[PATCH] uml: locking fixes in the ubd driver
Some small locking and formatting fixes in the ubd driver.
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/um/drivers/ubd_kern.c b/arch/um/drivers/ubd_kern.c
index d863482c..da0badc 100644
--- a/arch/um/drivers/ubd_kern.c
+++ b/arch/um/drivers/ubd_kern.c
@@ -131,7 +131,6 @@
/* Protected by ubd_lock */
static int fake_major = MAJOR_NR;
-
static struct gendisk *ubd_gendisk[MAX_DEV];
static struct gendisk *fake_gendisk[MAX_DEV];
@@ -142,10 +141,6 @@
#define OPEN_FLAGS ((struct openflags) { .r = 1, .w = 1, .s = 0, .c = 0, \
.cl = 1 })
#endif
-
-/* Not protected - changed only in ubd_setup_common and then only to
- * to enable O_SYNC.
- */
static struct openflags global_openflags = OPEN_FLAGS;
struct cow {
@@ -197,6 +192,7 @@
.lock = SPIN_LOCK_UNLOCKED, \
}
+/* Protected by ubd_lock */
struct ubd ubd_devs[MAX_DEV] = { [ 0 ... MAX_DEV - 1 ] = DEFAULT_UBD };
/* Only changed by fake_ide_setup which is a setup */
@@ -288,7 +284,7 @@
struct ubd *ubd_dev;
struct openflags flags = global_openflags;
char *backing_file;
- int n, err, i;
+ int n, err = 0, i;
if(index_out) *index_out = -1;
n = *str;
@@ -299,15 +295,16 @@
str++;
if(!strcmp(str, "sync")){
global_openflags = of_sync(global_openflags);
- return 0;
- }
- major = simple_strtoul(str, &end, 0);
- if((*end != '\0') || (end == str)){
- *error_out = "Didn't parse major number";
- return -EINVAL;
+ goto out1;
}
err = -EINVAL;
+ major = simple_strtoul(str, &end, 0);
+ if((*end != '\0') || (end == str)){
+ *error_out = "Didn't parse major number";
+ goto out1;
+ }
+
mutex_lock(&ubd_lock);
if(fake_major != MAJOR_NR){
*error_out = "Can't assign a fake major twice";
@@ -473,12 +470,6 @@
/* Only changed by ubd_init, which is an initcall. */
int thread_fd = -1;
-/* Changed by ubd_handler, which is serialized because interrupts only
- * happen on CPU 0.
- * XXX: currently unused.
- */
-static int intr_count = 0;
-
/* call ubd_finish if you need to serialize */
static void __ubd_finish(struct request *req, int error)
{
@@ -518,7 +509,6 @@
int n;
do_ubd = 0;
- intr_count++;
n = os_read_file(thread_fd, &req, sizeof(req));
if(n != sizeof(req)){
printk(KERN_ERR "Pid %d - spurious interrupt in ubd_handler, "
@@ -637,8 +627,7 @@
}
static int ubd_disk_register(int major, u64 size, int unit,
- struct gendisk **disk_out)
-
+ struct gendisk **disk_out)
{
struct gendisk *disk;
@@ -840,7 +829,7 @@
}
/* All these are called by mconsole in process context and without
- * ubd-specific locks.
+ * ubd-specific locks. The structure itself is const except for .list.
*/
static struct mc_device ubd_mc = {
.list = LIST_HEAD_INIT(ubd_mc.list),
@@ -863,13 +852,17 @@
{
struct ubd *ubd_dev = &ubd_devs[0];
+ mutex_lock(&ubd_lock);
if(ubd_dev->file == NULL)
ubd_dev->file = "root_fs";
+ mutex_unlock(&ubd_lock);
+
return(0);
}
__initcall(ubd0_init);
+/* Used in ubd_init, which is an initcall */
static struct platform_driver ubd_driver = {
.driver = {
.name = DRIVER_NAME,
@@ -892,12 +885,14 @@
return -1;
}
platform_driver_register(&ubd_driver);
+ mutex_lock(&ubd_lock);
for (i = 0; i < MAX_DEV; i++){
err = ubd_add(i, &error);
if(err)
printk(KERN_ERR "Failed to initialize ubd device %d :"
"%s\n", i, error);
}
+ mutex_unlock(&ubd_lock);
return 0;
}
@@ -1129,7 +1124,7 @@
sizeof(ubd_id)))
return(-EFAULT);
return(0);
-
+
case CDROMVOLREAD:
if(copy_from_user(&volume, (char __user *) arg, sizeof(volume)))
return(-EFAULT);