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gen_stats.c: Duplicate xstats buffer for later use

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The gnet_stats_copy_app() function gets called, more often than not, with its
second argument a pointer to an automatic variable in the caller's stack.
Therefore, to avoid copying garbage afterwards when calling
gnet_stats_finish_copy(), this data is better copied to a dynamically allocated
memory that gets freed after use.

[xiyou.wangcong@gmail.com: remove a useless kfree()]

Signed-off-by: Ignacy Gawędzki <ignacy.gawedzki@green-communications.fr>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Ignacy Gawędzki 2015-02-13 14:47:05 -08:00 committed by David S. Miller
parent 5c2770079f
commit 1c4cff0cf5
1 changed files with 14 additions and 1 deletions
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15
net/core/gen_stats.c
View file

@ -32,6 +32,9 @@ gnet_stats_copy(struct gnet_dump *d, int type, void *buf, int size)
return 0;
nla_put_failure:
kfree(d->xstats);
d->xstats = NULL;
d->xstats_len = 0;
spin_unlock_bh(d->lock);
return -1;
}
@ -305,7 +308,9 @@ int
gnet_stats_copy_app(struct gnet_dump *d, void *st, int len)
{
if (d->compat_xstats) {
d->xstats = st;
d->xstats = kmemdup(st, len, GFP_ATOMIC);
if (!d->xstats)
goto err_out;
d->xstats_len = len;
}
@ -313,6 +318,11 @@ gnet_stats_copy_app(struct gnet_dump *d, void *st, int len)
return gnet_stats_copy(d, TCA_STATS_APP, st, len);
return 0;
err_out:
d->xstats_len = 0;
spin_unlock_bh(d->lock);
return -1;
}
EXPORT_SYMBOL(gnet_stats_copy_app);
@ -345,6 +355,9 @@ gnet_stats_finish_copy(struct gnet_dump *d)
return -1;
}
kfree(d->xstats);
d->xstats = NULL;
d->xstats_len = 0;
spin_unlock_bh(d->lock);
return 0;
}