First step to tidying mddev recounting and locking.
This patches introduces
mddev_get which incs the refcount on an mddev
mddev_put which decs it and, if it becomes unused, frees it
mddev_find which finds or allocated an mddev for a given minor
This is mostly the old alloc_mddev
free_mddev no longer actually frees it. It just disconnects all drives
so that mddev_put will do the free.
Now the test for "does an mddev exist" is not "mddev != NULL"
but involves checking if the mddev has disks or a superblock
attached.
This makes the semantics of do_md_stop a bit cleaner. Previously
if do_md_stop succeed for a real stop (not a read-only stop) then
you didn't have to unlock the mddev, otherwise you did. Now
you always unlock the mddev after do_md_stop.
----------- Diffstat output ------------
./drivers/md/md.c | 125 +++++++++++++++++++++++++++---------------------------
1 files changed, 63 insertions(+), 62 deletions(-)
--- ./drivers/md/md.c 2002/06/18 04:37:53 1.12
+++ ./drivers/md/md.c 2002/06/18 04:40:56 1.13
@@ -145,13 +145,30 @@
return 0;
}
-static mddev_t * alloc_mddev(kdev_t dev)
+static inline mddev_t *mddev_get(mddev_t *mddev)
+{
+ atomic_inc(&mddev->active);
+ return mddev;
+}
+
+static void mddev_put(mddev_t *mddev)
+{
+ if (!atomic_dec_and_test(&mddev->active))
+ return;
+ if (!mddev->sb && list_empty(&mddev->disks)) {
+ list_del(&mddev->all_mddevs);
+ mddev_map[mdidx(mddev)] = NULL;
+ kfree(mddev);
+ MOD_DEC_USE_COUNT;
+ }
+}
+
+static mddev_t * mddev_find(int unit)
{
mddev_t *mddev;
- if (major(dev) != MD_MAJOR) {
- MD_BUG();
- return 0;
+ if ((mddev = mddev_map[unit])) {
+ return mddev_get(mddev);
}
mddev = (mddev_t *) kmalloc(sizeof(*mddev), GFP_KERNEL);
if (!mddev)
@@ -159,15 +176,15 @@
memset(mddev, 0, sizeof(*mddev));
- mddev->__minor = minor(dev);
+ mddev->__minor = unit;
init_MUTEX(&mddev->reconfig_sem);
init_MUTEX(&mddev->recovery_sem);
init_MUTEX(&mddev->resync_sem);
INIT_LIST_HEAD(&mddev->disks);
INIT_LIST_HEAD(&mddev->all_mddevs);
- atomic_set(&mddev->active, 0);
+ atomic_set(&mddev->active, 1);
- mddev_map[mdidx(mddev)] = mddev;
+ mddev_map[unit] = mddev;
list_add(&mddev->all_mddevs, &all_mddevs);
MOD_INC_USE_COUNT;
@@ -631,11 +648,6 @@
schedule();
while (atomic_read(&mddev->recovery_sem.count) != 1)
schedule();
-
- mddev_map[mdidx(mddev)] = NULL;
- list_del(&mddev->all_mddevs);
- kfree(mddev);
- MOD_DEC_USE_COUNT;
}
#undef BAD_CSUM
@@ -1803,8 +1815,6 @@
struct list_head *tmp;
mdk_rdev_t *rdev0, *rdev;
mddev_t *mddev;
- kdev_t md_kdev;
-
printk(KERN_INFO "md: autorun ...\n");
while (!list_empty(&pending_raid_disks)) {
@@ -1831,28 +1841,31 @@
* mostly sane superblocks. It's time to allocate the
* mddev.
