On Mon, Dec 11, 2023 at 02:42:51PM +0800, Qiang Yu wrote:

From: Bhaumik Bhatt bbhatt@codeaurora.org

Protect WP accesses such that multiple threads queueing buffers for incoming data do not race.

Meanwhile, if CONFIG_TRACE_IRQFLAGS is enabled, irq will be enabled once __local_bh_enable_ip is called as part of write_unlock_bh. Hence, let's take irqsave lock after TRE is generated to avoid running write_unlock_bh when irqsave lock is held.

Cc: stable@vger.kernel.org Fixes: 189ff97cca53 ("bus: mhi: core: Add support for data transfer") Signed-off-by: Bhaumik Bhatt bbhatt@codeaurora.org Signed-off-by: Qiang Yu quic_qianyu@quicinc.com

Reviewed-by: Manivannan Sadhasivam manivannan.sadhasivam@linaro.org

- Mani

---

drivers/bus/mhi/host/main.c | 22 +++++++++++++--------- 1 file changed, 13 insertions(+), 9 deletions(-)

diff --git a/drivers/bus/mhi/host/main.c b/drivers/bus/mhi/host/main.c index dcf627b..32021fe 100644 --- a/drivers/bus/mhi/host/main.c +++ b/drivers/bus/mhi/host/main.c @@ -1122,17 +1122,15 @@ static int mhi_queue(struct mhi_device *mhi_dev, struct mhi_buf_info *buf_info, if (unlikely(MHI_PM_IN_ERROR_STATE(mhi_cntrl->pm_state))) return -EIO;

• read_lock_irqsave(&mhi_cntrl->pm_lock, flags);
• ret = mhi_is_ring_full(mhi_cntrl, tre_ring);
• if (unlikely(ret)) {

• ret = -EAGAIN;
  

• goto exit_unlock;
  

• }

• if (unlikely(ret))

• return -EAGAIN;
  

ret = mhi_gen_tre(mhi_cntrl, mhi_chan, buf_info, mflags); if (unlikely(ret))

• goto exit_unlock;
  

• return ret;
  

• read_lock_irqsave(&mhi_cntrl->pm_lock, flags);

/* Packet is queued, take a usage ref to exit M3 if necessary * for host->device buffer, balanced put is done on buffer completion @@ -1152,7 +1150,6 @@ static int mhi_queue(struct mhi_device *mhi_dev, struct mhi_buf_info *buf_info, if (dir == DMA_FROM_DEVICE) mhi_cntrl->runtime_put(mhi_cntrl); -exit_unlock: read_unlock_irqrestore(&mhi_cntrl->pm_lock, flags); return ret; @@ -1204,6 +1201,9 @@ int mhi_gen_tre(struct mhi_controller *mhi_cntrl, struct mhi_chan *mhi_chan, int eot, eob, chain, bei; int ret;

• /* Protect accesses for reading and incrementing WP */
• write_lock_bh(&mhi_chan->lock);
• buf_ring = &mhi_chan->buf_ring; tre_ring = &mhi_chan->tre_ring;

@@ -1221,8 +1221,10 @@ int mhi_gen_tre(struct mhi_controller *mhi_cntrl, struct mhi_chan *mhi_chan, if (!info->pre_mapped) { ret = mhi_cntrl->map_single(mhi_cntrl, buf_info);

• if (ret)
  

• if (ret) {
  

• 	write_unlock_bh(&mhi_chan->lock);
  return ret;
  

• }
  

  }

eob = !!(flags & MHI_EOB); @@ -1239,6 +1241,8 @@ int mhi_gen_tre(struct mhi_controller *mhi_cntrl, struct mhi_chan *mhi_chan, mhi_add_ring_element(mhi_cntrl, tre_ring); mhi_add_ring_element(mhi_cntrl, buf_ring);

• write_unlock_bh(&mhi_chan->lock);
• return 0;

} -- 2.7.4