The patch below does not apply to the 5.10-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.10.y git checkout FETCH_HEAD git cherry-pick -x b89b6a863dd53bc70d8e52d50f9cfaef8ef5e9c9 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2024012614-satiable-cheese-4655@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^..

Possible dependencies:

b89b6a863dd5 ("bus: mhi: host: Add spinlock to protect WP access when queueing TREs") a0f5a630668c ("bus: mhi: Move host MHI code to "host" directory") 4547a749be99 ("bus: mhi: core: Fix MHI runtime_pm behavior") 68731852f6e5 ("bus: mhi: core: Return EAGAIN if MHI ring is full") a8f75cb348fd ("mhi: core: Factorize mhi queuing") 855a70c12021 ("bus: mhi: Add MHI PCI support for WWAN modems")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From b89b6a863dd53bc70d8e52d50f9cfaef8ef5e9c9 Mon Sep 17 00:00:00 2001 From: Bhaumik Bhatt bbhatt@codeaurora.org Date: Mon, 11 Dec 2023 14:42:51 +0800 Subject: [PATCH] bus: mhi: host: Add spinlock to protect WP access when queueing TREs

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: Jeffrey Hugo quic_jhugo@quicinc.com Tested-by: Jeffrey Hugo quic_jhugo@quicinc.com Reviewed-by: Manivannan Sadhasivam manivannan.sadhasivam@linaro.org Link: https://lore.kernel.org/r/1702276972-41296-2-git-send-email-quic_qianyu@quic... Signed-off-by: Manivannan Sadhasivam manivannan.sadhasivam@linaro.org

diff --git a/drivers/bus/mhi/host/main.c b/drivers/bus/mhi/host/main.c index d80975f4bba8..ad7807e4b523 100644 --- a/drivers/bus/mhi/host/main.c +++ b/drivers/bus/mhi/host/main.c @@ -1124,17 +1124,15 @@ 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 @@ -1154,7 +1152,6 @@ 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; @@ -1206,6 +1203,9 @@ 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;

@@ -1223,8 +1223,10 @@ 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); @@ -1241,6 +1243,8 @@ 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; }