[PATCH 3/8] ACPI: Change acpi_ioremap_lock into a mutex

Rafael J. Wysocki
2011-01-24T23:34:54Z

From: Rafael J. Wysocki <rjw@sisk.pl>

There's no reason why acpi_ioremap_lock has to be a spinlock,
because all of the functions it is used in may sleep anyway and
there's no reason why it should be locked with interrupts off.
Use a mutex instead (that's going to allow us to put some more
operations under the lock later).

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
---
drivers/acpi/osl.c | 21 +++++++++------------
1 file changed, 9 insertions(+), 12 deletions(-)

Index: linux-2.6/drivers/acpi/osl.c
===================================================================
--- linux-2.6.orig/drivers/acpi/osl.c
+++ linux-2.6/drivers/acpi/osl.c
@@ -109,7 +109,7 @@ struct acpi_ioremap {
};

static LIST_HEAD(acpi_ioremaps);
-static DEFINE_SPINLOCK(acpi_ioremap_lock);
+static DEFINE_MUTEX(acpi_ioremap_lock);

static void __init acpi_osi_setup_late(void);

@@ -303,7 +303,6 @@ void __iomem *__init_refok
acpi_os_map_memory(acpi_physical_address phys, acpi_size size)
{
struct acpi_ioremap *map, *tmp_map;
- unsigned long flags;
void __iomem *virt;
acpi_physical_address pg_off;
acpi_size pg_sz;
@@ -334,18 +333,18 @@ acpi_os_map_memory(acpi_physical_address
map->size = pg_sz;
kref_init(&map->ref);

- spin_lock_irqsave(&acpi_ioremap_lock, flags);
+ 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);
- spin_unlock_irqrestore(&acpi_ioremap_lock, flags);
+ 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);
- spin_unlock_irqrestore(&acpi_ioremap_lock, flags);
+ mutex_unlock(&acpi_ioremap_lock);

return map->virt + (phys - map->phys);
}
@@ -362,7 +361,6 @@ static void acpi_kref_del_iomap(struct k
void __ref acpi_os_unmap_memory(void __iomem *virt, acpi_size size)
{
struct acpi_ioremap *map;
- unsigned long flags;
int del;

if (!acpi_gbl_permanent_mmap) {
@@ -370,17 +368,17 @@ void __ref acpi_os_unmap_memory(void __i
return;
}

- spin_lock_irqsave(&acpi_ioremap_lock, flags);
+ mutex_lock(&acpi_ioremap_lock);
map = acpi_map_lookup_virt(virt, size);
if (!map) {
- spin_unlock_irqrestore(&acpi_ioremap_lock, flags);
+ mutex_unlock(&acpi_ioremap_lock);
printk(KERN_ERR PREFIX "%s: bad address %p\n", __func__, virt);
dump_stack();
return;
}

del = kref_put(&map->ref, acpi_kref_del_iomap);
- spin_unlock_irqrestore(&acpi_ioremap_lock, flags);
+ mutex_unlock(&acpi_ioremap_lock);

if (!del)
return;
@@ -417,7 +415,6 @@ static int acpi_os_map_generic_address(s
static void acpi_os_unmap_generic_address(struct acpi_generic_address *addr)
{
void __iomem *virt;
- unsigned long flags;
acpi_size size = addr->bit_width / 8;

if (addr->space_id != ACPI_ADR_SPACE_SYSTEM_MEMORY)
@@ -426,9 +423,9 @@ static void acpi_os_unmap_generic_addres
if (!addr->address || !addr->bit_width)
return;

- spin_lock_irqsave(&acpi_ioremap_lock, flags);
+ mutex_lock(&acpi_ioremap_lock);
virt = acpi_map_vaddr_lookup(addr->address, size);
- spin_unlock_irqrestore(&acpi_ioremap_lock, flags);
+ mutex_unlock(&acpi_ioremap_lock);

acpi_os_unmap_memory(virt, size);
}