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Commit d081d470 authored by Matthias Kaehlcke's avatar Matthias Kaehlcke Committed by Linus Torvalds
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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: default avatarMatthias Kaehlcke <matthias.kaehlcke@gmail.com>
Cc: Kylene Hall <kjhall@us.ibm.com>
Cc: Marcel Selhorst <tpm@selhorst.net>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 69f545ea

drivers/char/tpm/tpm.c

+13 −11
Original line number Diff line number Diff line
@@ -24,7 +24,9 @@ 
 */



#include <linux/poll.h>

#include <linux/mutex.h>

#include <linux/spinlock.h>



#include "tpm.h"



enum tpm_const {
@@ -328,10 +330,10 @@ 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 +382,7 @@ 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 +421,7 @@ static ssize_t tpm_transmit(struct tpm_chip *chip, const char *buf, 
		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 +968,14 @@ 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 +983,7 @@ 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 +1006,10 @@ 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;
@@ -1105,8 +1107,8 @@ struct tpm_chip *tpm_register_hardware(struct device *dev, const struct tpm_vend 
		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);

drivers/char/tpm/tpm.h

+3 −2
Original line number Diff line number Diff line
@@ -21,6 +21,7 @@ 
#include <linux/module.h>

#include <linux/delay.h>

#include <linux/fs.h>

#include <linux/mutex.h>

#include <linux/sched.h>

#include <linux/miscdevice.h>

#include <linux/platform_device.h>
@@ -94,11 +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;