From patchwork Tue Oct 10 03:32:59 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Cyril Bur X-Patchwork-Id: 823673 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=lists.infradead.org (client-ip=65.50.211.133; helo=bombadil.infradead.org; envelope-from=linux-mtd-bounces+incoming=patchwork.ozlabs.org@lists.infradead.org; receiver=) Authentication-Results: ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="JU8k9ia1"; dkim-atps=neutral Received: from bombadil.infradead.org (bombadil.infradead.org [65.50.211.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 3yB2m81s5Hz9tXl for ; Tue, 10 Oct 2017 14:34:32 +1100 (AEDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:MIME-Version:Cc:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id:Message-Id: References:In-Reply-To:Date:Subject:To:From:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Owner; bh=s5UKVNiAtMX/XP7KfkUX/JOiwTZyZOaMOjks3OC+i24=; b=JU8k9ia1Pwf8RISqkw5swC8tgt 86/xt8MoDHUYcVgphnBb6praN/RMvURBApVRy0s+lPsVNiAm4e8S2b3FhWUkuPIg1llv9SyDxtjp0 Bo4ijAZMdpN5eY7FCPtd2zWe8ANYM6L7bb9/nlhwVih1LOroi0u8uxDzC4a+bSRdi3B4r9brMLcCV J956WzMrltHhjPGuXKCjOS2YWasNsmiOFGcYnFyBedd73mXHErGOs8uclss5/PT2o/M0uFEbWwZJ3 vIg86TzBeocWCiaM4ZnuSP9v8NTWSPBAhf2Z6257ehaxEX7J6wZqB0mcfjVPr8yz1Or+YySLIhoaB rG8WRZMA==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.87 #1 (Red Hat Linux)) id 1e1lJI-0003Jp-Bl; Tue, 10 Oct 2017 03:34:24 +0000 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5] helo=mx0a-001b2d01.pphosted.com) by bombadil.infradead.org with esmtps (Exim 4.87 #1 (Red Hat Linux)) id 1e1lIh-0002kG-Cd for linux-mtd@lists.infradead.org; Tue, 10 Oct 2017 03:33:52 +0000 Received: from pps.filterd (m0098413.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.21/8.16.0.21) with SMTP id v9A3TFMI051998 for ; Mon, 9 Oct 2017 23:33:29 -0400 Received: from e06smtp10.uk.ibm.com (e06smtp10.uk.ibm.com [195.75.94.106]) by mx0b-001b2d01.pphosted.com with ESMTP id 2dggmapc4h-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Mon, 09 Oct 2017 23:33:29 -0400 Received: from localhost by e06smtp10.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 10 Oct 2017 04:33:28 +0100 Received: from b06cxnps3075.portsmouth.uk.ibm.com (9.149.109.195) by e06smtp10.uk.ibm.com (192.168.101.140) with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted; Tue, 10 Oct 2017 04:33:25 +0100 Received: from d23av04.au.ibm.com (d23av04.au.ibm.com [9.190.235.139]) by b06cxnps3075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id v9A3XNrK27328678 for ; Tue, 10 Oct 2017 03:33:24 GMT Received: from d23av04.au.ibm.com (localhost [127.0.0.1]) by d23av04.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id v9A3XQgc031581 for ; Tue, 10 Oct 2017 14:33:26 +1100 Received: from ozlabs.au.ibm.com (ozlabs.au.ibm.com [9.192.253.14]) by d23av04.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVin) with ESMTP id v9A3XQ0A031576; Tue, 10 Oct 2017 14:33:26 +1100 Received: from camb691.au.ibm.com (camb691.au.ibm.com [9.192.250.228]) (using TLSv1.2 with cipher DHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by ozlabs.au.ibm.com (Postfix) with ESMTPSA id AD55DA02D4; Tue, 10 Oct 2017 14:33:21 +1100 (AEDT) From: Cyril Bur To: linux-mtd@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, stewart@linux.vnet.ibm.com Subject: [PATCH v4 07/10] powernv/opal-sensor: remove not needed lock Date: Tue, 10 Oct 2017 14:32:59 +1100 X-Mailer: git-send-email 2.14.2 In-Reply-To: <20171010033302.20854-1-cyrilbur@gmail.com> References: <20171010033302.20854-1-cyrilbur@gmail.com> X-TM-AS-MML: disable x-cbid: 17101003-0040-0000-0000-000003E12379 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17101003-0041-0000-0000-000025E3253A Message-Id: <20171010033302.20854-8-cyrilbur@gmail.