linux-kernel - [PATCH] use mutex instead of semaphore in TPM driver

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Date:	Tue, 24 Apr 2007 21:12:20 +0200
From:	Matthias Kaehlcke <matthias.kaehlcke@...il.com>
To:	kjhall@...ibm.com, tpm@...horst.net,
	tpmdd-devel@...ts.sourceforge.net
Cc:	linux-kernel@...r.kernel.org
Subject: [PATCH] use mutex instead of semaphore in TPM driver

the TPM driver uses two semaphores as mutexes. use the mutex API
instead of the (binary) semaphores

Signed-off-by: Matthias Kaehlcke <matthias.kaehlcke@...il.com> 

--

diff --git a/drivers/char/tpm/tpm.c b/drivers/char/tpm/tpm.c
index e5a254a..0805d39 100644
--- a/drivers/char/tpm/tpm.c
+++ b/drivers/char/tpm/tpm.c
@@ -328,10 +328,10 @@ static void timeout_work(struct work_struct *work)
 {
 	struct tpm_chip *chip = container_of(work, struct tpm_chip, work);
 
-	down(&chip->buffer_mutex);
+	mutex_lock(&chip->buffer_mutex);
 	atomic_set(&chip->data_pending, 0);
 	memset(chip->data_buffer, 0, TPM_BUFSIZE);
-	up(&chip->buffer_mutex);
+	mutex_unlock(&chip->buffer_mutex);
 }
 
 /*
@@ -380,7 +380,7 @@ static ssize_t tpm_transmit(struct tpm_chip *chip, const char *buf,
 		return -E2BIG;
 	}
 
-	down(&chip->tpm_mutex);
+	mutex_lock(&chip->tpm_mutex);
 
 	if ((rc = chip->vendor.send(chip, (u8 *) buf, count)) < 0) {
 		dev_err(chip->dev,
@@ -419,7 +419,7 @@ out_recv:
 		dev_err(chip->dev,
 			"tpm_transmit: tpm_recv: error %zd\n", rc);
 out:
-	up(&chip->tpm_mutex);
+	mutex_unlock(&chip->tpm_mutex);
 	return rc;
 }
 
@@ -966,14 +966,14 @@ ssize_t tpm_write(struct file *file, const char __user *buf,
 	while (atomic_read(&chip->data_pending) != 0)
 		msleep(TPM_TIMEOUT);
 
-	down(&chip->buffer_mutex);
+	mutex_lock(&chip->buffer_mutex);
 
 	if (in_size > TPM_BUFSIZE)
 		in_size = TPM_BUFSIZE;
 
 	if (copy_from_user
 	    (chip->data_buffer, (void __user *) buf, in_size)) {
-		up(&chip->buffer_mutex);
+		mutex_unlock(&chip->buffer_mutex);
 		return -EFAULT;
 	}
 
@@ -981,7 +981,7 @@ ssize_t tpm_write(struct file *file, const char __user *buf,
 	out_size = tpm_transmit(chip, chip->data_buffer, TPM_BUFSIZE);
 
 	atomic_set(&chip->data_pending, out_size);
-	up(&chip->buffer_mutex);
+	mutex_unlock(&chip->buffer_mutex);
 
 	/* Set a timeout by which the reader must come claim the result */
 	mod_timer(&chip->user_read_timer, jiffies + (60 * HZ));
@@ -1004,10 +1004,10 @@ ssize_t tpm_read(struct file *file, char __user *buf,
 		if (size < ret_size)
 			ret_size = size;
 
-		down(&chip->buffer_mutex);
+		mutex_lock(&chip->buffer_mutex);
 		if (copy_to_user(buf, chip->data_buffer, ret_size))
 			ret_size = -EFAULT;
-		up(&chip->buffer_mutex);
+		mutex_unlock(&chip->buffer_mutex);
 	}
 
 	return ret_size;
@@ -1100,8 +1100,8 @@ struct tpm_chip *tpm_register_hardware(struct device *dev, const struct tpm_vend
 	if (chip == NULL)
 		return NULL;
 
-	init_MUTEX(&chip->buffer_mutex);
-	init_MUTEX(&chip->tpm_mutex);
+	mutex_init(&chip->buffer_mutex);
+	mutex_init(&chip->tpm_mutex);
 	INIT_LIST_HEAD(&chip->list);
 
 	INIT_WORK(&chip->work, timeout_work);
diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index bb9a43c..bf58aac 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -95,11 +95,11 @@ struct tpm_chip {
 	/* Data passed to and from the tpm via the read/write calls */
 	u8 *data_buffer;
 	atomic_t data_pending;
-	struct semaphore buffer_mutex;
+	struct mutex buffer_mutex;
 
 	struct timer_list user_read_timer;	/* user needs to claim result */
 	struct work_struct work;
-	struct semaphore tpm_mutex;	/* tpm is processing */
+	struct mutex tpm_mutex;	/* tpm is processing */
 
 	struct tpm_vendor_specific vendor;
 
-- 
Matthias Kaehlcke
Linux Application Developer
Barcelona

          Dreams and reality are opposites. Action synthesizes them
                             (Assata Shakur)
                                                                 .''`.
    using free software / Debian GNU/Linux | http://debian.org  : :'  :
                                                                `. `'`
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