From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Rafael J. Wysocki" Subject: [PATCH 8/11] ACPI: Do not use krefs under a mutex in osl.c Date: Thu, 20 Jan 2011 12:34:57 +0100 Message-ID: <201101201234.57619.rjw@sisk.pl> References: <201101201226.41021.rjw@sisk.pl> Mime-Version: 1.0 Content-Type: Text/Plain; charset="utf-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <201101201226.41021.rjw@sisk.pl> Sender: linux-kernel-owner@vger.kernel.org To: Len Brown Cc: Jeff Chua , LKML , ACPI Devel Maling List , Linux-pm mailing list , Matthew Garrett List-Id: linux-acpi@vger.kernel.org From: Rafael J. Wysocki 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(-) Index: linux-2.6/drivers/acpi/osl.c =================================================================== --- linux-2.6.orig/drivers/acpi/osl.c +++ linux-2.6/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 /* 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 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 } 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 __i 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(s 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_addres 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