diff options
Diffstat (limited to 'drivers/s390/char/monwriter.c')
| -rw-r--r-- | drivers/s390/char/monwriter.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/drivers/s390/char/monwriter.c b/drivers/s390/char/monwriter.c index 268598ef3efe..20442fbf9346 100644 --- a/drivers/s390/char/monwriter.c +++ b/drivers/s390/char/monwriter.c @@ -17,6 +17,7 @@ #include <linux/miscdevice.h> #include <linux/ctype.h> #include <linux/poll.h> +#include <linux/mutex.h> #include <asm/uaccess.h> #include <asm/ebcdic.h> #include <asm/io.h> @@ -41,6 +42,7 @@ struct mon_private { size_t hdr_to_read; size_t data_to_read; struct mon_buf *current_buf; + struct mutex thread_mutex; }; /* @@ -179,6 +181,7 @@ static int monwrite_open(struct inode *inode, struct file *filp) return -ENOMEM; INIT_LIST_HEAD(&monpriv->list); monpriv->hdr_to_read = sizeof(monpriv->hdr); + mutex_init(&monpriv->thread_mutex); filp->private_data = monpriv; return nonseekable_open(inode, filp); } @@ -209,6 +212,7 @@ static ssize_t monwrite_write(struct file *filp, const char __user *data, void *to; int rc; + mutex_lock(&monpriv->thread_mutex); for (written = 0; written < count; ) { if (monpriv->hdr_to_read) { len = min(count - written, monpriv->hdr_to_read); @@ -247,11 +251,13 @@ static ssize_t monwrite_write(struct file *filp, const char __user *data, } monpriv->hdr_to_read = sizeof(monpriv->hdr); } + mutex_unlock(&monpriv->thread_mutex); return written; out_error: monpriv->data_to_read = 0; monpriv->hdr_to_read = sizeof(struct monwrite_hdr); + mutex_unlock(&monpriv->thread_mutex); return rc; } |