Commit 2d091d62 authored by Pavel Begunkov's avatar Pavel Begunkov Committed by Jens Axboe
Browse files

io_uring: don't vmalloc rsrc tags 



We don't really need vmalloc for keeping tags, it's not a hot path and
is there out of convenience, so replace it with two level tables to not
litter kernel virtual memory mappings.

Signed-off-by: default avatarPavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/241a3422747113a8909e7e1030eb585d4a349e0d.1623634181.git.asml.silence@gmail.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 9123c8ff

fs/io_uring.c

+36 −16
Original line number Diff line number Diff line
@@ -100,6 +100,10 @@ 
#define IORING_MAX_RESTRICTIONS	(IORING_RESTRICTION_LAST + \

				 IORING_REGISTER_LAST + IORING_OP_LAST)



#define IO_RSRC_TAG_TABLE_SHIFT	9

#define IO_RSRC_TAG_TABLE_MAX	(1U << IO_RSRC_TAG_TABLE_SHIFT)

#define IO_RSRC_TAG_TABLE_MASK	(IO_RSRC_TAG_TABLE_MAX - 1)



#define IORING_MAX_REG_BUFFERS	(1U << 14)



#define SQE_VALID_FLAGS	(IOSQE_FIXED_FILE|IOSQE_IO_DRAIN|IOSQE_IO_LINK|	\
@@ -243,7 +247,8 @@ typedef void (rsrc_put_fn)(struct io_ring_ctx *ctx, struct io_rsrc_put *prsrc); 
struct io_rsrc_data {

	struct io_ring_ctx		*ctx;



	u64				*tags;

	u64				**tags;

	unsigned int			nr;

	rsrc_put_fn			*do_put;

	atomic_t			refs;

	struct completion		done;
@@ -7177,9 +7182,20 @@ static int io_rsrc_ref_quiesce(struct io_rsrc_data *data, struct io_ring_ctx *ct 
	return ret;

}



static u64 *io_get_tag_slot(struct io_rsrc_data *data, unsigned int idx)

{

	unsigned int off = idx & IO_RSRC_TAG_TABLE_MASK;

	unsigned int table_idx = idx >> IO_RSRC_TAG_TABLE_SHIFT;



	return &data->tags[table_idx][off];

}



static void io_rsrc_data_free(struct io_rsrc_data *data)

{

	kvfree(data->tags);

	size_t size = data->nr * sizeof(data->tags[0][0]);



	if (data->tags)

		io_free_page_table((void **)data->tags, size);

	kfree(data);

}
@@ -7188,33 +7204,37 @@ static int io_rsrc_data_alloc(struct io_ring_ctx *ctx, rsrc_put_fn *do_put, 
			      struct io_rsrc_data **pdata)

{

	struct io_rsrc_data *data;

	int ret = -ENOMEM;

	unsigned i;



	data = kzalloc(sizeof(*data), GFP_KERNEL);

	if (!data)

		return -ENOMEM;



	data->tags = kvcalloc(nr, sizeof(*data->tags), GFP_KERNEL);

	data->tags = (u64 **)io_alloc_page_table(nr * sizeof(data->tags[0][0]));

	if (!data->tags) {

		kfree(data);

		return -ENOMEM;

	}



	data->nr = nr;

	data->ctx = ctx;

	data->do_put = do_put;

	if (utags) {

		ret = -EFAULT;

		for (i = 0; i < nr; i++) {

			if (copy_from_user(&data->tags[i], &utags[i],

					   sizeof(data->tags[i]))) {

				io_rsrc_data_free(data);

				return -EFAULT;

			}

			if (copy_from_user(io_get_tag_slot(data, i), &utags[i],

					   sizeof(data->tags[i])))

				goto fail;

		}

	}



	atomic_set(&data->refs, 1);

	data->ctx = ctx;

	data->do_put = do_put;

	init_completion(&data->done);

	*pdata = data;

	return 0;

fail:

	io_rsrc_data_free(data);

	return ret;

}



static bool io_alloc_file_tables(struct io_file_table *table, unsigned nr_files)
@@ -7683,7 +7703,7 @@ static int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg, 
		/* allow sparse sets */

		if (fd == -1) {

			ret = -EINVAL;

			if (unlikely(ctx->file_data->tags[i]))

			if (unlikely(*io_get_tag_slot(ctx->file_data, i)))

				goto out_fput;

			continue;

		}
@@ -7781,7 +7801,7 @@ static int io_queue_rsrc_removal(struct io_rsrc_data *data, unsigned idx, 
	if (!prsrc)

		return -ENOMEM;



	prsrc->tag = data->tags[idx];

	prsrc->tag = *io_get_tag_slot(data, idx);

	prsrc->rsrc = rsrc;

	list_add(&prsrc->list, &node->rsrc_list);

	return 0;
@@ -7851,7 +7871,7 @@ static int __io_sqe_files_update(struct io_ring_ctx *ctx, 
				err = -EBADF;

				break;

			}

			data->tags[up->offset + done] = tag;

			*io_get_tag_slot(data, up->offset + done) = tag;

			io_fixed_file_set(file_slot, file);

			err = io_sqe_file_register(ctx, file, i);

			if (err) {
@@ -8437,7 +8457,7 @@ static int io_sqe_buffers_register(struct io_ring_ctx *ctx, void __user *arg, 
		ret = io_buffer_validate(&iov);

		if (ret)

			break;

		if (!iov.iov_base && data->tags[i]) {

		if (!iov.iov_base && *io_get_tag_slot(data, i)) {

			ret = -EINVAL;

			break;

		}
@@ -8510,7 +8530,7 @@ static int __io_sqe_buffers_update(struct io_ring_ctx *ctx, 
		}



		ctx->user_bufs[i] = imu;

		ctx->buf_data->tags[offset] = tag;

		*io_get_tag_slot(ctx->buf_data, offset) = tag;

	}



	if (needs_switch)