ACPI: Avoid walking the list of memory mappings in osl.c twice in a row
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>
diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
index 9706192..f6785bc 100644
--- a/drivers/acpi/osl.c
+++ b/drivers/acpi/osl.c
@@ -358,6 +358,13 @@
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 @@
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 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 @@
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