[PATCH 2/6] brcmfmac: fix scheduling while atomic issue when deleting flowring

[Alvin Šipraga]

From: Wright Feng <wright.feng@xxxxxxxxxxx>

We should not sleep while holding the spin lock. It makes
'scheduling while atomic' in brcmf_msgbuf_delete_flowring.
And to avoid race condition between deleting flowring and txflow,
we only hold spin lock when seting flowring status to RING_CLOSING.

Signed-off-by: Wright Feng <wright.feng@xxxxxxxxxxx>
Signed-off-by: Chi-Hsien Lin <chi-hsien.lin@xxxxxxxxxxx>
Signed-off-by: Ahmad Fatoum <a.fatoum@xxxxxxxxxxxxxx>
Signed-off-by: Alvin Šipraga <alsi@xxxxxxxxxxxxxxx>
---
 .../broadcom/brcm80211/brcmfmac/flowring.c         |  5 +----
 .../wireless/broadcom/brcm80211/brcmfmac/msgbuf.c  | 14 ++++++++------
 2 files changed, 9 insertions(+), 10 deletions(-)

diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/flowring.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/flowring.c
index 096f6b969dd8..e1127d7e086d 100644
--- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/flowring.c
+++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/flowring.c
@@ -419,7 +419,6 @@ void brcmf_flowring_configure_addr_mode(struct brcmf_flowring *flow, int ifidx,
 				flowid = flow->hash[i].flowid;
 				if (flow->rings[flowid]->status != RING_OPEN)
 					continue;
-				flow->rings[flowid]->status = RING_CLOSING;
 				brcmf_msgbuf_delete_flowring(drvr, flowid);
 			}
 		}
@@ -458,10 +457,8 @@ void brcmf_flowring_delete_peer(struct brcmf_flowring *flow, int ifidx,
 		if ((sta || (memcmp(hash[i].mac, peer, ETH_ALEN) == 0)) &&
 		    (hash[i].ifidx == ifidx)) {
 			flowid = flow->hash[i].flowid;
-			if (flow->rings[flowid]->status == RING_OPEN) {
-				flow->rings[flowid]->status = RING_CLOSING;
+			if (flow->rings[flowid]->status == RING_OPEN)
 				brcmf_msgbuf_delete_flowring(drvr, flowid);
-			}
 		}
 	}
 
diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/msgbuf.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/msgbuf.c
index 174584b42972..cec53f934940 100644
--- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/msgbuf.c
+++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/msgbuf.c
@@ -1400,22 +1400,24 @@ void brcmf_msgbuf_delete_flowring(struct brcmf_pub *drvr, u16 flowid)
 	struct brcmf_msgbuf *msgbuf = (struct brcmf_msgbuf *)drvr->proto->pd;
 	struct msgbuf_tx_flowring_delete_req *delete;
 	struct brcmf_commonring *commonring;
-	struct brcmf_commonring *commonring_del;
-
+	struct brcmf_commonring *commonring_del = msgbuf->flowrings[flowid];
+	struct brcmf_flowring *flow = msgbuf->flow;
 	void *ret_ptr;
 	u8 ifidx;
 	int err;
 	int retry = BRCMF_MAX_TXSTATUS_WAIT_RETRIES;
 
-	/* wait for commonring txflow finished */
-	commonring_del = msgbuf->flowrings[flowid];
+	/* make sure it is not in txflow */
 	brcmf_commonring_lock(commonring_del);
+	flow->rings[flowid]->status = RING_CLOSING;
+	brcmf_commonring_unlock(commonring_del);
+
+	/* wait for commonring txflow finished */
 	while (retry && atomic_read(&commonring_del->outstanding_tx)) {
 		usleep_range(5000, 10000);
 		retry--;
 	}
-	brcmf_commonring_unlock(commonring_del);
-	if (!retry && atomic_read(&commonring_del->outstanding_tx)) {
+	if (!retry) {
 		brcmf_err("timed out waiting for txstatus\n");
 		atomic_set(&commonring_del->outstanding_tx, 0);
 	}
-- 
2.37.0