From 4b851d20d325dc59f9abdce55d42dc4b68179db0 Mon Sep 17 00:00:00 2001 From: Pavel Begunkov Date: Fri, 29 Nov 2024 13:34:30 +0000 Subject: [PATCH] io_uring/memmap: add IO_REGION_F_SINGLE_REF Kernel allocated compound pages will have just one reference for the entire page array, add a flag telling io_free_region about that. Signed-off-by: Pavel Begunkov Link: https://lore.kernel.org/r/a7abfa7535e9728d5fcade29a1ea1605ec2c04ce.1732886067.git.asml.silence@gmail.com Signed-off-by: Jens Axboe --- io_uring/memmap.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/io_uring/memmap.c b/io_uring/memmap.c index 5d261e07c2e32..a37ccb167258c 100644 --- a/io_uring/memmap.c +++ b/io_uring/memmap.c @@ -207,15 +207,23 @@ enum { IO_REGION_F_VMAP = 1, /* memory is provided by user and pinned by the kernel */ IO_REGION_F_USER_PROVIDED = 2, + /* only the first page in the array is ref'ed */ + IO_REGION_F_SINGLE_REF = 4, }; void io_free_region(struct io_ring_ctx *ctx, struct io_mapped_region *mr) { if (mr->pages) { + long nr_refs = mr->nr_pages; + + if (mr->flags & IO_REGION_F_SINGLE_REF) + nr_refs = 1; + if (mr->flags & IO_REGION_F_USER_PROVIDED) - unpin_user_pages(mr->pages, mr->nr_pages); + unpin_user_pages(mr->pages, nr_refs); else - release_pages(mr->pages, mr->nr_pages); + release_pages(mr->pages, nr_refs); + kvfree(mr->pages); } if ((mr->flags & IO_REGION_F_VMAP) && mr->ptr) -- 2.47.2