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ACPI: Make acpi_os_map_memory() avoid creating unnecessary mappings 

Modify acpi_os_map_memory() so that it doesn't call acpi_os_ioremap()
unconditionally every time it is executed (except when
acpi_gbl_permanent_mmap is unset), which pretty much defeats the
purpose of maintaining the list of ACPI iomaps in osl.c.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
This commit is contained in:
Rafael J. Wysocki 2011-02-08 23:38:05 +01:00
parent 7fe135dc05
commit 7ffd0443f2
1 changed files with 15 additions and 13 deletions
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28
drivers/acpi/osl.c
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@ -302,7 +302,7 @@ acpi_map_lookup_virt(void __iomem *virt, acpi_size size)
void __iomem *__init_refok
acpi_os_map_memory(acpi_physical_address phys, acpi_size size)
{
struct acpi_ioremap *map, *tmp_map;
struct acpi_ioremap *map;
void __iomem *virt;
acpi_physical_address pg_off;
acpi_size pg_sz;
@ -315,14 +315,25 @@ acpi_os_map_memory(acpi_physical_address phys, acpi_size size)
if (!acpi_gbl_permanent_mmap)
return __acpi_map_table((unsigned long)phys, size);
mutex_lock(&acpi_ioremap_lock);
/* Check if there's a suitable mapping already. */
map = acpi_map_lookup(phys, size);
if (map) {
kref_get(&map->ref);
goto out;
}
map = kzalloc(sizeof(*map), GFP_KERNEL);
if (!map)
if (!map) {
mutex_unlock(&acpi_ioremap_lock);
return NULL;
}
pg_off = round_down(phys, PAGE_SIZE);
pg_sz = round_up(phys + size, PAGE_SIZE) - pg_off;
virt = acpi_os_ioremap(pg_off, pg_sz);
if (!virt) {
mutex_unlock(&acpi_ioremap_lock);
kfree(map);
return NULL;
}
@ -333,19 +344,10 @@ acpi_os_map_memory(acpi_physical_address phys, acpi_size size)
map->size = pg_sz;
kref_init(&map->ref);
mutex_lock(&acpi_ioremap_lock);
/* Check if page has already been mapped. */
tmp_map = acpi_map_lookup(phys, size);
if (tmp_map) {
kref_get(&tmp_map->ref);
mutex_unlock(&acpi_ioremap_lock);
iounmap(map->virt);
kfree(map);
return tmp_map->virt + (phys - tmp_map->phys);
}
list_add_tail_rcu(&map->list, &acpi_ioremaps);
mutex_unlock(&acpi_ioremap_lock);
out:
mutex_unlock(&acpi_ioremap_lock);
return map->virt + (phys - map->phys);
}
EXPORT_SYMBOL_GPL(acpi_os_map_memory);