d/numam-spdk
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

bdev_virtio: support UNMAP requests > 4GB

Browse Source 
With current SPDK_BDEV_LARGE_BUF_MAX_SIZE
set to 65536, we can allocate at most
4095 16-byte SCSI UNMAP block descriptors.
A single descriptor can UNMAP up to 4GB.
That gives us a hard limit of ~16 terabytes
of data that can be unmmapped by a single
request.

The same limit is also enforced by the
SCSI standard, as the entire UNMAP request
length must be smaller than 65536.

Change-Id: I4d91fa60fd28133a058b87e88a1a14ce662a659a
Signed-off-by: Dariusz Stojaczyk <dariuszx.stojaczyk@intel.com>
Reviewed-on: https://review.gerrithub.io/381447
Tested-by: SPDK Automated Test System <sys_sgsw@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
Reviewed-by: Daniel Verkamp <daniel.verkamp@intel.com>
This commit is contained in:
Dariusz Stojaczyk 2017-10-05 12:10:47 +02:00 committed by Daniel Verkamp
parent dbad65c383
commit 356a9bc7d3
1 changed files with 37 additions and 19 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

56
lib/bdev/virtio/bdev_virtio.c
View File

@ -167,29 +167,45 @@ bdev_virtio_unmap(struct spdk_io_channel *ch, struct spdk_bdev_io *bdev_io)
struct virtio_scsi_disk *disk = (struct virtio_scsi_disk *)bdev_io->bdev;
struct virtio_req *vreq = bdev_virtio_init_vreq(ch, bdev_io);
struct virtio_scsi_cmd_req *req = vreq->iov_req.iov_base;
struct spdk_scsi_unmap_bdesc *desc;
struct spdk_scsi_unmap_bdesc *desc, *first_desc;
uint8_t *buf;
uint16_t cmd_len = 24; /* 8 byte header + 16 byte descriptor */
uint64_t offset_blocks, num_blocks;
uint16_t cmd_len;
vreq->iov = bdev_io->u.bdev.iovs;
vreq->iovcnt = bdev_io->u.bdev.iovcnt;
buf = vreq->iov->iov_base;
offset_blocks = bdev_io->u.bdev.offset_blocks;
num_blocks = bdev_io->u.bdev.num_blocks;
/* (n-1) * 16-byte descriptors */
first_desc = desc = (struct spdk_scsi_unmap_bdesc *)&buf[8];
while (num_blocks > UINT32_MAX) {
to_be64(&desc->lba, offset_blocks);
to_be32(&desc->block_count, UINT32_MAX);
memset(&desc->reserved, 0, sizeof(desc->reserved));
offset_blocks += UINT32_MAX;
num_blocks -= UINT32_MAX;
desc++;
}
/* The last descriptor with block_count <= UINT32_MAX */
to_be64(&desc->lba, offset_blocks);
to_be32(&desc->block_count, num_blocks);
memset(&desc->reserved, 0, sizeof(desc->reserved));
/* 8-byte header + n * 16-byte block descriptor */
cmd_len = 8 + (desc - first_desc + 1) * sizeof(struct spdk_scsi_unmap_bdesc);
req->cdb[0] = SPDK_SBC_UNMAP;
to_be16(&req->cdb[7], cmd_len);
buf = vreq->iov->iov_base;
/* header */
/* 8-byte header */
to_be16(&buf[0], cmd_len - 2); /* total length (excluding the length field) */
to_be16(&buf[2], cmd_len - 8); /* length of block descriptors */
memset(&buf[4], 0, 4); /* reserved */
/* single block descriptor */
desc = (struct spdk_scsi_unmap_bdesc *)&buf[8];
to_be64(&desc->lba, bdev_io->u.bdev.offset_blocks);
to_be32(&desc->block_count, bdev_io->u.bdev.num_blocks);
memset(&desc->reserved, 0, sizeof(desc->reserved));
virtio_xmit_pkts(disk->vdev->vqs[2], vreq);
}
@ -206,17 +222,19 @@ static int _bdev_virtio_submit_request(struct spdk_io_channel *ch, struct spdk_b
case SPDK_BDEV_IO_TYPE_RESET:
spdk_bdev_io_complete(bdev_io, SPDK_BDEV_IO_STATUS_SUCCESS);
return 0;
case SPDK_BDEV_IO_TYPE_UNMAP:
if (bdev_io->u.bdev.num_blocks > UINT32_MAX) {
SPDK_ERRLOG("single UNMAP block count must be no bigger than 2^32 - 1\n");
case SPDK_BDEV_IO_TYPE_UNMAP: {
uint64_t buf_len = 8 /* header size */ +
(bdev_io->u.bdev.num_blocks + UINT32_MAX - 1) /
UINT32_MAX * sizeof(struct spdk_scsi_unmap_bdesc);
if (buf_len > SPDK_BDEV_LARGE_BUF_MAX_SIZE) {
SPDK_ERRLOG("Trying to UNMAP too many blocks: %"PRIu64"\n",
bdev_io->u.bdev.num_blocks);
return -1;
}
/* Since we support only bdev_io->u.bdev.num_blocks <= UINT32_MAX
* allocate just 24 bytes (8 byte header + 16 byte descriptor).
* A single block descriptor can UNMAP at most UINT32_MAX blocks.
*/
spdk_bdev_io_get_buf(bdev_io, bdev_virtio_unmap, 24);
spdk_bdev_io_get_buf(bdev_io, bdev_virtio_unmap, buf_len);
return 0;
}
case SPDK_BDEV_IO_TYPE_FLUSH:
default:
return -1;