ublk: handle UBLK_U_IO_COMMIT_IO_CMDS

Handle UBLK_U_IO_COMMIT_IO_CMDS by walking the uring_cmd fixed buffer:

- read each element into one temp buffer in batch style

- parse and apply each element for committing io result

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>

diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
index a3840b3f108110932a34c145fdabb75283912236..162b46c74f16eb27ae2f83047f6773015928189f 100644 (file)
--- a/drivers/block/ublk_drv.c
+++ b/drivers/block/ublk_drv.c
@@ -2267,7 +2267,7 @@ static inline int ublk_set_auto_buf_reg(struct ublk_io *io, struct io_uring_cmd
        return 0;
 }
 
-static int ublk_handle_auto_buf_reg(struct ublk_io *io,
+static void ublk_clear_auto_buf_reg(struct ublk_io *io,
                                    struct io_uring_cmd *cmd,
                                    u16 *buf_idx)
 {
@@ -2287,7 +2287,13 @@ static int ublk_handle_auto_buf_reg(struct ublk_io *io,
                if (io->buf_ctx_handle == io_uring_cmd_ctx_handle(cmd))
                        *buf_idx = io->buf.auto_reg.index;
        }
+}
 
+static int ublk_handle_auto_buf_reg(struct ublk_io *io,
+                                   struct io_uring_cmd *cmd,
+                                   u16 *buf_idx)
+{
+       ublk_clear_auto_buf_reg(io, cmd, buf_idx);
        return ublk_set_auto_buf_reg(io, cmd);
 }
 
@@ -2720,6 +2726,17 @@ static inline __u64 ublk_batch_buf_addr(const struct ublk_batch_io *uc,
        return 0;
 }
 
+static inline __u64 ublk_batch_zone_lba(const struct ublk_batch_io *uc,
+                                       const struct ublk_elem_header *elem)
+{
+       const void *buf = elem;
+
+       if (uc->flags & UBLK_BATCH_F_HAS_ZONE_LBA)
+               return *(const __u64 *)(buf + sizeof(*elem) +
+                               8 * !!(uc->flags & UBLK_BATCH_F_HAS_BUF_ADDR));
+       return -1;
+}
+
 static struct ublk_auto_buf_reg
 ublk_batch_auto_buf_reg(const struct ublk_batch_io *uc,
                        const struct ublk_elem_header *elem)
@@ -2875,6 +2892,84 @@ static int ublk_handle_batch_prep_cmd(const struct ublk_batch_io_data *data)
        return ret;
 }
 
