

return data;
}
@@ -225,6 +215,8 @@
INIT_LIST_HEAD(&hl->addr_list);
INIT_LIST_HEAD(&hl->host_info_list);

+ rwlock_init(&hl->host_info_lock);
+
hl->name = name;
hl->op = ops;

Index: drivers/ieee1394/highlevel.h
===================================================================
--- linux/drivers/ieee1394/highlevel.h (revision 893)
+++ linux/drivers/ieee1394/highlevel.h (working copy)
@@ -14,6 +14,7 @@

/* Used by the highlevel drivers to store data per host */
struct list_head host_info_list;
+ rwlock_t host_info_lock;
};


-
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