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ACPI: Avoid walking the list of memory mappings in osl.c twice in a row

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Make acpi_os_unmap_generic_address() use acpi_map_lookup() to find
the desired iomap and drop the reference to it directly (and
eventually remove it if necessary) instead of calling
acpi_os_unmap_memory(), which requires us to walk the list of ACPI
iomaps twice in a row (first, to get the virtual address associated
with the iomap and second, to get the iomap itself).

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
This commit is contained in:
Rafael J. Wysocki 2011-02-08 23:37:53 +01:00
parent 7bbb890358
commit 7fe135dc05
1 changed files with 20 additions and 13 deletions
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33
drivers/acpi/osl.c
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@ -358,6 +358,13 @@ static void acpi_kref_del_iomap(struct kref *ref)
list_del_rcu(&map->list);
}
static void acpi_os_remove_map(struct acpi_ioremap *map)
{
synchronize_rcu();
iounmap(map->virt);
kfree(map);
}
void __ref acpi_os_unmap_memory(void __iomem *virt, acpi_size size)
{
struct acpi_ioremap *map;
@ -372,20 +379,14 @@ void __ref acpi_os_unmap_memory(void __iomem *virt, acpi_size size)
map = acpi_map_lookup_virt(virt, size);
if (!map) {
mutex_unlock(&acpi_ioremap_lock);
printk(KERN_ERR PREFIX "%s: bad address %p\n", __func__, virt);
dump_stack();
WARN(true, PREFIX "%s: bad address %p\n", __func__, virt);
return;
}
del = kref_put(&map->ref, acpi_kref_del_iomap);
mutex_unlock(&acpi_ioremap_lock);
if (!del)
return;
synchronize_rcu();
iounmap(map->virt);
kfree(map);
if (del)
acpi_os_remove_map(map);
}
EXPORT_SYMBOL_GPL(acpi_os_unmap_memory);
@ -414,8 +415,8 @@ static int acpi_os_map_generic_address(struct acpi_generic_address *addr)
static void acpi_os_unmap_generic_address(struct acpi_generic_address *addr)
{
void __iomem *virt;
acpi_size size = addr->bit_width / 8;
struct acpi_ioremap *map;
int del;
if (addr->space_id != ACPI_ADR_SPACE_SYSTEM_MEMORY)
return;
@ -424,10 +425,16 @@ static void acpi_os_unmap_generic_address(struct acpi_generic_address *addr)
return;
mutex_lock(&acpi_ioremap_lock);
virt = acpi_map_vaddr_lookup(addr->address, size);
map = acpi_map_lookup(addr->address, addr->bit_width / 8);
if (!map) {
mutex_unlock(&acpi_ioremap_lock);
return;
}
del = kref_put(&map->ref, acpi_kref_del_iomap);
mutex_unlock(&acpi_ioremap_lock);
acpi_os_unmap_memory(virt, size);
if (del)
acpi_os_remove_map(map);
}
#ifdef ACPI_FUTURE_USAGE