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authorJason A. Donenfeld <Jason@zx2c4.com>2019-06-28 16:27:10 +0200
committerJason A. Donenfeld <Jason@zx2c4.com>2019-06-28 16:27:10 +0200
commit3af247a663e3e81a9c4fb1919e764c024128b37c (patch)
tree906bd4ecacb75aceb18d5810a609cb147d533326
parenttimekeeping: rename fast getter functions to be consistent (diff)
downloadlinux-dev-jd/timekeeping.tar.xz
linux-dev-jd/timekeeping.zip
netlink: use 48 byte ctx instead of 6 signed longs for callbackjd/timekeeping
People are inclined to stuff random things into cb->args[n] because it looks like an array of integers. Sometimes people even put u64s in there with comments noting that a certain member takes up two slots. The horror! Really this should mirror the usage of skb->cb, which are just 48 opaque bytes suitable for casting a struct. Then people can create their usual casting macros for accessing strongly typed members of a struct. As a plus, this also gives us the same amount of space on 32bit and 64bit. Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> Cc: Johannes Berg <johannes@sipsolutions.net>
-rw-r--r--include/linux/netlink.h9
1 files changed, 8 insertions, 1 deletions
diff --git a/include/linux/netlink.h b/include/linux/netlink.h
index 593d1b9c33a8..205fa7b1f07a 100644
--- a/include/linux/netlink.h
+++ b/include/linux/netlink.h
@@ -192,7 +192,14 @@ struct netlink_callback {
bool strict_check;
u16 answer_flags;
unsigned int prev_seq, seq;
- long args[6];
+ union {
+ u8 ctx[48];
+
+ /* args is deprecated. Cast a struct over ctx instead
+ * for proper type safety.
+ */
+ long args[6];
+ };
};
struct netlink_notify {