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:, , definitions=2017-10-09_07:, , signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=0 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1707230000 definitions=main-1710100050 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20171009_203347_635980_CAB9A067 X-CRM114-Status: GOOD ( 17.23 ) X-Spam-Score: -1.1 (-) X-Spam-Report: SpamAssassin version 3.4.1 on bombadil.infradead.org summary: Content analysis details: (-1.1 points) pts rule name description ---- ---------------------- -------------------------------------------------- -0.7 RCVD_IN_DNSWL_LOW RBL: Sender listed at http://www.dnswl.org/, low trust [148.163.158.5 listed in list.dnswl.org] -0.0 RCVD_IN_MSPIKE_H3 RBL: Good reputation (+3) [148.163.158.5 listed in wl.mailspike.net] 0.0 DKIM_ADSP_CUSTOM_MED No valid author signature, adsp_override is CUSTOM_MED 0.0 FREEMAIL_FROM Sender email is commonly abused enduser mail provider (cyrilbur[at]gmail.com) 0.7 SPF_SOFTFAIL SPF: sender does not match SPF record (softfail) -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] -0.0 RCVD_IN_MSPIKE_WL Mailspike good senders 0.9 NML_ADSP_CUSTOM_MED ADSP custom_med hit, and not from a mailing list X-BeenThere: linux-mtd@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: boris.brezillon@free-electrons.com, computersforpeace@gmail.com, dwmw2@infradead.org, sjitindarsingh@gmail.com MIME-Version: 1.0 Sender: "linux-mtd" Errors-To: linux-mtd-bounces+incoming=patchwork.ozlabs.org@lists.infradead.org From: Stewart Smith Parallel sensor reads could run out of async tokens due to opal_get_sensor_data grabbing tokens but then doing the sensor read behind a mutex, essentially serializing the (possibly asynchronous and relatively slow) sensor read. It turns out that the mutex isn't needed at all, not only should the OPAL interface allow concurrent reads, the implementation is certainly safe for that, and if any sensor we were reading from somewhere isn't, doing the mutual exclusion in the kernel is the wrong place to do it, OPAL should be doing it for the kernel. So, remove the mutex. Additionally, we shouldn't be printing out an error when we don't get a token as the only way this should happen is if we've been interrupted in down_interruptible() on the semaphore. Reported-by: Robert Lippert Signed-off-by: Stewart Smith Signed-off-by: Cyril Bur --- arch/powerpc/platforms/powernv/opal-sensor.c | 17 ++++------------- 1 file changed, 4 insertions(+), 13 deletions(-) diff --git a/arch/powerpc/platforms/powernv/opal-sensor.c b/arch/powerpc/platforms/powernv/opal-sensor.c index aa267f120033..0a7074bb91dc 100644 --- a/arch/powerpc/platforms/powernv/opal-sensor.c +++ b/arch/powerpc/platforms/powernv/opal-sensor.c @@ -19,13 +19,10 @@ */ #include -#include #include #include #include -static DEFINE_MUTEX(opal_sensor_mutex); - /* * This will return sensor information to driver based on the requested sensor * handle. A handle is an opaque id for the powernv, read by the driver from the @@ -38,13 +35,9 @@ int opal_get_sensor_data(u32 sensor_hndl, u32 *sensor_data) __be32 data; token = opal_async_get_token_interruptible(); - if (token < 0) { - pr_err("%s: Couldn't get the token, returning\n", __func__); - ret = token; - goto out; - } + if (token < 0) + return token; - mutex_lock(&opal_sensor_mutex); ret = opal_sensor_read(sensor_hndl, token, &data); switch (ret) { case OPAL_ASYNC_COMPLETION: @@ -52,7 +45,7 @@ int opal_get_sensor_data(u32 sensor_hndl, u32 *sensor_data) if (ret) { pr_err("%s: Failed to wait for the async response, %d\n", __func__, ret); - goto out_token; + goto out; } ret = opal_error_code(opal_get_async_rc(msg)); @@ -73,10 +66,8 @@ int opal_get_sensor_data(u32 sensor_hndl, u32 *sensor_data) break; } -out_token: - mutex_unlock(&opal_sensor_mutex); - opal_async_release_token(token); out: + opal_async_release_token(token); return ret; } EXPORT_SYMBOL_GPL(opal_get_sensor_data);