Goal of this patch is to use the new libnl API to align netlink attribute
when needed.
The layout of the netlink message will be a bit different after the patch,
because the padattr (TASKSTATS_TYPE_STATS) will be inside the nested
attribute instead of before it.
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@xxxxxxxxx>
---
kernel/taskstats.c | 37 +++++--------------------------------
1 file changed, 5 insertions(+), 32 deletions(-)
diff --git a/kernel/taskstats.c b/kernel/taskstats.c
index 21f82c29c914..b3f05ee20d18 100644
--- a/kernel/taskstats.c
+++ b/kernel/taskstats.c
@@ -357,10 +357,6 @@ static int parse(struct nlattr *na, struct cpumask *mask)
return ret;
}
-#if defined(CONFIG_64BIT) && !defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)
-#define TASKSTATS_NEEDS_PADDING 1
-#endif
-
static struct taskstats *mk_reply(struct sk_buff *skb, int type, u32 pid)
{
struct nlattr *na, *ret;
@@ -370,29 +366,6 @@ static struct taskstats *mk_reply(struct sk_buff *skb, int type, u32 pid)
? TASKSTATS_TYPE_AGGR_PID
: TASKSTATS_TYPE_AGGR_TGID;
- /*
- * The taskstats structure is internally aligned on 8 byte
- * boundaries but the layout of the aggregrate reply, with
- * two NLA headers and the pid (each 4 bytes), actually
- * force the entire structure to be unaligned. This causes
- * the kernel to issue unaligned access warnings on some
- * architectures like ia64. Unfortunately, some software out there
- * doesn't properly unroll the NLA packet and assumes that the start
- * of the taskstats structure will always be 20 bytes from the start
- * of the netlink payload. Aligning the start of the taskstats
- * structure breaks this software, which we don't want. So, for now
- * the alignment only happens on architectures that require it
- * and those users will have to update to fixed versions of those
- * packages. Space is reserved in the packet only when needed.
- * This ifdef should be removed in several years e.g. 2012 once
- * we can be confident that fixed versions are installed on most
- * systems. We add the padding before the aggregate since the
- * aggregate is already a defined type.
- */
-#ifdef TASKSTATS_NEEDS_PADDING
- if (nla_put(skb, TASKSTATS_TYPE_NULL, 0, NULL) < 0)
- goto err;
-#endif
na = nla_nest_start(skb, aggr);
if (!na)
goto err;
@@ -401,7 +374,8 @@ static struct taskstats *mk_reply(struct sk_buff *skb, int type, u32 pid)
nla_nest_cancel(skb, na);
goto err;
}
- ret = nla_reserve(skb, TASKSTATS_TYPE_STATS, sizeof(struct taskstats));
+ ret = nla_reserve_64bit(skb, TASKSTATS_TYPE_STATS,
+ sizeof(struct taskstats), TASKSTATS_TYPE_NULL);
if (!ret) {
nla_nest_cancel(skb, na);
goto err;
@@ -500,10 +474,9 @@ static size_t taskstats_packet_size(void)
size_t size;
size = nla_total_size(sizeof(u32)) +
- nla_total_size(sizeof(struct taskstats)) + nla_total_size(0);
-#ifdef TASKSTATS_NEEDS_PADDING
- size += nla_total_size(0); /* Padding for alignment */
-#endif
+ nla_total_size_64bit(sizeof(struct taskstats)) +
+ nla_total_size(0);
+
return size;
}
--
2.8.1
--
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