ipmi_devintf: Small lock rework

The mutex didn't really serve any useful purpose, from what I can
tell, and it would just get in the way.  So remove it.

Removing that required a mutex around the default value setting and
getting, so just use the receive mutex for that.

Also pull the fasync stuff outside of the lock for adding the data
to the queue, since it didn't need to be there.
Signed-off-by: Corey Minyard <cminyard@mvista.com>

drivers/char/ipmi/ipmi_devintf.c

@@ -37,7 +37,6 @@ struct ipmi_file_private
 	unsigned int         default_retry_time_ms;
 };
 
-static DEFINE_MUTEX(ipmi_mutex);
 static void file_receive_handler(struct ipmi_recv_msg *msg,
 				 void                 *handler_data)
 {
@@ -46,16 +45,14 @@ static void file_receive_handler(struct ipmi_recv_msg *msg,
 	unsigned long            flags;
 
 	spin_lock_irqsave(&priv->recv_msg_lock, flags);
-
 	was_empty = list_empty(&priv->recv_msgs);
 	list_add_tail(&msg->link, &priv->recv_msgs);
+	spin_unlock_irqrestore(&priv->recv_msg_lock, flags);
 
 	if (was_empty) {
 		wake_up_interruptible(&priv->wait);
 		kill_fasync(&priv->fasync_queue, SIGIO, POLL_IN);
 	}
-
-	spin_unlock_irqrestore(&priv->recv_msg_lock, flags);
 }
 
 static __poll_t ipmi_poll(struct file *file, poll_table *wait)
@@ -79,13 +76,8 @@ static __poll_t ipmi_poll(struct file *file, poll_table *wait)
 static int ipmi_fasync(int fd, struct file *file, int on)
 {
 	struct ipmi_file_private *priv = file->private_data;
-	int                      result;
-
-	mutex_lock(&ipmi_mutex); /* could race against open() otherwise */
-	result = fasync_helper(fd, file, on, &priv->fasync_queue);
-	mutex_unlock(&ipmi_mutex);
 
-	return (result);
+	return fasync_helper(fd, file, on, &priv->fasync_queue);
 }
 
 static const struct ipmi_user_hndl ipmi_hndlrs =
@@ -99,12 +91,10 @@ static int ipmi_open(struct inode *inode, struct file *file)
 	int                      rv;
 	struct ipmi_file_private *priv;
 
-
 	priv = kmalloc(sizeof(*priv), GFP_KERNEL);
 	if (!priv)
 		return -ENOMEM;
 
-	mutex_lock(&ipmi_mutex);
 	priv->file = file;
 
 	rv = ipmi_create_user(if_num,
@@ -129,7 +119,6 @@ static int ipmi_open(struct inode *inode, struct file *file)
 	priv->default_retry_time_ms = 0;
 
 out:
-	mutex_unlock(&ipmi_mutex);
 	return rv;
 }
 
@@ -137,7 +126,7 @@ static int ipmi_release(struct inode *inode, struct file *file)
 {
 	struct ipmi_file_private *priv = file->private_data;
 	int                      rv;
-	struct  ipmi_recv_msg *msg, *next;
+	struct ipmi_recv_msg *msg, *next;
 
 	rv = ipmi_destroy_user(priv->user);
 	if (rv)
@@ -303,9 +292,9 @@ static int copyout_recv(struct ipmi_recv *rsp, void __user *to)
 	return copy_to_user(to, rsp, sizeof(struct ipmi_recv)) ? -EFAULT : 0;
 }
 
-static int ipmi_ioctl(struct file   *file,
-		      unsigned int  cmd,
-		      unsigned long data)
+static long ipmi_ioctl(struct file   *file,
+		       unsigned int  cmd,
+		       unsigned long data)
 {
 	int                      rv = -EINVAL;
 	struct ipmi_file_private *priv = file->private_data;
@@ -316,16 +305,20 @@ static int ipmi_ioctl(struct file   *file,
 	case IPMICTL_SEND_COMMAND:
 	{
 		struct ipmi_req req;
+		int retries;
+		unsigned int retry_time_ms;
 
 		if (copy_from_user(&req, arg, sizeof(req))) {
 			rv = -EFAULT;
 			break;
 		}
 
-		rv = handle_send_req(priv->user,
-				     &req,
-				     priv->default_retries,
-				     priv->default_retry_time_ms);
+		mutex_lock(&priv->recv_mutex);
+		retries = priv->default_retries;
+		retry_time_ms = priv->default_retry_time_ms;
+		mutex_unlock(&priv->recv_mutex);
+
+		rv = handle_send_req(priv->user, &req, retries, retry_time_ms);
 		break;
 	}
 
