From ebf695f129367ed4b26df6baec2ea7fc50c9e6f0 Mon Sep 17 00:00:00 2001 From: Ming Lei Date: Thu, 27 Mar 2025 17:51:15 +0800 Subject: ublk: add segment parameter IO split is usually bad in io_uring world, since -EAGAIN is caused and IO handling may have to fallback to io-wq, this way does hurt performance. ublk starts to support zero copy recently, for avoiding unnecessary IO split, ublk driver's segment limit should be aligned with backend device's segment limit. Another reason is that io_buffer_register_bvec() needs to allocate bvecs, which number is aligned with ublk request segment number, so that big memory allocation can be avoided by setting reasonable max_segments limit. So add segment parameter for providing ublk server chance to align segment limit with backend, and keep it reasonable from implementation viewpoint. Signed-off-by: Ming Lei Link: https://lore.kernel.org/r/20250327095123.179113-7-ming.lei@redhat.com Signed-off-by: Jens Axboe --- include/uapi/linux/ublk_cmd.h | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) (limited to 'include') diff --git a/include/uapi/linux/ublk_cmd.h b/include/uapi/linux/ublk_cmd.h index 7255b36b5cf6..583b86681c93 100644 --- a/include/uapi/linux/ublk_cmd.h +++ b/include/uapi/linux/ublk_cmd.h @@ -410,6 +410,29 @@ struct ublk_param_dma_align { __u8 pad[4]; }; +#define UBLK_MIN_SEGMENT_SIZE 4096 +/* + * If any one of the three segment parameter is set as 0, the behavior is + * undefined. + */ +struct ublk_param_segment { + /* + * seg_boundary_mask + 1 needs to be power_of_2(), and the sum has + * to be >= UBLK_MIN_SEGMENT_SIZE(4096) + */ + __u64 seg_boundary_mask; + + /* + * max_segment_size could be override by virt_boundary_mask, so be + * careful when setting both. + * + * max_segment_size has to be >= UBLK_MIN_SEGMENT_SIZE(4096) + */ + __u32 max_segment_size; + __u16 max_segments; + __u8 pad[2]; +}; + struct ublk_params { /* * Total length of parameters, userspace has to set 'len' for both @@ -423,6 +446,7 @@ struct ublk_params { #define UBLK_PARAM_TYPE_DEVT (1 << 2) #define UBLK_PARAM_TYPE_ZONED (1 << 3) #define UBLK_PARAM_TYPE_DMA_ALIGN (1 << 4) +#define UBLK_PARAM_TYPE_SEGMENT (1 << 5) __u32 types; /* types of parameter included */ struct ublk_param_basic basic; @@ -430,6 +454,7 @@ struct ublk_params { struct ublk_param_devt devt; struct ublk_param_zoned zoned; struct ublk_param_dma_align dma; + struct ublk_param_segment seg; }; #endif -- cgit v1.2.3 From 296e16961817e8e5f574661febc608ac0c0c0108 Mon Sep 17 00:00:00 2001 From: Pavel Begunkov Date: Mon, 31 Mar 2025 08:55:47 +0100 Subject: io_uring: hide caches sqes from drivers There is now an io_uring private part of cmd async_data, move saved sqe into it. Drivers are accessing it via struct io_uring_cmd::cmd. Signed-off-by: Pavel Begunkov Link: https://lore.kernel.org/r/ecbe078dd57acefdbc4366d083327086c0879378.1743357121.git.asml.silence@gmail.com Signed-off-by: Jens Axboe --- include/linux/io_uring/cmd.h | 1 - 1 file changed, 1 deletion(-) (limited to 'include') diff --git a/include/linux/io_uring/cmd.h b/include/linux/io_uring/cmd.h index e6723fa95160..0634a3de1782 100644 --- a/include/linux/io_uring/cmd.h +++ b/include/linux/io_uring/cmd.h @@ -21,7 +21,6 @@ struct io_uring_cmd { struct io_uring_cmd_data { void *op_data; - struct io_uring_sqe sqes[2]; }; static inline const void *io_uring_sqe_cmd(const struct io_uring_sqe *sqe) -- cgit v1.2.3 From 149974fdb8e186a1c72b87cee806373624a8a375 Mon Sep 17 00:00:00 2001 From: Ming Lei Date: Tue, 25 Mar 2025 21:51:51 +0800 Subject: block: add for_each_mp_bvec() Add helper of for_each_mp_bvec() for io_uring to import fixed kernel buffer. Signed-off-by: Ming Lei Link: https://lore.kernel.org/r/20250325135155.935398-3-ming.lei@redhat.com Signed-off-by: Jens Axboe --- include/linux/bvec.h | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'include') diff --git a/include/linux/bvec.h b/include/linux/bvec.h index ba8f52d48b94..204b22a99c4b 100644 --- a/include/linux/bvec.h +++ b/include/linux/bvec.h @@ -184,6 +184,12 @@ static inline void bvec_iter_advance_single(const struct bio_vec *bv, ((bvl = bvec_iter_bvec((bio_vec), (iter))), 1); \ bvec_iter_advance_single((bio_vec), &(iter), (bvl).bv_len)) +#define for_each_mp_bvec(bvl, bio_vec, iter, start) \ + for (iter = (start); \ + (iter).bi_size && \ + ((bvl = mp_bvec_iter_bvec((bio_vec), (iter))), 1); \ + bvec_iter_advance_single((bio_vec), &(iter), (bvl).bv_len)) + /* for iterating one bio from start to end */ #define BVEC_ITER_ALL_INIT (struct bvec_iter) \ { \ -- cgit v1.2.3