[PATCH 1/1] mac80211: improve the contiguous mask checking
From: Zeng Zhaoxiu <hidden>
Date: 2015-12-17 15:00:55
Also in:
linux-wireless, lkml
Subsystem:
mac80211, the rest · Maintainers:
Johannes Berg, Linus Torvalds
If the result of adding the first set bit to the mask is power of 2, the mask must be contiguous. "mask & -mask" can get the first set bit of mask gracefully. Signed-off-by: Zeng Zhaoxiu <redacted> --- net/mac80211/iface.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/net/mac80211/iface.c b/net/mac80211/iface.c
index c9e325d..4c896e8 100644
--- a/net/mac80211/iface.c
+++ b/net/mac80211/iface.c@@ -1628,7 +1628,9 @@ static void ieee80211_assign_perm_addr(struct ieee80211_local *local, ((u64)m[2] << 3*8) | ((u64)m[3] << 2*8) | ((u64)m[4] << 1*8) | ((u64)m[5] << 0*8); - if (__ffs64(mask) + hweight64(mask) != fls64(mask)) { + inc = (mask & -mask); + val = mask + inc; + if ((val & (val - 1)) != 0) { /* not a contiguous mask ... not handled now! */ pr_info("not contiguous\n"); break;
@@ -1649,7 +1651,6 @@ static void ieee80211_assign_perm_addr(struct ieee80211_local *local, ((u64)m[2] << 3*8) | ((u64)m[3] << 2*8) | ((u64)m[4] << 1*8) | ((u64)m[5] << 0*8); - inc = 1ULL<<__ffs64(mask); val = (start & mask); addr = (start & ~mask) | (val & mask); do {
--
2.5.0