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 <ok...@kernel.org>
Sent: Sunday, September 27, 2020 11:28 PM
To: Zhao, Haifeng <haifeng.z...@intel.com>; bhelg...@google.com;
ooh...@gmail.com; rus...@russell.cc; lu...@wunner.de;
andriy.shevche...@linux.intel.com; stuart.w.ha...@gmail.com;
mr.nuke...@gmail.com; mika.westerb...@linux.intel.com; Keith Busch
<keith.bu...@intel.com>
Cc: linux-...@vger.kernel.org; linux-kernel@vger.kernel.org; Jia, Pei P
<pei.p....@intel.com>; ashok....@linux.intel.com; Kuppuswamy, Sathyanarayanan
<sathyanarayanan.kuppusw...@intel.com>
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
