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ACPI: Do not use krefs under a mutex in osl.c 

The reference counting of ACPI iomaps is carried out entirely under
acpi_ioremap_lock, so it is sufficient to use simple counters instead
of krefs for this purpose.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
This commit is contained in:
Rafael J. Wysocki 2011-02-08 23:38:15 +01:00
parent 7ffd0443f2
commit b7c1fadd6c
1 changed files with 16 additions and 20 deletions
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36
drivers/acpi/osl.c
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@ -105,7 +105,7 @@ struct acpi_ioremap {
void __iomem *virt;
acpi_physical_address phys;
acpi_size size;
struct kref ref;
unsigned long refcount;
};
static LIST_HEAD(acpi_ioremaps);
@ -319,7 +319,7 @@ acpi_os_map_memory(acpi_physical_address phys, acpi_size size)
/* Check if there's a suitable mapping already. */
map = acpi_map_lookup(phys, size);
if (map) {
kref_get(&map->ref);
map->refcount++;
goto out;
}
@ -342,7 +342,7 @@ acpi_os_map_memory(acpi_physical_address phys, acpi_size size)
map->virt = virt;
map->phys = pg_off;
map->size = pg_sz;
kref_init(&map->ref);
map->refcount = 1;
list_add_tail_rcu(&map->list, &acpi_ioremaps);
@ -352,25 +352,24 @@ acpi_os_map_memory(acpi_physical_address phys, acpi_size size)
}
EXPORT_SYMBOL_GPL(acpi_os_map_memory);
static void acpi_kref_del_iomap(struct kref *ref)
static void acpi_os_drop_map_ref(struct acpi_ioremap *map)
{
struct acpi_ioremap *map;
map = container_of(ref, struct acpi_ioremap, ref);
list_del_rcu(&map->list);
if (!--map->refcount)
list_del_rcu(&map->list);
}
static void acpi_os_remove_map(struct acpi_ioremap *map)
static void acpi_os_map_cleanup(struct acpi_ioremap *map)
{
synchronize_rcu();
iounmap(map->virt);
kfree(map);
if (!map->refcount) {
synchronize_rcu();
iounmap(map->virt);
kfree(map);
}
}
void __ref acpi_os_unmap_memory(void __iomem *virt, acpi_size size)
{
struct acpi_ioremap *map;
int del;
if (!acpi_gbl_permanent_mmap) {
__acpi_unmap_table(virt, size);
@ -384,11 +383,10 @@ void __ref acpi_os_unmap_memory(void __iomem *virt, acpi_size size)
WARN(true, PREFIX "%s: bad address %p\n", __func__, virt);
return;
}
del = kref_put(&map->ref, acpi_kref_del_iomap);
acpi_os_drop_map_ref(map);
mutex_unlock(&acpi_ioremap_lock);
if (del)
acpi_os_remove_map(map);
acpi_os_map_cleanup(map);
}
EXPORT_SYMBOL_GPL(acpi_os_unmap_memory);
@ -418,7 +416,6 @@ static int acpi_os_map_generic_address(struct acpi_generic_address *addr)
static void acpi_os_unmap_generic_address(struct acpi_generic_address *addr)
{
struct acpi_ioremap *map;
int del;
if (addr->space_id != ACPI_ADR_SPACE_SYSTEM_MEMORY)
return;
@ -432,11 +429,10 @@ static void acpi_os_unmap_generic_address(struct acpi_generic_address *addr)
mutex_unlock(&acpi_ioremap_lock);
return;
}
del = kref_put(&map->ref, acpi_kref_del_iomap);
acpi_os_drop_map_ref(map);
mutex_unlock(&acpi_ioremap_lock);
if (del)
acpi_os_remove_map(map);
acpi_os_map_cleanup(map);
}
#ifdef ACPI_FUTURE_USAGE