Commit b70b8e33 authored by Jens Axboe's avatar Jens Axboe
Browse files

io_uring: add basic fixed file allocator 



Applications currently always pick where they want fixed files to go.
In preparation for allowing these types of commands with multishot
support, add a basic allocator in the fixed file table.

Reviewed-by: default avatarHao Xu <howeyxu@tencent.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent d78bd8ad

fs/io_uring.c

+29 −0
Original line number Diff line number Diff line
@@ -258,6 +258,7 @@ struct io_rsrc_put { 
struct io_file_table {

	struct io_fixed_file *files;

	unsigned long *bitmap;

	unsigned int alloc_hint;

};



struct io_rsrc_node {
@@ -4696,6 +4697,31 @@ static int io_openat2_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) 
	return __io_openat_prep(req, sqe);

}



static int __maybe_unused io_file_bitmap_get(struct io_ring_ctx *ctx)

{

	struct io_file_table *table = &ctx->file_table;

	unsigned long nr = ctx->nr_user_files;

	int ret;



	if (table->alloc_hint >= nr)

		table->alloc_hint = 0;



	do {

		ret = find_next_zero_bit(table->bitmap, nr, table->alloc_hint);

		if (ret != nr) {

			table->alloc_hint = ret + 1;

			return ret;

		}

		if (!table->alloc_hint)

			break;



		nr = table->alloc_hint;

		table->alloc_hint = 0;

	} while (1);



	return -ENFILE;

}



static int io_openat2(struct io_kiocb *req, unsigned int issue_flags)

{

	struct open_flags op;
@@ -8664,11 +8690,14 @@ static inline void io_file_bitmap_set(struct io_file_table *table, int bit) 
{

	WARN_ON_ONCE(test_bit(bit, table->bitmap));

	__set_bit(bit, table->bitmap);

	if (bit == table->alloc_hint)

		table->alloc_hint++;

}



static inline void io_file_bitmap_clear(struct io_file_table *table, int bit)

{

	__clear_bit(bit, table->bitmap);

	table->alloc_hint = bit;

}



static void __io_sqe_files_unregister(struct io_ring_ctx *ctx)