Revert "scsi, block: fix duplicate bdi name registration crashes"

This reverts commit 0dba1314d4f81115dce711292ec7981d17231064. It causes
leaking of device numbers for SCSI when SCSI registers multiple gendisks
for one request_queue in succession. It can be easily reproduced using
Omar's script [1] on kernel with CONFIG_DEBUG_TEST_DRIVER_REMOVE.
Furthermore the protection provided by this commit is not needed anymore
as the problem it was fixing got also fixed by commit 165a5e22fafb
"block: Move bdi_unregister() to del_gendisk()".

[1]: http://marc.info/?l=linux-block&m=148554717109098&w=2

Signed-off-by: Jan Kara <jack@suse.cz>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Tested-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

diff --git a/block/blk-core.c b/block/blk-core.c
index 1086dac8724c995b85bf3c843a4aae080ab938a1..a76895c9776d9c5a652dfe3611c1292cc7bf2b22 100644 (file)
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -578,8 +578,6 @@ void blk_cleanup_queue(struct request_queue *q)
                q->queue_lock = &q->__queue_lock;
        spin_unlock_irq(lock);
 
-       put_disk_devt(q->disk_devt);
-
        /* @q is and will stay empty, shutdown and put */
        blk_put_queue(q);
 }

diff --git a/block/genhd.c b/block/genhd.c
index 94f323842b52744c78e5b0e9975f5a0b80cc3b84..a9c516a8b37dbceca9f46a74b7ccb7b4df35639c 100644 (file)
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -572,20 +572,6 @@ exit:
        disk_part_iter_exit(&piter);
 }
 
-void put_disk_devt(struct disk_devt *disk_devt)
-{
-       if (disk_devt && atomic_dec_and_test(&disk_devt->count))
-               disk_devt->release(disk_devt);
-}
-EXPORT_SYMBOL(put_disk_devt);
-
-void get_disk_devt(struct disk_devt *disk_devt)
-{
-       if (disk_devt)
-               atomic_inc(&disk_devt->count);
-}
-EXPORT_SYMBOL(get_disk_devt);
-
 /**
  * device_add_disk - add partitioning information to kernel list
  * @parent: parent device for the disk
@@ -626,13 +612,6 @@ void device_add_disk(struct device *parent, struct gendisk *disk)
 
        disk_alloc_events(disk);
 
-       /*
-        * Take a reference on the devt and assign it to queue since it
-        * must not be reallocated while the bdi is registered
-        */
-       disk->queue->disk_devt = disk->disk_devt;
-       get_disk_devt(disk->disk_devt);
-
        /* Register BDI before referencing it from bdev */
        bdi = disk->queue->backing_dev_info;
        bdi_register_owner(bdi, disk_to_dev(disk));

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index c7839f6c35ccc479c8f7a044407b35f203cd3102..d277e8620e3e39794584ac29dc55cc3ce476a03a 100644 (file)
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -3075,23 +3075,6 @@ static void sd_probe_async(void *data, async_cookie_t cookie)
        put_device(&sdkp->dev);
 }
 
-struct sd_devt {
-       int idx;
-       struct disk_devt disk_devt;
-};
-
-static void sd_devt_release(struct disk_devt *disk_devt)
-{
-       struct sd_devt *sd_devt = container_of(disk_devt, struct sd_devt,
-                       disk_devt);
-
-       spin_lock(&sd_index_lock);
-       ida_remove(&sd_index_ida, sd_devt->idx);
-       spin_unlock(&sd_index_lock);
-
-       kfree(sd_devt);
-}
-
 /**
  *     sd_probe - called during driver initialization and whenever a
  *     new scsi device is attached to the system. It is called once
@@ -3113,7 +3096,6 @@ static void sd_devt_release(struct disk_devt *disk_devt)
 static int sd_probe(struct device *dev)
 {
        struct scsi_device *sdp = to_scsi_device(dev);
-       struct sd_devt *sd_devt;
        struct scsi_disk *sdkp;
        struct gendisk *gd;
        int index;
@@ -3139,13 +3121,9 @@ static int sd_probe(struct device *dev)
        if (!sdkp)
                goto out;
 
-       sd_devt = kzalloc(sizeof(*sd_devt), GFP_KERNEL);
-       if (!sd_devt)
-               goto out_free;
-
        gd = alloc_disk(SD_MINORS);
        if (!gd)
-               goto out_free_devt;
+               goto out_free;
 
        do {
                if (!ida_pre_get(&sd_index_ida, GFP_KERNEL))
@@ -3161,11 +3139,6 @@ static int sd_probe(struct device *dev)
                goto out_put;
        }
 
-       atomic_set(&sd_devt->disk_devt.count, 1);
-       sd_devt->disk_devt.release = sd_devt_release;
-       sd_devt->idx = index;
-       gd->disk_devt = &sd_devt->disk_devt;
-
        error = sd_format_disk_name("sd", index, gd->disk_name, DISK_NAME_LEN);
        if (error) {
                sdev_printk(KERN_WARNING, sdp, "SCSI disk (sd) name length exceeded.\n");
@@ -3205,12 +3178,11 @@ static int sd_probe(struct device *dev)
        return 0;
 
  out_free_index:
-       put_disk_devt(&sd_devt->disk_devt);
-       sd_devt = NULL;
+       spin_lock(&sd_index_lock);
+       ida_remove(&sd_index_ida, index);
+       spin_unlock(&sd_index_lock);
  out_put:
        put_disk(gd);
- out_free_devt:
-       kfree(sd_devt);
  out_free:
        kfree(sdkp);
  out:
@@ -3271,7 +3243,10 @@ static void scsi_disk_release(struct device *dev)
        struct scsi_disk *sdkp = to_scsi_disk(dev);
        struct gendisk *disk = sdkp->disk;
        
-       put_disk_devt(disk->disk_devt);
+       spin_lock(&sd_index_lock);
+       ida_remove(&sd_index_ida, sdkp->index);
+       spin_unlock(&sd_index_lock);
+
        disk->private_data = NULL;
        put_disk(disk);
        put_device(&sdkp->device->sdev_gendev);

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 796016e63c1da7b64c59f8d9a1b4979d8059027b..5a7da607ca045f81a46e7b73bb31a8f1b978452a 100644 (file)
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -435,7 +435,6 @@ struct request_queue {
        struct delayed_work     delay_work;
 
        struct backing_dev_info *backing_dev_info;
-       struct disk_devt        *disk_devt;
 
        /*
         * The queue owner gets to use this for whatever they like.

diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index a999d281a2f1e41ce6cb7613dc5ecd8e0d4797c8..76f39754e7b0299df616bc3cb909f9a35fce9ea1 100644 (file)
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -167,13 +167,6 @@ struct blk_integrity {
 };
 
 #endif /* CONFIG_BLK_DEV_INTEGRITY */
-struct disk_devt {
-       atomic_t count;
-       void (*release)(struct disk_devt *disk_devt);
-};
-
-void put_disk_devt(struct disk_devt *disk_devt);
-void get_disk_devt(struct disk_devt *disk_devt);
 
 struct gendisk {
        /* major, first_minor and minors are input parameters only,
@@ -183,7 +176,6 @@ struct gendisk {
        int first_minor;
        int minors;                     /* maximum number of minors, =1 for
                                          * disks that can't be partitioned. */
-       struct disk_devt *disk_devt;
 
        char disk_name[DISK_NAME_LEN];  /* name of major driver */
        char *(*devnode)(struct gendisk *gd, umode_t *mode);