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authorBhaumik Bhatt <bbhatt@codeaurora.org>2023-12-11 09:42:51 +0300
committerManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>2023-12-16 08:20:08 +0300
commitb89b6a863dd53bc70d8e52d50f9cfaef8ef5e9c9 (patch)
tree6bd9563b95e9caeb175a9c39e56c048e5ded2160 /drivers/bus
parent327ec5f70609cf00c6f961073c01857555c6a8eb (diff)
downloadlinux-b89b6a863dd53bc70d8e52d50f9cfaef8ef5e9c9.tar.xz
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@quicinc.com Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Diffstat (limited to 'drivers/bus')
-rw-r--r--drivers/bus/mhi/host/main.c22
1 files changed, 13 insertions, 9 deletions
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;
}