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Commit 7fe135dc authored by Rafael J. Wysocki's avatar Rafael J. Wysocki
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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: default avatarRafael J. Wysocki <rjw@sisk.pl>
parent 7bbb8903

drivers/acpi/osl.c

+20 −13
Original line number Diff line number Diff line
@@ -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