From a99b661c3187365f81026d89b1133a76cd2652b3 Mon Sep 17 00:00:00 2001 From: Loic Poulain Date: Fri, 26 Feb 2021 11:53:02 +0100 Subject: [PATCH] bus: mhi: core: Fix invalid error returning in mhi_queue commit 0ecc1c70dcd32c0f081b173a1a5d89952686f271 upstream. mhi_queue returns an error when the doorbell is not accessible in the current state. This can happen when the device is in non M0 state, like M3, and needs to be waken-up prior ringing the DB. This case is managed earlier by triggering an asynchronous M3 exit via controller resume/suspend callbacks, that in turn will cause M0 transition and DB update. So, since it's not an error but just delaying of doorbell update, there is no reason to return an error. This also fixes a use after free error for skb case, indeed a caller queuing skb will try to free the skb if the queueing fails, but in that case queueing has been done. Fixes: a8f75cb348fd ("mhi: core: Factorize mhi queuing") Signed-off-by: Loic Poulain Reviewed-by: Jeffrey Hugo Reviewed-by: Bhaumik Bhatt Reviewed-by: Manivannan Sadhasivam Link: https://lore.kernel.org/r/1614336782-5809-1-git-send-email-loic.poulain@linaro.org Signed-off-by: Manivannan Sadhasivam Signed-off-by: Greg Kroah-Hartman --- drivers/bus/mhi/core/main.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-) diff --git a/drivers/bus/mhi/core/main.c b/drivers/bus/mhi/core/main.c index 1068234e6c7e8..34dd430624e4f 100644 --- a/drivers/bus/mhi/core/main.c +++ b/drivers/bus/mhi/core/main.c @@ -1077,12 +1077,8 @@ static int mhi_queue(struct mhi_device *mhi_dev, struct mhi_buf_info *buf_info, if (mhi_chan->dir == DMA_TO_DEVICE) atomic_inc(&mhi_cntrl->pending_pkts); - if (unlikely(!MHI_DB_ACCESS_VALID(mhi_cntrl))) { - ret = -EIO; - goto exit_unlock; - } - - mhi_ring_chan_db(mhi_cntrl, mhi_chan); + if (likely(MHI_DB_ACCESS_VALID(mhi_cntrl))) + mhi_ring_chan_db(mhi_cntrl, mhi_chan); if (dir == DMA_FROM_DEVICE) mhi_cntrl->runtime_put(mhi_cntrl); -- 2.47.3