virtio: use size-based config accessors.
This lets the transport do endian conversion if necessary, and insulates
the drivers from the difference.
Most drivers can use the simple helpers virtio_cread() and virtio_cwrite().
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index 89245b5..6b66252 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -456,18 +456,15 @@
static int virtblk_getgeo(struct block_device *bd, struct hd_geometry *geo)
{
struct virtio_blk *vblk = bd->bd_disk->private_data;
- struct virtio_blk_geometry vgeo;
- int err;
/* see if the host passed in geometry config */
- err = virtio_config_val(vblk->vdev, VIRTIO_BLK_F_GEOMETRY,
- offsetof(struct virtio_blk_config, geometry),
- &vgeo);
-
- if (!err) {
- geo->heads = vgeo.heads;
- geo->sectors = vgeo.sectors;
- geo->cylinders = vgeo.cylinders;
+ if (virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_GEOMETRY)) {
+ virtio_cread(vblk->vdev, struct virtio_blk_config,
+ geometry.cylinders, &geo->cylinders);
+ virtio_cread(vblk->vdev, struct virtio_blk_config,
+ geometry.heads, &geo->heads);
+ virtio_cread(vblk->vdev, struct virtio_blk_config,
+ geometry.sectors, &geo->sectors);
} else {
/* some standard values, similar to sd */
geo->heads = 1 << 6;
@@ -529,8 +526,7 @@
goto done;
/* Host must always specify the capacity. */
- vdev->config->get(vdev, offsetof(struct virtio_blk_config, capacity),
- &capacity, sizeof(capacity));
+ virtio_cread(vdev, struct virtio_blk_config, capacity, &capacity);
/* If capacity is too big, truncate with warning. */
if ((sector_t)capacity != capacity) {
@@ -608,9 +604,9 @@
u8 writeback;
int err;
- err = virtio_config_val(vdev, VIRTIO_BLK_F_CONFIG_WCE,
- offsetof(struct virtio_blk_config, wce),
- &writeback);
+ err = virtio_cread_feature(vdev, VIRTIO_BLK_F_CONFIG_WCE,
+ struct virtio_blk_config, wce,
+ &writeback);
if (err)
writeback = virtio_has_feature(vdev, VIRTIO_BLK_F_WCE);
@@ -642,7 +638,6 @@
struct virtio_blk *vblk = disk->private_data;
struct virtio_device *vdev = vblk->vdev;
int i;
- u8 writeback;
BUG_ON(!virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_CONFIG_WCE));
for (i = ARRAY_SIZE(virtblk_cache_types); --i >= 0; )
@@ -652,11 +647,7 @@
if (i < 0)
return -EINVAL;
- writeback = i;
- vdev->config->set(vdev,
- offsetof(struct virtio_blk_config, wce),
- &writeback, sizeof(writeback));
-
+ virtio_cwrite8(vdev, offsetof(struct virtio_blk_config, wce), i);
virtblk_update_cache_mode(vdev);
return count;
}
@@ -699,9 +690,9 @@
index = err;
/* We need to know how many segments before we allocate. */
- err = virtio_config_val(vdev, VIRTIO_BLK_F_SEG_MAX,
- offsetof(struct virtio_blk_config, seg_max),
- &sg_elems);
+ err = virtio_cread_feature(vdev, VIRTIO_BLK_F_SEG_MAX,
+ struct virtio_blk_config, seg_max,
+ &sg_elems);
/* We need at least one SG element, whatever they say. */
if (err || !sg_elems)
@@ -772,8 +763,7 @@
set_disk_ro(vblk->disk, 1);
/* Host must always specify the capacity. */
- vdev->config->get(vdev, offsetof(struct virtio_blk_config, capacity),
- &cap, sizeof(cap));
+ virtio_cread(vdev, struct virtio_blk_config, capacity, &cap);
/* If capacity is too big, truncate with warning. */
if ((sector_t)cap != cap) {
@@ -794,46 +784,45 @@
/* Host can optionally specify maximum segment size and number of
* segments. */
- err = virtio_config_val(vdev, VIRTIO_BLK_F_SIZE_MAX,
- offsetof(struct virtio_blk_config, size_max),
- &v);
+ err = virtio_cread_feature(vdev, VIRTIO_BLK_F_SIZE_MAX,
+ struct virtio_blk_config, size_max, &v);
if (!err)
blk_queue_max_segment_size(q, v);
else
blk_queue_max_segment_size(q, -1U);
/* 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);
+ err = virtio_cread_feature(vdev, VIRTIO_BLK_F_BLK_SIZE,
+ struct virtio_blk_config, blk_size,
+ &blk_size);
if (!err)
blk_queue_logical_block_size(q, blk_size);
else
blk_size = queue_logical_block_size(q);
/* Use topology information if available */
- err = virtio_config_val(vdev, VIRTIO_BLK_F_TOPOLOGY,
- offsetof(struct virtio_blk_config, physical_block_exp),
- &physical_block_exp);
+ err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY,
+ struct virtio_blk_config, physical_block_exp,
+ &physical_block_exp);
if (!err && physical_block_exp)
blk_queue_physical_block_size(q,
blk_size * (1 << physical_block_exp));
- err = virtio_config_val(vdev, VIRTIO_BLK_F_TOPOLOGY,
- offsetof(struct virtio_blk_config, alignment_offset),
- &alignment_offset);
+ err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY,
+ struct virtio_blk_config, alignment_offset,
+ &alignment_offset);
if (!err && alignment_offset)
blk_queue_alignment_offset(q, blk_size * alignment_offset);
- err = virtio_config_val(vdev, VIRTIO_BLK_F_TOPOLOGY,
- offsetof(struct virtio_blk_config, min_io_size),
- &min_io_size);
+ err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY,
+ struct virtio_blk_config, min_io_size,
+ &min_io_size);
if (!err && min_io_size)
blk_queue_io_min(q, blk_size * min_io_size);
- err = virtio_config_val(vdev, VIRTIO_BLK_F_TOPOLOGY,
- offsetof(struct virtio_blk_config, opt_io_size),
- &opt_io_size);
+ err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY,
+ struct virtio_blk_config, opt_io_size,
+ &opt_io_size);
if (!err && opt_io_size)
blk_queue_io_opt(q, blk_size * opt_io_size);