netdev - [PATCH 04/15] ath10k: fix gcc-10 zero-length-bounds warnings

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Date:   Thu, 30 Apr 2020 23:30:46 +0200
From:   Arnd Bergmann <arnd@...db.de>
To:     linux-kernel@...r.kernel.org, Kalle Valo <kvalo@...eaurora.org>,
        "David S. Miller" <davem@...emloft.net>,
        "Gustavo A. R. Silva" <gustavo@...eddedor.com>,
        Michal Kazior <michal.kazior@...to.com>
Cc:     Arnd Bergmann <arnd@...db.de>, Kalle Valo <kvalo@....qualcomm.com>,
        Maharaja Kennadyrajan <mkenna@...eaurora.org>,
        Wen Gong <wgong@...eaurora.org>,
        Erik Stromdahl <erik.stromdahl@...il.com>,
        ath10k@...ts.infradead.org, linux-wireless@...r.kernel.org,
        netdev@...r.kernel.org
Subject: [PATCH 04/15] ath10k: fix gcc-10 zero-length-bounds warnings

gcc-10 started warning about out-of-bounds access for zero-length
arrays:

In file included from drivers/net/wireless/ath/ath10k/core.h:18,
                 from drivers/net/wireless/ath/ath10k/htt_rx.c:8:
drivers/net/wireless/ath/ath10k/htt_rx.c: In function 'ath10k_htt_rx_tx_fetch_ind':
drivers/net/wireless/ath/ath10k/htt.h:1683:17: warning: array subscript 65535 is outside the bounds of an interior zero-length array 'struct htt_tx_fetch_record[0]' [-Wzero-length-bounds]
 1683 |  return (void *)&ind->records[le16_to_cpu(ind->num_records)];
      |                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/net/wireless/ath/ath10k/htt.h:1676:29: note: while referencing 'records'
 1676 |  struct htt_tx_fetch_record records[0];
      |                             ^~~~~~~

The structure was already converted to have a flexible-array member in
the past, but there are two zero-length members in the end and only
one of them can be a flexible-array member.

Swap the two around to avoid the warning, as 'resp_ids' is not accessed
in a way that causes a warning.

Fixes: 3ba225b506a2 ("treewide: Replace zero-length array with flexible-array member")
Fixes: 22e6b3bc5d96 ("ath10k: add new htt definitions")
Signed-off-by: Arnd Bergmann <arnd@...db.de>
---
 drivers/net/wireless/ath/ath10k/htt.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wireless/ath/ath10k/htt.h b/drivers/net/wireless/ath/ath10k/htt.h
index e7096a73c6ca..7621f0a3dc77 100644
--- a/drivers/net/wireless/ath/ath10k/htt.h
+++ b/drivers/net/wireless/ath/ath10k/htt.h
@@ -1673,8 +1673,8 @@ struct htt_tx_fetch_ind {
 	__le32 token;
 	__le16 num_resp_ids;
 	__le16 num_records;
-	struct htt_tx_fetch_record records[0];
-	__le32 resp_ids[]; /* ath10k_htt_get_tx_fetch_ind_resp_ids() */
+	__le32 resp_ids[0]; /* ath10k_htt_get_tx_fetch_ind_resp_ids() */
+	struct htt_tx_fetch_record records[];
 } __packed;
 
 static inline void *
-- 
2.26.0