[SCSI] bsg: use lib/idr.c to find a unique minor number
This replaces the current linear search for a unique minor number with
lib/idr.c.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Acked-by: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
diff --git a/block/bsg.c b/block/bsg.c
index b571869..8e4de53 100644
--- a/block/bsg.c
+++ b/block/bsg.c
@@ -24,6 +24,7 @@
#include <linux/cdev.h>
#include <linux/percpu.h>
#include <linux/uio.h>
+#include <linux/idr.h>
#include <linux/bsg.h>
#include <scsi/scsi.h>
@@ -70,13 +71,12 @@
#endif
static DEFINE_MUTEX(bsg_mutex);
-static int bsg_device_nr, bsg_minor_idx;
+static DEFINE_IDR(bsg_minor_idr);
#define BSG_LIST_ARRAY_SIZE 8
static struct hlist_head bsg_device_list[BSG_LIST_ARRAY_SIZE];
static struct class *bsg_class;
-static LIST_HEAD(bsg_class_list);
static int bsg_major;
static struct kmem_cache *bsg_cmd_cachep;
@@ -781,23 +781,18 @@
static struct bsg_device *bsg_get_device(struct inode *inode, struct file *file)
{
- struct bsg_device *bd = __bsg_get_device(iminor(inode));
- struct bsg_class_device *bcd, *__bcd;
+ struct bsg_device *bd;
+ struct bsg_class_device *bcd;
+ bd = __bsg_get_device(iminor(inode));
if (bd)
return bd;
/*
* find the class device
*/
- bcd = NULL;
mutex_lock(&bsg_mutex);
- list_for_each_entry(__bcd, &bsg_class_list, list) {
- if (__bcd->minor == iminor(inode)) {
- bcd = __bcd;
- break;
- }
- }
+ bcd = idr_find(&bsg_minor_idr, iminor(inode));
mutex_unlock(&bsg_mutex);
if (!bcd)
@@ -936,13 +931,12 @@
return;
mutex_lock(&bsg_mutex);
+ idr_remove(&bsg_minor_idr, bcd->minor);
sysfs_remove_link(&q->kobj, "bsg");
class_device_unregister(bcd->class_dev);
put_device(bcd->dev);
bcd->class_dev = NULL;
bcd->dev = NULL;
- list_del_init(&bcd->list);
- bsg_device_nr--;
mutex_unlock(&bsg_mutex);
}
EXPORT_SYMBOL_GPL(bsg_unregister_queue);
@@ -950,9 +944,9 @@
int bsg_register_queue(struct request_queue *q, struct device *gdev,
const char *name)
{
- struct bsg_class_device *bcd, *__bcd;
+ struct bsg_class_device *bcd;
dev_t dev;
- int ret = -EMFILE;
+ int ret, minor;
struct class_device *class_dev = NULL;
const char *devname;
@@ -969,28 +963,26 @@
bcd = &q->bsg_dev;
memset(bcd, 0, sizeof(*bcd));
- INIT_LIST_HEAD(&bcd->list);
mutex_lock(&bsg_mutex);
- if (bsg_device_nr == BSG_MAX_DEVS) {
+
+ ret = idr_pre_get(&bsg_minor_idr, GFP_KERNEL);
+ if (!ret) {
+ ret = -ENOMEM;
+ goto unlock;
+ }
+
+ ret = idr_get_new(&bsg_minor_idr, bcd, &minor);
+ if (ret < 0)
+ goto unlock;
+
+ if (minor >= BSG_MAX_DEVS) {
printk(KERN_ERR "bsg: too many bsg devices\n");
- goto err;
+ ret = -EINVAL;
+ goto remove_idr;
}
-retry:
- list_for_each_entry(__bcd, &bsg_class_list, list) {
- if (__bcd->minor == bsg_minor_idx) {
- bsg_minor_idx++;
- if (bsg_minor_idx == BSG_MAX_DEVS)
- bsg_minor_idx = 0;
- goto retry;
- }
- }
-
- bcd->minor = bsg_minor_idx++;
- if (bsg_minor_idx == BSG_MAX_DEVS)
- bsg_minor_idx = 0;
-
+ bcd->minor = minor;
bcd->queue = q;
bcd->dev = get_device(gdev);
dev = MKDEV(bsg_major, bcd->minor);
@@ -998,27 +990,26 @@
devname);
if (IS_ERR(class_dev)) {
ret = PTR_ERR(class_dev);
- goto err_put;
+ goto put_dev;
}
bcd->class_dev = class_dev;
if (q->kobj.sd) {
ret = sysfs_create_link(&q->kobj, &bcd->class_dev->kobj, "bsg");
if (ret)
- goto err_unregister;
+ goto unregister_class_dev;
}
- list_add_tail(&bcd->list, &bsg_class_list);
- bsg_device_nr++;
-
mutex_unlock(&bsg_mutex);
return 0;
-err_unregister:
+unregister_class_dev:
class_device_unregister(class_dev);
-err_put:
+put_dev:
put_device(gdev);
-err:
+remove_idr:
+ idr_remove(&bsg_minor_idr, minor);
+unlock:
mutex_unlock(&bsg_mutex);
return ret;
}