Re: [PATCH v3] net: core: annotate socks of struct sock_reuseport with __counted_by

[Gustavo A. R. Silva]

On 01/08/24 08:23, Dmitry Antipov wrote:

According to '__reuseport_alloc()', annotate flexible array member
'sock' of 'struct sock_reuseport' with '__counted_by()' and use
convenient 'struct_size()' to simplify the math used in 'kzalloc()'.

Signed-off-by: Dmitry Antipov <dmanti...@yandex.ru>

Reviewed-by: Gustavo A. R. Silva <gustavo...@kernel.org>

Thanks
-Gustavo

---
v3: one more style nit (Jakub)
     https://lore.kernel.org/netdev/20240731165029.5f4b4...@kernel.org
v2: style (Jakub), title and commit message (Gustavo) adjustments
     https://lore.kernel.org/netdev/20240730170142.32a6e...@kernel.org
     
https://lore.kernel.org/netdev/c815078e-67f9-4235-b66c-29f8bdd1a...@embeddedor.com
---
  include/net/sock_reuseport.h | 2 +-
  net/core/sock_reuseport.c    | 5 ++---
  2 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/include/net/sock_reuseport.h b/include/net/sock_reuseport.h
index 6ec140b0a61b..6e4faf3ee76f 100644
--- a/include/net/sock_reuseport.h
+++ b/include/net/sock_reuseport.h
@@ -26,7 +26,7 @@ struct sock_reuseport {
        unsigned int            bind_inany:1;
        unsigned int            has_conns:1;
        struct bpf_prog __rcu   *prog;          /* optional BPF sock selector */
-       struct sock             *socks[];       /* array of sock pointers */
+       struct sock             *socks[] __counted_by(max_socks);
  };

extern int reuseport_alloc(struct sock *sk, bool bind_inany);

diff --git a/net/core/sock_reuseport.c b/net/core/sock_reuseport.c
index 5a165286e4d8..4211710393a8 100644
--- a/net/core/sock_reuseport.c
+++ b/net/core/sock_reuseport.c
@@ -173,10 +173,9 @@ static bool __reuseport_detach_closed_sock(struct sock *sk,

static struct sock_reuseport *__reuseport_alloc(unsigned int max_socks)

  {
-       unsigned int size = sizeof(struct sock_reuseport) +
-                     sizeof(struct sock *) * max_socks;
-       struct sock_reuseport *reuse = kzalloc(size, GFP_ATOMIC);
+       struct sock_reuseport *reuse;

+ reuse = kzalloc(struct_size(reuse, socks, max_socks), GFP_ATOMIC);

        if (!reuse)
                return NULL;