net: netprio: fix files lock and remove useless d_path bits
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>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/netprio_cgroup.c b/net/core/netprio_cgroup.c
index ed0c043..f65dba3 100644
--- a/net/core/netprio_cgroup.c
+++ b/net/core/netprio_cgroup.c
@@ -277,12 +277,6 @@
void net_prio_attach(struct cgroup *cgrp, struct cgroup_taskset *tset)
{
struct task_struct *p;
- char *tmp = kzalloc(sizeof(char) * PATH_MAX, GFP_KERNEL);
-
- if (!tmp) {
- pr_warn("Unable to attach cgrp due to alloc failure!\n");
- return;
- }
cgroup_taskset_for_each(p, cgrp, tset) {
unsigned int fd;
@@ -296,32 +290,24 @@
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);
}
static struct cftype ss_files[] = {