drbd: Replaced the minor_table array by an idr

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drivers/block/drbd/drbd_int.h

@@ -168,8 +168,8 @@ drbd_insert_fault(struct drbd_conf *mdev, unsigned int type) {
 /* 4th incarnation of the disk layout. */
 #define DRBD_MD_MAGIC (DRBD_MAGIC+4)
 
-extern struct drbd_conf **minor_table;
 extern struct ratelimit_state drbd_ratelimit_state;
+extern struct idr minors;
 extern struct list_head drbd_tconns;
 
 /* on the wire */
@@ -1109,11 +1109,7 @@ struct drbd_conf {
 
 static inline struct drbd_conf *minor_to_mdev(unsigned int minor)
 {
-	struct drbd_conf *mdev;
-
-	mdev = minor < minor_count ? minor_table[minor] : NULL;
-
-	return mdev;
+	return (struct drbd_conf *)idr_find(&minors, minor);
 }
 
 static inline unsigned int mdev_to_minor(struct drbd_conf *mdev)

drivers/block/drbd/drbd_main.c

@@ -74,7 +74,7 @@ MODULE_AUTHOR("Philipp Reisner <phil@linbit.com>, "
 MODULE_DESCRIPTION("drbd - Distributed Replicated Block Device v" REL_VERSION);
 MODULE_VERSION(REL_VERSION);
 MODULE_LICENSE("GPL");
-MODULE_PARM_DESC(minor_count, "Maximum number of drbd devices ("
+MODULE_PARM_DESC(minor_count, "Approximate number of drbd devices ("
 		 __stringify(DRBD_MINOR_COUNT_MIN) "-" __stringify(DRBD_MINOR_COUNT_MAX) ")");
 MODULE_ALIAS_BLOCKDEV_MAJOR(DRBD_MAJOR);
 
@@ -120,7 +120,7 @@ module_param_string(usermode_helper, usermode_helper, sizeof(usermode_helper), 0
 /* in 2.6.x, our device mapping and config info contains our virtual gendisks
  * as member "struct gendisk *vdisk;"
  */
-struct drbd_conf **minor_table;
+struct idr minors;
 struct list_head drbd_tconns;  /* list of struct drbd_tconn */
 
 struct kmem_cache *drbd_request_cache;
@@ -2118,11 +2118,13 @@ void drbd_delete_device(unsigned int minor)
 	 * allocated from drbd_new_device
 	 * and actually free the mdev itself */
 	drbd_free_mdev(mdev);
+	idr_remove(&minors, minor);
 }
 
 static void drbd_cleanup(void)
 {
 	unsigned int i;
+	struct drbd_conf *mdev;
 
 	unregister_reboot_notifier(&drbd_notifier);
 
@@ -2139,17 +2141,13 @@ static void drbd_cleanup(void)
 
 	drbd_nl_cleanup();
 
-	if (minor_table) {
-		i = minor_count;
-		while (i--)
+	idr_for_each_entry(&minors, mdev, i)
 		drbd_delete_device(i);
 	drbd_destroy_mempools();
-	}
-
-	kfree(minor_table);
-
 	unregister_blkdev(DRBD_MAJOR, "drbd");
 
+	idr_destroy(&minors);
+
 	printk(KERN_INFO "drbd: module cleanup done.\n");
 }
 
@@ -2286,6 +2284,7 @@ enum drbd_ret_code conn_new_minor(struct drbd_tconn *tconn, unsigned int minor,
 	struct gendisk *disk;
 	struct request_queue *q;
 	int vnr_got = vnr;
+	int minor_got = minor;
 
 	mdev = minor_to_mdev(minor);
 	if (mdev)
@@ -2361,13 +2360,20 @@ enum drbd_ret_code conn_new_minor(struct drbd_tconn *tconn, unsigned int minor,
 	INIT_LIST_HEAD(&mdev->current_epoch->list);
 	mdev->epochs = 1;
 
