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Rewrite pcu_sock_write() 

The code in that function is pretty rotten:
* osmo_fd_write_disable() is called for each message in the queue,
  there's no need for that. Let's simply call it at the end if the queue
  is empty.
* Asserting for obvious stuff like dequeue returning the first entry in
  the list.
* Having error code path for empty message: That shouldn't happen, abort
  immediately.

With all thse changes, the function is way simpler, easy to read and
more efficient.

Change-Id: I7ffff98cd8cdf2041bff486c3fde6f16365028d5
This commit is contained in:
Pau Espin 2023-03-15 17:25:59 +01:00
parent 50de553a1f
commit ca72961bbd
1 changed files with 11 additions and 25 deletions
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36
src/common/pcu_sock.c
View File

@ -28,6 +28,7 @@
#include <inttypes.h>
#include <osmocom/core/talloc.h>
#include <osmocom/core/utils.h>
#include <osmocom/core/select.h>
#include <osmocom/core/socket.h>
#include <osmocom/gsm/gsm23003.h>
@ -1087,48 +1088,33 @@ close:
static int pcu_sock_write(struct osmo_fd *bfd)
{
struct pcu_sock_state *state = bfd->data;
struct msgb *msg;
int rc;
while (!llist_empty(&state->upqueue)) {
struct msgb *msg, *msg2;
struct gsm_pcu_if *pcu_prim;
/* peek at the beginning of the queue */
msg = llist_entry(state->upqueue.next, struct msgb, list);
pcu_prim = (struct gsm_pcu_if *)msg->data;
osmo_fd_write_disable(bfd);
while ((msg = msgb_dequeue(&state->upqueue))) {
/* bug hunter 8-): maybe someone forgot msgb_put(...) ? */
if (!msgb_length(msg)) {
LOGP(DPCU, LOGL_ERROR, "message type (%d) with ZERO "
"bytes!\n", pcu_prim->msg_type);
goto dontsend;
}
OSMO_ASSERT(msgb_length(msg) > 0);
/* try to send it over the socket */
rc = write(bfd->fd, msgb_data(msg), msgb_length(msg));
if (rc == 0)
if (OSMO_UNLIKELY(rc == 0))
goto close;
if (rc < 0) {
if (OSMO_UNLIKELY(rc < 0)) {
if (errno == EAGAIN) {
osmo_fd_write_enable(bfd);
break;
/* Re-insert at the start of the queue, skip disabling fd WRITE */
llist_add(&msg->list, &state->upqueue);
return 0;
}
goto close;
}
dontsend:
/* _after_ we send it, we can deueue */
msg2 = msgb_dequeue(&state->upqueue);
assert(msg == msg2);
msgb_free(msg);
}
osmo_fd_write_disable(bfd);
return 0;
close:
msgb_free(msg);
pcu_sock_close(state);
return -1;
}