/*
* Return values:
* 0 : try and take the lock again in local memory
* -ret: return -ret
*/
int
lock_take_contention(cos_lock_t *l, union cos_lock_atomic_struct *result,
union cos_lock_atomic_struct *prev_val, u16_t owner)
{
int lock_id = l->lock_id;
spdid_t spdid = cos_spd_id();
int ret;
if (lock_component_pretake(spdid, lock_id, owner)) return -1;
/* Must access memory (be volatile) as we want
* to detect changes here */
if (owner != l->atom.c.owner) return 0;
/* Mark the lock as contested */
if (!l->atom.c.contested) {
result->c.contested = 1;
result->c.owner = owner;
if (!cos_cas((unsigned long*)&l->atom.v, prev_val->v, result->v)) return 0;
assert(l->atom.c.contested);
}
/* Note if a 1 is returned, there is a
* generation mismatch, and we just want to
* try and take the lock again anyway */
ret = lock_component_take(spdid, lock_id, owner);
return ret < 0 ? ret : 0;
}
static inline int block_ser_if_block_track_lock_component_take(spdid_t spdid,
ul_t lock_id,
u32_t thd_id)
{
int ret = 0;
struct track_block tb; // track on stack
do {
if (sched_component_take(cos_spd_id()))
BUG();
} while (0);
if (unlikely(!tracking_block_list[spdid].next)) {
INIT_LIST(&tracking_block_list[spdid], next, prev);
}
INIT_LIST(&tb, next, prev);
tb.lock_id = lock_id;
ADD_LIST(&tracking_block_list[spdid], &tb, next, prev);
do {
if (sched_component_release(cos_spd_id()))
BUG();
} while (0);
ret = lock_component_take(spdid, lock_id, thd_id);
do {
if (sched_component_take(cos_spd_id()))
BUG();
} while (0);
REM_LIST(&tb, next, prev);
do {
if (sched_component_release(cos_spd_id()))
BUG();
} while (0);
return ret;
}
