Gitweb:
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=4f3bf19c6e8164b441faaee476e734b4f612a78d
Commit: 4f3bf19c6e8164b441faaee476e734b4f612a78d
Parent: 135da0b037984c0284acdf40aaf4f7f31eb5cbd0
Author: Christian Borntraeger <[EMAIL PROTECTED]>
AuthorDate: Thu Jan 31 15:53:53 2008 +0100
Committer: Rusty Russell <[EMAIL PROTECTED]>
CommitDate: Mon Feb 4 23:50:10 2008 +1100
virtio_blk: Dont waste major numbers
Rusty,
currently virtio_blk uses one major number per device. While this works
quite well on most systems it is wasteful and will exhaust major numbers
on larger installations.
This patch allocates a major number on init and will use 16 minor numbers
for each disk. That will allow ~64k virtio_blk disks.
Signed-off-by: Christian Borntraeger <[EMAIL PROTECTED]>
Signed-off-by: Rusty Russell <[EMAIL PROTECTED]>
---
drivers/block/virtio_blk.c | 28 ++++++++++++++++------------
1 files changed, 16 insertions(+), 12 deletions(-)
diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index d2fe679..559c322 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -7,8 +7,11 @@
#include <linux/scatterlist.h>
#define VIRTIO_MAX_SG (3+MAX_PHYS_SEGMENTS)
+#define PART_BITS 4
static unsigned char virtblk_index = 'a';
+static int major, minor;
+
struct virtio_blk
{
spinlock_t lock;
@@ -171,10 +174,13 @@ static struct block_device_operations virtblk_fops = {
static int virtblk_probe(struct virtio_device *vdev)
{
struct virtio_blk *vblk;
- int err, major;
+ int err;
u64 cap;
u32 v;
+ if (minor >= 1 << MINORBITS)
+ return -ENOSPC;
+
vdev->priv = vblk = kmalloc(sizeof(*vblk), GFP_KERNEL);
if (!vblk) {
err = -ENOMEM;
@@ -198,17 +204,11 @@ static int virtblk_probe(struct virtio_device *vdev)
goto out_free_vq;
}
- major = register_blkdev(0, "virtblk");
- if (major < 0) {
- err = major;
- goto out_mempool;
- }
-
/* FIXME: How many partitions? How long is a piece of string? */
- vblk->disk = alloc_disk(1 << 4);
+ vblk->disk = alloc_disk(1 << PART_BITS);
if (!vblk->disk) {
err = -ENOMEM;
- goto out_unregister_blkdev;
+ goto out_mempool;
}
vblk->disk->queue = blk_init_queue(do_virtblk_request, &vblk->lock);
@@ -219,10 +219,12 @@ static int virtblk_probe(struct virtio_device *vdev)
sprintf(vblk->disk->disk_name, "vd%c", virtblk_index++);
vblk->disk->major = major;
- vblk->disk->first_minor = 0;
+ vblk->disk->first_minor = minor;
vblk->disk->private_data = vblk;
vblk->disk->fops = &virtblk_fops;
+ minor += 1 << PART_BITS;
+
/* If barriers are supported, tell block layer that queue is ordered */
if (vdev->config->feature(vdev, VIRTIO_BLK_F_BARRIER))
blk_queue_ordered(vblk->disk->queue, QUEUE_ORDERED_TAG, NULL);
@@ -258,8 +260,6 @@ static int virtblk_probe(struct virtio_device *vdev)
out_put_disk:
put_disk(vblk->disk);
-out_unregister_blkdev:
- unregister_blkdev(major, "virtblk");
out_mempool:
mempool_destroy(vblk->pool);
out_free_vq:
@@ -304,11 +304,15 @@ static struct virtio_driver virtio_blk = {
static int __init init(void)
{
+ major = register_blkdev(0, "virtblk");
+ if (major < 0)
+ return major;
return register_virtio_driver(&virtio_blk);
}
static void __exit fini(void)
{
+ unregister_blkdev(major, "virtblk");
unregister_virtio_driver(&virtio_blk);
}
module_init(init);
-
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