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ath9k: dfs: remove accidental use of stack VLA

PATCH In review Gustavo A. R. Silva 2 participants 2 messages Mar 30, 2018 – Apr 10, 2018

Subsystems (3)
Networking Network drivers Qualcomm Atheros ATH9K wireless driver
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Gustavo A. R. Silva

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PATCH 1/1 ath9k: dfs: remove accidental use of stack VLA

In preparation to enabling -Wvla, remove accidental use of stack VLA.

This avoids an accidental stack VLA (since the compiler thinks the value of FFT_NUM_SAMPLES can change, even when marked "const"). This just replaces it with a #define.

Also, fixed as part of the directive to remove all VLAs from the kernel: https://lkml.org/lkml/2018/3/7/621

Signed-off-by Gustavo A. R. Silva <[email protected]>
---
 drivers/net/wireless/ath/ath9k/dfs.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)
drivers/net/wireless/ath/ath9k/dfs.c +3 -3
index 6fee9a4..c8844f5 100644
@@ -41,7 +41,7 @@ static const int BIN_DELTA_MAX		= 10;
 
 /* we need at least 3 deltas / 4 samples for a reliable chirp detection */
 #define NUM_DIFFS 3
-static const int FFT_NUM_SAMPLES	= (NUM_DIFFS + 1);
+#define FFT_NUM_SAMPLES		(NUM_DIFFS + 1)
 
 /* Threshold for difference of delta peaks */
 static const int MAX_DIFF		= 2;

@@ -114,7 +114,7 @@ static bool ath9k_check_chirping(struct ath_softc *sc, u8 *data,
 
 		ath_dbg(common, DFS, "HT40: datalen=%d, num_fft_packets=%d\n",
 			datalen, num_fft_packets);
-		if (num_fft_packets < (FFT_NUM_SAMPLES)) {
+		if (num_fft_packets < FFT_NUM_SAMPLES) {
 			ath_dbg(common, DFS, "not enough packets for chirp\n");
 			return false;
 		}

@@ -136,7 +136,7 @@ static bool ath9k_check_chirping(struct ath_softc *sc, u8 *data,
 			return false;
 		ath_dbg(common, DFS, "HT20: datalen=%d, num_fft_packets=%d\n",
 			datalen, num_fft_packets);
-		if (num_fft_packets < (FFT_NUM_SAMPLES)) {
+		if (num_fft_packets < FFT_NUM_SAMPLES) {
 			ath_dbg(common, DFS, "not enough packets for chirp\n");
 			return false;
 		}
Signature · 1 line
2.7.4
#1 lore raw
Quoted 11 lines · Gustavo A. R. Silva

In preparation to enabling -Wvla, remove accidental use of stack VLA.

This avoids an accidental stack VLA (since the compiler thinks the value of FFT_NUM_SAMPLES can change, even when marked "const"). This just replaces it with a #define.

Also, fixed as part of the directive to remove all VLAs from the kernel: https://lkml.org/lkml/2018/3/7/621

Signed-off-by Gustavo A. R. Silva <[email protected]>
Signed-off-by Kalle Valo <[email protected]>

Patch applied to ath-next branch of ath.git, thanks.

9c27489a3454 ath9k: dfs: remove accidental use of stack VLA

Signature · 3 lines
https://patchwork.kernel.org/patch/10318271/

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches