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mini_receive() clean up

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- for better readability xpp is substitued by sender

- makes sure that the dequeued sender has p_q_link == NULL and that
  this condition holds when enqueuing the sender again. This is a
  sanity check to make sure that the new sender is not enqueued
  already

- Before this change the dequeued sender's p_q_link may not be NULL
  and it was only set to NULL when enqueued again
This commit is contained in:
Tomas Hruby 2010-06-23 10:36:19 +00:00
parent 921bacd244
commit 76708e9bf4
1 changed files with 17 additions and 14 deletions
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31
kernel/proc.c
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@ -588,10 +588,10 @@ PUBLIC int mini_send(
caller_ptr->p_sendto_e = dst_e;
/* Process is now blocked. Put in on the destination's queue. */
assert(caller_ptr->p_q_link == NULL);
xpp = &dst_ptr->p_caller_q; /* find end of list */
while (*xpp) xpp = &(*xpp)->p_q_link;
*xpp = caller_ptr; /* add caller to end */
caller_ptr->p_q_link = NULL; /* mark new end of list */
}
return(OK);
}
@ -689,37 +689,40 @@ PRIVATE int mini_receive(struct proc * caller_ptr,
/* Check caller queue. Use pointer pointers to keep code simple. */
xpp = &caller_ptr->p_caller_q;
while (*xpp) {
if (src_e == ANY || src_p == proc_nr(*xpp)) {
struct proc * sender = *xpp;
if (src_e == ANY || src_p == proc_nr(sender)) {
int call;
assert(!RTS_ISSET(*xpp, RTS_SLOT_FREE));
assert(!RTS_ISSET(*xpp, RTS_NO_ENDPOINT));
assert(!RTS_ISSET(sender, RTS_SLOT_FREE));
assert(!RTS_ISSET(sender, RTS_NO_ENDPOINT));
/* Found acceptable message. Copy it and update status. */
assert(!(caller_ptr->p_misc_flags & MF_DELIVERMSG));
caller_ptr->p_delivermsg = (*xpp)->p_sendmsg;
caller_ptr->p_delivermsg.m_source = (*xpp)->p_endpoint;
caller_ptr->p_delivermsg = sender->p_sendmsg;
caller_ptr->p_delivermsg.m_source = sender->p_endpoint;
caller_ptr->p_misc_flags |= MF_DELIVERMSG;
RTS_UNSET(*xpp, RTS_SENDING);
RTS_UNSET(sender, RTS_SENDING);
call = ((*xpp)->p_misc_flags & MF_REPLY_PEND ? SENDREC : SEND);
call = (sender->p_misc_flags & MF_REPLY_PEND ? SENDREC : SEND);
IPC_STATUS_ADD_CALL(caller_ptr, call);
/*
* if the message is originaly from the kernel on behalf of this
* process, we must send the status flags accordingly
*/
if ((*xpp)->p_misc_flags & MF_SENDING_FROM_KERNEL) {
if (sender->p_misc_flags & MF_SENDING_FROM_KERNEL) {
IPC_STATUS_ADD_FLAGS(caller_ptr, IPC_FLG_MSG_FROM_KERNEL);
/* we can clean the flag now, not need anymore */
(*xpp)->p_misc_flags &= ~MF_SENDING_FROM_KERNEL;
sender->p_misc_flags &= ~MF_SENDING_FROM_KERNEL;
}
if ((*xpp)->p_misc_flags & MF_SIG_DELAY)
sig_delay_done(*xpp);
if (sender->p_misc_flags & MF_SIG_DELAY)
sig_delay_done(sender);
*xpp = (*xpp)->p_q_link; /* remove from queue */
*xpp = sender->p_q_link; /* remove from queue */
sender->p_q_link = NULL;
return(OK); /* report success */
}
xpp = &(*xpp)->p_q_link; /* proceed to next */
xpp = &sender->p_q_link; /* proceed to next */
}
}