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It'll be used later for (slow path) ring setup. Signed-off-by: Pavel Begunkov --- io_uring/memmap.c | 12 ++++++++++++ io_uring/memmap.h | 2 ++ 2 files changed, 14 insertions(+) diff --git a/io_uring/memmap.c b/io_uring/memmap.c index b329cee8d6e8..83faef350b9d 100644 --- a/io_uring/memmap.c +++ b/io_uring/memmap.c @@ -232,6 +232,18 @@ int io_create_region(struct io_ring_ctx *ctx, struct io_mapped_region *mr, return ret; } +void *io_region_slice(struct io_mapped_region *mr, size_t off, size_t size) +{ + if (WARN_ON_ONCE(!size) || !io_region_is_set(mr)) + return NULL; + + size = size_add(off, size); + if (size == SIZE_MAX || size > io_region_size(mr)) + return NULL; + + return io_region_get_ptr(mr) + off; +} + static struct io_mapped_region *io_mmap_get_region(struct io_ring_ctx *ctx, loff_t pgoff) { diff --git a/io_uring/memmap.h b/io_uring/memmap.h index d4b8b6363a7d..fa7a45cdb6dd 100644 --- a/io_uring/memmap.h +++ b/io_uring/memmap.h @@ -21,6 +21,8 @@ int io_create_region(struct io_ring_ctx *ctx, struct io_mapped_region *mr, struct io_uring_region_desc *reg, unsigned long mmap_offset); +void *io_region_slice(struct io_mapped_region *mr, size_t off, size_t size); + static inline void *io_region_get_ptr(struct io_mapped_region *mr) { return mr->ptr; -- 2.49.0