Messages in this thread | | | Date | Fri, 10 May 2024 21:22:31 +0200 | From | Klara Modin <> | Subject | Re: [PATCH] p2sb: Don't init until unassigned resources have been assigned. |
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On 2024-05-10 16:50, Andy Shevchenko wrote: > On Thu, May 09, 2024 at 07:04:32PM +0200, Lukas Wunner wrote: >> [cc += Shin'ichiro, Klara, Andy, Danil] > > Thank you! > >> On Thu, May 09, 2024 at 04:49:34PM +0000, bcfradella@proton.me wrote: >>> From: Ben Fradella <bfradell@netapp.com> >>> >>> The P2SB could get an invalid BAR from the BIOS, and that won't be fixed >>> up until pcibios_assign_resources(), which is an fs_initcall(). >>> >>> - Move p2sb_fs_init() to an fs_initcall_sync(). This is still early >>> enough to avoid a race with any dependent drivers. >>> >>> - Add a check for IORESOURCE_UNSET in p2sb_valid_resource() to catch >>> unset BARs going forward. >>> >>> - Return error values from p2sb_fs_init() so that the 'initcall_debug' >>> cmdline arg provides useful data. > > ... > >>> /* >>> - * pci_rescan_remove_lock to avoid access to unhidden P2SB devices can >>> - * not be locked in sysfs pci bus rescan path because of deadlock. To >>> - * avoid the deadlock, access to P2SB devices with the lock at an early >>> - * step in kernel initialization and cache required resources. This >>> - * should happen after subsys_initcall which initializes PCI subsystem >>> - * and before device_initcall which requires P2SB resources. >>> + * pci_rescan_remove_lock() can not be locked in sysfs pci bus rescan path > > PCI bus > >>> + * because of deadlock. To avoid the deadlock, access P2SB devices with the lock >>> + * at an early step in kernel initialization and cache required resources. >>> + * >>> + * We want to run as early as possible. If the P2SB was assigned a bad BAR, >>> + * we'll need to wait on pcibios_assign_resources() to fix it. So, our list of >>> + * initcall dependencies looks something like this: >>> + * >>> + * ... >>> + * subsys_initcall (pci_subsys_init) >>> + * fs_initcall (pcibios_assign_resources) >>> */ > > This makes sense to me > Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> > > I assume others will conduct the proper review and testing. >
This patch did not introduce any new issues on my previously problematic system.
Tested-by: Klara Modin <klarasmodin@gmail.com>
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