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Message-Id: <200701231927.l0NJReOw005343@ccure.user-mode-linux.org>
Date: Tue, 23 Jan 2007 14:27:40 -0500
From: Jeff Dike <jdike@...toit.com>
To: akpm@...l.org
cc: linux-kernel@...r.kernel.org,
user-mode-linux-devel@...ts.sourceforge.net
Subject: [PATCH 2/7] UML - locking fixes in the ubd driver
Some small locking and formatting fixes in the ubd driver.
Signed-off-by: Jeff Dike <jdike@...toit.com>
--
arch/um/drivers/ubd_kern.c | 35 +++++++++++++++--------------------
1 file changed, 15 insertions(+), 20 deletions(-)
Index: linux-2.6.18-mm/arch/um/drivers/ubd_kern.c
===================================================================
--- linux-2.6.18-mm.orig/arch/um/drivers/ubd_kern.c 2007-01-17 12:46:28.000000000 +1100
+++ linux-2.6.18-mm/arch/um/drivers/ubd_kern.c 2007-01-17 12:46:31.000000000 +1100
@@ -131,7 +131,6 @@ static const struct block_device_operati
/* 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 @@ static struct gendisk *fake_gendisk[MAX_
#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 @@ struct ubd {
.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 */
@@ -287,7 +283,7 @@ static int ubd_setup_common(char *str, i
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;
@@ -298,15 +294,16 @@ static int ubd_setup_common(char *str, i
str++;
if(!strcmp(str, "sync")){
global_openflags = of_sync(global_openflags);
- return 0;
+ goto out1;
}
+
+ err = -EINVAL;
major = simple_strtoul(str, &end, 0);
if((*end != '\0') || (end == str)){
*error_out = "Didn't parse major number";
- return -EINVAL;
+ goto out1;
}
- err = -EINVAL;
mutex_lock(&ubd_lock);
if(fake_major != MAJOR_NR){
*error_out = "Can't assign a fake major twice";
@@ -472,12 +469,6 @@ static void do_ubd_request(request_queue
/* 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)
{
@@ -517,7 +508,6 @@ static void ubd_handler(void)
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, "
@@ -636,8 +626,7 @@ static int ubd_open_dev(struct ubd *ubd_
}
static int ubd_disk_register(int major, u64 size, int unit,
- struct gendisk **disk_out)
-
+ struct gendisk **disk_out)
{
struct gendisk *disk;
@@ -839,7 +828,7 @@ out:
}
/* 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),
@@ -862,13 +851,17 @@ static int __init ubd0_init(void)
{
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,
@@ -891,12 +884,14 @@ static int __init ubd_init(void)
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;
}
@@ -1128,7 +1123,7 @@ static int ubd_ioctl(struct inode * inod
sizeof(ubd_id)))
return(-EFAULT);
return(0);
-
+
case CDROMVOLREAD:
if(copy_from_user(&volume, (char __user *) arg, sizeof(volume)))
return(-EFAULT);
-
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