minix/servers/vfs/comm.c
Thomas Veerman 8f55767619 VFS: make m_in job local
By making m_in job local (i.e., each job has its own copy of m_in instead
of refering to the global m_in) we don't have to store and restore m_in
on every thread yield. This reduces overhead. Moreover, remove the
assumption that m_in is preserved. Do_XXX functions have to copy the
system call parameters as soon as possible and only pass those copies to
other functions.

Furthermore, this patch cleans up some code and uses better types in a lot
of places.
2012-04-13 12:50:38 +00:00

178 lines
4.9 KiB
C

#include "fs.h"
#include "glo.h"
#include "vmnt.h"
#include "fproc.h"
#include <minix/vfsif.h>
#include <assert.h>
static int sendmsg(struct vmnt *vmp, struct fproc *rfp);
static int queuemsg(struct vmnt *vmp);
/*===========================================================================*
* sendmsg *
*===========================================================================*/
static int sendmsg(vmp, rfp)
struct vmnt *vmp;
struct fproc *rfp;
{
/* This is the low level function that sends requests to FS processes.
*/
int r, transid;
vmp->m_comm.c_cur_reqs++; /* One more request awaiting a reply */
transid = rfp->fp_wtid + VFS_TRANSID;
rfp->fp_sendrec->m_type = TRNS_ADD_ID(rfp->fp_sendrec->m_type, transid);
rfp->fp_task = vmp->m_fs_e;
if ((r = asynsend3(vmp->m_fs_e, rfp->fp_sendrec, AMF_NOREPLY)) != OK) {
printf("VFS: sendmsg: error sending message. "
"FS_e: %d req_nr: %d err: %d\n", vmp->m_fs_e,
rfp->fp_sendrec->m_type, r);
util_stacktrace();
return(r);
}
return(r);
}
/*===========================================================================*
* send_work *
*===========================================================================*/
void send_work(void)
{
/* Try to send out as many requests as possible */
struct vmnt *vmp;
if (sending == 0) return;
for (vmp = &vmnt[0]; vmp < &vmnt[NR_MNTS]; vmp++)
fs_sendmore(vmp);
}
/*===========================================================================*
* fs_cancel *
*===========================================================================*/
void fs_cancel(struct vmnt *vmp)
{
/* Cancel all pending requests for this vmp */
struct worker_thread *worker;
while ((worker = vmp->m_comm.c_req_queue) != NULL) {
vmp->m_comm.c_req_queue = worker->w_next;
worker->w_next = NULL;
sending--;
worker_stop(worker);
}
}
/*===========================================================================*
* fs_sendmore *
*===========================================================================*/
void fs_sendmore(struct vmnt *vmp)
{
struct worker_thread *worker;
/* Can we send more requests? */
if (vmp->m_fs_e == NONE) return;
if ((worker = vmp->m_comm.c_req_queue) == NULL) /* No process is queued */
return;
if (vmp->m_comm.c_cur_reqs >= vmp->m_comm.c_max_reqs)/*No room to send more*/
return;
if (vmp->m_flags & VMNT_CALLBACK) /* Hold off for now */
return;
vmp->m_comm.c_req_queue = worker->w_next; /* Remove head */
worker->w_next = NULL;
sending--;
assert(sending >= 0);
sendmsg(vmp, worker->w_job.j_fp);
}
/*===========================================================================*
* fs_sendrec *
*===========================================================================*/
int fs_sendrec(endpoint_t fs_e, message *reqmp)
{
struct vmnt *vmp;
int r;
if ((vmp = find_vmnt(fs_e)) == NULL) {
printf("Trying to talk to non-existent FS endpoint %d\n", fs_e);
return(EIO);
}
if (fs_e == fp->fp_endpoint) return(EDEADLK);
if (!force_sync) {
fp->fp_sendrec = reqmp; /* Where to store request and reply */
/* Find out whether we can send right away or have to enqueue */
if ( !(vmp->m_flags & VMNT_CALLBACK) &&
vmp->m_comm.c_cur_reqs < vmp->m_comm.c_max_reqs) {
/* There's still room to send more and no proc is queued */
r = sendmsg(vmp, fp);
} else {
r = queuemsg(vmp);
}
self->w_next = NULL; /* End of list */
if (r != OK) return(r);
worker_wait(); /* Yield execution until we've received the reply. */
} else if (force_sync == 1) {
int r;
if (OK != (r = sendrec(fs_e, reqmp))) {
printf("VFS: sendrec failed: %d\n", r);
util_stacktrace();
return(r);
}
} else if (force_sync == 2) {
int r, status;
if (OK != (r = asynsend(fs_e, reqmp)) ||
OK != (r = receive(fs_e, reqmp, &status))) {
printf("VFS: asynrec failed: %d\n", r);
util_stacktrace();
return(r);
}
} else if (force_sync == 3) {
int r, status;
if (OK != (r = send(fs_e, reqmp)) ||
OK != (r = receive(fs_e, reqmp, &status))) {
printf("VFS: sendreceive failed: %d\n", r);
util_stacktrace();
return(r);
}
}
if (force_sync != 0 && reqmp->m_type > 0) {
/* XXX: Keep this as long as we're interested in having support
* for synchronous communication. */
nested_fs_call(reqmp);
return fs_sendrec(fs_e, reqmp);
}
return(reqmp->m_type);
}
/*===========================================================================*
* queuemsg *
*===========================================================================*/
static int queuemsg(struct vmnt *vmp)
{
/* Put request on queue for vmnt */
struct worker_thread *queue;
if (vmp->m_comm.c_req_queue == NULL) {
vmp->m_comm.c_req_queue = self;
} else {
/* Walk the list ... */
queue = vmp->m_comm.c_req_queue;
while (queue->w_next != NULL) queue = queue->w_next;
/* ... and append this worker */
queue->w_next = self;
}
self->w_next = NULL; /* End of list */
sending++;
return(OK);
}