fix deadlock in loop.c

[powerpc.git] / drivers / block / loop.c

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index af6d727..5526ead 100644 (file)
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -243,17 +243,13 @@ static int do_lo_send_aops(struct loop_device *lo, struct bio_vec *bvec,
                transfer_result = lo_do_transfer(lo, WRITE, page, offset,
                                bvec->bv_page, bv_offs, size, IV);
                if (unlikely(transfer_result)) {
-                       char *kaddr;
-
                        /*
                         * The transfer failed, but we still write the data to
                         * keep prepare/commit calls balanced.
                         */
                        printk(KERN_ERR "loop: transfer error block %llu\n",
                               (unsigned long long)index);
-                       kaddr = kmap_atomic(page, KM_USER0);
-                       memset(kaddr + offset, 0, size);
-                       kunmap_atomic(kaddr, KM_USER0);
+                       zero_user_page(page, offset, size, KM_USER0);
                }
                flush_dcache_page(page);
                ret = aops->commit_write(file, page, offset,
@@ -1321,18 +1317,6 @@ static long lo_compat_ioctl(struct file *file, unsigned int cmd, unsigned long a
 }
 #endif
 
-static struct loop_device *loop_find_dev(int number)
-{
-       struct loop_device *lo;
-
-       list_for_each_entry(lo, &loop_devices, lo_list) {
-               if (lo->lo_number == number)
-                       return lo;
-       }
-       return NULL;
-}
-
-static struct loop_device *loop_init_one(int i);
 static int lo_open(struct inode *inode, struct file *file)
 {
        struct loop_device *lo = inode->i_bdev->bd_disk->private_data;
@@ -1341,11 +1325,6 @@ static int lo_open(struct inode *inode, struct file *file)
        lo->lo_refcnt++;
        mutex_unlock(&lo->lo_ctl_mutex);
 
-       mutex_lock(&loop_devices_mutex);
-       if (!loop_find_dev(lo->lo_number + 1))
-               loop_init_one(lo->lo_number + 1);
-       mutex_unlock(&loop_devices_mutex);
-
        return 0;
 }
 
@@ -1420,6 +1399,11 @@ static struct loop_device *loop_init_one(int i)
        struct loop_device *lo;
        struct gendisk *disk;
 
+       list_for_each_entry(lo, &loop_devices, lo_list) {
+               if (lo->lo_number == i)
+                       return lo;
+       }
+
        lo = kzalloc(sizeof(*lo), GFP_KERNEL);
        if (!lo)
                goto out;
@@ -1452,7 +1436,7 @@ out_free_queue:
 out_free_dev:
        kfree(lo);
 out:
-       return ERR_PTR(-ENOMEM);
+       return NULL;
 }
 
 static void loop_del_one(struct loop_device *lo)
@@ -1466,35 +1450,25 @@ static void loop_del_one(struct loop_device *lo)
 
 static struct kobject *loop_probe(dev_t dev, int *part, void *data)
 {
-       unsigned int number = dev & MINORMASK;
        struct loop_device *lo;
+       struct kobject *kobj;
 
        mutex_lock(&loop_devices_mutex);
-       lo = loop_find_dev(number);
-       if (lo == NULL)
-               lo = loop_init_one(number);
+       lo = loop_init_one(dev & MINORMASK);
+       kobj = lo ? get_disk(lo->lo_disk) : ERR_PTR(-ENOMEM);
        mutex_unlock(&loop_devices_mutex);
 
        *part = 0;
-       if (IS_ERR(lo))
-               return (void *)lo;
-       else
-               return &lo->lo_disk->kobj;
+       return kobj;
 }
 
 static int __init loop_init(void)
 {
-       struct loop_device *lo;
-
        if (register_blkdev(LOOP_MAJOR, "loop"))
                return -EIO;
        blk_register_region(MKDEV(LOOP_MAJOR, 0), 1UL << MINORBITS,
                                  THIS_MODULE, loop_probe, NULL, NULL);
 
-       lo = loop_init_one(0);
-       if (IS_ERR(lo))
-               goto out;
-
        if (max_loop) {
                printk(KERN_INFO "loop: the max_loop option is obsolete "
                                 "and will be removed in March 2008\n");
@@ -1502,11 +1476,6 @@ static int __init loop_init(void)
        }
        printk(KERN_INFO "loop: module loaded\n");
        return 0;
-
-out:
-       unregister_blkdev(LOOP_MAJOR, "loop");
-       printk(KERN_ERR "loop: ran out of memory\n");
-       return -ENOMEM;
 }
 
 static void __exit loop_exit(void)