From d3237316314c3d6f75a58192971f66e3822cd250 Mon Sep 17 00:00:00 2001 From: Siena Richard Date: Thu, 26 Jan 2017 15:02:42 -0800 Subject: drivers: soc: add mutex to prevent response being processed twice Add a mutex to prevent two threads from processing the same response at the same time. This ensures responses are processed completely and sequentially. CRs-Fixed: 1116015 Change-Id: Id2ef32edb939f8af2850b54bd6f6f447939c0732 Signed-off-by: Siena Richard --- drivers/soc/qcom/qdsp6v2/voice_svc.c | 26 ++++++++++++++++++++------ 1 file changed, 20 insertions(+), 6 deletions(-) diff --git a/drivers/soc/qcom/qdsp6v2/voice_svc.c b/drivers/soc/qcom/qdsp6v2/voice_svc.c index 50dd925..10f71b8 100644 --- a/drivers/soc/qcom/qdsp6v2/voice_svc.c +++ b/drivers/soc/qcom/qdsp6v2/voice_svc.c @@ -1,4 +1,4 @@ -/* Copyright (c) 2014-2016, The Linux Foundation. All rights reserved. +/* Copyright (c) 2014-2017, The Linux Foundation. All rights reserved. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 and @@ -42,6 +42,12 @@ struct voice_svc_prvt { struct list_head response_queue; wait_queue_head_t response_wait; spinlock_t response_lock; + /* + * This mutex ensures responses are processed in sequential order and + * that no two threads access and free the same response at the same + * time. + */ + struct mutex response_mutex_lock; }; struct apr_data { @@ -467,6 +473,7 @@ static ssize_t voice_svc_read(struct file *file, char __user *arg, goto done; } + mutex_lock(&prtd->response_mutex_lock); spin_lock_irqsave(&prtd->response_lock, spin_flags); if (list_empty(&prtd->response_queue)) { @@ -480,7 +487,7 @@ static ssize_t voice_svc_read(struct file *file, char __user *arg, pr_debug("%s: Read timeout\n", __func__); ret = -ETIMEDOUT; - goto done; + goto unlock; } else if (ret > 0 && !list_empty(&prtd->response_queue)) { pr_debug("%s: Interrupt recieved for response\n", __func__); @@ -488,7 +495,7 @@ static ssize_t voice_svc_read(struct file *file, char __user *arg, pr_debug("%s: Interrupted by SIGNAL %d\n", __func__, ret); - goto done; + goto unlock; } spin_lock_irqsave(&prtd->response_lock, spin_flags); @@ -507,7 +514,7 @@ static ssize_t voice_svc_read(struct file *file, char __user *arg, __func__, count, size); ret = -ENOMEM; - goto done; + goto unlock; } if (!access_ok(VERIFY_WRITE, arg, size)) { @@ -515,7 +522,7 @@ static ssize_t voice_svc_read(struct file *file, char __user *arg, __func__); ret = -EPERM; - goto done; + goto unlock; } ret = copy_to_user(arg, &resp->resp, @@ -525,7 +532,7 @@ static ssize_t voice_svc_read(struct file *file, char __user *arg, pr_err("%s: copy_to_user failed %d\n", __func__, ret); ret = -EPERM; - goto done; + goto unlock; } spin_lock_irqsave(&prtd->response_lock, spin_flags); @@ -539,6 +546,8 @@ static ssize_t voice_svc_read(struct file *file, char __user *arg, ret = count; +unlock: + mutex_unlock(&prtd->response_mutex_lock); done: return ret; } @@ -594,6 +603,7 @@ static int voice_svc_open(struct inode *inode, struct file *file) INIT_LIST_HEAD(&prtd->response_queue); init_waitqueue_head(&prtd->response_wait); spin_lock_init(&prtd->response_lock); + mutex_init(&prtd->response_mutex_lock); file->private_data = (void *)prtd; /* Current APR implementation doesn't support session based @@ -644,6 +654,7 @@ static int voice_svc_release(struct inode *inode, struct file *file) pr_err("%s: Failed to dereg MVM %d\n", __func__, ret); } + mutex_lock(&prtd->response_mutex_lock); spin_lock_irqsave(&prtd->response_lock, spin_flags); while (!list_empty(&prtd->response_queue)) { @@ -657,6 +668,9 @@ static int voice_svc_release(struct inode *inode, struct file *file) } spin_unlock_irqrestore(&prtd->response_lock, spin_flags); + mutex_unlock(&prtd->response_mutex_lock); + + mutex_destroy(&prtd->response_mutex_lock); kfree(file->private_data); file->private_data = NULL; -- cgit v1.1