From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Chan Subject: [PATCH 1/2] [ARM] omap-pm: resource: Lock resource list in update_resource_level Date: Mon, 3 May 2010 17:34:30 -0700 Message-ID: <1272933271-12937-1-git-send-email-mike@android.com> Return-path: Received: from smtp-out.google.com ([216.239.44.51]:40755 "EHLO smtp-out.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752875Ab0EDAeg (ORCPT ); Mon, 3 May 2010 20:34:36 -0400 Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org Cc: khilman@deeprootsystems.com, linux-omap@vger.kernel.org, Mike Chan Take the resource mutex when iterating over the resource user_list. A race can occur if resource_request() adds a first time user to the user_list while update_resource_level() is called. Signed-off-by: Mike Chan --- arch/arm/plat-omap/resource.c | 9 +++++++-- 1 files changed, 7 insertions(+), 2 deletions(-) diff --git a/arch/arm/plat-omap/resource.c b/arch/arm/plat-omap/resource.c index f769f7c..6d3bba6 100644 --- a/arch/arm/plat-omap/resource.c +++ b/arch/arm/plat-omap/resource.c @@ -106,6 +106,7 @@ static int update_resource_level(struct shared_resource *resp) unsigned long target_level; int ret; + mutex_lock(&resp->resource_mutex); /* Regenerate the target_value for the resource */ if (resp->flags & RES_TYPE_PERFORMANCE) { target_level = RES_PERFORMANCE_DEFAULTLEVEL; @@ -118,9 +119,11 @@ static int update_resource_level(struct shared_resource *resp) if (user->level < target_level) target_level = user->level; } else { + mutex_unlock(&resp->resource_mutex); pr_debug("SRF: Unknown resource type\n"); return -EINVAL; } + mutex_unlock(&resp->resource_mutex); pr_debug("SRF: Changing Level for resource %s to %ld\n", resp->name, target_level); @@ -439,10 +442,12 @@ int resource_release(const char *name, struct device *dev) list_del(&user->node); free_user(user); - /* Recompute and set the current level for the resource */ - ret = update_resource_level(resp); res_unlock: mutex_unlock(&resp->resource_mutex); + /* Recompute and set the current level for the resource */ + if (!ret) + ret = update_resource_level(resp); + return ret; } EXPORT_SYMBOL(resource_release); -- 1.7.0.1