[PATCH v5] wifi: ath11k: Fix NULL pointer check in ath11k_ce_rx_post_pipe()

[Baichuan Qi <zghbqbc@gmail.com>]

Current implementation of `ath11k_ce_rx_post_pipe()` checks for
NON-NULL of either `dest_ring` or `status_ring` using an OR (||).
Both rings, especially `dest_ring`, should be ensured to be
NON-NULL in this function.

If only one of the rings is valid, such as `dest_ring` is NULL
and `status_ring` is NON-NULL, the OR (||) check would not stop
`ath11k_ce_rx_post_pipe()`, the subsequent call to
`ath11k_ce_rx_buf_enqueue_pipe()` will access the NULL pointer,
resulting in a driver crash.

Fix the NON-NULL check by changing the OR (||) to AND (&&),
and return an error code `-EIO` to indicate
`ath11k_ce_rx_post_pipe()` is stopped with an NULL pointer 
error, ensuring that the function only proceeds when both 
`dest_ring` and `status_ring` are NON-NULL.

Link: https://lore.kernel.org/ath11k/a9ccc947-20b2-4322-84e5-c96aaa604e63@web.de
Fixes: d5c65159f289 ("ath11k: driver for Qualcomm IEEE 802.11ax devices")
Signed-off-by: Baichuan Qi <zghbqbc@gmail.com>
---
V4 -> V5: add err code in NULL check
V3 -> V4: reorder describe info
V2 -> V3: add Link URL to mailing list archives
V1 -> V2: rewrite commit message and fix tag

 drivers/net/wireless/ath/ath11k/ce.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wireless/ath/ath11k/ce.c b/drivers/net/wireless/ath/ath11k/ce.c
index e66e86bdec20..223dab928453 100644
--- a/drivers/net/wireless/ath/ath11k/ce.c
+++ b/drivers/net/wireless/ath/ath11k/ce.c
@@ -324,8 +324,10 @@ static int ath11k_ce_rx_post_pipe(struct ath11k_ce_pipe *pipe)
 	dma_addr_t paddr;
 	int ret = 0;
 
-	if (!(pipe->dest_ring || pipe->status_ring))
-		return 0;
+	if (!(pipe->dest_ring && pipe->status_ring)) {
+		ret = -EIO;
+		return ret;
+	}
 
 	spin_lock_bh(&ab->ce.ce_lock);
 	while (pipe->rx_buf_needed) {
-- 
2.34.1