On Fri, Jul 20, 2018 at 4:16 AM Hari Vyas <hari.vyas@xxxxxxxxxxxx> wrote: > > On Thu, Jul 19, 2018 at 11:11 PM, Bjorn Helgaas <helgaas@xxxxxxxxxx> wrote: > > On Tue, Jul 03, 2018 at 02:35:41PM +0530, Hari Vyas wrote: > >> When a pci device is detected, a variable is_added is set to > >> 1 in pci device structure and proc, sys entries are created. > >> > >> When a pci device is removed, first is_added is checked for one > >> and then device is detached with clearing of proc and sys > >> entries and at end, is_added is set to 0. > >> > >> is_added and is_busmaster are bit fields in pci_dev structure > >> sharing same memory location. > >> > >> A strange issue was observed with multiple times removal and > >> rescan of a pcie nvme device using sysfs commands where is_added > >> flag was observed as zero instead of one while removing device > >> and proc,sys entries are not cleared. This causes issue in > >> later device addition with warning message "proc_dir_entry" > >> already registered. > >> > >> Debugging revealed a race condition between pcie core driver > >> enabling is_added bit(pci_bus_add_device()) and nvme driver > >> reset work-queue enabling is_busmaster bit (by pci_set_master()). > >> As both fields are not handled in atomic manner and that clears > >> is_added bit. > >> > >> Fix moves device addition is_added bit to separate private flag > >> variable and use different atomic functions to set and retrieve > >> device addition state. As is_added shares different memory > >> location so race condition is avoided. > > > > If/when you post a v4 of this, can you include the bugzilla URL > > right here, i.e., > > > > Link: https://bugzilla.kernel.org/show_bug.cgi?id=200283 > >> Signed-off-by: Hari Vyas <hari.vyas@xxxxxxxxxxxx> > > > > That way we can connect the commit with the bugzilla, which contains > > more information that may be useful in the future. > Bit confused. Do I need to change commit message for including bugzila link ? > Believe v3 should be Okay from code perspective time-being. Please confirm You don't need to repost it just to update the commit message (I'll try to remember to add the link when I apply it). But if you do repost it for some other reason, it helps me out if you include the link.
