From ce16274a6b8d1483d0d8383272deb2bfd1b577ca Mon Sep 17 00:00:00 2001 From: Bhaumik Bhatt Date: Mon, 11 Dec 2023 14:42:51 +0800 Subject: [PATCH] bus: mhi: host: Add spinlock to protect WP access when queueing TREs commit b89b6a863dd53bc70d8e52d50f9cfaef8ef5e9c9 upstream. 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 Signed-off-by: Qiang Yu Reviewed-by: Jeffrey Hugo Tested-by: Jeffrey Hugo Reviewed-by: Manivannan Sadhasivam Link: https://lore.kernel.org/r/1702276972-41296-2-git-send-email-quic_qianyu@quicinc.com Signed-off-by: Manivannan Sadhasivam Signed-off-by: Greg Kroah-Hartman --- 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 25a4745..d6653cb 100644 --- a/drivers/bus/mhi/host/main.c +++ b/drivers/bus/mhi/host/main.c @@ -1127,17 +1127,15 @@ 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 @@ -1157,7 +1155,6 @@ 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; @@ -1209,6 +1206,9 @@ 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; @@ -1226,8 +1226,10 @@ 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); @@ -1244,6 +1246,8 @@ 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