Messages in this thread | | | Date | Thu, 7 Dec 2023 17:20:51 +0800 | Subject | Re: [PATCH v4 4/4] bus: mhi: host: Take irqsave lock after TRE is generated | From | Qiang Yu <> |
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On 12/7/2023 2:38 PM, Manivannan Sadhasivam wrote: > On Mon, Nov 27, 2023 at 03:19:49PM +0800, Qiang Yu wrote: >> On 11/24/2023 6:09 PM, Manivannan Sadhasivam wrote: >>> On Tue, Nov 14, 2023 at 01:27:41PM +0800, Qiang Yu wrote: >>>> From: Hemant Kumar <quic_hemantk@quicinc.com> >>>> >>>> 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 >>> "__local_bh_enable_ip" is a function name, so you should not break it. >> Thanks for let me know, will note this in following patch. >>>> lock after TRE is generated to avoid running write_unlock_bh when irqsave >>>> lock is held. >>>> >>> I still don't understand this commit message. Where is the write_unlock_bh() >>> being called? >>> >>> - Mani >> Write_unlock_bh() is invoked in mhi_gen_te() >> The calling flow is like >> mhi_queue >> read_lock_irqsave(&mhi_cntrl->pm_lock, flags) >> mhi_gen_tre >> write_lock_bh(&mhi_chan->lock) >> write_unlock_bh(&mhi_chan->lock) // Will enable irq if >> CONFIG_TRACE_IRQFLAGS is enabled >> read_lock_irqsave(&mhi_cntrl->pm_lock, flags) >> >> after adding this patch, the calling flow becomes >> >> mhi_queue >> mhi_gen_tre >> write_lock_bh(&mhi_chan->lock) >> write_unlock_bh(&mhi_chan->lock) >> read_lock_irqsave(&mhi_cntrl->pm_lock, flags) >> read_lock_irqsave(&mhi_cntrl->pm_lock, flags) > So this patch essentially fixes the issue caused by patch 1? If so, this should > be squashed into patch 1. > > - Mani
Yes, this patch is to fix the issue caused by patch 1. Will squash patch 1 and this patch into one patch
in next version.
> >>>> Signed-off-by: Hemant Kumar <quic_hemantk@quicinc.com> >>>> Signed-off-by: Lazarus Motha <quic_lmotha@quicinc.com> >>>> Signed-off-by: Qiang Yu <quic_qianyu@quicinc.com> >>>> --- >>>> drivers/bus/mhi/host/main.c | 13 +++++-------- >>>> 1 file changed, 5 insertions(+), 8 deletions(-) >>>> >>>> diff --git a/drivers/bus/mhi/host/main.c b/drivers/bus/mhi/host/main.c >>>> index 33f27e2..d7abd0b 100644 >>>> --- a/drivers/bus/mhi/host/main.c >>>> +++ b/drivers/bus/mhi/host/main.c >>>> @@ -1128,17 +1128,15 @@ 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 >>>> @@ -1158,7 +1156,6 @@ 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; >>>> -- >>>> 2.7.4 >>>> >>>>
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