The patch titled
taskstats: cleanup reply assembling
has been added to the -mm tree. Its filename is
taskstats-cleanup-reply-assembling.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: taskstats: cleanup reply assembling
From: Oleg Nesterov <oleg@xxxxxxxxxx>
Thomas Graf wrote:
>
> nla_nest_start() may return NULL, either rely on prepare_reply() to be
> correct and BUG() on failure or do proper error handling for all
> functions.
nla_put() in taskstat.c can fail only if the 'size' argument of alloc_skb()
was not right. This is a kernel bug, we should not hide it. So add 'BUG()'
on error path and check for 'na == NULL'.
> genlmsg_cancel() is only required in error paths for dumping
> procedures.
So we can remove 'genlmsg_cancel()' calls and 'void *reply' (saves 227 bytes).
Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Thomas Graf <tgraf@xxxxxxx>
Cc: Shailabh Nagar <nagar@xxxxxxxxxxxxxx>
Cc: Balbir Singh <balbir@xxxxxxxxxx>
Cc: Jay Lan <jlan@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
kernel/taskstats.c | 38 ++++++++++++++++----------------------
1 files changed, 16 insertions(+), 22 deletions(-)
diff -puN kernel/taskstats.c~taskstats-cleanup-reply-assembling kernel/taskstats.c
--- a/kernel/taskstats.c~taskstats-cleanup-reply-assembling
+++ a/kernel/taskstats.c
@@ -69,7 +69,7 @@ enum actions {
};
static int prepare_reply(struct genl_info *info, u8 cmd, struct sk_buff **skbp,
- void **replyp, size_t size)
+ size_t size)
{
struct sk_buff *skb;
void *reply;
@@ -99,7 +99,6 @@ static int prepare_reply(struct genl_inf
}
*skbp = skb;
- *replyp = reply;
return 0;
}
@@ -356,11 +355,13 @@ static struct taskstats *mk_reply(struct
struct nlattr *na, *ret;
int aggr;
- aggr = TASKSTATS_TYPE_AGGR_TGID;
- if (type == TASKSTATS_TYPE_PID)
- aggr = TASKSTATS_TYPE_AGGR_PID;
+ aggr = (type == TASKSTATS_TYPE_PID)
+ ? TASKSTATS_TYPE_AGGR_PID
+ : TASKSTATS_TYPE_AGGR_TGID;
na = nla_nest_start(skb, aggr);
+ if (!na)
+ goto err;
if (nla_put(skb, type, sizeof(pid), &pid) < 0)
goto err;
ret = nla_reserve(skb, TASKSTATS_TYPE_STATS, sizeof(struct taskstats));
@@ -378,7 +379,6 @@ static int taskstats_user_cmd(struct sk_
int rc = 0;
struct sk_buff *rep_skb;
struct taskstats *stats;
- void *reply;
size_t size;
cpumask_t mask;
@@ -400,7 +400,7 @@ static int taskstats_user_cmd(struct sk_
size = nla_total_size(sizeof(u32)) +
nla_total_size(sizeof(struct taskstats)) + nla_total_size(0);
- rc = prepare_reply(info, TASKSTATS_CMD_NEW, &rep_skb, &reply, size);
+ rc = prepare_reply(info, TASKSTATS_CMD_NEW, &rep_skb, size);
if (rc < 0)
return rc;
@@ -409,27 +409,24 @@ static int taskstats_user_cmd(struct sk_
u32 pid = nla_get_u32(info->attrs[TASKSTATS_CMD_ATTR_PID]);
stats = mk_reply(rep_skb, TASKSTATS_TYPE_PID, pid);
if (!stats)
- goto nla_err;
+ goto err;
rc = fill_pid(pid, NULL, stats);
if (rc < 0)
- goto nla_err;
+ goto err;
} else if (info->attrs[TASKSTATS_CMD_ATTR_TGID]) {
u32 tgid = nla_get_u32(info->attrs[TASKSTATS_CMD_ATTR_TGID]);
stats = mk_reply(rep_skb, TASKSTATS_TYPE_TGID, tgid);
if (!stats)
- goto nla_err;
+ goto err;
rc = fill_tgid(tgid, NULL, stats);
if (rc < 0)
- goto nla_err;
+ goto err;
} else
goto err;
return send_reply(rep_skb, info->snd_pid);
-
-nla_err:
- genlmsg_cancel(rep_skb, reply);
err:
nlmsg_free(rep_skb);
return rc;
@@ -466,7 +463,6 @@ void taskstats_exit(struct task_struct *
struct listener_list *listeners;
struct taskstats *stats;
struct sk_buff *rep_skb;
- void *reply;
size_t size;
int is_thread_group;
@@ -491,17 +487,17 @@ void taskstats_exit(struct task_struct *
if (list_empty(&listeners->list))
return;
- rc = prepare_reply(NULL, TASKSTATS_CMD_NEW, &rep_skb, &reply, size);
+ rc = prepare_reply(NULL, TASKSTATS_CMD_NEW, &rep_skb, size);
if (rc < 0)
return;
stats = mk_reply(rep_skb, TASKSTATS_TYPE_PID, tsk->pid);
if (!stats)
- goto nla_err;
+ goto err;
rc = fill_pid(tsk->pid, tsk, stats);
if (rc < 0)
- goto nla_err;
+ goto err;
/*
* Doesn't matter if tsk is the leader or the last group member leaving
@@ -511,16 +507,14 @@ void taskstats_exit(struct task_struct *
stats = mk_reply(rep_skb, TASKSTATS_TYPE_TGID, tsk->tgid);
if (!stats)
- goto nla_err;
+ goto err;
memcpy(stats, tsk->signal->stats, sizeof(*stats));
send:
send_cpu_listeners(rep_skb, listeners);
return;
-
-nla_err:
- genlmsg_cancel(rep_skb, reply);
+err:
nlmsg_free(rep_skb);
}
_
Patches currently in -mm which might be from oleg@xxxxxxxxxx are
origin.patch
taskstats_exit_alloc-optimize-simplify.patch
taskstats-cleanup-do_exit-path.patch
taskstats-cleanup-signal-stats-allocation.patch
taskstats-factor-out-reply-assembling.patch
taskstats-use-nla_reserve-for-reply-assembling.patch
taskstats-cleanup-reply-assembling.patch
tty-signal-tty-locking.patch
do_task_stat-dont-take-tty_mutex.patch
do_acct_process-dont-take-tty_mutex.patch
trivial-make-set_special_pids-static.patch
sys_unshare-remove-a-broken-clone_sighand-code.patch
sys_setpgid-eliminate-unnecessary-do_each_task_pidpidtype_pgid.patch
session_of_pgrp-kill-unnecessary-do_each_task_pidpidtype_pgid.patch
pidhash-temporary-debug-checks.patch
-
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