[PATCH bpf-next 1/2] net-tun: add type safety to tun_xdp_to_ptr() and tun_ptr_to_xdp()

[PATCH bpf-next 1/2] net-tun: add type safety to tun_xdp_to_ptr() and tun_ptr_to_xdp()

[Maciej Żenczykowski]

From: Maciej Żenczykowski <maze@google.com>

This reduces likelihood of incorrect use.

Test: builds
Signed-off-by: Maciej Żenczykowski <maze@google.com>
---
 drivers/net/tun.c      | 6 +++---
 include/linux/if_tun.h | 8 ++++----
 2 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 3c11a77f5709..5dd7f353eeef 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -225,13 +225,13 @@ bool tun_is_xdp_frame(void *ptr)
 }
 EXPORT_SYMBOL(tun_is_xdp_frame);
 
-void *tun_xdp_to_ptr(void *ptr)
+void *tun_xdp_to_ptr(struct xdp_frame *xdp)
 {
-	return (void *)((unsigned long)ptr | TUN_XDP_FLAG);
+	return (void *)((unsigned long)xdp | TUN_XDP_FLAG);
 }
 EXPORT_SYMBOL(tun_xdp_to_ptr);
 
-void *tun_ptr_to_xdp(void *ptr)
+struct xdp_frame *tun_ptr_to_xdp(void *ptr)
 {
 	return (void *)((unsigned long)ptr & ~TUN_XDP_FLAG);
 }
diff --git a/include/linux/if_tun.h b/include/linux/if_tun.h
index 5bda8cf457b6..6c37e1dbc5df 100644
--- a/include/linux/if_tun.h
+++ b/include/linux/if_tun.h
@@ -28,8 +28,8 @@ struct tun_xdp_hdr {
 struct socket *tun_get_socket(struct file *);
 struct ptr_ring *tun_get_tx_ring(struct file *file);
 bool tun_is_xdp_frame(void *ptr);
-void *tun_xdp_to_ptr(void *ptr);
-void *tun_ptr_to_xdp(void *ptr);
+void *tun_xdp_to_ptr(struct xdp_frame *xdp);
+struct xdp_frame *tun_ptr_to_xdp(void *ptr);
 void tun_ptr_free(void *ptr);
 #else
 #include <linux/err.h>
@@ -48,11 +48,11 @@ static inline bool tun_is_xdp_frame(void *ptr)
 {
 	return false;
 }
-static inline void *tun_xdp_to_ptr(void *ptr)
+static inline void *tun_xdp_to_ptr(struct xdp_frame *xdp)
 {
 	return NULL;
 }
-static inline void *tun_ptr_to_xdp(void *ptr)
+static inline struct xdp_frame *tun_ptr_to_xdp(void *ptr)
 {
 	return NULL;
 }
-- 
2.28.0.220.ged08abb693-goog

[PATCH bpf-next 2/2] net-tun: eliminate two tun/xdp related function calls from vhost-net

[Maciej Żenczykowski]

From: Maciej Żenczykowski <maze@google.com>

This provides a minor performance boost by virtue of inlining
instead of cross module function calls.

Test: builds
Signed-off-by: Maciej Żenczykowski <maze@google.com>
---
 drivers/net/tun.c      | 18 ------------------
 include/linux/if_tun.h | 15 ++++++++++++---
 2 files changed, 12 insertions(+), 21 deletions(-)

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 5dd7f353eeef..efaef83b8897 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -219,24 +219,6 @@ struct veth {
 	__be16 h_vlan_TCI;
 };
 
-bool tun_is_xdp_frame(void *ptr)
-{
-	return (unsigned long)ptr & TUN_XDP_FLAG;
-}
-EXPORT_SYMBOL(tun_is_xdp_frame);
-
-void *tun_xdp_to_ptr(struct xdp_frame *xdp)
-{
-	return (void *)((unsigned long)xdp | TUN_XDP_FLAG);
-}
-EXPORT_SYMBOL(tun_xdp_to_ptr);
-
-struct xdp_frame *tun_ptr_to_xdp(void *ptr)
-{
-	return (void *)((unsigned long)ptr & ~TUN_XDP_FLAG);
-}
-EXPORT_SYMBOL(tun_ptr_to_xdp);
-
 static int tun_napi_receive(struct napi_struct *napi, int budget)
 {
 	struct tun_file *tfile = container_of(napi, struct tun_file, napi);
diff --git a/include/linux/if_tun.h b/include/linux/if_tun.h
index 6c37e1dbc5df..2a7660843444 100644
--- a/include/linux/if_tun.h
+++ b/include/linux/if_tun.h
@@ -27,9 +27,18 @@ struct tun_xdp_hdr {
 #if defined(CONFIG_TUN) || defined(CONFIG_TUN_MODULE)
 struct socket *tun_get_socket(struct file *);
 struct ptr_ring *tun_get_tx_ring(struct file *file);
-bool tun_is_xdp_frame(void *ptr);
-void *tun_xdp_to_ptr(struct xdp_frame *xdp);
-struct xdp_frame *tun_ptr_to_xdp(void *ptr);
+static inline bool tun_is_xdp_frame(void *ptr)
+{
+       return (unsigned long)ptr & TUN_XDP_FLAG;
+}
+static inline void *tun_xdp_to_ptr(struct xdp_frame *xdp)
+{
+       return (void *)((unsigned long)xdp | TUN_XDP_FLAG);
+}
+static inline struct xdp_frame *tun_ptr_to_xdp(void *ptr)
+{
+       return (void *)((unsigned long)ptr & ~TUN_XDP_FLAG);
+}
 void tun_ptr_free(void *ptr);
 #else
 #include <linux/err.h>
-- 
2.28.0.220.ged08abb693-goog

Re: [PATCH bpf-next 1/2] net-tun: add type safety to tun_xdp_to_ptr() and tun_ptr_to_xdp()

[Alexei Starovoitov]

On Tue, Aug 18, 2020 at 6:07 PM Maciej Żenczykowski
<zenczykowski@gmail.com> wrote:
>
> From: Maciej Żenczykowski <maze@google.com>
>
> This reduces likelihood of incorrect use.
>
> Test: builds
> Signed-off-by: Maciej Żenczykowski <maze@google.com>

Applied. Thanks