+static int ublk_batch_commit_io_check(const struct ublk_queue *ubq,
+                                     struct ublk_io *io,
+                                     union ublk_io_buf *buf)
+{
+       if (!(io->flags & UBLK_IO_FLAG_OWNED_BY_SRV))
+               return -EBUSY;
+
+       /* BATCH_IO doesn't support UBLK_F_NEED_GET_DATA */
+       if (ublk_need_map_io(ubq) && !buf->addr)
+               return -EINVAL;
+       return 0;
+}
+
+static int ublk_batch_commit_io(struct ublk_queue *ubq,
+                               const struct ublk_batch_io_data *data,
+                               const struct ublk_elem_header *elem)
+{
+       struct ublk_io *io = &ubq->ios[elem->tag];
+       const struct ublk_batch_io *uc = &data->header;
+       u16 buf_idx = UBLK_INVALID_BUF_IDX;
+       union ublk_io_buf buf = { 0 };
+       struct request *req = NULL;
+       bool auto_reg = false;
+       bool compl = false;
+       int ret;
+
+       if (ublk_dev_support_auto_buf_reg(data->ub)) {
+               buf.auto_reg = ublk_batch_auto_buf_reg(uc, elem);
+               auto_reg = true;
+       } else if (ublk_dev_need_map_io(data->ub))
+               buf.addr = ublk_batch_buf_addr(uc, elem);
+
+       ublk_io_lock(io);
+       ret = ublk_batch_commit_io_check(ubq, io, &buf);
+       if (!ret) {
+               io->res = elem->result;
+               io->buf = buf;
+               req = ublk_fill_io_cmd(io, data->cmd);
+
+               if (auto_reg)
+                       ublk_clear_auto_buf_reg(io, data->cmd, &buf_idx);
+               compl = ublk_need_complete_req(data->ub, io);
+       }
+       ublk_io_unlock(io);
+
+       if (unlikely(ret)) {
+               pr_warn_ratelimited("%s: dev %u queue %u io %u: commit failure %d\n",
+                       __func__, data->ub->dev_info.dev_id, ubq->q_id,
+                       elem->tag, ret);
+               return ret;
+       }
+
+       /* can't touch 'ublk_io' any more */
+       if (buf_idx != UBLK_INVALID_BUF_IDX)
+               io_buffer_unregister_bvec(data->cmd, buf_idx, data->issue_flags);
+       if (req_op(req) == REQ_OP_ZONE_APPEND)
+               req->__sector = ublk_batch_zone_lba(uc, elem);
+       if (compl)
+               __ublk_complete_rq(req, io, ublk_dev_need_map_io(data->ub));
+       return 0;
+}
+
+static int ublk_handle_batch_commit_cmd(const struct ublk_batch_io_data *data)
+{
+       const struct ublk_batch_io *uc = &data->header;
+       struct io_uring_cmd *cmd = data->cmd;
+       struct ublk_batch_io_iter iter = {
+               .uaddr = u64_to_user_ptr(READ_ONCE(cmd->sqe->addr)),
+               .total = uc->nr_elem * uc->elem_bytes,
+               .elem_bytes = uc->elem_bytes,
+       };
+       int ret;
+
+       ret = ublk_walk_cmd_buf(&iter, data, ublk_batch_commit_io);
+
+       return iter.done == 0 ? ret : iter.done;
+}
+
 static int ublk_check_batch_cmd_flags(const struct ublk_batch_io *uc)
 {
        unsigned elem_bytes = sizeof(struct ublk_elem_header);
@@ -2950,7 +3045,7 @@ static int ublk_ch_batch_io_uring_cmd(struct io_uring_cmd *cmd,
                ret = ublk_check_batch_cmd(&data);
                if (ret)
                        goto out;
-               ret = -EOPNOTSUPP;
+               ret = ublk_handle_batch_commit_cmd(&data);
                break;
        default:
                ret = -EOPNOTSUPP;
@@ -3659,6 +3754,10 @@ static int ublk_ctrl_add_dev(const struct ublksrv_ctrl_cmd *header)
                                UBLK_F_AUTO_BUF_REG))
                ub->dev_info.flags &= ~UBLK_F_NEED_GET_DATA;
 
+       /* UBLK_F_BATCH_IO doesn't support GET_DATA */
+       if (ublk_dev_support_batch_io(ub))
+               ub->dev_info.flags &= ~UBLK_F_NEED_GET_DATA;
+
        /*
         * Zoned storage support requires reuse `ublksrv_io_cmd->addr` for
         * returning write_append_lba, which is only allowed in case of

diff --git a/include/uapi/linux/ublk_cmd.h b/include/uapi/linux/ublk_cmd.h
index 1a3d4d33c1d1239d44f2d2c865369d95ca4b89aa..3894d676dd02c8cfd3ccd3554b02371948adb3a7 100644 (file)
--- a/include/uapi/linux/ublk_cmd.h
+++ b/include/uapi/linux/ublk_cmd.h
@@ -110,6 +110,14 @@
  */
 #define        UBLK_U_IO_PREP_IO_CMDS  \
        _IOWR('u', 0x25, struct ublk_batch_io)
+/*
+ * If failure code is returned, nothing in the command buffer is handled.
+ * Otherwise, the returned value means how many bytes in command buffer
+ * are handled actually, then number of handled IOs can be calculated with
+ * `elem_bytes` for each IO. IOs in the remained bytes are not committed,
+ * userspace has to check return value for dealing with partial committing
+ * correctly.
+ */
 #define        UBLK_U_IO_COMMIT_IO_CMDS        \
        _IOWR('u', 0x26, struct ublk_batch_io)