Add an interface for the user to notify the kernel that it is done
reading the NET_RX dmabuf pages returned as cmsg. The kernel will
drop the reference on the NET_RX pages to make them available for
re-use.
Signed-off-by: Willem de Bruijn <willemb@xxxxxxxxxx>
Signed-off-by: Kaiyuan Zhang <kaiyuanz@xxxxxxxxxx>
Signed-off-by: Mina Almasry <almasrymina@xxxxxxxxxx>
---
include/uapi/asm-generic/socket.h | 1 +
include/uapi/linux/uio.h | 4 ++++
net/core/sock.c | 36 +++++++++++++++++++++++++++++++
3 files changed, 41 insertions(+)
diff --git a/include/uapi/asm-generic/socket.h b/include/uapi/asm-generic/socket.h
index aacb97f16b78..eb93b43394d4 100644
--- a/include/uapi/asm-generic/socket.h
+++ b/include/uapi/asm-generic/socket.h
@@ -135,6 +135,7 @@
#define SO_PASSPIDFD 76
#define SO_PEERPIDFD 77
+#define SO_DEVMEM_DONTNEED 97
#define SO_DEVMEM_HEADER 98
#define SCM_DEVMEM_HEADER SO_DEVMEM_HEADER
#define SO_DEVMEM_OFFSET 99
diff --git a/include/uapi/linux/uio.h b/include/uapi/linux/uio.h
index ae94763b1963..71314bf41590 100644
--- a/include/uapi/linux/uio.h
+++ b/include/uapi/linux/uio.h
@@ -26,6 +26,10 @@ struct cmsg_devmem {
__u32 frag_token;
};
+struct devmemtoken {
+ __u32 token_start;
+ __u32 token_count;
+};
/*
* UIO_MAXIOV shall be at least 16 1003.1g (5.4.1.1)
*/
diff --git a/net/core/sock.c b/net/core/sock.c
index ab1e8d1bd5a1..2736b770a399 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -1049,6 +1049,39 @@ static int sock_reserve_memory(struct sock *sk, int bytes)
return 0;
}
+static noinline_for_stack int
+sock_devmem_dontneed(struct sock *sk, sockptr_t optval, unsigned int optlen)
+{
+ struct devmemtoken tokens[128];
+ unsigned int num_tokens, i, j;
+ int ret;
+
+ if (sk->sk_type != SOCK_STREAM || sk->sk_protocol != IPPROTO_TCP)
+ return -EBADF;
+
+ if (optlen % sizeof(struct devmemtoken) || optlen > sizeof(tokens))
+ return -EINVAL;
+
+ num_tokens = optlen / sizeof(struct devmemtoken);
+ if (copy_from_sockptr(tokens, optval, optlen))
+ return -EFAULT;
+
+ ret = 0;
+ for (i = 0; i < num_tokens; i++) {
+ for (j = 0; j < tokens[i].token_count; j++) {
+ struct page *page = xa_erase(&sk->sk_user_pages,
+ tokens[i].token_start + j);
+
+ if (page) {
+ page_pool_page_put_many(page, 1);
+ ret++;
+ }
+ }
+ }
+
+ return ret;
+}
+
void sockopt_lock_sock(struct sock *sk)
{
/* When current->bpf_ctx is set, the setsockopt is called from
@@ -1528,6 +1561,9 @@ int sk_setsockopt(struct sock *sk, int level, int optname,
WRITE_ONCE(sk->sk_txrehash, (u8)val);
break;
+ case SO_DEVMEM_DONTNEED:
+ ret = sock_devmem_dontneed(sk, optval, optlen);
+ break;
default:
ret = -ENOPROTOOPT;
break;
--
2.41.0.640.ga95def55d0-goog
