Commit 992da01a authored by Pavel Begunkov's avatar Pavel Begunkov Committed by Jens Axboe
Browse files

io_uring: change registration/upd/rsrc tagging ABI 



There are ABI moments about recently added rsrc registration/update and
tagging that might become a nuisance in the future. First,
IORING_REGISTER_RSRC[_UPD] hide different types of resources under it,
so breaks fine control over them by restrictions. It works for now, but
once those are wanted under restrictions it would require a rework.

It was also inconvenient trying to fit a new resource not supporting
all the features (e.g. dynamic update) into the interface, so better
to return to IORING_REGISTER_* top level dispatching.

Second, register/update were considered to accept a type of resource,
however that's not a good idea because there might be several ways of
registration of a single resource type, e.g. we may want to add
non-contig buffers or anything more exquisite as dma mapped memory.
So, remove IORING_RSRC_[FILE,BUFFER] out of the ABI, and place them
internally for now to limit changes.

Signed-off-by: default avatarPavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/9b554897a7c17ad6e3becc48dfed2f7af9f423d5.1623339162.git.asml.silence@gmail.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 216e5835

fs/io_uring.c

+27 −12
Original line number Diff line number Diff line
@@ -783,6 +783,11 @@ struct io_task_work { 
	task_work_func_t	func;

};



enum {

	IORING_RSRC_FILE		= 0,

	IORING_RSRC_BUFFER		= 1,

};



/*

 * NOTE! Each of the iocb union members has the file pointer

 * as the first entry in their struct definition. So you can
@@ -9911,7 +9916,7 @@ static int io_register_files_update(struct io_ring_ctx *ctx, void __user *arg, 
}



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

				   unsigned size)

				   unsigned size, unsigned type)

{

	struct io_uring_rsrc_update2 up;
@@ -9919,13 +9924,13 @@ static int io_register_rsrc_update(struct io_ring_ctx *ctx, void __user *arg, 
		return -EINVAL;

	if (copy_from_user(&up, arg, sizeof(up)))

		return -EFAULT;

	if (!up.nr)

	if (!up.nr || up.resv)

		return -EINVAL;

	return __io_register_rsrc_update(ctx, up.type, &up, up.nr);

	return __io_register_rsrc_update(ctx, type, &up, up.nr);

}



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

			    unsigned int size)

			    unsigned int size, unsigned int type)

{

	struct io_uring_rsrc_register rr;
@@ -9936,10 +9941,10 @@ static int io_register_rsrc(struct io_ring_ctx *ctx, void __user *arg, 
	memset(&rr, 0, sizeof(rr));

	if (copy_from_user(&rr, arg, size))

		return -EFAULT;

	if (!rr.nr)

	if (!rr.nr || rr.resv || rr.resv2)

		return -EINVAL;



	switch (rr.type) {

	switch (type) {

	case IORING_RSRC_FILE:

		return io_sqe_files_register(ctx, u64_to_user_ptr(rr.data),

					     rr.nr, u64_to_user_ptr(rr.tags));
@@ -9961,8 +9966,10 @@ static bool io_register_op_must_quiesce(int op) 
	case IORING_REGISTER_PROBE:

	case IORING_REGISTER_PERSONALITY:

	case IORING_UNREGISTER_PERSONALITY:

	case IORING_REGISTER_RSRC:

	case IORING_REGISTER_RSRC_UPDATE:

	case IORING_REGISTER_FILES2:

	case IORING_REGISTER_FILES_UPDATE2:

	case IORING_REGISTER_BUFFERS2:

	case IORING_REGISTER_BUFFERS_UPDATE:

		return false;

	default:

		return true;
@@ -10088,11 +10095,19 @@ static int __io_uring_register(struct io_ring_ctx *ctx, unsigned opcode, 
	case IORING_REGISTER_RESTRICTIONS:

		ret = io_register_restrictions(ctx, arg, nr_args);

		break;

	case IORING_REGISTER_RSRC:

		ret = io_register_rsrc(ctx, arg, nr_args);

	case IORING_REGISTER_FILES2:

		ret = io_register_rsrc(ctx, arg, nr_args, IORING_RSRC_FILE);

		break;

	case IORING_REGISTER_FILES_UPDATE2:

		ret = io_register_rsrc_update(ctx, arg, nr_args,

					      IORING_RSRC_FILE);

		break;

	case IORING_REGISTER_BUFFERS2:

		ret = io_register_rsrc(ctx, arg, nr_args, IORING_RSRC_BUFFER);

		break;

	case IORING_REGISTER_RSRC_UPDATE:

		ret = io_register_rsrc_update(ctx, arg, nr_args);

	case IORING_REGISTER_BUFFERS_UPDATE:

		ret = io_register_rsrc_update(ctx, arg, nr_args,

					      IORING_RSRC_BUFFER);

		break;

	default:

		ret = -EINVAL;

include/uapi/linux/io_uring.h

+9 −9
Original line number Diff line number Diff line
@@ -298,8 +298,12 @@ enum { 
	IORING_UNREGISTER_PERSONALITY		= 10,

	IORING_REGISTER_RESTRICTIONS		= 11,

	IORING_REGISTER_ENABLE_RINGS		= 12,

	IORING_REGISTER_RSRC			= 13,

	IORING_REGISTER_RSRC_UPDATE		= 14,



	/* extended with tagging */

	IORING_REGISTER_FILES2			= 13,

	IORING_REGISTER_FILES_UPDATE2		= 14,

	IORING_REGISTER_BUFFERS2		= 15,

	IORING_REGISTER_BUFFERS_UPDATE		= 16,



	/* this goes last */

	IORING_REGISTER_LAST
@@ -312,14 +316,10 @@ struct io_uring_files_update { 
	__aligned_u64 /* __s32 * */ fds;

};



enum {

	IORING_RSRC_FILE		= 0,

	IORING_RSRC_BUFFER		= 1,

};



struct io_uring_rsrc_register {

	__u32 type;

	__u32 nr;

	__u32 resv;

	__u64 resv2;

	__aligned_u64 data;

	__aligned_u64 tags;

};
@@ -335,8 +335,8 @@ struct io_uring_rsrc_update2 { 
	__u32 resv;

	__aligned_u64 data;

	__aligned_u64 tags;

	__u32 type;

	__u32 nr;

	__u32 resv2;

};



/* Skip updating fd indexes set to this value in the fd table */