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#pragma once
#include <kernel/types.h>
#include <shared/ring.h>
#include <stdbool.h>
#include <stddef.h>
struct ReqQueue {
VfsReq *head;
VfsReq **slot; /* points to the place where new entries should be placed */
};
struct VfsBackend {
/* amount of using references
* VfsMount
* VfsReq
* Handle
* once it reaches 0, it'll never increase */
size_t usehcnt; /* VfsMount */
bool is_user;
union {
struct {
Proc *handler;
ReqQueue queue; /* kernel backends keep their own queues */
/* amount of processes that control this backend
* won't ever increase if it becomes 0 */
size_t provhcnt;
} user;
struct {
void (*accept)(VfsReq *);
void (*cleanup)(VfsBackend *);
void *data;
} kern;
};
};
/* describes an in-progress vfs call */
struct VfsReq {
enum vfs_op type;
/* "kernel" input - an allocation owned by this struct, contains a NUL
* terminated string. the NUL isn't counted in the kinlen (for compat
* with old code). used for the path in open() */
char *kin;
size_t kinlen;
/* user inputs and outputs - just point to some buffer in the caller */
char __user *uin;
size_t uinlen;
char __user *out;
size_t outlen;
/* those correspond to handle.file.id
* id2 is used for duplex() */
void __user *id, *id2;
long offset;
int flags;
Proc *caller;
VfsBackend *backend;
VfsReq *reqqueue_next;
};
/** Assigns the vfs_request to the caller, and dispatches the call */
void vfsreq_dispatchcopy(VfsReq);
void vfsreq_finish(VfsReq*, char __user *stored, long ret, int flags, Proc *handler);
static inline void vfsreq_finish_short(VfsReq *req, long ret) {
vfsreq_finish(req, (void __user *)ret, ret, 0, NULL);
}
/** Try to accept an enqueued request */
void vfsback_useraccept(VfsReq *);
/** Decrements the "user" reference count. */
void vfsback_userdown(VfsBackend *);
/** Decrements the "provider" reference count. */
void vfsback_provdown(VfsBackend *);
void reqqueue_init(ReqQueue *q);
void reqqueue_join(ReqQueue *q, VfsReq *req);
VfsReq *reqqueue_pop(ReqQueue *q);
/** If there are any pending read requests, and the ring buffer isn't empty,
* fulfill them all with a single read. */
void reqqueue_ringreadall(ReqQueue *q, ring_t *r);
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