Sinan, I explained the reason why locks don't protect this case in the patch description part. Write side and read side hold different semaphore and mutex.
Thanks, Ethan -----Original Message----- From: Sinan Kaya <[email protected]> Sent: Sunday, September 27, 2020 11:28 PM To: Zhao, Haifeng <[email protected]>; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; Keith Busch <[email protected]> Cc: [email protected]; [email protected]; Jia, Pei P <[email protected]>; [email protected]; Kuppuswamy, Sathyanarayanan <[email protected]> Subject: Re: [PATCH 2/5 V2] PCI: pciehp: check and wait port status out of DPC before handling DLLSC and PDC On 9/26/2020 11:28 PM, Ethan Zhao wrote: > diff --git a/drivers/pci/hotplug/pciehp_hpc.c > b/drivers/pci/hotplug/pciehp_hpc.c > index 53433b37e181..6f271160f18d 100644 > --- a/drivers/pci/hotplug/pciehp_hpc.c > +++ b/drivers/pci/hotplug/pciehp_hpc.c > @@ -710,8 +710,10 @@ static irqreturn_t pciehp_ist(int irq, void *dev_id) > down_read(&ctrl->reset_lock); > if (events & DISABLE_SLOT) > pciehp_handle_disable_request(ctrl); > - else if (events & (PCI_EXP_SLTSTA_PDC | PCI_EXP_SLTSTA_DLLSC)) > + else if (events & (PCI_EXP_SLTSTA_PDC | PCI_EXP_SLTSTA_DLLSC)) { > + pci_wait_port_outdpc(pdev); > pciehp_handle_presence_or_link_change(ctrl, events); > + } > up_read(&ctrl->reset_lock); This looks like a hack TBH. Lukas, Keith; What is your take on this? Why is device lock not protecting this situation? Is there a lock missing in hotplug driver? Sinan
