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. > > Bjorn 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
