From: Hans de Goede <hdegoede@redhat.com>
To: bcfradella@proton.me,
"Ilpo Järvinen" <ilpo.jarvinen@linux.intel.com>,
platform-driver-x86@vger.kernel.org,
linux-kernel@vger.kernel.org
Cc: Ben Fradella <bfradell@netapp.com>,
Ranjan Dutta <ranjan.dutta@intel.com>,
Yifan2 Li <yifan2.li@intel.com>,
Jonathan Yong <jonathan.yong@intel.com>
Subject: Re: [PATCH] p2sb: Don't init until unassigned resources have been assigned.
Date: Mon, 13 May 2024 14:03:20 +0200 [thread overview]
Message-ID: <7867b308-7cea-4282-82e8-551d88fe70c4@redhat.com> (raw)
In-Reply-To: <20240509164905.41016-1-bcfradella@proton.me>
Hi,
On 5/9/24 6:49 PM, 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.
>
> Signed-off-by: Ben Fradella <bfradell@netapp.com>
Thank you for your patch, I've applied this patch to my review-hans
branch:
https://git.kernel.org/pub/scm/linux/kernel/git/pdx86/platform-drivers-x86.git/log/?h=review-hans
Note it will show up in my review-hans branch once I've pushed my
local branch there, which might take a while.
Once I've run some tests on this branch the patches there will be
added to the platform-drivers-x86/for-next branch and eventually
will be included in the pdx86 pull-request to Linus for the next
merge-window.
Regards,
Hans
> ---
> drivers/platform/x86/p2sb.c | 29 +++++++++++++++--------------
> 1 file changed, 15 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/platform/x86/p2sb.c b/drivers/platform/x86/p2sb.c
> index 3d66e1d4eb1f..1938a3ef9480 100644
> --- a/drivers/platform/x86/p2sb.c
> +++ b/drivers/platform/x86/p2sb.c
> @@ -56,12 +56,9 @@ static int p2sb_get_devfn(unsigned int *devfn)
> return 0;
> }
>
> -static bool p2sb_valid_resource(struct resource *res)
> +static bool p2sb_valid_resource(const struct resource *res)
> {
> - if (res->flags)
> - return true;
> -
> - return false;
> + return res->flags & ~IORESOURCE_UNSET;
> }
>
> /* Copy resource from the first BAR of the device in question */
> @@ -220,16 +217,20 @@ EXPORT_SYMBOL_GPL(p2sb_bar);
>
> static int __init p2sb_fs_init(void)
> {
> - p2sb_cache_resources();
> - return 0;
> + return p2sb_cache_resources();
> }
>
> /*
> - * 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
> + * 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)
> */
> -fs_initcall(p2sb_fs_init);
> +fs_initcall_sync(p2sb_fs_init);
next prev parent reply other threads:[~2024-05-13 12:03 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-09 16:49 [PATCH] p2sb: Don't init until unassigned resources have been assigned bcfradella
2024-05-09 17:04 ` Lukas Wunner
2024-05-10 14:50 ` Andy Shevchenko
2024-05-10 19:22 ` Klara Modin
2024-05-12 10:23 ` Shinichiro Kawasaki
2024-05-13 12:03 ` Hans de Goede [this message]
2024-05-13 15:53 ` Fradella, Ben
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