You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
81 lines
2.8 KiB
81 lines
2.8 KiB
2 months ago
|
/*
|
||
|
|
* UCW Library -- Asynchronous I/O
|
||
|
|
*
|
||
|
|
* (c) 2006 Martin Mares <mj@ucw.cz>
|
||
|
|
*
|
||
|
|
* This software may be freely distributed and used according to the terms
|
||
|
|
* of the GNU Lesser General Public License.
|
||
|
|
*/
|
||
|
|
|
||
|
|
#ifndef _UCW_ASIO_H
|
||
|
|
#define _UCW_ASIO_H
|
||
|
|
|
||
|
|
#include <ucw/workqueue.h>
|
||
|
|
#include <ucw/clists.h>
|
||
|
|
|
||
|
|
#ifdef CONFIG_UCW_CLEAN_ABI
|
||
|
|
#define asio_cleanup_queue ucw_asio_cleanup_queue
|
||
|
|
#define asio_get ucw_asio_get
|
||
|
|
#define asio_init_queue ucw_asio_init_queue
|
||
|
|
#define asio_put ucw_asio_put
|
||
|
|
#define asio_submit ucw_asio_submit
|
||
|
|
#define asio_sync ucw_asio_sync
|
||
|
|
#define asio_wait ucw_asio_wait
|
||
|
|
#endif
|
||
|
|
|
||
|
|
/*
|
||
|
|
* This module takes care of scheduling and executing asynchronous I/O requests
|
||
|
|
* on files opened with O_DIRECT. It is primarily used by the fb-direct fastbuf
|
||
|
|
* back-end, but you can use it explicitly, too.
|
||
|
|
*
|
||
|
|
* You can define several I/O queues, each for use by a single thread. Requests
|
||
|
|
* on a single queue are always processed in order of their submits, requests
|
||
|
|
* from different queues may be interleaved (although the current implementation
|
||
|
|
* does not do so). Normal read and write requests are returned to their queue
|
||
|
|
* when they are completed. Write-back requests are automatically freed when
|
||
|
|
* done, but the number of such requests in fly is limited in order to avoid
|
||
|
|
* consuming all memory, so a submit of a write-back request can block.
|
||
|
|
*/
|
||
|
|
|
||
|
|
struct asio_queue {
|
||
|
|
uint buffer_size; // How large buffers do we use [user-settable]
|
||
|
|
uint max_writebacks; // Maximum number of writeback requests active [user-settable]
|
||
|
|
uint allocated_requests;
|
||
|
|
uint running_requests; // Total number of running requests
|
||
|
|
uint running_writebacks; // How many of them are writebacks
|
||
|
|
clist idle_list; // Recycled requests waiting for get
|
||
|
|
clist done_list; // Finished requests
|
||
|
|
struct work_queue queue;
|
||
|
|
uint use_count; // For use by the caller
|
||
|
|
};
|
||
|
|
|
||
|
|
enum asio_op {
|
||
|
|
ASIO_FREE,
|
||
|
|
ASIO_READ,
|
||
|
|
ASIO_WRITE,
|
||
|
|
ASIO_WRITE_BACK, // Background write with no success notification
|
||
|
|
};
|
||
|
|
|
||
|
|
struct asio_request {
|
||
|
|
struct work work; // asio_requests are internally just work nodes
|
||
|
|
struct asio_queue *queue;
|
||
|
|
byte *buffer;
|
||
|
|
int fd;
|
||
|
|
enum asio_op op;
|
||
|
|
uint len;
|
||
|
|
int status;
|
||
|
|
int returned_errno;
|
||
|
|
int submitted;
|
||
|
|
void *user_data; // For use by the caller
|
||
|
|
};
|
||
|
|
|
||
|
|
void asio_init_queue(struct asio_queue *q); // Initialize a new queue
|
||
|
|
void asio_cleanup_queue(struct asio_queue *q);
|
||
|
|
struct asio_request *asio_get(struct asio_queue *q); // Get an empty request
|
||
|
|
void asio_submit(struct asio_request *r); // Submit the request (can block if too many writebacks)
|
||
|
|
struct asio_request *asio_wait(struct asio_queue *q); // Wait for the first finished request, NULL if no more
|
||
|
|
void asio_put(struct asio_request *r); // Return a finished request for recycling
|
||
|
|
void asio_sync(struct asio_queue *q); // Wait until all requests are finished
|
||
|
|
|
||
|
|
#endif /* !_UCW_ASIO_H */
|