Merge "drivers: mailbox: fix race resulting in multiple message submission" (79db072a) · Commits · e / devices / android_kernel_fairphone_FP3

drivers/mailbox/mailbox.c

+13 −6

Original line number	Diff line number	Diff line
		@@ -53,17 +53,16 @@ static int add_to_rbuf(struct mbox_chan chan, void mssg)
		return idx;
		}

		static void msg_submit(struct mbox_chan *chan)
		static int __msg_submit(struct mbox_chan *chan)
		{
		unsigned count, idx;
		unsigned long flags;
		void *data;
		int err = -EBUSY;

		again:
		spin_lock_irqsave(&chan->lock, flags);

		if (!chan->msg_count \|\| (chan->active_req && err != -EAGAIN))
		if (!chan->msg_count \|\| chan->active_req)
		goto exit;

		count = chan->msg_count;
		@@ -86,15 +85,23 @@ static void msg_submit(struct mbox_chan *chan)
		exit:
		spin_unlock_irqrestore(&chan->lock, flags);

		return err;
		}

		static void msg_submit(struct mbox_chan *chan)
		{
		int err = 0;

		/*
		* If the controller returns -EAGAIN, then it means, our spinlock
		* here is preventing the controller from receiving its interrupt,
		* that would help clear the controller channels that are currently
		* blocked waiting on the interrupt response.
		* Unlock and retry again.
		* Retry again.
		*/
		if (err == -EAGAIN)
		goto again;
		do {
		err = __msg_submit(chan);
		} while (err == -EAGAIN);

		if (!err && (chan->txdone_method & TXDONE_BY_POLL))
		/* kick start the timer immediately to avoid delays */