From patchwork Thu Jan 11 16:53:02 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lucas Stach X-Patchwork-Id: 10158237 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 32862602D8 for ; Thu, 11 Jan 2018 16:53:13 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 2500E28751 for ; Thu, 11 Jan 2018 16:53:13 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 1988B287B2; Thu, 11 Jan 2018 16:53:13 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.2 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id DAC3B28751 for ; Thu, 11 Jan 2018 16:53:12 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id AB4376E60D; Thu, 11 Jan 2018 16:53:06 +0000 (UTC) X-Original-To: dri-devel@lists.freedesktop.org Delivered-To: dri-devel@lists.freedesktop.org Received: from metis.ext.pengutronix.de (metis.ext.pengutronix.de [IPv6:2001:67c:670:201:290:27ff:fe1d:cc33]) by gabe.freedesktop.org (Postfix) with ESMTPS id DB66B6E60D for ; Thu, 11 Jan 2018 16:53:05 +0000 (UTC) Received: from dude.hi.pengutronix.de ([2001:67c:670:100:1d::7] helo=dude.pengutronix.de.) by metis.ext.pengutronix.de with esmtp (Exim 4.89) (envelope-from ) id 1eZg6B-000097-8B; Thu, 11 Jan 2018 17:53:03 +0100 From: Lucas Stach To: Sumit Semwal , =?UTF-8?q?Christian=20K=C3=B6nig?= Subject: [Patch v2 2/2] dma-buf: clarify locking documentation for reservation_object_get_excl Date: Thu, 11 Jan 2018 17:53:02 +0100 Message-Id: <20180111165302.25556-2-l.stach@pengutronix.de> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20180111165302.25556-1-l.stach@pengutronix.de> References: <20180111165302.25556-1-l.stach@pengutronix.de> X-SA-Exim-Connect-IP: 2001:67c:670:100:1d::7 X-SA-Exim-Mail-From: l.stach@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: dri-devel@lists.freedesktop.org Cc: linaro-mm-sig@lists.linaro.org, kernel@pengutronix.de, dri-devel@lists.freedesktop.org, patchwork-lst@pengutronix.de X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" X-Virus-Scanned: ClamAV using ClamSMTP The documentation was misleading, as for a lot of use-cases holding the RCU read side lock is sufficient. Signed-off-by: Lucas Stach --- include/linux/reservation.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/include/linux/reservation.h b/include/linux/reservation.h index 21fc84d82d41..ae1175e5997c 100644 --- a/include/linux/reservation.h +++ b/include/linux/reservation.h @@ -204,7 +204,8 @@ reservation_object_unlock(struct reservation_object *obj) * @obj: the reservation object * * Returns the exclusive fence (if any). Does NOT take a - * reference. The obj->lock must be held. + * reference. Writers must hold obj->lock, readers may only + * hold a RCU read side lock. * * RETURNS * The exclusive fence or NULL