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Re: [PATCH v1] ath5k: fix WARNING opportunity for swap.

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On 8/14/2023 3:28 PM, Jeff Johnson wrote:
On 8/14/2023 1:02 PM, Mahmoud Maatuq wrote:
coccinielle reported the following:
./drivers/net/wireless/ath/ath5k/phy.c:1573:25-26: WARNING opportunity for swap()

Suggest you add something like:

This revealed that ath5k_hw_get_median_noise_floor() had open-coded sort() functionality. Since ath5k_hw_get_median_noise_floor() only executes once every 10 seconds, any extra overhead due to sort() calling it's "compare" and "swap" functions can be ignored, so replace the

<blush> and of course that should be its and not it's </blush>

existing logic with a call to sort().

and before your SOB add:
Suggested-by: Jiri Slaby <jirislaby@xxxxxxxxxx>

Signed-off-by: Mahmoud Maatuq <mahmoudmatook.mm@xxxxxxxxx>
---
changes in v1:
- replace the entire double loop with sort()
   as suggested by Jiri Slaby <jirislaby@xxxxxxxxxx>
---
  drivers/net/wireless/ath/ath5k/phy.c | 29 +++++++++++++---------------
  1 file changed, 13 insertions(+), 16 deletions(-)

diff --git a/drivers/net/wireless/ath/ath5k/phy.c b/drivers/net/wireless/ath/ath5k/phy.c
index 5797ef9c73d7..7ee4e1616f45 100644
--- a/drivers/net/wireless/ath/ath5k/phy.c
+++ b/drivers/net/wireless/ath/ath5k/phy.c
@@ -26,6 +26,7 @@
  #include <linux/delay.h>
  #include <linux/slab.h>
+#include <linux/sort.h>
  #include <asm/unaligned.h>
  #include "ath5k.h"
@@ -1554,6 +1555,11 @@ static void ath5k_hw_update_nfcal_hist(struct ath5k_hw *ah, s16 noise_floor)
      hist->nfval[hist->index] = noise_floor;
  }
+static int cmps16(const void *a, const void *b)
+{
+    return *(s16 *)a - *(s16 *)b;
+}
+
  /**
   * ath5k_hw_get_median_noise_floor() - Get median NF from history buffer
   * @ah: The &struct ath5k_hw
@@ -1561,25 +1567,16 @@ static void ath5k_hw_update_nfcal_hist(struct ath5k_hw *ah, s16 noise_floor)
  static s16
  ath5k_hw_get_median_noise_floor(struct ath5k_hw *ah)
  {
-    s16 sort[ATH5K_NF_CAL_HIST_MAX];
-    s16 tmp;
-    int i, j;
-
-    memcpy(sort, ah->ah_nfcal_hist.nfval, sizeof(sort));
-    for (i = 0; i < ATH5K_NF_CAL_HIST_MAX - 1; i++) {
-        for (j = 1; j < ATH5K_NF_CAL_HIST_MAX - i; j++) {
-            if (sort[j] > sort[j - 1]) {
-                tmp = sort[j];
-                sort[j] = sort[j - 1];
-                sort[j - 1] = tmp;
-            }
-        }
-    }
+    s16 sorted_nfval[ATH5K_NF_CAL_HIST_MAX];
+    int i;
+
+    memcpy(sorted_nfval, ah->ah_nfcal_hist.nfval, sizeof(sorted_nfval));
+    sort(sorted_nfval, ATH5K_NF_CAL_HIST_MAX, sizeof(s16), cmps16, NULL);
      for (i = 0; i < ATH5K_NF_CAL_HIST_MAX; i++) {
          ATH5K_DBG(ah, ATH5K_DEBUG_CALIBRATE,
-            "cal %d:%d\n", i, sort[i]);
+            "cal %d:%d\n", i, sorted_nfval[i]);
      }
-    return sort[(ATH5K_NF_CAL_HIST_MAX - 1) / 2];
+    return sorted_nfval[(ATH5K_NF_CAL_HIST_MAX - 1) / 2];
  }
  /**





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