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o I'm afraid that wu and wl etc. is just too confusing.... I've changed it

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to up_write() and down_write() etc so that you can see what kind of a lock
   it is (otherwise it could be anything.. semaphore, spinlock, spinlock_bh,
   spinlock_irq, br_lock, etc.)
This commit is contained in:
Steven Whitehouse 2001-09-13 11:29:38 +00:00
parent 2565c99f8b
commit 5c8de1dbd5
1 changed files with 46 additions and 51 deletions
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97
driver/device-mapper/dm.c
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@ -50,11 +50,6 @@ struct io_hook {
kmem_cache_t *_io_hook_cache;
#define rl down_read(&_dev_lock)
#define ru up_read(&_dev_lock)
#define wl down_write(&_dev_lock)
#define wu up_write(&_dev_lock)
struct rw_semaphore _dev_lock;
static struct mapped_device *_devs[MAX_DEVICES];
@ -136,16 +131,16 @@ static int blk_open(struct inode *inode, struct file *file)
if (minor >= MAX_DEVICES)
return -ENXIO;
wl;
down_write(&_dev_lock);
md = _devs[minor];
if (!md || !is_active(md)) {
wu;
up_write(&_dev_lock);
return -ENXIO;
}
md->use_count++;
wu;
up_write(&_dev_lock);
MOD_INC_USE_COUNT;
return 0;
@ -159,16 +154,16 @@ static int blk_close(struct inode *inode, struct file *file)
if (minor >= MAX_DEVICES)
return -ENXIO;
wl;
down_write(&_dev_lock);
md = _devs[minor];
if (!md || md->use_count < 1) {
WARN("reference count in mapped_device incorrect");
wu;
up_write(&_dev_lock);
return -ENXIO;
}
md->use_count--;
wu;
up_write(&_dev_lock);
MOD_DEC_USE_COUNT;
return 0;
@ -276,9 +271,9 @@ static int queue_io(struct mapped_device *md, struct buffer_head *bh, int rw)
if (!di)
return -ENOMEM;
wl;
down_write(&_dev_lock);
if (test_bit(DM_ACTIVE, &md->state)) {
wu;
up_write(&_dev_lock);
return 0;
}
@ -286,7 +281,7 @@ static int queue_io(struct mapped_device *md, struct buffer_head *bh, int rw)
di->rw = rw;
di->next = md->deferred;
md->deferred = di;
wu;
up_write(&_dev_lock);
return 1;
}
@ -366,7 +361,7 @@ static int request(request_queue_t *q, int rw, struct buffer_head *bh)
if (minor >= MAX_DEVICES)
goto bad_no_lock;
rl;
down_read(&_dev_lock);
md = _devs[minor];
if (!md || !md->map)
@ -374,7 +369,7 @@ static int request(request_queue_t *q, int rw, struct buffer_head *bh)
/* if we're suspended we have to queue this io for later */
if (!test_bit(DM_ACTIVE, &md->state)) {
ru;
up_read(&_dev_lock);
r = queue_io(md, bh, rw);
if (r < 0)
@ -383,17 +378,17 @@ static int request(request_queue_t *q, int rw, struct buffer_head *bh)
else if (r > 0)
return 0; /* deferred successfully */
rl; /* FIXME: there's still a race here */
down_read(&_dev_lock); /* FIXME: there's still a race here */
}
if (!__map_buffer(md, bh, __find_node(md->map, bh)))
goto bad;
ru;
up_read(&_dev_lock);
return 1;
bad:
ru;
up_read(&_dev_lock);
bad_no_lock:
buffer_IO_error(bh);
@ -439,12 +434,12 @@ static struct mapped_device *alloc_dev(int minor)
struct mapped_device *md = kmalloc(sizeof(*md), GFP_KERNEL);
memset(md, 0, sizeof(*md));
wl;
down_write(&_dev_lock);
minor = (minor < 0) ? __any_old_dev() : __specific_dev(minor);
