1 files changed, 22 insertions, 14 deletions

diff --git a/drivers/spi/spidev.c b/drivers/spi/spidev.c
index 799337f7fde1..e5e0cfed5e3b 100644
--- a/drivers/spi/spidev.c
+++ b/drivers/spi/spidev.c
@@ -30,6 +30,7 @@
 #include <linux/errno.h>
 #include <linux/mutex.h>
 #include <linux/slab.h>
+#include <linux/smp_lock.h>
 
 #include <linux/spi/spi.h>
 #include <linux/spi/spidev.h>
@@ -167,14 +168,14 @@ spidev_read(struct file *filp, char __user *buf, size_t count, loff_t *f_pos)
 
 	mutex_lock(&spidev->buf_lock);
 	status = spidev_sync_read(spidev, count);
-	if (status == 0) {
+	if (status > 0) {
 		unsigned long	missing;
 
-		missing = copy_to_user(buf, spidev->buffer, count);
-		if (count && missing == count)
+		missing = copy_to_user(buf, spidev->buffer, status);
+		if (missing == status)
 			status = -EFAULT;
 		else
-			status = count - missing;
+			status = status - missing;
 	}
 	mutex_unlock(&spidev->buf_lock);
 
@@ -200,8 +201,6 @@ spidev_write(struct file *filp, const char __user *buf,
 	missing = copy_from_user(spidev->buffer, buf, count);
 	if (missing == 0) {
 		status = spidev_sync_write(spidev, count);
-		if (status == 0)
-			status = count;
 	} else
 		status = -EFAULT;
 	mutex_unlock(&spidev->buf_lock);
@@ -229,7 +228,6 @@ static int spidev_message(struct spidev_data *spidev,
 	 * We walk the array of user-provided transfers, using each one
 	 * to initialize a kernel version of the same transfer.
 	 */
-	mutex_lock(&spidev->buf_lock);
 	buf = spidev->buffer;
 	total = 0;
 	for (n = n_xfers, k_tmp = k_xfers, u_tmp = u_xfers;
@@ -297,14 +295,12 @@ static int spidev_message(struct spidev_data *spidev,
 	status = total;
 
 done:
-	mutex_unlock(&spidev->buf_lock);
 	kfree(k_xfers);
 	return status;
 }
 
-static int
-spidev_ioctl(struct inode *inode, struct file *filp,
-		unsigned int cmd, unsigned long arg)
+static long
+spidev_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 {
 	int			err = 0;
 	int			retval = 0;
@@ -342,6 +338,14 @@ spidev_ioctl(struct inode *inode, struct file *filp,
 	if (spi == NULL)
 		return -ESHUTDOWN;
 
+	/* use the buffer lock here for triple duty:
+	 *  - prevent I/O (from us) so calling spi_setup() is safe;
+	 *  - prevent concurrent SPI_IOC_WR_* from morphing
+	 *    data fields while SPI_IOC_RD_* reads them;
+	 *  - SPI_IOC_MESSAGE needs the buffer locked "normally".
+	 */
+	mutex_lock(&spidev->buf_lock);
+
 	switch (cmd) {
 	/* read requests */
 	case SPI_IOC_RD_MODE:
@@ -457,6 +461,8 @@ spidev_ioctl(struct inode *inode, struct file *filp,
 		kfree(ioc);
 		break;
 	}
+
+	mutex_unlock(&spidev->buf_lock);
 	spi_dev_put(spi);
 	return retval;
 }
@@ -466,6 +472,7 @@ static int spidev_open(struct inode *inode, struct file *filp)
 	struct spidev_data	*spidev;
 	int			status = -ENXIO;
 
+	lock_kernel();
 	mutex_lock(&device_list_lock);
 
 	list_for_each_entry(spidev, &device_list, device_entry) {
@@ -491,6 +498,7 @@ static int spidev_open(struct inode *inode, struct file *filp)
 		pr_debug("spidev: nothing for minor %d\n", iminor(inode));
 
 	mutex_unlock(&device_list_lock);
+	unlock_kernel();
 	return status;
 }
 
@@ -532,7 +540,7 @@ static struct file_operations spidev_fops = {
 	 */
 	.write =	spidev_write,
 	.read =		spidev_read,
-	.ioctl =	spidev_ioctl,
+	.unlocked_ioctl = spidev_ioctl,
 	.open =		spidev_open,
 	.release =	spidev_release,
 };
@@ -575,7 +583,8 @@ static int spidev_probe(struct spi_device *spi)
 		struct device *dev;
 
 		spidev->devt = MKDEV(SPIDEV_MAJOR, minor);
-		dev = device_create(spidev_class, &spi->dev, spidev->devt,
+		dev = device_create_drvdata(spidev_class, &spi->dev,
+				spidev->devt, spidev,
 				"spidev%d.%d",
 				spi->master->bus_num, spi->chip_select);
 		status = IS_ERR(dev) ? PTR_ERR(dev) : 0;
@@ -585,7 +594,6 @@ static int spidev_probe(struct spi_device *spi)
 	}
 	if (status == 0) {
 		set_bit(minor, minors);
-		spi_set_drvdata(spi, spidev);
 		list_add(&spidev->device_entry, &device_list);
 	}
 	mutex_unlock(&device_list_lock);