Messages in this thread | | | Date | Mon, 16 Oct 2023 16:49:08 +0800 | Subject | Re: [PATCH v2 2/2] bus: mhi: host: Take irqsave lock after TRE is generated | From | Qiang Yu <> |
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On 9/29/2023 11:25 PM, Jeffrey Hugo wrote: > On 9/24/2023 10:08 PM, Qiang Yu wrote: >> >> On 9/22/2023 10:50 PM, Jeffrey Hugo wrote: >>> On 9/13/2023 2:47 AM, 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. >>> >>> Where is local_bh_enable() being called? What patch? What is >>> upstream of the codebase you submitted this to? Why is it safe to >>> call mhi_gen_tre() without the lock? >> >> This patch is to fix the issue included by "[PATCH v2 1/2] bus: mhi: >> host: Add spinlock to protect WP access when queueing TREs". In that >> patch, we add write_lock_bh/write_unlock_bh in mhi_gen_tre(). >> >> However, before mhi_gen_tre() is invoked, mhi_cntrl->pm_lock is >> getted, line 1125, and it is a spin lock. So it becomes we want to >> get and release bh lock after spin lock. __local_bh_enable_ip is >> called as part of write_unlock_bh >> >> and local_bh_enable. When CONFIG_TRACE_IRQFLAGS is enabled, irq will >> be enabled once __local_bh_enable_ip is called. The commit message is >> not clear and confusing, will change it in [patch v3]. >> > > In addition to clarifying the commit message, I recommend looking at > adding this to the other patch. It seems very odd to review a series > where one patch introduces a known issue, and a following patch > corrects that issue. It would be better to not introduce the issue in > the first place. OK, will squash two patches into one patch after we achieve an agreement.
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