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A small mini_receive() cleanup

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- this patch substitutes *xpp for sender to increase readability of
  mini_receive().

- makes sure that the dequeued sender has p_q_link == NULL and that
  this condition holds when enqueuing the sender again. 

- it 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 2010-05-07 11:22:49 +00:00
parent b8eddf00d8
commit 4f962b4798
1 changed files with 17 additions and 14 deletions
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31
kernel/proc.c
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@ -581,10 +581,10 @@ const int flags;
caller_ptr->p_sendto_e = dst_e; caller_ptr->p_sendto_e = dst_e;
/* Process is now blocked. Put in on the destination's queue. */ /* 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 */ xpp = &dst_ptr->p_caller_q; /* find end of list */
while (*xpp) xpp = &(*xpp)->p_q_link; while (*xpp) xpp = &(*xpp)->p_q_link;
*xpp = caller_ptr; /* add caller to end */ *xpp = caller_ptr; /* add caller to end */
caller_ptr->p_q_link = NULL; /* mark new end of list */
} }
return(OK); return(OK);
} }
@ -690,37 +690,40 @@ const int flags;
/* Check caller queue. Use pointer pointers to keep code simple. */ /* Check caller queue. Use pointer pointers to keep code simple. */
xpp = &caller_ptr->p_caller_q; xpp = &caller_ptr->p_caller_q;
while (*xpp) { 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; int call;
assert(!RTS_ISSET(*xpp, RTS_SLOT_FREE)); assert(!RTS_ISSET(sender, RTS_SLOT_FREE));
assert(!RTS_ISSET(*xpp, RTS_NO_ENDPOINT)); assert(!RTS_ISSET(sender, RTS_NO_ENDPOINT));
/* Found acceptable message. Copy it and update status. */ /* Found acceptable message. Copy it and update status. */
assert(!(caller_ptr->p_misc_flags & MF_DELIVERMSG)); assert(!(caller_ptr->p_misc_flags & MF_DELIVERMSG));
caller_ptr->p_delivermsg = (*xpp)->p_sendmsg; caller_ptr->p_delivermsg = sender->p_sendmsg;
caller_ptr->p_delivermsg.m_source = (*xpp)->p_endpoint; caller_ptr->p_delivermsg.m_source = sender->p_endpoint;
caller_ptr->p_misc_flags |= MF_DELIVERMSG; 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); IPC_STATUS_ADD_CALL(caller_ptr, call);
/* /*
* if the message is originaly from the kernel on behalf of this * if the message is originaly from the kernel on behalf of this
* process, we must send the status flags accordingly * 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); IPC_STATUS_ADD_FLAGS(caller_ptr, IPC_FLG_MSG_FROM_KERNEL);
/* we can clean the flag now, not need anymore */ /* 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) if (sender->p_misc_flags & MF_SIG_DELAY)
sig_delay_done(*xpp); 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 */ return(OK); /* report success */
} }
xpp = &(*xpp)->p_q_link; /* proceed to next */ xpp = &sender->p_q_link; /* proceed to next */
} }
} }