1 files changed, 7 insertions, 6 deletions

diff --git a/drivers/spi/spidev.c b/drivers/spi/spidev.c
index 799337f7fde1..ddbe1a5e970e 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);
@@ -466,6 +465,7 @@ 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 +491,7 @@ 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;
 }