*/
- md_kdev = mk_kdev(MD_MAJOR, rdev0->sb->md_minor);
- mddev = kdev_to_mddev(md_kdev);
- if (mddev) {
+
+ mddev = mddev_find(rdev0->sb->md_minor);
+ if (!mddev) {
+ printk(KERN_ERR "md: cannot allocate memory for md drive.\n");
+ ITERATE_RDEV_GENERIC(candidates,pending,rdev,tmp)
+ export_rdev(rdev);
+ break;
+ }
+ if (mddev->sb || !list_empty(&mddev->disks)) {
printk(KERN_WARNING "md: md%d already running, cannot run %s\n",
mdidx(mddev), partition_name(rdev0->dev));
ITERATE_RDEV_GENERIC(candidates,pending,rdev,tmp)
export_rdev(rdev);
+ mddev_put(mddev);
continue;
}
- mddev = alloc_mddev(md_kdev);
- if (!mddev) {
- printk(KERN_ERR "md: cannot allocate memory for md drive.\n");
- break;
- }
- if (kdev_same(md_kdev, countdev))
- atomic_inc(&mddev->active);
printk(KERN_INFO "md: created md%d\n", mdidx(mddev));
ITERATE_RDEV_GENERIC(candidates,pending,rdev,tmp) {
bind_rdev_to_array(rdev, mddev);
list_del_init(&rdev->pending);
}
autorun_array(mddev);
+ if (minor(countdev) != mdidx(mddev))
+ mddev_put(mddev);
+ /* else put will happen at md_close time */
}
printk(KERN_INFO "md: ... autorun DONE.\n");
}
@@ -2486,29 +2499,16 @@
* Commands creating/starting a new array:
*/
- mddev = kdev_to_mddev(dev);
+ mddev = mddev_find(minor);
- switch (cmd)
- {
- case SET_ARRAY_INFO:
- case START_ARRAY:
- if (mddev) {
- printk(KERN_WARNING "md: array md%d already exists!\n",
- mdidx(mddev));
- err = -EEXIST;
- goto abort;
- }
- default:;
+ if (!mddev) {
+ err = -ENOMEM;
+ goto abort;
}
+
switch (cmd)
{
case SET_ARRAY_INFO:
- mddev = alloc_mddev(dev);
- if (!mddev) {
- err = -ENOMEM;
- goto abort;
- }
- atomic_inc(&mddev->active);
/*
* alloc_mddev() should possibly self-lock.
@@ -2519,7 +2519,12 @@
err, cmd);
goto abort;
}
-
+ if (!list_empty(&mddev->disks)) {
+ printk(KERN_WARNING "md: array md%d already has disks!\n",
+ mdidx(mddev));
+ err = -EBUSY;
+ goto abort_unlock;
+ }
if (mddev->sb) {
printk(KERN_WARNING "md: array md%d already has a superblock!\n",
mdidx(mddev));
@@ -2559,10 +2564,6 @@
* Commands querying/configuring an existing array:
*/
- if (!mddev) {
- err = -ENODEV;
- goto abort;
- }
err = lock_mddev(mddev);
if (err) {
printk(KERN_INFO "md: ioctl lock interrupted, reason %d, cmd %d\n",err, cmd);
@@ -2592,8 +2593,7 @@
goto done_unlock;
case STOP_ARRAY:
- if (!(err = do_md_stop (mddev, 0)))
- mddev = NULL;
+ err = do_md_stop (mddev, 0);
goto done_unlock;
case STOP_ARRAY_RO:
@@ -2672,8 +2672,7 @@
*/
if (err) {
mddev->sb_dirty = 0;
- if (!do_md_stop (mddev, 0))
- mddev = NULL;
+ do_md_stop (mddev, 0);
}
goto done_unlock;
}
@@ -2688,8 +2687,8 @@
done_unlock:
abort_unlock:
- if (mddev)
- unlock_mddev(mddev);
+ unlock_mddev(mddev);
+ mddev_put(mddev);
return err;
done:
@@ -2706,7 +2705,7 @@
*/
mddev_t *mddev = kdev_to_mddev(inode->i_rdev);
if (mddev)
- atomic_inc(&mddev->active);
+ mddev_get(mddev);
return (0);
}
@@ -2714,7 +2713,7 @@
{
mddev_t *mddev = kdev_to_mddev(inode->i_rdev);
if (mddev)
- atomic_dec(&mddev->active);
+ mddev_put(mddev);
return 0;
}
@@ -3688,19 +3687,20 @@
if (!md_setup_args.device_set[minor])
continue;
- if (mddev_map[minor]) {
- printk(KERN_WARNING
- "md: Ignoring md=%d, already autodetected. (Use raid=noautodetect)\n",
- minor);
- continue;
- }
printk(KERN_INFO "md: Loading md%d: %s\n", minor, md_setup_args.device_names[minor]);
- mddev = alloc_mddev(mk_kdev(MD_MAJOR,minor));
+ mddev = mddev_find(minor);
if (!mddev) {
printk(KERN_ERR "md: kmalloc failed - cannot start array %d\n", minor);
continue;
}
+ if (mddev->sb || !list_empty(&mddev->disks)) {
+ printk(KERN_WARNING
+ "md: Ignoring md=%d, already autodetected. (Use raid=noautodetect)\n",
+ minor);
+ mddev_put(mddev);
+ continue;
+ }
if (md_setup_args.pers[minor]) {
/* non-persistent */
mdu_array_info_t ainfo;
@@ -3752,6 +3752,7 @@
do_md_stop(mddev, 0);
printk(KERN_WARNING "md: starting md%d failed\n", minor);
}
+ mddev_put(mddev);
}
}
-
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