-	minor_table[minor] = mdev;
+	if (!idr_pre_get(&minors, GFP_KERNEL))
+		goto out_no_minor_idr;
+	if (idr_get_new(&minors, mdev, &minor_got))
+		goto out_no_minor_idr;
+	if (minor_got != minor) {
+		idr_remove(&minors, minor_got);
+		goto out_no_minor_idr;
+	}
 	add_disk(disk);
 
 	return NO_ERROR;
 
-/* out_whatever_else:
-	kfree(mdev->current_epoch); */
+out_no_minor_idr:
+	kfree(mdev->current_epoch);
 out_no_epoch:
 	drbd_bm_cleanup(mdev);
 out_no_bitmap:
@@ -2436,10 +2442,7 @@ int __init drbd_init(void)
 	init_waitqueue_head(&drbd_pp_wait);
 
 	drbd_proc = NULL; /* play safe for drbd_cleanup */
-	minor_table = kzalloc(sizeof(struct drbd_conf *)*minor_count,
-				GFP_KERNEL);
-	if (!minor_table)
-		goto Enomem;
+	idr_init(&minors);
 
 	err = drbd_create_mempools();
 	if (err)
@@ -2460,7 +2463,6 @@ int __init drbd_init(void)
 	printk(KERN_INFO "drbd: %s\n", drbd_buildtag());
 	printk(KERN_INFO "drbd: registered as block device major %d\n",
 		DRBD_MAJOR);
-	printk(KERN_INFO "drbd: minor_table @ 0x%p\n", minor_table);
 
 	return 0; /* Success! */
 

drivers/block/drbd/drbd_proc.c

@@ -194,7 +194,7 @@ static void resync_dump_detail(struct seq_file *seq, struct lc_element *e)
 
 static int drbd_seq_show(struct seq_file *seq, void *v)
 {
-	int i, hole = 0;
+	int i, prev_i = -1;
 	const char *sn;
 	struct drbd_conf *mdev;
 
@@ -227,16 +227,10 @@ static int drbd_seq_show(struct seq_file *seq, void *v)
 	 oos .. known out-of-sync kB
 	*/
 
-	for (i = 0; i < minor_count; i++) {
-		mdev = minor_to_mdev(i);
-		if (!mdev) {
-			hole = 1;
-			continue;
-		}
-		if (hole) {
-			hole = 0;
+	idr_for_each_entry(&minors, mdev, i) {
+		if (prev_i != i - 1)
 			seq_printf(seq, "\n");
-		}
+		prev_i = i;
 
 		sn = drbd_conn_str(mdev->state.conn);
 

drivers/block/drbd/drbd_receiver.c

@@ -284,7 +284,7 @@ static void drbd_pp_free(struct drbd_conf *mdev, struct page *page, int is_net)
 	atomic_t *a = is_net ? &mdev->pp_in_use_by_net : &mdev->pp_in_use;
 	int i;
 
-	if (drbd_pp_vacant > (DRBD_MAX_BIO_SIZE/PAGE_SIZE)*minor_count)
+	if (drbd_pp_vacant > (DRBD_MAX_BIO_SIZE/PAGE_SIZE) * minor_count)
 		i = page_chain_free(page);
 	else {
 		struct page *tmp;

drivers/block/drbd/drbd_worker.c

@@ -1349,10 +1349,7 @@ static int _drbd_pause_after(struct drbd_conf *mdev)
 	struct drbd_conf *odev;
 	int i, rv = 0;
 
-	for (i = 0; i < minor_count; i++) {
-		odev = minor_to_mdev(i);
-		if (!odev)
-			continue;
+	idr_for_each_entry(&minors, odev, i) {
 		if (odev->state.conn == C_STANDALONE && odev->state.disk == D_DISKLESS)
 			continue;
 		if (!_drbd_may_sync_now(odev))
@@ -1374,10 +1371,7 @@ static int _drbd_resume_next(struct drbd_conf *mdev)
 	struct drbd_conf *odev;
 	int i, rv = 0;
 
-	for (i = 0; i < minor_count; i++) {
-		odev = minor_to_mdev(i);
-		if (!odev)
-			continue;
+	idr_for_each_entry(&minors, odev, i) {
 		if (odev->state.conn == C_STANDALONE && odev->state.disk == D_DISKLESS)
 			continue;
 		if (odev->state.aftr_isp) {