net: add napi_if_scheduled_mark_missed

The function napi_if_scheduled_mark_missed is used to check if the
NAPI context is scheduled, if so set NAPIF_STATE_MISSED and return
true. Used by the AF_XDP zero-copy i40e Tx code implementation in
order to make sure that irq affinity is honored by the napi context.

Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Magnus Karlsson 2018-08-28 14:44:28 +02:00 committed by Alexei Starovoitov
parent 9025403420
commit 6c5c958104
1 changed files with 26 additions and 0 deletions

View File

@ -535,6 +535,32 @@ static inline void napi_synchronize(const struct napi_struct *n)
barrier();
}
/**
* napi_if_scheduled_mark_missed - if napi is running, set the
* NAPIF_STATE_MISSED
* @n: NAPI context
*
* If napi is running, set the NAPIF_STATE_MISSED, and return true if
* NAPI is scheduled.
**/
static inline bool napi_if_scheduled_mark_missed(struct napi_struct *n)
{
unsigned long val, new;
do {
val = READ_ONCE(n->state);
if (val & NAPIF_STATE_DISABLE)
return true;
if (!(val & NAPIF_STATE_SCHED))
return false;
new = val | NAPIF_STATE_MISSED;
} while (cmpxchg(&n->state, val, new) != val);
return true;
}
enum netdev_queue_state_t {
__QUEUE_STATE_DRV_XOFF,
__QUEUE_STATE_STACK_XOFF,