@@ -565,8 +558,10 @@ static int ipmi_ioctl(struct file   *file,
 			break;
 		}
 
+		mutex_lock(&priv->recv_mutex);
 		priv->default_retries = parms.retries;
 		priv->default_retry_time_ms = parms.retry_time_ms;
+		mutex_unlock(&priv->recv_mutex);
 		rv = 0;
 		break;
 	}
@@ -575,8 +570,10 @@ static int ipmi_ioctl(struct file   *file,
 	{
 		struct ipmi_timing_parms parms;
 
+		mutex_lock(&priv->recv_mutex);
 		parms.retries = priv->default_retries;
 		parms.retry_time_ms = priv->default_retry_time_ms;
+		mutex_unlock(&priv->recv_mutex);
 
 		if (copy_to_user(arg, &parms, sizeof(parms))) {
 			rv = -EFAULT;
@@ -616,25 +613,7 @@ static int ipmi_ioctl(struct file   *file,
 	return rv;
 }
 
-/*
- * Note: it doesn't make sense to take the BKL here but
- *       not in compat_ipmi_ioctl. -arnd
- */
-static long ipmi_unlocked_ioctl(struct file   *file,
-			        unsigned int  cmd,
-			        unsigned long data)
-{
-	int ret;
-
-	mutex_lock(&ipmi_mutex);
-	ret = ipmi_ioctl(file, cmd, data);
-	mutex_unlock(&ipmi_mutex);
-
-	return ret;
-}
-
 #ifdef CONFIG_COMPAT
-
 /*
  * The following code contains code for supporting 32-bit compatible
  * ioctls on 64-bit kernels.  This allows running 32-bit apps on the
@@ -745,15 +724,21 @@ static long compat_ipmi_ioctl(struct file *filep, unsigned int cmd,
 	{
 		struct ipmi_req	rp;
 		struct compat_ipmi_req r32;
+		int retries;
+		unsigned int retry_time_ms;
 
 		if (copy_from_user(&r32, compat_ptr(arg), sizeof(r32)))
 			return -EFAULT;
 
 		get_compat_ipmi_req(&rp, &r32);
 
+		mutex_lock(&priv->recv_mutex);
+		retries = priv->default_retries;
+		retry_time_ms = priv->default_retry_time_ms;
+		mutex_unlock(&priv->recv_mutex);
+
 		return handle_send_req(priv->user, &rp,
-				priv->default_retries,
-				priv->default_retry_time_ms);
+				       retries, retry_time_ms);
 	}
 	case COMPAT_IPMICTL_SEND_COMMAND_SETTIME:
 	{
@@ -787,25 +772,13 @@ static long compat_ipmi_ioctl(struct file *filep, unsigned int cmd,
 		return ipmi_ioctl(filep, cmd, arg);
 	}
 }
-
-static long unlocked_compat_ipmi_ioctl(struct file *filep, unsigned int cmd,
-				       unsigned long arg)
-{
-	int ret;
-
-	mutex_lock(&ipmi_mutex);
-	ret = compat_ipmi_ioctl(filep, cmd, arg);
-	mutex_unlock(&ipmi_mutex);
-
-	return ret;
-}
 #endif
 
 static const struct file_operations ipmi_fops = {
 	.owner		= THIS_MODULE,
-	.unlocked_ioctl	= ipmi_unlocked_ioctl,
+	.unlocked_ioctl	= ipmi_ioctl,
 #ifdef CONFIG_COMPAT
-	.compat_ioctl   = unlocked_compat_ipmi_ioctl,
+	.compat_ioctl   = compat_ipmi_ioctl,
 #endif
 	.open		= ipmi_open,
 	.release	= ipmi_release,