[PATCH v2 6/8] selftests: ublk: add support for --io_desc_size
From: Caleb Sander Mateos
Date: Mon Aug 03 2026 - 17:16:32 EST
Add an optional --io_desc_size argument to the kublk add/recover
commands to enable UBLK_F_IO_DESC on the ublk device. The mmap()
arguments and ublk_get_iod() computation are adjusted accordingly.
Display the configured io_desc_size in the kublk list output for ublk
devices with UBLK_F_IO_DESC.
Signed-off-by: Caleb Sander Mateos <csander@xxxxxxxxxxxxxxx>
---
tools/testing/selftests/ublk/kublk.c | 29 +++++++++++++++++++---------
tools/testing/selftests/ublk/kublk.h | 6 ++++--
2 files changed, 24 insertions(+), 11 deletions(-)
diff --git a/tools/testing/selftests/ublk/kublk.c b/tools/testing/selftests/ublk/kublk.c
index 5c4a1f18d0a3..0e3e2d74cc4d 100644
--- a/tools/testing/selftests/ublk/kublk.c
+++ b/tools/testing/selftests/ublk/kublk.c
@@ -350,10 +350,12 @@ static void ublk_ctrl_dump(struct ublk_dev *dev)
info->dev_id, info->nr_hw_queues, info->queue_depth,
1 << p.basic.logical_bs_shift, p.basic.dev_sectors);
ublk_log("\tmax rq size %d daemon pid %d flags 0x%llx state %s\n",
info->max_io_buf_bytes, info->ublksrv_pid, info->flags,
ublk_dev_state_desc(dev));
+ if (info->flags & UBLK_F_IO_DESC_SIZE)
+ ublk_log("\tio_desc_size %u\n", info->io_desc_size);
if (affinity) {
char buf[512];
int i;
@@ -398,26 +400,26 @@ static struct ublk_dev *ublk_ctrl_init(void)
dev->nr_fds = 1;
return dev;
}
-static int __ublk_queue_cmd_buf_sz(unsigned depth)
+static size_t __ublk_queue_cmd_buf_sz(const struct ublk_queue *q, __u16 depth)
{
- int size = depth * sizeof(struct ublksrv_io_desc);
- unsigned int page_sz = getpagesize();
+ size_t size = depth * (size_t)q->io_desc_size;
+ size_t page_sz = getpagesize();
return round_up(size, page_sz);
}
-static int ublk_queue_max_cmd_buf_sz(void)
+static size_t ublk_queue_max_cmd_buf_sz(const struct ublk_queue *q)
{
- return __ublk_queue_cmd_buf_sz(UBLK_MAX_QUEUE_DEPTH);
+ return __ublk_queue_cmd_buf_sz(q, UBLK_MAX_QUEUE_DEPTH);
}
-static int ublk_queue_cmd_buf_sz(struct ublk_queue *q)
+static size_t ublk_queue_cmd_buf_sz(const struct ublk_queue *q)
{
- return __ublk_queue_cmd_buf_sz(q->q_depth);
+ return __ublk_queue_cmd_buf_sz(q, q->q_depth);
}
static void ublk_queue_deinit(struct ublk_queue *q)
{
int i;
@@ -451,26 +453,27 @@ static int ublk_queue_init(struct ublk_queue *q, unsigned long long extra_flags,
__u8 metadata_size)
{
struct ublk_dev *dev = q->dev;
int depth = dev->dev_info.queue_depth;
int i;
- int cmd_buf_size, io_buf_size, integrity_size;
+ size_t cmd_buf_size, io_buf_size, integrity_size;
unsigned long off;
pthread_spin_init(&q->lock, PTHREAD_PROCESS_PRIVATE);
q->tgt_ops = dev->tgt.ops;
q->flags = 0;
q->q_depth = depth;
q->flags = dev->dev_info.flags;
q->flags |= extra_flags;
q->metadata_size = metadata_size;
+ q->io_desc_size = dev->dev_info.io_desc_size;
/* Cache fd in queue for fast path access */
q->ublk_fd = dev->fds[0];
cmd_buf_size = ublk_queue_cmd_buf_sz(q);
- off = UBLKSRV_CMD_BUF_OFFSET + q->q_id * ublk_queue_max_cmd_buf_sz();
+ off = UBLKSRV_CMD_BUF_OFFSET + q->q_id * ublk_queue_max_cmd_buf_sz(q);
q->io_cmd_buf = mmap(0, cmd_buf_size, PROT_READ,
MAP_SHARED | MAP_POPULATE, dev->fds[0], off);
if (q->io_cmd_buf == MAP_FAILED) {
ublk_err("ublk dev %d queue %d map io_cmd_buf failed %m\n",
q->dev->dev_info.dev_id, q->q_id);
@@ -1706,10 +1709,11 @@ static int __cmd_dev_add(const struct dev_ctx *ctx)
info = &dev->dev_info;
