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net: ppp: consume ringbuf until it is empty

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ringbuf claim API returns pointer to contiguous area. In cases when data
in ringbuf wraps the end of internal buffer, then single call to claim
data is not enough to get all data - there is remaining part on the
beginning of internal buffer. Those remaining bytes will need to wait
for next ISR handler to trigger workqueue. Theoretically this means that
data on the beginning of ringbuf can wait there forever, or simply to
the next timeout in PPP stack when data traffic continues.

Consume data from ringbuf in a loop, stopping only when claiming results
in empty buffer. This will make sure that there is no stale data in the
ringbuf.

Signed-off-by: Marcin Niestroj <m.niestroj@grinn-global.com>
This commit is contained in:
Marcin Niestroj 2020-06-26 22:58:23 +02:00 • committed by Maureen Helm
commit 67f106820b
1 changed files with 15 additions and 4 deletions
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19
drivers/net/ppp.c
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@ -632,10 +632,8 @@ static int ppp_send(struct device *dev, struct net_pkt *pkt)
}
#if !defined(CONFIG_NET_TEST)
static void ppp_isr_cb_work(struct k_work *work)
static int ppp_consume_ringbuf(struct ppp_driver_context *ppp)
{
struct ppp_driver_context *ppp =
CONTAINER_OF(work, struct ppp_driver_context, cb_work);
uint8_t *data;
size_t len, tmp;
int ret;
@ -644,7 +642,7 @@ static void ppp_isr_cb_work(struct k_work *work)
CONFIG_NET_PPP_RINGBUF_SIZE);
if (len == 0) {
LOG_DBG("Ringbuf %p is empty!", &ppp->rx_ringbuf);
return;
return 0;
}
/* This will print too much data, enable only if really needed */
@ -667,6 +665,19 @@ static void ppp_isr_cb_work(struct k_work *work)
if (ret < 0) {
LOG_DBG("Cannot flush ring buffer (%d)", ret);
}
return -EAGAIN;
}
static void ppp_isr_cb_work(struct k_work *work)
{
struct ppp_driver_context *ppp =
CONTAINER_OF(work, struct ppp_driver_context, cb_work);
int ret = -EAGAIN;
while (ret == -EAGAIN) {
ret = ppp_consume_ringbuf(ppp);
}
}
#endif /* !CONFIG_NET_TEST */