| Message ID | 1699939661-7385-5-git-send-email-quic_qianyu@quicinc.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | bus: mhi: host: Add lock to avoid race when ringing channel DB | expand |
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. > 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 > 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 > >
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) > >> 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 >> >>
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 > > > > > 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 > > > > > > >
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 >>>> >>>>
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;