ublk: add new batch command UBLK_U_IO_PREP_IO_CMDS & UBLK_U_IO_COMMIT_IO_CMDS

Add new command UBLK_U_IO_PREP_IO_CMDS, which is the batch version of
UBLK_IO_FETCH_REQ.

Add new command UBLK_U_IO_COMMIT_IO_CMDS, which is for committing io command
result only, still the batch version.

The new command header type is `struct ublk_batch_io`.

This patch doesn't actually implement these commands yet, just validates the
SQE fields.

Reviewed-by: Caleb Sander Mateos <csander@purestorage.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 86 insertions, 1 deletions

diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
index 0f9fcd16258b..22c7296d90f3 100644
--- a/drivers/block/ublk_drv.c
+++ b/drivers/block/ublk_drv.c
@@ -91,6 +91,11 @@
 	 UBLK_PARAM_TYPE_DMA_ALIGN | UBLK_PARAM_TYPE_SEGMENT | \
 	 UBLK_PARAM_TYPE_INTEGRITY)
 
+#define UBLK_BATCH_F_ALL  \
+	(UBLK_BATCH_F_HAS_ZONE_LBA | \
+	 UBLK_BATCH_F_HAS_BUF_ADDR | \
+	 UBLK_BATCH_F_AUTO_BUF_REG_FALLBACK)
+
 struct ublk_uring_cmd_pdu {
 	/*
 	 * Store requests in same batch temporarily for queuing them to
@@ -114,6 +119,13 @@ struct ublk_uring_cmd_pdu {
 	u16 tag;
 };
 
+struct ublk_batch_io_data {
+	struct ublk_device *ub;
+	struct io_uring_cmd *cmd;
+	struct ublk_batch_io header;
+	unsigned int issue_flags;
+};
+
 /*
  * io command is active: sqe cmd is received, and its cqe isn't done
  *
@@ -2687,10 +2699,83 @@ static int ublk_ch_uring_cmd(struct io_uring_cmd *cmd, unsigned int issue_flags)
 	return ublk_ch_uring_cmd_local(cmd, issue_flags);
 }
 
+static int ublk_check_batch_cmd_flags(const struct ublk_batch_io *uc)
+{
+	unsigned elem_bytes = sizeof(struct ublk_elem_header);
+
+	if (uc->flags & ~UBLK_BATCH_F_ALL)
+		return -EINVAL;
+
+	/* UBLK_BATCH_F_AUTO_BUF_REG_FALLBACK requires buffer index */
+	if ((uc->flags & UBLK_BATCH_F_AUTO_BUF_REG_FALLBACK) &&
+			(uc->flags & UBLK_BATCH_F_HAS_BUF_ADDR))
+		return -EINVAL;
+
+	elem_bytes += (uc->flags & UBLK_BATCH_F_HAS_ZONE_LBA ? sizeof(u64) : 0) +
+		(uc->flags & UBLK_BATCH_F_HAS_BUF_ADDR ? sizeof(u64) : 0);
+	if (uc->elem_bytes != elem_bytes)
+		return -EINVAL;
+	return 0;
+}
+
+static int ublk_check_batch_cmd(const struct ublk_batch_io_data *data)
+{
+
+	const struct ublk_batch_io *uc = &data->header;
+
+	if (uc->nr_elem > data->ub->dev_info.queue_depth)
+		return -E2BIG;
+
+	if ((uc->flags & UBLK_BATCH_F_HAS_ZONE_LBA) &&
+			!ublk_dev_is_zoned(data->ub))
+		return -EINVAL;
+
+	if ((uc->flags & UBLK_BATCH_F_HAS_BUF_ADDR) &&
+			!ublk_dev_need_map_io(data->ub))
+		return -EINVAL;
+
+	if ((uc->flags & UBLK_BATCH_F_AUTO_BUF_REG_FALLBACK) &&
+			!ublk_dev_support_auto_buf_reg(data->ub))
+		return -EINVAL;
+
+	return ublk_check_batch_cmd_flags(uc);
+}
+
 static int ublk_ch_batch_io_uring_cmd(struct io_uring_cmd *cmd,
 				       unsigned int issue_flags)
 {
-	return -EOPNOTSUPP;
+	const struct ublk_batch_io *uc = io_uring_sqe_cmd(cmd->sqe);
+	struct ublk_device *ub = cmd->file->private_data;
+	struct ublk_batch_io_data data = {
+		.ub  = ub,
+		.cmd = cmd,
+		.header = (struct ublk_batch_io) {
+			.q_id = READ_ONCE(uc->q_id),
+			.flags = READ_ONCE(uc->flags),
+			.nr_elem = READ_ONCE(uc->nr_elem),
+			.elem_bytes = READ_ONCE(uc->elem_bytes),
+		},
+		.issue_flags = issue_flags,
+	};
+	u32 cmd_op = cmd->cmd_op;
+	int ret = -EINVAL;
+
+	if (data.header.q_id >= ub->dev_info.nr_hw_queues)
+		goto out;
+
+	switch (cmd_op) {
+	case UBLK_U_IO_PREP_IO_CMDS:
+	case UBLK_U_IO_COMMIT_IO_CMDS:
+		ret = ublk_check_batch_cmd(&data);
+		if (ret)
+			goto out;
+		ret = -EOPNOTSUPP;
+		break;
+	default:
+		ret = -EOPNOTSUPP;
+	}
+out:
+	return ret;
 }
 
 static inline bool ublk_check_ubuf_dir(const struct request *req,