[PATCH 07/17] io_uring: add support for uring_cmd with fixed-buffer

Kanchan Joshi
2022-03-08T15:46:03Z

Add IORING_OP_URING_CMD_FIXED opcode that enables performing the
operation with previously registered buffers.

Signed-off-by: Kanchan Joshi <joshi.k@samsung.com>
Signed-off-by: Anuj Gupta <anuj20.g@samsung.com>
---
fs/io_uring.c | 29 ++++++++++++++++++++++++++++-
include/linux/io_uring.h | 1 +
include/uapi/linux/io_uring.h | 1 +
3 files changed, 30 insertions(+), 1 deletion(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index ead0cbae8416..6a1dcea0f538 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -1107,6 +1107,9 @@ static const struct io_op_def io_op_defs[] = {
[IORING_OP_URING_CMD] = {
.needs_file = 1,
},
+ [IORING_OP_URING_CMD_FIXED] = {
+ .needs_file = 1,
+ },
};

/* requests with any of those set should undergo io_disarm_next() */
@@ -4148,16 +4151,25 @@ EXPORT_SYMBOL_GPL(io_uring_cmd_done);
static int io_uring_cmd_prep(struct io_kiocb *req,
const struct io_uring_sqe *sqe)
{
+ struct io_ring_ctx *ctx = req->ctx;
struct io_uring_cmd *ioucmd = &req->uring_cmd;

if (!req->file->f_op->async_cmd || !(req->ctx->flags & IORING_SETUP_SQE128))
return -EOPNOTSUPP;
if (req->ctx->flags & IORING_SETUP_IOPOLL)
return -EOPNOTSUPP;
+ if (req->opcode == IORING_OP_URING_CMD_FIXED) {
+ req->imu = NULL;
+ io_req_set_rsrc_node(req, ctx);
+ req->buf_index = READ_ONCE(sqe->buf_index);
+ ioucmd->flags = IO_URING_F_UCMD_FIXEDBUFS;
+ } else {
+ ioucmd->flags = 0;
+ }
+
ioucmd->cmd = (void *) &sqe->cmd;
ioucmd->cmd_op = READ_ONCE(sqe->cmd_op);
ioucmd->cmd_len = READ_ONCE(sqe->cmd_len);
- ioucmd->flags = 0;
return 0;
}

@@ -4167,6 +4179,19 @@ static int io_uring_cmd(struct io_kiocb *req, unsigned int issue_flags)
int ret;
struct io_uring_cmd *ioucmd = &req->uring_cmd;

+ if (req->opcode == IORING_OP_URING_CMD_FIXED) {
+ u32 index, buf_index = req->buf_index;
+ struct io_ring_ctx *ctx = req->ctx;
+ struct io_mapped_ubuf *imu = req->imu;
+
+ if (likely(!imu)) {
+ if (unlikely(buf_index >= ctx->nr_user_bufs))
+ return -EFAULT;
+ index = array_index_nospec(buf_index, ctx->nr_user_bufs);
+ imu = READ_ONCE(ctx->user_bufs[index]);
+ req->imu = imu;
+ }
+ }
ioucmd->flags |= issue_flags;
ret = file->f_op->async_cmd(ioucmd);
/* queued async, consumer will call io_uring_cmd_done() when complete */
@@ -6656,6 +6681,7 @@ static int io_req_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
case IORING_OP_LINKAT:
return io_linkat_prep(req, sqe);
case IORING_OP_URING_CMD:
+ case IORING_OP_URING_CMD_FIXED:
return io_uring_cmd_prep(req, sqe);
}

@@ -6941,6 +6967,7 @@ static int io_issue_sqe(struct io_kiocb *req, unsigned int issue_flags)
ret = io_linkat(req, issue_flags);
break;
case IORING_OP_URING_CMD:
+ case IORING_OP_URING_CMD_FIXED:
ret = io_uring_cmd(req, issue_flags);
break;
default:
diff --git a/include/linux/io_uring.h b/include/linux/io_uring.h
index 1888a5ea7dbe..abad6175739e 100644
--- a/include/linux/io_uring.h
+++ b/include/linux/io_uring.h
@@ -8,6 +8,7 @@
enum io_uring_cmd_flags {
IO_URING_F_COMPLETE_DEFER = 1,
IO_URING_F_UNLOCKED = 2,
+ IO_URING_F_UCMD_FIXEDBUFS = 4,
/* int's last bit, sign checks are usually faster than a bit test */
IO_URING_F_NONBLOCK = INT_MIN,
};
diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h
index 9bf1d6c0ed7f..ee84be4b6be8 100644
--- a/include/uapi/linux/io_uring.h
+++ b/include/uapi/linux/io_uring.h
@@ -155,6 +155,7 @@ enum {
IORING_OP_SYMLINKAT,
IORING_OP_LINKAT,
IORING_OP_URING_CMD,
+ IORING_OP_URING_CMD_FIXED,

/* this goes last, obviously */
IORING_OP_LAST,
--
2.25.1