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smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=clgaYSXp; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="clgaYSXp" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 59078C4CED2; Thu, 31 Oct 2024 11:46:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1730375187; bh=1jKG/ZtSe2X1u9yvpJEpArPI5jFJt8rVIUMOW8xcXkg=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=clgaYSXpeDVyfYuO45fv7TfP+JvPICNt0aYoi09jAXWYkcGLndpFQncY5BiDxJijK G/VMHvLhE3TUQzg9zw5bl/ofvqVO00+mF+n7sKZqzQkTa6KEZoI6vpH/Ns9wFM6dgw BthjWCD2sWnaaIWC/C0Zslh2QNCmb0q1rZygSsZjR65BbeqgU5gd4wdoqsCf0vvwj+ fIln5lO5Y7mrcq3UPPV9sJs3tLM+2T/GwHn3iO6COtGzhDf6PvrdAOR3UmOpoaLbBo uVp3MW/u0azdy0gZCiShIUjuPBjkY/KLW/pOBsExeJi/FIXiJrbRANHt7BrlCJ/3ZE RchTpZXOS5Idw== Message-ID: <91b55df5-b023-4fbd-925e-7ac97f287ac4@kernel.org> Date: Thu, 31 Oct 2024 12:46:21 +0100 Precedence: bulk X-Mailing-List: linux-bluetooth@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 2/2] Bluetooth: btbcm: automate node cleanup in btbcm_get_board_name() To: Javier Carrasco , Marcel Holtmann , Luiz Augusto von Dentz , Linus Walleij Cc: linux-bluetooth@vger.kernel.org, linux-kernel@vger.kernel.org References: <20241030-bluetooth-btbcm-node-cleanup-v1-0-fdc4b9df9fe3@gmail.com> <20241030-bluetooth-btbcm-node-cleanup-v1-2-fdc4b9df9fe3@gmail.com> <07eef877-622a-4651-8a15-9e507146642c@gmail.com> <79c00d2c-8062-4c65-9bdf-1a87e7624e8b@kernel.org> <26d090ef-5630-4afd-8e77-e20019cd018a@gmail.com> From: Krzysztof Kozlowski Content-Language: en-US Autocrypt: addr=krzk@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 31/10/2024 12:41, Javier Carrasco wrote: > On 31/10/2024 12:30, Krzysztof Kozlowski wrote: >> On 31/10/2024 12:14, Krzysztof Kozlowski wrote: >>> On 31/10/2024 12:10, Javier Carrasco wrote: >>>> On 31/10/2024 12:08, Krzysztof Kozlowski wrote: >>>>> On 30/10/2024 16:46, Javier Carrasco wrote: >>>>>> Switch to a more robust approach by automating the node release when it >>>>>> goes out of scope, removing the need for explicit calls to >>>>>> of_node_put(). >>>>>> >>>>>> Signed-off-by: Javier Carrasco >>>>>> --- >>>>>> drivers/bluetooth/btbcm.c | 8 ++------ >>>>>> 1 file changed, 2 insertions(+), 6 deletions(-) >>>>>> >>>>>> diff --git a/drivers/bluetooth/btbcm.c b/drivers/bluetooth/btbcm.c >>>>>> index 400c2663d6b0..a1153ada74d2 100644 >>>>>> --- a/drivers/bluetooth/btbcm.c >>>>>> +++ b/drivers/bluetooth/btbcm.c >>>>>> @@ -541,23 +541,19 @@ static const struct bcm_subver_table bcm_usb_subver_table[] = { >>>>>> static const char *btbcm_get_board_name(struct device *dev) >>>>>> { >>>>>> #ifdef CONFIG_OF >>>>>> - struct device_node *root; >>>>>> + struct device_node *root __free(device_node) = of_find_node_by_path("/"); >>>>>> char *board_type; >>>>>> const char *tmp; >>>>>> >>>>>> - root = of_find_node_by_path("/"); >>>>>> if (!root) >>>>>> return NULL; >>>>>> >>>>>> - if (of_property_read_string_index(root, "compatible", 0, &tmp)) { >>>>>> - of_node_put(root); >>>>> >>>>> You just added this. Don't add code which is immediately removed. It's a >>>>> noop or wrong code. >>>>> >>>>> >>>>> >>>>> Best regards, >>>>> Krzysztof >>>>> >>>> >>>> Exactly, I added that code to fix the issue in stable kernels that don't >>> >>> Then send backport for stable. >>> >>>> support the __free() macro, and then I removed it to use a safer >>>> approach from now on. >>> >>> This is not correct approach. We work here on mainline and in mainline >>> this is one logical change: fixing issue. Whether you fix issue with >>> of_node_put or cleanup or by removing of_find_node_by_path() call, it >>> does not matter. All of these are fixing the same, one issue. >>> >>> If you think about stable kernels, then work on backports, not inflate >>> mainline kernel with multiple commits doing the same, creating >>> artificial history. >>> >> >> And to clarify even more: these stable backports are close to useless, >> because it does not matter for them. No impact, not much benefits, >> nothing improved for users/developers. There is no need to backport >> them, although of course there is no loss by doing so. Therefore entire >> dance affects mainline kernel without any real benefits for stable. >> >> Your split suggests you don't really know what this dropping reference >> is for. > > Such splits were suggested in other threads, and they came exactly for You mention it third time, but never provided a link. I tried to look briefly for it but failed. Can you share a lore link? > those reasons: they could not be applied to stable. That was not my > first approach, which was just using __free() to fix the issue. I am not > looking forward to inflating any history, as that's in the end more work > for me. > > If a simple patch that adds the cleanup attribute is enough, that's > awesome. I will go for that approach for all cases then, and use your > explanation as a reference if I am asked to split the fix again. If maintainer asks you to split trivial things like of_node_put() for simple patches, feel free to Cc me, so I can provide counter arguments. Best regards, Krzysztof