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authorKarl Beldan <karl.beldan@rivierawaves.com>2013-11-13 10:54:19 +0100
committerJohannes Berg <johannes.berg@intel.com>2013-11-25 20:52:09 +0100
commitf7d8ad81ca8c447124821e58f876d1aff996c85f (patch)
tree27f1f34298ad2c6143f2919e684bc0b4e44411ef /net
parentmac80211: minstrel_ht: replace some occurences of MCS_GROUP_RATES (diff)
downloadlinux-f7d8ad81ca8c447124821e58f876d1aff996c85f.tar.xz
linux-f7d8ad81ca8c447124821e58f876d1aff996c85f.zip
mac80211: minstrels: spare numerous useless calls to get_random_bytes
ATM, only the first array value returned by get_random_bytes is used. This change moves the call to get_random_bytes from the nested loop it is in to its parent. While at it, replace get_random_bytes with prandom_bytes since PRNs are way enough for the selection process. After this, minstrel_ht reclaims 80 PR-bytes instead of 640 R-bytes. minstrels use sample tables to probe different rates in a randomized manner. minstrel_ht inits one single sample table upon registration (during subsys_initcalls) and minstrel uses one per STA addition in minstrel. Signed-off-by: Karl Beldan <karl.beldan@rivierawaves.com> Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Diffstat (limited to 'net')
-rw-r--r--net/mac80211/rc80211_minstrel.c3
-rw-r--r--net/mac80211/rc80211_minstrel_ht.c3
2 files changed, 2 insertions, 4 deletions
diff --git a/net/mac80211/rc80211_minstrel.c b/net/mac80211/rc80211_minstrel.c
index 7fa1b36e6202..d2f19f7e7091 100644
--- a/net/mac80211/rc80211_minstrel.c
+++ b/net/mac80211/rc80211_minstrel.c
@@ -422,10 +422,9 @@ init_sample_table(struct minstrel_sta_info *mi)
memset(mi->sample_table, 0xff, SAMPLE_COLUMNS * mi->n_rates);
for (col = 0; col < SAMPLE_COLUMNS; col++) {
+ prandom_bytes(rnd, sizeof(rnd));
for (i = 0; i < mi->n_rates; i++) {
- get_random_bytes(rnd, sizeof(rnd));
new_idx = (i + rnd[i & 7]) % mi->n_rates;
-
while (SAMPLE_TBL(mi, new_idx, col) != 0xff)
new_idx = (new_idx + 1) % mi->n_rates;
diff --git a/net/mac80211/rc80211_minstrel_ht.c b/net/mac80211/rc80211_minstrel_ht.c
index 0a4a7c78e814..e66e9f9fd0db 100644
--- a/net/mac80211/rc80211_minstrel_ht.c
+++ b/net/mac80211/rc80211_minstrel_ht.c
@@ -1051,10 +1051,9 @@ init_sample_table(void)
memset(sample_table, 0xff, sizeof(sample_table));
for (col = 0; col < SAMPLE_COLUMNS; col++) {
+ prandom_bytes(rnd, sizeof(rnd));
for (i = 0; i < MCS_GROUP_RATES; i++) {
- get_random_bytes(rnd, sizeof(rnd));
new_idx = (i + rnd[i]) % MCS_GROUP_RATES;
-
while (sample_table[col][new_idx] != 0xff)
new_idx = (new_idx + 1) % MCS_GROUP_RATES;