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authorMing Lei <ming.lei@canonical.com>2012-08-04 12:01:23 +0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-08-16 13:28:50 -0700
commit0cfc1e1e7b5347b4b6df1212f365ce6620bdd98f (patch)
tree4d976455cea5dc6055c132b0f9833b01afe5c285 /drivers/base/firmware_class.c
parent2887b3959c8b2f6ed1f62ce95c0888aedb1ea84b (diff)
firmware loader: fix device lifetime
Callers of request_firmware* must hold the reference count of @device, otherwise it is easy to trigger oops since the firmware loader device is the child of @device. This patch adds comments about the usage. In fact, most of drivers call request_firmware* in its probe() or open(), so the constraint should be reasonable and can be satisfied. Also this patch holds the reference count of @device before schedule_work() in request_firmware_nowait() to avoid that the @device is released after request_firmware_nowait returns and before the worker function is scheduled. Signed-off-by: Ming Lei <ming.lei@canonical.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/base/firmware_class.c')
-rw-r--r--drivers/base/firmware_class.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/drivers/base/firmware_class.c b/drivers/base/firmware_class.c
index fc119ce6fdb8..7d3a83bb1318 100644
--- a/drivers/base/firmware_class.c
+++ b/drivers/base/firmware_class.c
@@ -742,6 +742,8 @@ err_put_dev:
* @name will be used as $FIRMWARE in the uevent environment and
* should be distinctive enough not to be confused with any other
* firmware image for this or any other device.
+ *
+ * Caller must hold the reference count of @device.
**/
int
request_firmware(const struct firmware **firmware_p, const char *name,
@@ -823,6 +825,7 @@ static void request_firmware_work_func(struct work_struct *work)
out:
fw_work->cont(fw, fw_work->context);
+ put_device(fw_work->device);
module_put(fw_work->module);
kfree(fw_work);
@@ -841,6 +844,8 @@ static void request_firmware_work_func(struct work_struct *work)
* @cont: function will be called asynchronously when the firmware
* request is over.
*
+ * Caller must hold the reference count of @device.
+ *
* Asynchronous variant of request_firmware() for user contexts where
* it is not possible to sleep for long time. It can't be called
* in atomic contexts.
@@ -869,6 +874,7 @@ request_firmware_nowait(
return -EFAULT;
}
+ get_device(fw_work->device);
INIT_WORK(&fw_work->work, request_firmware_work_func);
schedule_work(&fw_work->work);
return 0;