From 087f997870a948820ec366701d178f402c6a23a3 Mon Sep 17 00:00:00 2001 From: Pavel Begunkov Date: Fri, 29 Nov 2024 13:34:32 +0000 Subject: io_uring/memmap: implement mmap for regions The patch implements mmap for the param region and enables the kernel allocation mode. Internally it uses a fixed mmap offset, however the user has to use the offset returned in struct io_uring_region_desc::mmap_offset. Note, mmap doesn't and can't take ->uring_lock and the region / ring lookup is protected by ->mmap_lock, and it's directly peeking at ctx->param_region. We can't protect io_create_region() with the mmap_lock as it'd deadlock, which is why io_create_region_mmap_safe() initialises it for us in a temporary variable and then publishes it with the lock taken. It's intentionally decoupled from main region helpers, and in the future we might want to have a list of active regions, which then could be protected by the ->mmap_lock. Signed-off-by: Pavel Begunkov Link: https://lore.kernel.org/r/0f1212bd6af7fb39b63514b34fae8948014221d1.1732886067.git.asml.silence@gmail.com Signed-off-by: Jens Axboe --- io_uring/memmap.h | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) (limited to 'io_uring/memmap.h') diff --git a/io_uring/memmap.h b/io_uring/memmap.h index 2096a8427277..2402bca3d700 100644 --- a/io_uring/memmap.h +++ b/io_uring/memmap.h @@ -1,6 +1,8 @@ #ifndef IO_URING_MEMMAP_H #define IO_URING_MEMMAP_H +#define IORING_MAP_OFF_PARAM_REGION 0x20000000ULL + struct page **io_pin_pages(unsigned long ubuf, unsigned long len, int *npages); void io_pages_free(struct page ***pages, int npages); int io_uring_mmap_pages(struct io_ring_ctx *ctx, struct vm_area_struct *vma, @@ -24,7 +26,13 @@ int io_uring_mmap(struct file *file, struct vm_area_struct *vma); void io_free_region(struct io_ring_ctx *ctx, struct io_mapped_region *mr); int io_create_region(struct io_ring_ctx *ctx, struct io_mapped_region *mr, - struct io_uring_region_desc *reg); + struct io_uring_region_desc *reg, + unsigned long mmap_offset); + +int io_create_region_mmap_safe(struct io_ring_ctx *ctx, + struct io_mapped_region *mr, + struct io_uring_region_desc *reg, + unsigned long mmap_offset); static inline void *io_region_get_ptr(struct io_mapped_region *mr) { -- cgit v1.2.3