Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 066f4d82 authored by Christian Borntraeger's avatar Christian Borntraeger Committed by Rusty Russell
Browse files

virtio_blk: check for hardsector size from host 



Currently virtio_blk assumes a 512 byte hard sector size. This can cause
trouble / performance issues if the backing has a different block size
(like a file on an ext3 file system formatted with 4k block size or a dasd).

Lets add a feature flag that tells the guest to use a different hard sector
size than 512 byte.

Signed-off-by: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
parent e962fa66

drivers/block/virtio_blk.c

+9 −1
Original line number Diff line number Diff line
@@ -196,6 +196,7 @@ static int virtblk_probe(struct virtio_device *vdev) 
	int err;

	u64 cap;

	u32 v;

	u32 blk_size;



	if (index_to_minor(index) >= 1 << MINORBITS)

		return -ENOSPC;
@@ -290,6 +291,13 @@ static int virtblk_probe(struct virtio_device *vdev) 
	if (!err)

		blk_queue_max_hw_segments(vblk->disk->queue, v);



	/* Host can optionally specify the block size of the device */

	err = virtio_config_val(vdev, VIRTIO_BLK_F_BLK_SIZE,

				offsetof(struct virtio_blk_config, blk_size),

				&blk_size);

	if (!err)

		blk_queue_hardsect_size(vblk->disk->queue, blk_size);



	add_disk(vblk->disk);

	return 0;
@@ -330,7 +338,7 @@ static struct virtio_device_id id_table[] = { 


static unsigned int features[] = {

	VIRTIO_BLK_F_BARRIER, VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX,

	VIRTIO_BLK_F_GEOMETRY, VIRTIO_BLK_F_RO,

	VIRTIO_BLK_F_GEOMETRY, VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE,

};



static struct virtio_driver virtio_blk = {

include/linux/virtio_blk.h

+3 −0
Original line number Diff line number Diff line
@@ -13,6 +13,7 @@ 
#define VIRTIO_BLK_F_SEG_MAX	2	/* Indicates maximum # of segments */

#define VIRTIO_BLK_F_GEOMETRY	4	/* Legacy geometry available  */

#define VIRTIO_BLK_F_RO		5	/* Disk is read-only */

#define VIRTIO_BLK_F_BLK_SIZE	6	/* Block size of disk is available*/



struct virtio_blk_config

{
@@ -28,6 +29,8 @@ struct virtio_blk_config 
		__u8 heads;

		__u8 sectors;

	} geometry;

	/* block size of device (if VIRTIO_BLK_F_BLK_SIZE) */

	__u32 blk_size;

} __attribute__((packed));



/* These two define direction. */