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[188.28.125.106]) by smtp.gmail.com with ESMTPSA id h13-20020adff4cd000000b002103aebe8absm4800939wrp.93.2022.06.25.03.55.59 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 25 Jun 2022 03:55:59 -0700 (PDT) From: Pavel Begunkov To: io-uring@vger.kernel.org Cc: Jens Axboe , asml.silence@gmail.com Subject: [PATCH for-next] io_uring: let to set a range for file slot allocation Date: Sat, 25 Jun 2022 11:55:38 +0100 Message-Id: <66ab0394e436f38437cf7c44676e1920d09687ad.1656154403.git.asml.silence@gmail.com> X-Mailer: git-send-email 2.36.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org >From recently io_uring provides an option to allocate a file index for operation registering fixed files. However, it's utterly unusable with mixed approaches when for a part of files the userspace knows better where to place it, as it may race and users don't have any sane way to pick a slot and hoping it will not be taken. Let the userspace to register a range of fixed file slots in which the auto-allocation happens. The use case is splittting the fixed table in two parts, where on of them is used for auto-allocation and another for slot-specified operations. Signed-off-by: Pavel Begunkov --- Some quick tests: https://github.com/isilence/liburing/tree/range-file-alloc include/linux/io_uring_types.h | 3 +++ include/uapi/linux/io_uring.h | 13 +++++++++++++ io_uring/filetable.c | 24 ++++++++++++++++++++---- io_uring/filetable.h | 20 +++++++++++++++++--- io_uring/io_uring.c | 6 ++++++ io_uring/rsrc.c | 2 ++ 6 files changed, 61 insertions(+), 7 deletions(-) diff --git a/include/linux/io_uring_types.h b/include/linux/io_uring_types.h index 918165a20053..1054b8b1ad69 100644 --- a/include/linux/io_uring_types.h +++ b/include/linux/io_uring_types.h @@ -233,6 +233,9 @@ struct io_ring_ctx { unsigned long check_cq; + unsigned int file_alloc_start; + unsigned int file_alloc_end; + struct { /* * We cache a range of free CQEs we can use, once exhausted it diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h index 09e7c3b13d2d..84dd240e7147 100644 --- a/include/uapi/linux/io_uring.h +++ b/include/uapi/linux/io_uring.h @@ -429,6 +429,9 @@ enum { /* sync cancelation API */ IORING_REGISTER_SYNC_CANCEL = 24, + /* register a range of fixed file slots for automatic slot allocation */ + IORING_REGISTER_FILE_ALLOC_RANGE = 25, + /* this goes last */ IORING_REGISTER_LAST }; @@ -575,4 +578,14 @@ struct io_uring_sync_cancel_reg { __u64 pad[4]; }; +/* + * Argument for IORING_REGISTER_FILE_ALLOC_RANGE + * The range is specified as [off, off + len) + */ +struct io_uring_file_index_range { + __u32 off; + __u32 len; + __u64 resv; +}; + #endif diff --git a/io_uring/filetable.c b/io_uring/filetable.c index 534e1a3c625d..5d2207654e0e 100644 --- a/io_uring/filetable.c +++ b/io_uring/filetable.c @@ -16,7 +16,7 @@ static int io_file_bitmap_get(struct io_ring_ctx *ctx) { struct io_file_table *table = &ctx->file_table; - unsigned long nr = ctx->nr_user_files; + unsigned long nr = ctx->file_alloc_end; int ret; do { @@ -24,11 +24,10 @@ static int io_file_bitmap_get(struct io_ring_ctx *ctx) if (ret != nr) return ret; - if (!table->alloc_hint) + if (table->alloc_hint == ctx->file_alloc_start) break; - nr = table->alloc_hint; - table->alloc_hint = 0; + table->alloc_hint = ctx->file_alloc_start; } while (1); return -ENFILE; @@ -139,3 +138,20 @@ int io_fixed_fd_install(struct io_kiocb *req, unsigned int issue_flags, fput(file); return ret; } + +int io_register_file_alloc_range(struct io_ring_ctx *ctx, + struct io_uring_file_index_range __user *arg) +{ + struct io_uring_file_index_range range; + u32 end; + + if (copy_from_user(&range, arg, sizeof(range))) + return -EFAULT; + if (check_add_overflow(range.off, range.len, &end)) + return -EOVERFLOW; + if (range.resv || end > ctx->nr_user_files) + return -EINVAL; + + io_file_table_set_alloc_range(ctx, range.off, range.len); + return 0; +} diff --git a/io_uring/filetable.h b/io_uring/filetable.h index fb5a274c08ff..acd5e6463733 100644 --- a/io_uring/filetable.h +++ b/io_uring/filetable.h @@ -3,9 +3,7 @@ #define IOU_FILE_TABLE_H #include - -struct io_ring_ctx; -struct io_kiocb; +#include /* * FFS_SCM is only available on 64-bit archs, for 32-bit we just define it as 0 @@ -30,6 +28,9 @@ void io_free_file_tables(struct io_file_table *table); int io_fixed_fd_install(struct io_kiocb *req, unsigned int issue_flags, struct file *file, unsigned int file_slot); +int io_register_file_alloc_range(struct io_ring_ctx *ctx, + struct io_uring_file_index_range __user *arg); + unsigned int io_file_get_flags(struct file *file); static inline void io_file_bitmap_clear(struct io_file_table *table, int bit) @@ -68,4 +69,17 @@ static inline void io_fixed_file_set(struct io_fixed_file *file_slot, file_slot->file_ptr = file_ptr; } +static inline void io_reset_alloc_hint(struct io_ring_ctx *ctx) +{ + ctx->file_table.alloc_hint = ctx->file_alloc_start; +} + +static inline void io_file_table_set_alloc_range(struct io_ring_ctx *ctx, + unsigned off, unsigned len) +{ + ctx->file_alloc_start = off; + ctx->file_alloc_end = off + len; + io_reset_alloc_hint(ctx); +} + #endif diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c index 45538b3c3a76..8ab17e2325bc 100644 --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -3877,6 +3877,12 @@ static int __io_uring_register(struct io_ring_ctx *ctx, unsigned opcode, break; ret = io_sync_cancel(ctx, arg); break; + case IORING_REGISTER_FILE_ALLOC_RANGE: + ret = -EINVAL; + if (!arg || nr_args) + break; + ret = io_register_file_alloc_range(ctx, arg); + break; default: ret = -EINVAL; break; diff --git a/io_uring/rsrc.c b/io_uring/rsrc.c index 3a2a5ef263f0..edca7c750f99 100644 --- a/io_uring/rsrc.c +++ b/io_uring/rsrc.c @@ -1009,6 +1009,8 @@ int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg, io_file_bitmap_set(&ctx->file_table, i); } + /* default it to the whole table */ + io_file_table_set_alloc_range(ctx, 0, ctx->nr_user_files); io_rsrc_node_switch(ctx, NULL); return 0; fail: -- 2.36.1