io_uring/kbuf.h

Source file repositories/reference/linux-study-clean/io_uring/kbuf.h

File Facts

System
Linux kernel
Corpus path
io_uring/kbuf.h
Extension
.h
Size
3892 bytes
Lines
142
Domain
Kernel Services
Bucket
io_uring
Inferred role
Kernel Services: implementation source
Status
source implementation candidate

Why This File Exists

Shared kernel service surface used by multiple subsystems, including helpers, cryptography, virtualization support, and async I/O infrastructure.

Dependency Surface

Detected Declarations

Annotated Snippet

struct io_buffer_list {
	/*
	 * If the IOBL_BUF_RING flag is set, then buf_ring is used. If not, then
	 * these are classic provided buffers and ->buf_list is used.
	 */
	union {
		struct list_head buf_list;
		struct io_uring_buf_ring *buf_ring;
	};
	/* count of classic/legacy buffers in buffer list */
	int nbufs;

	__u16 bgid;

	/* below is for ring provided buffers */
	__u16 head;
	__u16 mask;

	__u16 flags;

	/*
	 * minimum required amount to be left to reuse an incrementally
	 * consumed buffer. If less than this is left at consumption time,
	 * buffer is done and head is incremented to the next buffer.
	 */
	__u32 min_left_sub_one;

	struct io_mapped_region region;
};

struct io_buffer {
	struct list_head list;
	__u64 addr;
	__u32 len;
	__u16 bid;
	__u16 bgid;
};

enum {
	/* can alloc a bigger vec */
	KBUF_MODE_EXPAND	= 1,
	/* if bigger vec allocated, free old one */
	KBUF_MODE_FREE		= 2,
};

struct buf_sel_arg {
	struct iovec *iovs;
	size_t out_len;
	size_t max_len;
	unsigned short nr_iovs;
	unsigned short mode;
	unsigned short buf_group;
	unsigned short partial_map;
};

struct io_br_sel io_buffer_select(struct io_kiocb *req, size_t *len,
				  unsigned buf_group, unsigned int issue_flags);
int io_buffers_select(struct io_kiocb *req, struct buf_sel_arg *arg,
		      struct io_br_sel *sel, unsigned int issue_flags);
int io_buffers_peek(struct io_kiocb *req, struct buf_sel_arg *arg,
		    struct io_br_sel *sel);
void io_destroy_buffers(struct io_ring_ctx *ctx);

int io_remove_buffers_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe);
int io_provide_buffers_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe);
int io_manage_buffers_legacy(struct io_kiocb *req, unsigned int issue_flags);

int io_register_pbuf_ring(struct io_ring_ctx *ctx, void __user *arg);
int io_unregister_pbuf_ring(struct io_ring_ctx *ctx, void __user *arg);
int io_register_pbuf_status(struct io_ring_ctx *ctx, void __user *arg);

bool io_kbuf_recycle_legacy(struct io_kiocb *req, unsigned issue_flags);
void io_kbuf_drop_legacy(struct io_kiocb *req);

unsigned int __io_put_kbufs(struct io_kiocb *req, struct io_buffer_list *bl,
			    int len, int nbufs);
bool io_kbuf_commit(struct io_kiocb *req,
		    struct io_buffer_list *bl, int len, int nr);

struct io_mapped_region *io_pbuf_get_region(struct io_ring_ctx *ctx,
					    unsigned int bgid);

static inline bool io_kbuf_recycle_ring(struct io_kiocb *req,
					struct io_buffer_list *bl)
{
	if (bl) {
		req->flags &= ~(REQ_F_BUFFER_RING|REQ_F_BUFFERS_COMMIT);
		return true;
	}
	return false;

Annotation

Implementation Notes