info->dev_id = ctx->dev_id;
info->nr_hw_queues = nr_queues;
info->queue_depth = depth;
+ info->io_desc_size = ctx->io_desc_size;
info->flags = ctx->flags;
if ((features & UBLK_F_QUIESCE) &&
(info->flags & UBLK_F_USER_RECOVERY))
info->flags |= UBLK_F_QUIESCE;
dev->nthreads = nthreads;
@@ -2067,10 +2071,11 @@ static void __cmd_create_help(char *exe, bool recovery)
printf("\t[-e 0|1 ] [-i 0|1] [--no_ublk_fixed_fd]\n");
printf("\t[--nthreads threads] [--per_io_tasks]\n");
printf("\t[--integrity_capable] [--integrity_reftag] [--metadata_size SIZE] "
"[--pi_offset OFFSET] [--csum_type ip|t10dif|nvme] [--tag_size SIZE]\n");
printf("\t[--batch|-b] [--no_auto_part_scan]\n");
+ printf("\t[--io_desc_size SIZE]\n");
printf("\t[target options] [backfile1] [backfile2] ...\n");
printf("\tdefault: nr_queues=2(max 32), depth=128(max 1024), dev_id=-1(auto allocation)\n");
printf("\tdefault: nthreads=nr_queues");
for (i = 0; i < ARRAY_SIZE(tgt_ops_list); i++) {
@@ -2144,10 +2149,11 @@ int main(int argc, char *argv[])
{ "batch", 0, NULL, 'b'},
{ "no_auto_part_scan", 0, NULL, 0 },
{ "shmem_zc", 0, NULL, 0 },
{ "htlb", 1, NULL, 0 },
{ "rdonly_shmem_buf", 0, NULL, 0 },
+ { "io_desc_size", 1, NULL, 0 },
{ 0, 0, 0, 0 }
};
const struct ublk_tgt_ops *ops = NULL;
int option_idx, opt;
const char *cmd = argv[1];
@@ -2156,10 +2162,11 @@ int main(int argc, char *argv[])
.queue_depth = 128,
.nr_hw_queues = 2,
.dev_id = -1,
.tgt_type = "unknown",
.csum_type = LBMD_PI_CSUM_NONE,
+ .io_desc_size = sizeof(struct ublksrv_io_desc),
};
int ret = -EINVAL, i;
int tgt_argc = 1;
char *tgt_argv[MAX_NR_TGT_ARG] = { NULL };
int value;
@@ -2265,10 +2272,14 @@ int main(int argc, char *argv[])
ctx.flags |= UBLK_F_SHMEM_ZC;
if (!strcmp(longopts[option_idx].name, "htlb"))
ctx.htlb_path = strdup(optarg);
if (!strcmp(longopts[option_idx].name, "rdonly_shmem_buf"))
ctx.rdonly_shmem_buf = 1;
+ if (!strcmp(longopts[option_idx].name, "io_desc_size")) {
+ ctx.flags |= UBLK_F_IO_DESC_SIZE;
+ ctx.io_desc_size = strtoul(optarg, NULL, 0);
+ }
break;
case '?':
/*
* target requires every option must have argument
*/
diff --git a/tools/testing/selftests/ublk/kublk.h b/tools/testing/selftests/ublk/kublk.h
index 742c41d77df1..15b56ff45bb6 100644
--- a/tools/testing/selftests/ublk/kublk.h
+++ b/tools/testing/selftests/ublk/kublk.h
@@ -85,10 +85,11 @@ struct dev_ctx {
__u32 integrity_flags;
__u8 metadata_size;
__u8 pi_offset;
__u8 csum_type;
__u8 tag_size;
+ __u16 io_desc_size;
int _evtfd;
int _shmid;
/* built from shmem, only for ublk_dump_dev() */
@@ -185,10 +186,11 @@ struct ublk_queue {
#define UBLKS_Q_NO_UBLK_FIXED_FD (1ULL << 62)
#define UBLKS_Q_PREPARED (1ULL << 61)
__u64 flags;
int ublk_fd; /* cached ublk char device fd */
__u8 metadata_size;
+ __u16 io_desc_size;
struct ublk_io ios[UBLK_QUEUE_DEPTH];
/* used for prep io commands */
pthread_spinlock_t lock;
};
@@ -459,13 +461,13 @@ static inline void ublk_mark_io_done(struct ublk_io *io, int res)
{
io->flags |= (UBLKS_IO_NEED_COMMIT_RQ_COMP | UBLKS_IO_FREE);
io->result = res;
}
-static inline const struct ublksrv_io_desc *ublk_get_iod(const struct ublk_queue *q, int tag)
+static inline const struct ublksrv_io_desc *ublk_get_iod(const struct ublk_queue *q, __u16 tag)
{
- return &q->io_cmd_buf[tag];
+ return (void *)q->io_cmd_buf + tag * (size_t)q->io_desc_size;
}
static inline void ublk_set_sqe_cmd_op(struct io_uring_sqe *sqe, __u32 cmd_op)
{
__u32 *addr = (__u32 *)&sqe->off;
--
2.54.0