Received-SPF: pass (google.com: domain of linux-kernel+bounces-154616-linux.lists.archive=gmail.com@vger.kernel.org designates 147.75.80.249 as permitted sender) client-ip=147.75.80.249;
Date: Tue, 23 Apr 2024 15:38:58 +0800
From: Xu Yilun <yilun.xu@linux.intel.com>
To: Marco Pagani <marpagan@redhat.com>
Cc: Moritz Fischer <mdf@kernel.org>, Wu Hao <hao.wu@intel.com>,
	Xu Yilun <yilun.xu@intel.com>, Tom Rix <trix@redhat.com>,
	Jonathan Corbet <corbet@lwn.net>,
	Alan Tull <atull@opensource.altera.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Russ Weight <russ.weight@linux.dev>, linux-fpga@vger.kernel.org,
	linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v6] fpga: region: add owner module and take its refcount
Message-ID: <ZidlkofF4YSj9xeW@yilunxu-OptiPlex-7050>
References: <20240419083601.77403-1-marpagan@redhat.com>
Precedence: bulk
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20240419083601.77403-1-marpagan@redhat.com>

On Fri, Apr 19, 2024 at 10:35:59AM +0200, Marco Pagani wrote:
> The current implementation of the fpga region assumes that the low-level
> module registers a driver for the parent device and uses its owner pointer
> to take the module's refcount. This approach is problematic since it can
> lead to a null pointer dereference while attempting to get the region
> during programming if the parent device does not have a driver.
> 
> To address this problem, add a module owner pointer to the fpga_region
> struct and use it to take the module's refcount. Modify the functions for
> registering a region to take an additional owner module parameter and
> rename them to avoid conflicts. Use the old function names for helper
> macros that automatically set the module that registers the region as the
> owner. This ensures compatibility with existing low-level control modules
> and reduces the chances of registering a region without setting the owner.
> 
> Also, update the documentation to keep it consistent with the new interface
> for registering an fpga region.
> 
> Fixes: 0fa20cdfcc1f ("fpga: fpga-region: device tree control for FPGA")
> Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Suggested-by: Xu Yilun <yilun.xu@intel.com>
> Reviewed-by: Russ Weight <russ.weight@linux.dev>
> Signed-off-by: Marco Pagani <marpagan@redhat.com>
> Acked-by: Xu Yilun <yilun.xu@intel.com>

Applied to for-next instead of v5