Commit 69edf98b authored by Ming Lei's avatar Ming Lei Committed by Jens Axboe
Browse files

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 1f6540e2 ("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: 1f6540e2 ("ublk: zc register/unregister bvec")
Signed-off-by: default avatarMing Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20250429022941.1718671-3-ming.lei@redhat.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 730d8379

drivers/block/ublk_drv.c

+23 −12
Original line number Diff line number Diff line
@@ -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;

	}