From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 63B2BCAC5B5 for ; Thu, 25 Sep 2025 20:36:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=l66vPUYO6qAiXGMjpxlui3KNqTDmW4IVuyx4wLrx4tM=; b=JaftzwlW+TySnuTaHi6jJV7tmD TWPFZ+r2tv2S5z0Fwd2THAIKruonv3/mt+mHQQKA0nvr98JfHAt8iwom9w1hWgMNbvO8PT4CDBnsm 1x43t+11o7Q65s7yYU3hvHP6W2GTMM265Sg0GyBVglasPhRn/Guz5hnpjrxFmoUACI4JGGt76HqCj UBHHqkPpWNavE6NxLWsUVxgAl7mnlFBDnd4pRa4iHIBe/1lOHEqkuXhLyJOKaGiOCE8caI5bWcJaA UmLorx0/waWaS3ej+1/fd7Zvhr259O734L7f3nizVuVirZK0kHYmANXvjM4zFeV/god2o0He5wrpP P48a4iWw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1v1shf-0000000CmvB-17CN; Thu, 25 Sep 2025 20:36:35 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1v1shX-0000000Cmq7-3Xoi for linux-arm-kernel@lists.infradead.org; Thu, 25 Sep 2025 20:36:29 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id A72041692; Thu, 25 Sep 2025 13:36:18 -0700 (PDT) Received: from pluto.fritz.box (usa-sjc-mx-foss1.foss.arm.com [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 094F33F694; Thu, 25 Sep 2025 13:36:23 -0700 (PDT) From: Cristian Marussi To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, arm-scmi@vger.kernel.org Cc: sudeep.holla@arm.com, james.quinlan@broadcom.com, f.fainelli@gmail.com, vincent.guittot@linaro.org, etienne.carriere@st.com, peng.fan@oss.nxp.com, michal.simek@amd.com, quic_sibis@quicinc.com, dan.carpenter@linaro.org, d-gole@ti.com, souvik.chakravarty@arm.com, Cristian Marussi Subject: [PATCH 02/10] firmware: arm_scmi: Reduce the scope of protocols mutex Date: Thu, 25 Sep 2025 21:35:46 +0100 Message-ID: <20250925203554.482371-3-cristian.marussi@arm.com> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20250925203554.482371-1-cristian.marussi@arm.com> References: <20250925203554.482371-1-cristian.marussi@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250925_133628_008383_91817F82 X-CRM114-Status: GOOD ( 15.14 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Currently the mutex dedicated to the protection of the list of registered protocols is held during all the protocol initialization phase. Such a wide locking region is not needed and causes problem when trying to initialize notifications from within a protocol initialization routine. Reduce the scope of the protocol mutex. Signed-off-by: Cristian Marussi --- drivers/firmware/arm_scmi/driver.c | 53 +++++++++++++++--------------- 1 file changed, 26 insertions(+), 27 deletions(-) diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c index bd56a877fdfc..71ee25b78624 100644 --- a/drivers/firmware/arm_scmi/driver.c +++ b/drivers/firmware/arm_scmi/driver.c @@ -17,6 +17,7 @@ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include +#include #include #include #include @@ -2179,10 +2180,13 @@ scmi_alloc_init_protocol_instance(struct scmi_info *info, if (ret) goto clean; - ret = idr_alloc(&info->protocols, pi, proto->id, proto->id + 1, - GFP_KERNEL); - if (ret != proto->id) - goto clean; + /* Finally register the initialized protocol */ + scoped_guard(mutex, &info->protocols_mtx) { + ret = idr_alloc(&info->protocols, pi, proto->id, proto->id + 1, + GFP_KERNEL); + if (ret != proto->id) + goto clean; + } /* * Warn but ignore events registration errors since we do not want @@ -2243,25 +2247,22 @@ scmi_alloc_init_protocol_instance(struct scmi_info *info, static struct scmi_protocol_instance * __must_check scmi_get_protocol_instance(const struct scmi_handle *handle, u8 protocol_id) { - struct scmi_protocol_instance *pi; + struct scmi_protocol_instance *pi = ERR_PTR(-EPROBE_DEFER); struct scmi_info *info = handle_to_scmi_info(handle); + const struct scmi_protocol *proto; - mutex_lock(&info->protocols_mtx); - pi = idr_find(&info->protocols, protocol_id); - - if (pi) { - refcount_inc(&pi->users); - } else { - const struct scmi_protocol *proto; - - /* Fails if protocol not registered on bus */ - proto = scmi_protocol_get(protocol_id, &info->version); - if (proto) - pi = scmi_alloc_init_protocol_instance(info, proto); - else - pi = ERR_PTR(-EPROBE_DEFER); + scoped_guard(mutex, &info->protocols_mtx) { + pi = idr_find(&info->protocols, protocol_id); + if (pi) { + refcount_inc(&pi->users); + return pi; + } } - mutex_unlock(&info->protocols_mtx); + + /* Fails if protocol not registered on bus */ + proto = scmi_protocol_get(protocol_id, &info->version); + if (proto) + pi = scmi_alloc_init_protocol_instance(info, proto); return pi; } @@ -2294,10 +2295,11 @@ void scmi_protocol_release(const struct scmi_handle *handle, u8 protocol_id) struct scmi_info *info = handle_to_scmi_info(handle); struct scmi_protocol_instance *pi; - mutex_lock(&info->protocols_mtx); - pi = idr_find(&info->protocols, protocol_id); - if (WARN_ON(!pi)) - goto out; + scoped_guard(mutex, &info->protocols_mtx) { + pi = idr_find(&info->protocols, protocol_id); + if (WARN_ON(!pi)) + return; + } if (refcount_dec_and_test(&pi->users)) { void *gid = pi->gid; @@ -2316,9 +2318,6 @@ void scmi_protocol_release(const struct scmi_handle *handle, u8 protocol_id) dev_dbg(handle->dev, "De-Initialized protocol: 0x%X\n", protocol_id); } - -out: - mutex_unlock(&info->protocols_mtx); } void scmi_setup_protocol_implemented(const struct scmi_protocol_handle *ph, -- 2.51.0