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SubjectRe: [PATCH v3 4/4] bus: mhi: host: Take irqsave lock after TRE is generated
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On 11/10/2023 12:29 AM, Manivannan Sadhasivam wrote:
> On Tue, Nov 07, 2023 at 03:16:05PM +0800, Qiang Yu wrote:
>> From: Hemant Kumar <quic_hemantk@quicinc.com>
>>
>> Take irqsave lock after TRE is generated to avoid deadlock due to core
>> getting interrupts enabled as local_bh_enable must not be called with
>> irqs disabled based on upstream patch.
>>
> You still didn't address any of the comments provided by Jeff in v2.
>
> - Mani

Hi Mani, thanks for review. Sorry, missing this part. Will change to
following commit message.

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.

>> 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 b137d54..93b5110 100644
>> --- a/drivers/bus/mhi/host/main.c
>> +++ b/drivers/bus/mhi/host/main.c
>> @@ -1129,17 +1129,15 @@ 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
>> @@ -1159,7 +1157,6 @@ 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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