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qcacmn: Perform napi state comparison before releasing napi lock

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Release napi spinlock only after performing napi state
comparison to avoid any race condition.

Change-Id: Icd7b713e474a818dfc6d0fa402496bbe06a3af66
CRs-Fixed: 2078294
This commit is contained in:
Poddar, Siddarth
2017-07-18 16:10:07 +05:30
committed by snandini
parent fc77960e38
commit 0efe289db5
1 changed files with 11 additions and 1 deletions
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12
hif/src/hif_napi.c
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@@ -410,6 +410,7 @@ int hif_napi_event(struct hif_opaque_softc *hif_ctx, enum qca_napi_event event,
int rc = 0;
uint32_t prev_state;
int i;
bool state_changed;
struct napi_struct *napi;
struct hif_softc *hif = HIF_GET_SOFTC(hif_ctx);
struct qca_napi_data *napid = &(hif->napi_data);
@@ -559,9 +560,18 @@ int hif_napi_event(struct hif_opaque_softc *hif_ctx, enum qca_napi_event event,
break;
} /* switch blacklist_pending */
/* we want to perform the comparison in lock:
* there is a possiblity of hif_napi_event get called
* from two different contexts (driver unload and cpu hotplug
* notification) and napid->state get changed
* in driver unload context and can lead to race condition
* in cpu hotplug context. Therefore, perform the napid->state
* comparison before releasing lock.
*/
state_changed = (prev_state != napid->state);
qdf_spin_unlock_bh(&(napid->lock));
if (prev_state != napid->state) {
if (state_changed) {
if (napid->state == ENABLE_NAPI_MASK) {
rc = 1;
for (i = 0; i < CE_COUNT_MAX; i++) {