From 69edf98be844375807f299397c516fb1e962b3cc Mon Sep 17 00:00:00 2001 From: Ming Lei Date: Tue, 29 Apr 2025 10:29:37 +0800 Subject: [PATCH] ublk: decouple zero copy from user copy UBLK_F_USER_COPY and UBLK_F_SUPPORT_ZERO_COPY are two different features, and shouldn't be coupled together. Commit 1f6540e2aabb ("ublk: zc register/unregister bvec") enables user copy automatically in case of UBLK_F_SUPPORT_ZERO_COPY, this way isn't correct. So decouple zero copy from user copy, and use independent helper to check each one. Fixes: 1f6540e2aabb ("ublk: zc register/unregister bvec") Signed-off-by: Ming Lei Link: https://lore.kernel.org/r/20250429022941.1718671-3-ming.lei@redhat.com Signed-off-by: Jens Axboe --- drivers/block/ublk_drv.c | 35 +++++++++++++++++++++++------------ 1 file changed, 23 insertions(+), 12 deletions(-) diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c index 40f971a66d3e..0a3a3c64316d 100644 --- a/drivers/block/ublk_drv.c +++ b/drivers/block/ublk_drv.c @@ -205,11 +205,6 @@ static inline struct request *__ublk_check_and_get_req(struct ublk_device *ub, static inline unsigned int ublk_req_build_flags(struct request *req); static inline struct ublksrv_io_desc *ublk_get_iod(struct ublk_queue *ubq, int tag); -static inline bool ublk_dev_is_user_copy(const struct ublk_device *ub) -{ - return ub->dev_info.flags & (UBLK_F_USER_COPY | UBLK_F_SUPPORT_ZERO_COPY); -} - static inline bool ublk_dev_is_zoned(const struct ublk_device *ub) { return ub->dev_info.flags & UBLK_F_ZONED; @@ -609,14 +604,19 @@ static void ublk_apply_params(struct ublk_device *ub) ublk_dev_param_zoned_apply(ub); } +static inline bool ublk_support_zero_copy(const struct ublk_queue *ubq) +{ + return ubq->flags & UBLK_F_SUPPORT_ZERO_COPY; +} + static inline bool ublk_support_user_copy(const struct ublk_queue *ubq) { - return ubq->flags & (UBLK_F_USER_COPY | UBLK_F_SUPPORT_ZERO_COPY); + return ubq->flags & UBLK_F_USER_COPY; } static inline bool ublk_need_map_io(const struct ublk_queue *ubq) { - return !ublk_support_user_copy(ubq); + return !ublk_support_user_copy(ubq) && !ublk_support_zero_copy(ubq); } static inline bool ublk_need_req_ref(const struct ublk_queue *ubq) @@ -624,8 +624,11 @@ static inline bool ublk_need_req_ref(const struct ublk_queue *ubq) /* * read()/write() is involved in user copy, so request reference * has to be grabbed + * + * for zero copy, request buffer need to be registered to io_uring + * buffer table, so reference is needed */ - return ublk_support_user_copy(ubq); + return ublk_support_user_copy(ubq) || ublk_support_zero_copy(ubq); } static inline void ublk_init_req_ref(const struct ublk_queue *ubq, @@ -2245,6 +2248,9 @@ static struct request *ublk_check_and_get_req(struct kiocb *iocb, if (!ubq) return ERR_PTR(-EINVAL); + if (!ublk_support_user_copy(ubq)) + return ERR_PTR(-EACCES); + if (tag >= ubq->q_depth) return ERR_PTR(-EINVAL); @@ -2783,13 +2789,18 @@ static int ublk_ctrl_add_dev(const struct ublksrv_ctrl_cmd *header) 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 (ublk_dev_is_user_copy(ub)) + /* GET_DATA isn't needed any more with USER_COPY or ZERO COPY */ + if (ub->dev_info.flags & (UBLK_F_USER_COPY | UBLK_F_SUPPORT_ZERO_COPY)) ub->dev_info.flags &= ~UBLK_F_NEED_GET_DATA; - /* Zoned storage support requires user copy feature */ + /* + * Zoned storage support requires reuse `ublksrv_io_cmd->addr` for + * returning write_append_lba, which is only allowed in case of + * user copy or zero copy + */ if (ublk_dev_is_zoned(ub) && - (!IS_ENABLED(CONFIG_BLK_DEV_ZONED) || !ublk_dev_is_user_copy(ub))) { + (!IS_ENABLED(CONFIG_BLK_DEV_ZONED) || !(ub->dev_info.flags & + (UBLK_F_USER_COPY | UBLK_F_SUPPORT_ZERO_COPY)))) { ret = -EINVAL; goto out_free_dev_number; } -- 2.25.1