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authorMelissa Howland <melissah@us.ibm.com>2007-08-10 14:32:35 +0200
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2007-08-10 14:32:39 +0200
commitcbea66d9788a344e16e161f22a6e0c4deef2c0ed (patch)
tree3fb41c221aac478ccae176b4d088624f9acb833c /drivers/s390/char/monwriter.c
parent3eed13cc3beaa9ee07b126a662def88f7281394e (diff)
[S390] monwriter: Serialization bug for multithreaded applications.
Locking added so that multithreaded applications can now do writes from different threads without the risk of storage corruption. Signed-off-by: Melissa Howland <melissah@us.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'drivers/s390/char/monwriter.c')
-rw-r--r--drivers/s390/char/monwriter.c6
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;
}