wifi: ath: dfs_pattern_detector: Use flex array to simplify code

At the time of the writing, the value of 'num_radar_types' is 7 or 9. So
on a 64 bits system, only 56 or 72 bytes are allocated for the
'detectors' array.

Turn it into a flex array, in order to simplify memory management and save
an indirection when the array is used.

Doing so, cd->detectors can't be NULL, and channel_detector_exit() can be
simplified as well.

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Reviewed-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
Link: https://lore.kernel.org/r/1920cc38db2e570633e13b37d50852f3202a7270.1695538105.git.christophe.jaillet@wanadoo.fr

diff --git a/drivers/net/wireless/ath/dfs_pattern_detector.c b/drivers/net/wireless/ath/dfs_pattern_detector.c
index 2788a1b06c17cad6f9672e72b9a6be4f5921c4ea..700da9f4531e3ca69865de30bcea11422e101f35 100644 (file)
--- a/drivers/net/wireless/ath/dfs_pattern_detector.c
+++ b/drivers/net/wireless/ath/dfs_pattern_detector.c
@@ -161,7 +161,7 @@ get_dfs_domain_radar_types(enum nl80211_dfs_regions region)
 struct channel_detector {
        struct list_head head;
        u16 freq;
-       struct pri_detector **detectors;
+       struct pri_detector *detectors[];
 };
 
 /* channel_detector_reset() - reset detector lines for a given channel */
@@ -183,14 +183,13 @@ static void channel_detector_exit(struct dfs_pattern_detector *dpd,
        if (cd == NULL)
                return;
        list_del(&cd->head);
-       if (cd->detectors) {
-               for (i = 0; i < dpd->num_radar_types; i++) {
-                       struct pri_detector *de = cd->detectors[i];
-                       if (de != NULL)
-                               de->exit(de);
-               }
+
+       for (i = 0; i < dpd->num_radar_types; i++) {
+               struct pri_detector *de = cd->detectors[i];
+               if (de != NULL)
+                       de->exit(de);
        }
-       kfree(cd->detectors);
+
        kfree(cd);
 }
 
@@ -200,16 +199,12 @@ channel_detector_create(struct dfs_pattern_detector *dpd, u16 freq)
        u32 i;
        struct channel_detector *cd;
 
-       cd = kmalloc(sizeof(*cd), GFP_ATOMIC);
+       cd = kzalloc(struct_size(cd, detectors, dpd->num_radar_types), GFP_ATOMIC);
        if (cd == NULL)
                goto fail;
 
        INIT_LIST_HEAD(&cd->head);
        cd->freq = freq;
-       cd->detectors = kcalloc(dpd->num_radar_types,
-                                     sizeof(*cd->detectors), GFP_ATOMIC);
-       if (cd->detectors == NULL)
-               goto fail;
 
        for (i = 0; i < dpd->num_radar_types; i++) {
                const struct radar_detector_specs *rs = &dpd->radar_spec[i];