Commit 3a3c6d61 authored by Pavel Begunkov's avatar Pavel Begunkov Committed by Jens Axboe
Browse files

io_uring/rsrc: don't rely on user vaddr alignment 



There is no guaranteed alignment for user pointers, however the
calculation of an offset of the first page into a folio after coalescing
uses some weird bit mask logic, get rid of it.

Cc: stable@vger.kernel.org
Reported-by: default avatarDavid Hildenbrand <david@redhat.com>
Fixes: a8edbb42 ("io_uring/rsrc: enable multi-hugepage buffer coalescing")
Signed-off-by: default avatarPavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/io-uring/e387b4c78b33f231105a601d84eefd8301f57954.1750771718.git.asml.silence@gmail.com/


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 5afb4bf9

io_uring/rsrc.c

+6 −1
Original line number Diff line number Diff line
@@ -734,6 +734,7 @@ bool io_check_coalesce_buffer(struct page **page_array, int nr_pages, 


	data->nr_pages_mid = folio_nr_pages(folio);

	data->folio_shift = folio_shift(folio);

	data->first_folio_page_idx = folio_page_idx(folio, page_array[0]);



	/*

	 * Check if pages are contiguous inside a folio, and all folios have
@@ -827,7 +828,11 @@ static struct io_rsrc_node *io_sqe_buffer_register(struct io_ring_ctx *ctx, 
	if (coalesced)

		imu->folio_shift = data.folio_shift;

	refcount_set(&imu->refs, 1);

	off = (unsigned long) iov->iov_base & ((1UL << imu->folio_shift) - 1);



	off = (unsigned long)iov->iov_base & ~PAGE_MASK;

	if (coalesced)

		off += data.first_folio_page_idx << PAGE_SHIFT;



	node->buf = imu;

	ret = 0;

io_uring/rsrc.h

+1 −0
Original line number Diff line number Diff line
@@ -49,6 +49,7 @@ struct io_imu_folio_data { 
	unsigned int	nr_pages_mid;

	unsigned int	folio_shift;

	unsigned int	nr_folios;

	unsigned long	first_folio_page_idx;

};



bool io_rsrc_cache_init(struct io_ring_ctx *ctx);