Patchwork [net,v1,1/2] net: netprio: fix files lock and remove useless d_path bits

login
register
mail settings
Submitter John Fastabend
Date Aug. 14, 2012, 1:39 a.m.
Message ID <20120814013939.3144.13167.stgit@jf-dev1-dcblab>
Download mbox | patch
Permalink /patch/177150/
State Superseded
Delegated to: David Miller
Headers show

Comments

John Fastabend - Aug. 14, 2012, 1:39 a.m.
Add lock to prevent a race with a file closing and also remove
useless and ugly sscanf code. The extra code was never needed
and the case it supposedly protected against is in fact handled
correctly by sock_from_file as pointed out by Al Viro.

CC: Neil Horman <nhorman@tuxdriver.com>
Reported-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: John Fastabend <john.r.fastabend@intel.com>
---

 net/core/netprio_cgroup.c |   15 ++++-----------
 1 files changed, 4 insertions(+), 11 deletions(-)


--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Al Viro - Aug. 14, 2012, 2:29 a.m.
On Mon, Aug 13, 2012 at 06:39:39PM -0700, John Fastabend wrote:
> -			path = d_path(&file->f_path, tmp, PAGE_SIZE);

What's using tmp after that patch and do you still need to bother
allocating it?
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
John Fastabend - Aug. 14, 2012, 2:59 a.m.
On 8/13/2012 7:29 PM, Al Viro wrote:
> On Mon, Aug 13, 2012 at 06:39:39PM -0700, John Fastabend wrote:
>> -			path = d_path(&file->f_path, tmp, PAGE_SIZE);
>
> What's using tmp after that patch and do you still need to bother
> allocating it?
>

nothing removed it in v2.
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Patch

diff --git a/net/core/netprio_cgroup.c b/net/core/netprio_cgroup.c
index ed0c043..0323ec3 100644
--- a/net/core/netprio_cgroup.c
+++ b/net/core/netprio_cgroup.c
@@ -296,29 +296,22 @@  void net_prio_attach(struct cgroup *cgrp, struct cgroup_taskset *tset)
 			continue;
 		}
 
-		rcu_read_lock();
+		spin_lock(&files->file_lock);
 		fdt = files_fdtable(files);
 		for (fd = 0; fd < fdt->max_fds; fd++) {
-			char *path;
 			struct file *file;
 			struct socket *sock;
-			unsigned long s;
-			int rv, err = 0;
+			int err;
 
 			file = fcheck_files(files, fd);
 			if (!file)
 				continue;
 
-			path = d_path(&file->f_path, tmp, PAGE_SIZE);
-			rv = sscanf(path, "socket:[%lu]", &s);
-			if (rv <= 0)
-				continue;
-
 			sock = sock_from_file(file, &err);
-			if (!err)
+			if (sock)
 				sock_update_netprioidx(sock->sk, p);
 		}
-		rcu_read_unlock();
+		spin_unlock(&files->file_lock);
 		task_unlock(p);
 	}
 	kfree(tmp);