Re: [PATCH v6 0/2] platform/x86: p2sb: Fix deadlock at sysfs PCI bus rescan

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On 1/8/24 07:20, Shin'ichiro Kawasaki wrote:
> When PCI devices call p2sb_bar() during probe for sysfs PCI bus rescan, deadlock
> happens due to double lock of pci_rescan_remove_lock [1]. The first patch in
> this series addresses the deadlock. The second patch is a code improvement which
> was pointed out during review for the first patch.
> [1]
> The first patch of the v5 series was upstreamed to the kernel v6.7-rc8. However,
> it caused IDE controller detection failure on an old platform [2] then the patch
> was reverted at v6.7. The failure happened because the IDE controller had same
> DEVFN as P2SB device. To avoid this failure, I added device class check per
> suggestion by Lukas. If the device at P2SB DEVFN does not have the device class
> expected for P2SB, avoid touching the device.
> [2]
> I confirmed the patches fix the problem [1] on the kernel v6.7, using a system
> with i2c_i801 device, building i2c_i801 module as both built-in and loadable.
> Reviews and comments will be appreciated.
> Klara,
> I hesitated to add your Tested-by tag to the v6 patch, since I modified the code
> slightly from the code you tested (I used pci_bus_read_config_word() instead of
> pci_bus_read_config_dword() to avoid a shift operator). I hope you have time to
> afford to test this series again.

Thank you for your patch-series, I've applied this series to
my review-hans branch:

I will include this series in my next fixes pull-req to Linus
for the current kernel development cycle.

Note I have re-added Andy's and Ilpo's Reviewed-by for patch 1/2 since
there is only one small change there.



> Changes from v5:
> * Added device class check to avoid old IDE controller detection failure
> Changes from v4:
> * Separated a hunk for pci_resource_n() as the second patch
> * Reflected other review comments by Ilpo
> Changes from v3:
> * Modified p2sb_valid_resource() to return boolean
> Changes from v2:
> * Improved p2sb_scan_and_cache() and p2sb_scan_and_cache_devfn()
> * Reflected other review comments by Andy
> Changes from v1:
> * Reflected review comments by Andy
> * Removed RFC prefix
> Changes from RFC v2:
> * Reflected review comments on the list
> Changes from RFC v1:
> * Fixed a build warning poitned out in llvm list by kernel test robot
> Shin'ichiro Kawasaki (2):
>   platform/x86: p2sb: Allow p2sb_bar() calls during PCI device probe
>   platform/x86: p2sb: Use pci_resource_n() in p2sb_read_bar0()
>  drivers/platform/x86/p2sb.c | 183 +++++++++++++++++++++++++++---------
>  1 file changed, 141 insertions(+), 42 deletions(-)

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