Re: [PATCH iwl-net] i40e: Fix XDP program unloading while removing the driver

[Simon Horman <horms@kernel.org>]

On Thu, May 16, 2024 at 06:41:08PM +0200, Michal Kubiak wrote:
> The commit 6533e558c650 ("i40e: Fix reset path while removing
> the driver") introduced a new PF state "__I40E_IN_REMOVE" to block
> modifying the XDP program while the driver is being removed.
> Unfortunately, such a change is useful only if the ".ndo_bpf()"
> callback was called out of the rmmod context because unloading the
> existing XDP program is also a part of driver removing procedure.
> In other words, from the rmmod context the driver is expected to
> unload the XDP program without reporting any errors. Otherwise,
> the kernel warning with callstack is printed out to dmesg.
> 
> Example failing scenario:
>  1. Load the i40e driver.
>  2. Load the XDP program.
>  3. Unload the i40e driver (using "rmmod" command).
> 
> Fix this by improving checks in ".ndo_bpf()" to determine if that
> callback was called from the removing context and if the kernel
> wants to unload the XDP program. Allow for unloading the XDP program
> in such a case.
> 
> Fixes: 6533e558c650 ("i40e: Fix reset path while removing the driver")
> Reviewed-by: Wojciech Drewek <wojciech.drewek@intel.com>
> Signed-off-by: Michal Kubiak <michal.kubiak@intel.com>

Reviewed-by: Simon Horman <horms@kernel.org>