Commit 7427b0b4 authored by Pavel Begunkov's avatar Pavel Begunkov Committed by Jens Axboe
Browse files

io_uring/rsrc: export io_check_coalesce_buffer 



io_try_coalesce_buffer() is a useful helper collecting useful info about
a set of pages, I want to reuse it for analysing ring/etc. mappings. I
don't need the entire thing and only interested if it can be coalesced
into a single page, but that's better than duplicating the parsing.

Signed-off-by: default avatarPavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/353b447953cd5d34c454a7d909bb6024c391d6e2.1732886067.git.asml.silence@gmail.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 943d0609

io_uring/rsrc.c

+12 −10
Original line number Diff line number Diff line
@@ -626,11 +626,12 @@ static int io_buffer_account_pin(struct io_ring_ctx *ctx, struct page **pages, 
	return ret;

}



static bool io_do_coalesce_buffer(struct page ***pages, int *nr_pages,

				struct io_imu_folio_data *data, int nr_folios)

static bool io_coalesce_buffer(struct page ***pages, int *nr_pages,

				struct io_imu_folio_data *data)

{

	struct page **page_array = *pages, **new_array = NULL;

	int nr_pages_left = *nr_pages, i, j;

	int nr_folios = data->nr_folios;



	/* Store head pages only*/

	new_array = kvmalloc_array(nr_folios, sizeof(struct page *),
@@ -667,15 +668,14 @@ static bool io_do_coalesce_buffer(struct page ***pages, int *nr_pages, 
	return true;

}



static bool io_try_coalesce_buffer(struct page ***pages, int *nr_pages,

bool io_check_coalesce_buffer(struct page **page_array, int nr_pages,

			      struct io_imu_folio_data *data)

{

	struct page **page_array = *pages;

	struct folio *folio = page_folio(page_array[0]);

	unsigned int count = 1, nr_folios = 1;

	int i;



	if (*nr_pages <= 1)

	if (nr_pages <= 1)

		return false;



	data->nr_pages_mid = folio_nr_pages(folio);
@@ -687,7 +687,7 @@ static bool io_try_coalesce_buffer(struct page ***pages, int *nr_pages, 
	 * Check if pages are contiguous inside a folio, and all folios have

	 * the same page count except for the head and tail.

	 */

	for (i = 1; i < *nr_pages; i++) {

	for (i = 1; i < nr_pages; i++) {

		if (page_folio(page_array[i]) == folio &&

			page_array[i] == page_array[i-1] + 1) {

			count++;
@@ -715,7 +715,8 @@ static bool io_try_coalesce_buffer(struct page ***pages, int *nr_pages, 
	if (nr_folios == 1)

		data->nr_pages_head = count;



	return io_do_coalesce_buffer(pages, nr_pages, data, nr_folios);

	data->nr_folios = nr_folios;

	return true;

}



static struct io_rsrc_node *io_sqe_buffer_register(struct io_ring_ctx *ctx,
@@ -729,7 +730,7 @@ static struct io_rsrc_node *io_sqe_buffer_register(struct io_ring_ctx *ctx, 
	size_t size;

	int ret, nr_pages, i;

	struct io_imu_folio_data data;

	bool coalesced;

	bool coalesced = false;



	if (!iov->iov_base)

		return NULL;
@@ -749,7 +750,8 @@ static struct io_rsrc_node *io_sqe_buffer_register(struct io_ring_ctx *ctx, 
	}



	/* If it's huge page(s), try to coalesce them into fewer bvec entries */

	coalesced = io_try_coalesce_buffer(&pages, &nr_pages, &data);

	if (io_check_coalesce_buffer(pages, nr_pages, &data))

		coalesced = io_coalesce_buffer(&pages, &nr_pages, &data);



	imu = kvmalloc(struct_size(imu, bvec, nr_pages), GFP_KERNEL);

	if (!imu)

io_uring/rsrc.h

+4 −0
Original line number Diff line number Diff line
@@ -40,6 +40,7 @@ struct io_imu_folio_data { 
	/* For non-head/tail folios, has to be fully included */

	unsigned int	nr_pages_mid;

	unsigned int	folio_shift;

	unsigned int	nr_folios;

};



struct io_rsrc_node *io_rsrc_node_alloc(struct io_ring_ctx *ctx, int type);
@@ -66,6 +67,9 @@ int io_register_rsrc_update(struct io_ring_ctx *ctx, void __user *arg, 
int io_register_rsrc(struct io_ring_ctx *ctx, void __user *arg,

			unsigned int size, unsigned int type);



bool io_check_coalesce_buffer(struct page **page_array, int nr_pages,

			      struct io_imu_folio_data *data);



static inline struct io_rsrc_node *io_rsrc_node_lookup(struct io_rsrc_data *data,

						       int index)

{