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Commit 7ffd0443 authored by Rafael J. Wysocki's avatar Rafael J. Wysocki
Browse files

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: default avatarRafael J. Wysocki <rjw@sisk.pl>
parent 7fe135dc

drivers/acpi/osl.c

+15 −13
Original line number Diff line number Diff line
@@ -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);