net: netprio_cgroup: rework update socket logic

Instead of updating the sk_cgrp_prioidx struct field on every send
this only updates the field when a task is moved via cgroup
infrastructure.

This allows sockets that may be used by a kernel worker thread
to be managed. For example in the iscsi case today a user can
put iscsid in a netprio cgroup and control traffic will be sent
with the correct sk_cgrp_prioidx value set but as soon as data
is sent the kernel worker thread isssues a send and sk_cgrp_prioidx
is updated with the kernel worker threads value which is the
default case.

It seems more correct to only update the field when the user
explicitly sets it via control group infrastructure. This allows
the users to manage sockets that may be used with other threads.

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/include/linux/net.h b/include/linux/net.h
index dc95700de5dfcec249914f6d07f0acbc6adb4fa4..99276c3dc89aef2f3d2014ca87b427877247d6f8 100644 (file)
--- a/include/linux/net.h
+++ b/include/linux/net.h
@@ -248,6 +248,7 @@ extern int       sock_recvmsg(struct socket *sock, struct msghdr *msg,
                                  size_t size, int flags);
 extern int          sock_map_fd(struct socket *sock, int flags);
 extern struct socket *sockfd_lookup(int fd, int *err);
+extern struct socket *sock_from_file(struct file *file, int *err);
 #define                     sockfd_put(sock) fput(sock->file)
 extern int          net_ratelimit(void);
 

diff --git a/include/net/netprio_cgroup.h b/include/net/netprio_cgroup.h
index d58fdec47597bccc095a9da28066bd6b67acfc2f..2719dec6b5a8d32c6d36f818adc8ba006eabc02e 100644 (file)
--- a/include/net/netprio_cgroup.h
+++ b/include/net/netprio_cgroup.h
@@ -35,7 +35,7 @@ struct cgroup_netprio_state {
 extern int net_prio_subsys_id;
 #endif
 
-extern void sock_update_netprioidx(struct sock *sk);
+extern void sock_update_netprioidx(struct sock *sk, struct task_struct *task);
 
 #if IS_BUILTIN(CONFIG_NETPRIO_CGROUP)
 
@@ -82,7 +82,7 @@ static inline u32 task_netprioidx(struct task_struct *p)
 #endif /* CONFIG_NETPRIO_CGROUP */
 
 #else
-#define sock_update_netprioidx(sk)
+#define sock_update_netprioidx(sk, task)
 #endif
 
 #endif  /* _NET_CLS_CGROUP_H */

diff --git a/net/core/netprio_cgroup.c b/net/core/netprio_cgroup.c
index b2e9caa1ad1aa761ba98886a23ce3823bdc179ee..63d15e8f80e91c1f86461df2918d63cffeab5e8a 100644 (file)
--- a/net/core/netprio_cgroup.c
+++ b/net/core/netprio_cgroup.c
@@ -25,6 +25,8 @@
 #include <net/sock.h>
 #include <net/netprio_cgroup.h>
 
+#include <linux/fdtable.h>
+
 #define PRIOIDX_SZ 128
 
 static unsigned long prioidx_map[PRIOIDX_SZ];
@@ -272,6 +274,56 @@ out_free_devname:
        return ret;
 }
 
+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;
+               struct fdtable *fdt;
+               struct files_struct *files;
+
+               task_lock(p);
+               files = p->files;
+               if (!files) {
+                       task_unlock(p);
+                       continue;
+               }
+
+               rcu_read_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;
+
+                       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)
+                               sock_update_netprioidx(sock->sk, p);
+               }
+               rcu_read_unlock();
+               task_unlock(p);
+       }
+       kfree(tmp);
+}
+
 static struct cftype ss_files[] = {
        {
                .name = "prioidx",
@@ -289,6 +341,7 @@ struct cgroup_subsys net_prio_subsys = {
        .name           = "net_prio",
        .create         = cgrp_create,
        .destroy        = cgrp_destroy,
+       .attach         = net_prio_attach,
 #ifdef CONFIG_NETPRIO_CGROUP
        .subsys_id      = net_prio_subsys_id,
 #endif

diff --git a/net/core/sock.c b/net/core/sock.c
index 24039ac12426dbfaf3d16492bc802c2334e04cf3..2676a88f533e60d969b41f3ddf85313b6bd43a71 100644 (file)
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -1180,12 +1180,12 @@ void sock_update_classid(struct sock *sk)
 }
 EXPORT_SYMBOL(sock_update_classid);
 
-void sock_update_netprioidx(struct sock *sk)
+void sock_update_netprioidx(struct sock *sk, struct task_struct *task)
 {
        if (in_interrupt())
                return;
 
-       sk->sk_cgrp_prioidx = task_netprioidx(current);
+       sk->sk_cgrp_prioidx = task_netprioidx(task);
 }
 EXPORT_SYMBOL_GPL(sock_update_netprioidx);
 #endif
@@ -1215,7 +1215,7 @@ struct sock *sk_alloc(struct net *net, int family, gfp_t priority,
                atomic_set(&sk->sk_wmem_alloc, 1);
 
                sock_update_classid(sk);
-               sock_update_netprioidx(sk);
+               sock_update_netprioidx(sk, current);
        }
 
        return sk;

diff --git a/net/socket.c b/net/socket.c
index 0452dca4cd24d7e97923fa28cf8095453a1b71bc..dfe5b66c97e0bc836efed43ad080dec620301306 100644 (file)
--- a/net/socket.c
+++ b/net/socket.c
@@ -398,7 +398,7 @@ int sock_map_fd(struct socket *sock, int flags)
 }
 EXPORT_SYMBOL(sock_map_fd);
 
-static struct socket *sock_from_file(struct file *file, int *err)
+struct socket *sock_from_file(struct file *file, int *err)
 {
        if (file->f_op == &socket_file_ops)
                return file->private_data;      /* set in sock_map_fd */
@@ -406,6 +406,7 @@ static struct socket *sock_from_file(struct file *file, int *err)
        *err = -ENOTSOCK;
        return NULL;
 }
+EXPORT_SYMBOL(sock_from_file);
 
 /**
  *     sockfd_lookup - Go from a file number to its socket slot
@@ -554,8 +555,6 @@ static inline int __sock_sendmsg_nosec(struct kiocb *iocb, struct socket *sock,
 
        sock_update_classid(sock->sk);
 
-       sock_update_netprioidx(sock->sk);
-
        si->sock = sock;
        si->scm = NULL;
        si->msg = msg;