[PATCH v2] usb: gadget: function: fix missing spinlock in f_uac1_legacy

[PATCH v2] usb: gadget: function: fix missing spinlock in f_uac1_legacy

[qiang.zhang]

From: Zhang Qiang <qiang.zhang@windriver.com>

Add a missing spinlock protection to the add operation of the "audio->play_queue"
in "f_audio_out_ep_complete" function.

Signed-off-by: Zhang Qiang <qiang.zhang@windriver.com>
---
 v1->v2:
 Add changelog text.

 drivers/usb/gadget/function/f_uac1_legacy.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/usb/gadget/function/f_uac1_legacy.c b/drivers/usb/gadget/function/f_uac1_legacy.c
index 349deae7cabd..e2d7f69128a0 100644
--- a/drivers/usb/gadget/function/f_uac1_legacy.c
+++ b/drivers/usb/gadget/function/f_uac1_legacy.c
@@ -336,7 +336,9 @@ static int f_audio_out_ep_complete(struct usb_ep *ep, struct usb_request *req)
 
 	/* Copy buffer is full, add it to the play_queue */
 	if (audio_buf_size - copy_buf->actual < req->actual) {
+		spin_lock_irq(&audio->lock);
 		list_add_tail(&copy_buf->list, &audio->play_queue);
+		spin_unlock_irq(&audio->lock);
 		schedule_work(&audio->playback_work);
 		copy_buf = f_audio_buffer_alloc(audio_buf_size);
 		if (IS_ERR(copy_buf))
-- 
2.24.1

Re: [PATCH v2] usb: gadget: function: fix missing spinlock in f_uac1_legacy

[Greg KH]

On Sun, Jul 05, 2020 at 02:16:16PM +0800, qiang.zhang@windriver.com wrote:
> From: Zhang Qiang <qiang.zhang@windriver.com>
> 
> Add a missing spinlock protection to the add operation of the "audio->play_queue"
> in "f_audio_out_ep_complete" function.

That says _what_ you did, but not _why_ you did that.  Why is a lock
needed here?  What does this protect?

What kernel commit does this "fix"?  Put that in the "Fixes:" line, and
probably you need a "cc: stable" in that area too, right?

thanks,

greg k-h

回复: [PATCH v2] usb: gadget: function: fix missing spinlock in f_uac1_legacy

[Zhang, Qiang]

Thanks for your suggestin Greg KH
I think there is not need fix tags. I will resend.

thanks,
Zhang Qiang

________________________________________
发件人: Greg KH <gregkh@linuxfoundation.org>
发送时间: 2020年7月6日 18:31
收件人: Zhang, Qiang
抄送: balbi@kernel.org; colin.king@canonical.com; linux-usb@vger.kernel.org; linux-kernel@vger.kernel.org
主题: Re: [PATCH v2] usb: gadget: function: fix missing spinlock in f_uac1_legacy

On Sun, Jul 05, 2020 at 02:16:16PM +0800, qiang.zhang@windriver.com wrote:
> From: Zhang Qiang <qiang.zhang@windriver.com>
>
> Add a missing spinlock protection to the add operation of the "audio->play_queue"
> in "f_audio_out_ep_complete" function.

That says _what_ you did, but not _why_ you did that.  Why is a lock
needed here?  What does this protect?

What kernel commit does this "fix"?  Put that in the "Fixes:" line, and
probably you need a "cc: stable" in that area too, right?

thanks,

greg k-h

[PATCH v2] usb: gadget: function: fix missing spinlock in f_uac1_legacy

[qiang.zhang]

From: Zhang Qiang <qiang.zhang@windriver.com>

Add a missing spinlock protection to the add operation of the play_queue
in "f_audio_out_ep_complete" function.

Signed-off-by: Zhang Qiang <qiang.zhang@windriver.com>
---
 v1->v2:
 Add missing changelog.

 drivers/usb/gadget/function/f_uac1_legacy.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/usb/gadget/function/f_uac1_legacy.c b/drivers/usb/gadget/function/f_uac1_legacy.c
index 349deae7cabd..e2d7f69128a0 100644
--- a/drivers/usb/gadget/function/f_uac1_legacy.c
+++ b/drivers/usb/gadget/function/f_uac1_legacy.c
@@ -336,7 +336,9 @@ static int f_audio_out_ep_complete(struct usb_ep *ep, struct usb_request *req)
 
 	/* Copy buffer is full, add it to the play_queue */
 	if (audio_buf_size - copy_buf->actual < req->actual) {
+		spin_lock_irq(&audio->lock);
 		list_add_tail(&copy_buf->list, &audio->play_queue);
+		spin_unlock_irq(&audio->lock);
 		schedule_work(&audio->playback_work);
 		copy_buf = f_audio_buffer_alloc(audio_buf_size);
 		if (IS_ERR(copy_buf))
-- 
2.24.1