if (minor < 0) {
WARN("no free devices available");
wu;
up_write(&_dev_lock);
kfree(md);
return 0;
}
@ -456,7 +451,7 @@ static struct mapped_device *alloc_dev(int minor)
init_waitqueue_head(&md->wait);
_devs[minor] = md;
wu;
up_write(&_dev_lock);
return md;
}
@ -538,9 +533,9 @@ struct mapped_device *dm_find_by_name(const char *name)
{
struct mapped_device *md;
rl;
down_read(&_dev_lock);
md = __find_by_name(name);
ru;
up_read(&_dev_lock);
return md;
}
@ -549,9 +544,9 @@ struct mapped_device *dm_find_by_minor(int minor)
{
struct mapped_device *md;
rl;
down_read(&_dev_lock);
md = _devs[minor];
ru;
up_read(&_dev_lock);
return md;
}
@ -590,11 +585,11 @@ int dm_create(const char *name, int minor)
if (!(md = alloc_dev(minor)))
return -ENOMEM;
wl;
down_write(&_dev_lock);
if (__find_by_name(name)) {
WARN("device with that name already exists");
kfree(md);
wu;
up_write(&_dev_lock);
return -EINVAL;
}
@ -602,10 +597,10 @@ int dm_create(const char *name, int minor)
_devs[minor] = md;
if ((r = register_device(md))) {
wu;
up_write(&_dev_lock);
return r;
}
wu;
up_write(&_dev_lock);
return 0;
}
@ -620,26 +615,26 @@ int dm_remove(const char *name)
struct mapped_device *md;
int minor, r;
wl;
down_write(&_dev_lock);
if (!(md = __find_by_name(name))) {
wu;
up_write(&_dev_lock);
return -ENXIO;
}
if (md->use_count) {
wu;
up_write(&_dev_lock);
return -EPERM;
}
if ((r = unregister_device(md))) {
wu;
up_write(&_dev_lock);
return r;
}
minor = MINOR(md->dev);
kfree(md);
_devs[minor] = 0;
wu;
up_write(&_dev_lock);
return 0;
}
@ -708,24 +703,24 @@ int dm_activate(struct mapped_device *md, struct dm_table *table)
if (!table->num_targets)
return -EINVAL;
wl;
down_write(&_dev_lock);
/* you must be deactivated first */
if (is_active(md)) {
wu;
up_write(&_dev_lock);
return -EPERM;
}
__bind(md, table);
if ((r = open_devices(md->map->devices))) {
wu;
up_write(&_dev_lock);
return r;
}
set_bit(DM_ACTIVE, &md->state);
__flush_deferred_io(md);
wu;
up_write(&_dev_lock);
return 0;
}
@ -736,27 +731,27 @@ int dm_activate(struct mapped_device *md, struct dm_table *table)
*/
int dm_deactivate(struct mapped_device *md)
{
rl;
down_read(&_dev_lock);
if (md->use_count) {
ru;
up_read(&_dev_lock);
return -EPERM;
}
fsync_dev(md->dev);
ru;
up_read(&_dev_lock);
wl;
down_write(&_dev_lock);
if (md->use_count) {
/* drat, somebody got in quick ... */
wu;
up_write(&_dev_lock);
return -EPERM;
}
close_devices(md->map->devices);
md->map = 0;
clear_bit(DM_ACTIVE, &md->state);
wu;
up_write(&_dev_lock);
return 0;
}
@ -774,24 +769,24 @@ void dm_suspend(struct mapped_device *md)
{
DECLARE_WAITQUEUE(wait, current);
wl;
down_write(&_dev_lock);
if (!is_active(md)) {
wu;
up_write(&_dev_lock);
return;
}
clear_bit(DM_ACTIVE, &md->state);
wu;
up_write(&_dev_lock);
/* wait for all the pending io to flush */
add_wait_queue(&md->wait, &wait);
current->state = TASK_INTERRUPTIBLE;
do {
wl;
down_write(&_dev_lock);
if (!atomic_read(&md->pending))
break;
wu;
up_write(&_dev_lock);
schedule();
} while (1);
@ -802,7 +797,7 @@ void dm_suspend(struct mapped_device *md)
close_devices(md->map->devices);
md->map = 0;
wu;
up_write(&_dev_lock);
}