[PATCHv2 1/3] staging: vme: use image mutex for ioctl()

From: Dmitry Kalinkin
Date: Thu Feb 26 2015 - 10:53:52 EST


This implements more granular locking in vme_user_ioctl() by using separate
locks for each devfs device.

This also provides a synchronization between vme_user_read(), vme_user_write()
and vme_user_ioctl().

Signed-off-by: Dmitry Kalinkin <dmitry.kalinkin@xxxxxxxxx>
Cc: Igor Alekseev <igor.alekseev@xxxxxxx>
---
drivers/staging/vme/devices/vme_user.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/staging/vme/devices/vme_user.c b/drivers/staging/vme/devices/vme_user.c
index 8b1f533..8731838 100644
--- a/drivers/staging/vme/devices/vme_user.c
+++ b/drivers/staging/vme/devices/vme_user.c
@@ -41,7 +41,6 @@

#include "vme_user.h"

-static DEFINE_MUTEX(vme_user_mutex);
static const char driver_name[] = "vme_user";

static int bus[VME_USER_BUS_MAX];
@@ -555,10 +554,12 @@ static long
vme_user_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
int ret;
+ struct inode *inode = file_inode(file);
+ unsigned int minor = MINOR(inode->i_rdev);

- mutex_lock(&vme_user_mutex);
- ret = vme_user_ioctl(file_inode(file), file, cmd, arg);
- mutex_unlock(&vme_user_mutex);
+ mutex_lock(&image[minor].mutex);
+ ret = vme_user_ioctl(inode, file, cmd, arg);
+ mutex_unlock(&image[minor].mutex);

return ret;
}
--
1.9.1

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