ublk: support user copy

[linux-block.git] / drivers / block / ublk_drv.c

diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
index ec40ac4f9af3c8ac9a487fa6668a653296cb40ff..e00733b6fea83d13f8b82b35a266ef7c7116ed5e 100644 (file)
--- a/drivers/block/ublk_drv.c
+++ b/drivers/block/ublk_drv.c
@@ -55,7 +55,8 @@
                | UBLK_F_USER_RECOVERY \
                | UBLK_F_USER_RECOVERY_REISSUE \
                | UBLK_F_UNPRIVILEGED_DEV \
-               | UBLK_F_CMD_IOCTL_ENCODE)
+               | UBLK_F_CMD_IOCTL_ENCODE \
+               | UBLK_F_USER_COPY)
 
 /* All UBLK_PARAM_TYPE_* should be included here */
 #define UBLK_PARAM_TYPE_ALL (UBLK_PARAM_TYPE_BASIC | \
@@ -312,9 +313,18 @@ static int ublk_apply_params(struct ublk_device *ub)
        return 0;
 }
 
+static inline bool ublk_support_user_copy(const struct ublk_queue *ubq)
+{
+       return ubq->flags & UBLK_F_USER_COPY;
+}
+
 static inline bool ublk_need_req_ref(const struct ublk_queue *ubq)
 {
-       return false;
+       /*
+        * read()/write() is involved in user copy, so request reference
+        * has to be grabbed
+        */
+       return ublk_support_user_copy(ubq);
 }
 
 static inline void ublk_init_req_ref(const struct ublk_queue *ubq,
@@ -591,6 +601,9 @@ static int ublk_map_io(const struct ublk_queue *ubq, const struct request *req,
 {
        const unsigned int rq_bytes = blk_rq_bytes(req);
 
+       if (ublk_support_user_copy(ubq))
+               return rq_bytes;
+
        /*
         * no zero copy, we delay copy WRITE request data into ublksrv
         * context and the big benefit is that pinning pages in current
@@ -615,6 +628,9 @@ static int ublk_unmap_io(const struct ublk_queue *ubq,
 {
        const unsigned int rq_bytes = blk_rq_bytes(req);
 
+       if (ublk_support_user_copy(ubq))
+               return rq_bytes;
+
        if (ublk_need_unmap_req(req)) {
                struct iov_iter iter;
                struct iovec iov;
@@ -1390,6 +1406,11 @@ static int __ublk_ch_uring_cmd(struct io_uring_cmd *cmd,
                        ^ (_IOC_NR(cmd_op) == UBLK_IO_NEED_GET_DATA))
                goto out;
 
+       if (ublk_support_user_copy(ubq) && ub_cmd->addr) {
+               ret = -EINVAL;
+               goto out;
+       }
+
        ret = ublk_check_cmd_op(cmd_op);
        if (ret)
                goto out;
@@ -1408,23 +1429,34 @@ static int __ublk_ch_uring_cmd(struct io_uring_cmd *cmd,
                 */
                if (io->flags & UBLK_IO_FLAG_OWNED_BY_SRV)
                        goto out;
-               /* FETCH_RQ has to provide IO buffer if NEED GET DATA is not enabled */
-               if (!ub_cmd->addr && !ublk_need_get_data(ubq))
-                       goto out;
+
+               if (!ublk_support_user_copy(ubq)) {
+                       /*
+                        * FETCH_RQ has to provide IO buffer if NEED GET
+                        * DATA is not enabled
+                        */
+                       if (!ub_cmd->addr && !ublk_need_get_data(ubq))
+                               goto out;
+               }
 
                ublk_fill_io_cmd(io, cmd, ub_cmd->addr);
                ublk_mark_io_ready(ub, ubq);
                break;
        case UBLK_IO_COMMIT_AND_FETCH_REQ:
                req = blk_mq_tag_to_rq(ub->tag_set.tags[ub_cmd->q_id], tag);
-               /*
-                * COMMIT_AND_FETCH_REQ has to provide IO buffer if NEED GET DATA is
-                * not enabled or it is Read IO.
-                */
-               if (!ub_cmd->addr && (!ublk_need_get_data(ubq) || req_op(req) == REQ_OP_READ))
-                       goto out;
+
                if (!(io->flags & UBLK_IO_FLAG_OWNED_BY_SRV))
                        goto out;
+
+               if (!ublk_support_user_copy(ubq)) {
+                       /*
+                        * COMMIT_AND_FETCH_REQ has to provide IO buffer if
+                        * NEED GET DATA is not enabled or it is Read IO.
+                        */
+                       if (!ub_cmd->addr && (!ublk_need_get_data(ubq) ||
+                                               req_op(req) == REQ_OP_READ))
+                               goto out;
+               }
                ublk_fill_io_cmd(io, cmd, ub_cmd->addr);
                ublk_commit_completion(ub, ub_cmd);
                break;
@@ -1996,6 +2028,10 @@ static int ublk_ctrl_add_dev(struct io_uring_cmd *cmd)
        ub->dev_info.flags |= UBLK_F_CMD_IOCTL_ENCODE |
                UBLK_F_URING_CMD_COMP_IN_TASK;
 
+       /* GET_DATA isn't needed any more with USER_COPY */
+       if (ub->dev_info.flags & UBLK_F_USER_COPY)
+               ub->dev_info.flags &= ~UBLK_F_NEED_GET_DATA;
+
        /* We are not ready to support zero copy */
        ub->dev_info.flags &= ~UBLK_F_SUPPORT_ZERO_COPY;