From b7c1fadd6c2eead56d0664a3a921980120de0c11 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Tue, 8 Feb 2011 23:38:15 +0100 Subject: [PATCH] ACPI: Do not use krefs under a mutex in osl.c The reference counting of ACPI iomaps is carried out entirely under acpi_ioremap_lock, so it is sufficient to use simple counters instead of krefs for this purpose. Signed-off-by: Rafael J. Wysocki --- drivers/acpi/osl.c | 36 ++++++++++++++++-------------------- 1 file changed, 16 insertions(+), 20 deletions(-) diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c index 445f205752a2..5389f9f2e2ff 100644 --- a/drivers/acpi/osl.c +++ b/drivers/acpi/osl.c @@ -105,7 +105,7 @@ struct acpi_ioremap { void __iomem *virt; acpi_physical_address phys; acpi_size size; - struct kref ref; + unsigned long refcount; }; static LIST_HEAD(acpi_ioremaps); @@ -319,7 +319,7 @@ acpi_os_map_memory(acpi_physical_address phys, acpi_size size) /* Check if there's a suitable mapping already. */ map = acpi_map_lookup(phys, size); if (map) { - kref_get(&map->ref); + map->refcount++; goto out; } @@ -342,7 +342,7 @@ acpi_os_map_memory(acpi_physical_address phys, acpi_size size) map->virt = virt; map->phys = pg_off; map->size = pg_sz; - kref_init(&map->ref); + map->refcount = 1; list_add_tail_rcu(&map->list, &acpi_ioremaps); @@ -352,25 +352,24 @@ acpi_os_map_memory(acpi_physical_address phys, acpi_size size) } EXPORT_SYMBOL_GPL(acpi_os_map_memory); -static void acpi_kref_del_iomap(struct kref *ref) +static void acpi_os_drop_map_ref(struct acpi_ioremap *map) { - struct acpi_ioremap *map; - - map = container_of(ref, struct acpi_ioremap, ref); - list_del_rcu(&map->list); + if (!--map->refcount) + list_del_rcu(&map->list); } -static void acpi_os_remove_map(struct acpi_ioremap *map) +static void acpi_os_map_cleanup(struct acpi_ioremap *map) { - synchronize_rcu(); - iounmap(map->virt); - kfree(map); + if (!map->refcount) { + synchronize_rcu(); + iounmap(map->virt); + kfree(map); + } } void __ref acpi_os_unmap_memory(void __iomem *virt, acpi_size size) { struct acpi_ioremap *map; - int del; if (!acpi_gbl_permanent_mmap) { __acpi_unmap_table(virt, size); @@ -384,11 +383,10 @@ void __ref acpi_os_unmap_memory(void __iomem *virt, acpi_size size) WARN(true, PREFIX "%s: bad address %p\n", __func__, virt); return; } - del = kref_put(&map->ref, acpi_kref_del_iomap); + acpi_os_drop_map_ref(map); mutex_unlock(&acpi_ioremap_lock); - if (del) - acpi_os_remove_map(map); + acpi_os_map_cleanup(map); } EXPORT_SYMBOL_GPL(acpi_os_unmap_memory); @@ -418,7 +416,6 @@ static int acpi_os_map_generic_address(struct acpi_generic_address *addr) static void acpi_os_unmap_generic_address(struct acpi_generic_address *addr) { struct acpi_ioremap *map; - int del; if (addr->space_id != ACPI_ADR_SPACE_SYSTEM_MEMORY) return; @@ -432,11 +429,10 @@ static void acpi_os_unmap_generic_address(struct acpi_generic_address *addr) mutex_unlock(&acpi_ioremap_lock); return; } - del = kref_put(&map->ref, acpi_kref_del_iomap); + acpi_os_drop_map_ref(map); mutex_unlock(&acpi_ioremap_lock); - if (del) - acpi_os_remove_map(map); + acpi_os_map_cleanup(map); } #ifdef ACPI_FUTURE_USAGE -- 2.20.1