From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752868AbdJ3Kfq (ORCPT ); Mon, 30 Oct 2017 06:35:46 -0400 Received: from mail-lf0-f65.google.com ([209.85.215.65]:51898 "EHLO mail-lf0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751770AbdJ3Kfo (ORCPT ); Mon, 30 Oct 2017 06:35:44 -0400 X-Google-Smtp-Source: ABhQp+QQF4Adzn4PKirq2qoiUkHmKYktuKMtmd3n91VQgy91ajVygV0c3rSgy+O6xI1xdZOypO0Ndg== From: Johan Hovold To: Mark Brown Cc: linux-spi@vger.kernel.org, linux-kernel@vger.kernel.org, Lars-Peter Clausen , Johan Hovold Subject: [PATCH v2 2/3] spi: document odd controller reference handling Date: Mon, 30 Oct 2017 11:35:26 +0100 Message-Id: <20171030103527.13535-2-johan@kernel.org> X-Mailer: git-send-email 2.14.3 In-Reply-To: <20171030103527.13535-1-johan@kernel.org> References: <20171030103527.13535-1-johan@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Document the fact that a reference to the controller is dropped as part of deregistration. This is an odd pattern as the reference is typically taken in __spi_alloc_controller() rather than spi_register_controller(). Most controller drivers gets it right these days and notably the device-managed interface relies on this behaviour. Signed-off-by: Johan Hovold --- drivers/spi/spi.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index 3ff0ee88c467..b33a727a0158 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -2200,7 +2200,7 @@ static void devm_spi_unregister(struct device *dev, void *res) * Context: can sleep * * Register a SPI device as with spi_register_controller() which will - * automatically be unregister + * automatically be unregistered and freed. * * Return: zero on success, else a negative error code. */ @@ -2241,6 +2241,8 @@ static int __unregister(struct device *dev, void *null) * only ones directly touching chip registers. * * This must be called from context that can sleep. + * + * Note that this function also drops a reference to the controller. */ void spi_unregister_controller(struct spi_controller *ctlr) { -- 2.14.3