Re: [RFC PATCH net-next v6 04/14] af_vsock: generalize bind table functions

[Amery Hung <ameryhung@gmail.com>]

On Tue, Jul 30, 2024 at 1:00 AM Stefano Garzarella <sgarzare@redhat.com> wrote:
>
> On Sun, Jul 28, 2024 at 11:52:54AM GMT, Amery Hung wrote:
> >On Tue, Jul 23, 2024 at 7:40 AM Stefano Garzarella <sgarzare@redhat.com> wrote:
> >>
> >> On Wed, Jul 10, 2024 at 09:25:45PM GMT, Amery Hung wrote:
> >> >From: Bobby Eshleman <bobby.eshleman@bytedance.com>
> >> >
> >> >This commit makes the bind table management functions in vsock usable
> >> >for different bind tables. Future work will introduce a new table for
> >> >datagrams to avoid address collisions, and these functions will be used
> >> >there.
> >> >
> >> >Signed-off-by: Bobby Eshleman <bobby.eshleman@bytedance.com>
> >> >---
> >> > net/vmw_vsock/af_vsock.c | 34 +++++++++++++++++++++++++++-------
> >> > 1 file changed, 27 insertions(+), 7 deletions(-)
> >> >
> >> >diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
> >> >index acc15e11700c..d571be9cdbf0 100644
> >> >--- a/net/vmw_vsock/af_vsock.c
> >> >+++ b/net/vmw_vsock/af_vsock.c
> >> >@@ -232,11 +232,12 @@ static void __vsock_remove_connected(struct vsock_sock *vsk)
> >> >       sock_put(&vsk->sk);
> >> > }
> >> >
> >> >-static struct sock *__vsock_find_bound_socket(struct sockaddr_vm *addr)
> >> >+static struct sock *vsock_find_bound_socket_common(struct sockaddr_vm *addr,
> >> >+                                                 struct list_head *bind_table)
> >> > {
> >> >       struct vsock_sock *vsk;
> >> >
> >> >-      list_for_each_entry(vsk, vsock_bound_sockets(addr), bound_table) {
> >> >+      list_for_each_entry(vsk, bind_table, bound_table) {
> >> >               if (vsock_addr_equals_addr(addr, &vsk->local_addr))
> >> >                       return sk_vsock(vsk);
> >> >
> >> >@@ -249,6 +250,11 @@ static struct sock *__vsock_find_bound_socket(struct sockaddr_vm *addr)
> >> >       return NULL;
> >> > }
> >> >
> >> >+static struct sock *__vsock_find_bound_socket(struct sockaddr_vm *addr)
> >> >+{
> >> >+      return vsock_find_bound_socket_common(addr, vsock_bound_sockets(addr));
> >> >+}
> >> >+
> >> > static struct sock *__vsock_find_connected_socket(struct sockaddr_vm *src,
> >> >                                                 struct sockaddr_vm *dst)
> >> > {
> >> >@@ -671,12 +677,18 @@ static void vsock_pending_work(struct work_struct *work)
> >> >
> >> > /**** SOCKET OPERATIONS ****/
> >> >
> >> >-static int __vsock_bind_connectible(struct vsock_sock *vsk,
> >> >-                                  struct sockaddr_vm *addr)
> >> >+static int vsock_bind_common(struct vsock_sock *vsk,
> >> >+                           struct sockaddr_vm *addr,
> >> >+                           struct list_head *bind_table,
> >> >+                           size_t table_size)
> >> > {
> >> >       static u32 port;
> >> >       struct sockaddr_vm new_addr;
> >> >
> >> >+      if (WARN_ONCE(table_size < VSOCK_HASH_SIZE,
> >> >+                    "table size too small, may cause overflow"))
> >> >+              return -EINVAL;
> >> >+
> >>
> >> I'd add this in another commit.
> >>
> >> >       if (!port)
> >> >               port = get_random_u32_above(LAST_RESERVED_PORT);
> >> >
> >> >@@ -692,7 +704,8 @@ static int __vsock_bind_connectible(struct
> >> >vsock_sock *vsk,
> >> >
> >> >                       new_addr.svm_port = port++;
> >> >
> >> >-                      if (!__vsock_find_bound_socket(&new_addr)) {
> >> >+                      if (!vsock_find_bound_socket_common(&new_addr,
> >> >+                                                          &bind_table[VSOCK_HASH(addr)])) {
> >>
> >> Can we add a macro for `&bind_table[VSOCK_HASH(addr)])` ?
> >>
> >
> >Definitely. I will add the following macro:
> >
> >#define vsock_bound_sockets_in_table(bind_table, addr) \
> >        (&bind_table[VSOCK_HASH(addr)])
>
> yeah.
>
> >
> >> >                               found = true;
> >> >                               break;
> >> >                       }
> >> >@@ -709,7 +722,8 @@ static int __vsock_bind_connectible(struct vsock_sock *vsk,
> >> >                       return -EACCES;
> >> >               }
> >> >
> >> >-              if (__vsock_find_bound_socket(&new_addr))
> >> >+              if (vsock_find_bound_socket_common(&new_addr,
> >> >+                                                 &bind_table[VSOCK_HASH(addr)]))
> >> >                       return -EADDRINUSE;
> >> >       }
> >> >
> >> >@@ -721,11 +735,17 @@ static int __vsock_bind_connectible(struct vsock_sock *vsk,
> >> >        * by AF_UNIX.
> >> >        */
> >> >       __vsock_remove_bound(vsk);
> >> >-      __vsock_insert_bound(vsock_bound_sockets(&vsk->local_addr), vsk);
> >> >+      __vsock_insert_bound(&bind_table[VSOCK_HASH(&vsk->local_addr)], vsk);
> >> >
> >> >       return 0;
> >> > }
> >> >
> >> >+static int __vsock_bind_connectible(struct vsock_sock *vsk,
> >> >+                                  struct sockaddr_vm *addr)
> >> >+{
> >> >+      return vsock_bind_common(vsk, addr, vsock_bind_table, VSOCK_HASH_SIZE + 1);
> >>
> >> What about using ARRAY_SIZE(x) ?
> >>
> >> BTW we are using that size just to check it, but all the arrays we use
> >> are statically allocated, so what about a compile time check like
> >> BUILD_BUG_ON()?
> >>
> >
> >I will remove the table_size check you mentioned earlier and the
> >argument here as the arrays are allocated statically like you
> >mentioned.
> >
> >If you think this check may be a good addition, I can add a
> >BUILD_BUG_ON() in the new vsock_bound_sockets_in_table() macro.
>
> If you want to add it, we need to do it in a separate commit. But since
> we already have so many changes and both arrays are statically allocated
> in the same file, IMHO we can avoid the check.
>
> Stefano
>

Okay. I will not add the check.

Thanks,
Amery