Commit e390510a authored by Pavel Begunkov's avatar Pavel Begunkov Committed by Jens Axboe
Browse files

io_uring: don't pass around fixed index for scm 



There is an old API nuisance where io_uring's SCM accounting functions
traverse fixed file tables and so requires them to be set in advance,
which leads to some implicit rules of how io_sqe_file_register() should
be used.

__io_sqe_files_scm() now works with only one file at a time, pass a file
directly and get rid of all fixed table dereferencing inside. Clean
io_sqe_file_register() callers.

Signed-off-by: default avatarPavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/fb32031d892e61a7748c70da7999725d5e798671.1649334991.git.asml.silence@gmail.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent dca58c6a

fs/io_uring.c

+14 −23
Original line number Diff line number Diff line
@@ -8609,9 +8609,8 @@ static struct io_sq_data *io_get_sq_data(struct io_uring_params *p, 
 * files because otherwise they can't form a loop and so are not interesting

 * for GC.

 */

static int __io_sqe_files_scm(struct io_ring_ctx *ctx, int offset)

static int __io_sqe_files_scm(struct io_ring_ctx *ctx, struct file *file)

{

	struct file *file = io_file_from_index(ctx, offset);

	struct sock *sk = ctx->ring_sock->sk;

	struct scm_fp_list *fpl;

	struct sk_buff *skb;
@@ -8761,8 +8760,7 @@ static void io_rsrc_put_work(struct work_struct *work) 
	}

}



static int io_sqe_file_register(struct io_ring_ctx *ctx, struct file *file,

				int index);

static int io_sqe_file_register(struct io_ring_ctx *ctx, struct file *file);



static int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg,

				 unsigned nr_args, u64 __user *tags)
@@ -8825,14 +8823,13 @@ static int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg, 
			fput(file);

			goto fail;

		}

		file_slot = io_fixed_file_slot(&ctx->file_table, i);

		io_fixed_file_set(file_slot, file);

		ret = io_sqe_file_register(ctx, file, i);

		ret = io_sqe_file_register(ctx, file);

		if (ret) {

			file_slot->file_ptr = 0;

			fput(file);

			goto fail;

		}

		file_slot = io_fixed_file_slot(&ctx->file_table, i);

		io_fixed_file_set(file_slot, file);

	}



	io_rsrc_node_switch(ctx, NULL);
@@ -8842,8 +8839,7 @@ static int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg, 
	return ret;

}



static int io_sqe_file_register(struct io_ring_ctx *ctx, struct file *file,

				int index)

static int io_sqe_file_register(struct io_ring_ctx *ctx, struct file *file)

{

#if defined(CONFIG_UNIX)

	struct sock *sock = ctx->ring_sock->sk;
@@ -8882,7 +8878,7 @@ static int io_sqe_file_register(struct io_ring_ctx *ctx, struct file *file, 
		return 0;

	}



	return __io_sqe_files_scm(ctx, index);

	return __io_sqe_files_scm(ctx, file);

#else

	return 0;

#endif
@@ -8942,15 +8938,11 @@ static int io_install_fixed_file(struct io_kiocb *req, struct file *file, 
		needs_switch = true;

	}



	ret = io_sqe_file_register(ctx, file);

	if (!ret) {

		*io_get_tag_slot(ctx->file_data, slot_index) = 0;

		io_fixed_file_set(file_slot, file);

	ret = io_sqe_file_register(ctx, file, slot_index);

	if (ret) {

		file_slot->file_ptr = 0;

		goto err;

	}



	ret = 0;

err:

	if (needs_switch)

		io_rsrc_node_switch(ctx, ctx->file_data);
@@ -9061,14 +9053,13 @@ static int __io_sqe_files_update(struct io_ring_ctx *ctx, 
				err = -EBADF;

				break;

			}

			*io_get_tag_slot(data, i) = tag;

			io_fixed_file_set(file_slot, file);

			err = io_sqe_file_register(ctx, file, i);

			err = io_sqe_file_register(ctx, file);

			if (err) {

				file_slot->file_ptr = 0;

				fput(file);

				break;

			}

			*io_get_tag_slot(data, i) = tag;

			io_fixed_file_set(file_slot, file);

		}

	}