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dm target: use module refcount directly

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The tt_internal's 'use' field is superfluous: the module's refcount can do
the work properly.  An acceptable side-effect is that this increases the
reference counts reported by 'lsmod'.

Remove the superfluous test when removing a target module.

[Crash possible without this on SMP - agk]

Cc: stable@kernel.org
Signed-off-by: Cheng Renquan <crquan@gmail.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Reviewed-by: Alasdair G Kergon <agk@redhat.com>
Reviewed-by: Jonathan Brassow <jbrassow@redhat.com>
This commit is contained in:
Cheng Renquan
2009-04-02 19:55:27 +01:00
committed by Alasdair G Kergon
parent 35bf659b00
commit 5642b8a61a
1 changed files with 3 additions and 17 deletions
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20
drivers/md/dm-target.c
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@@ -18,7 +18,6 @@ struct tt_internal {
struct target_type tt; struct target_type tt;
struct list_head list; struct list_head list;
long use;
}; };
static LIST_HEAD(_targets); static LIST_HEAD(_targets);
@@ -44,12 +43,8 @@ static struct tt_internal *get_target_type(const char *name)
down_read(&_lock); down_read(&_lock);
ti = __find_target_type(name); ti = __find_target_type(name);
if (ti) { if (ti && !try_module_get(ti->tt.module))
if ((ti->use == 0) && !try_module_get(ti->tt.module)) ti = NULL;
ti = NULL;
else
ti->use++;
}
up_read(&_lock); up_read(&_lock);
return ti; return ti;
@@ -77,10 +72,7 @@ void dm_put_target_type(struct target_type *t)
struct tt_internal *ti = (struct tt_internal *) t; struct tt_internal *ti = (struct tt_internal *) t;
down_read(&_lock); down_read(&_lock);
if (--ti->use == 0) module_put(ti->tt.module);
module_put(ti->tt.module);
BUG_ON(ti->use < 0);
up_read(&_lock); up_read(&_lock);
return; return;
@@ -140,12 +132,6 @@ void dm_unregister_target(struct target_type *t)
BUG(); BUG();
} }
if (ti->use) {
DMCRIT("Attempt to unregister target still in use: %s",
t->name);
BUG();
}
list_del(&ti->list); list_del(&ti->list);
kfree(ti); kfree(ti);