Merge branch 'xdp-a-fistful-of-generic-changes-pt-iii'

Alexander Lobakin says:

====================
xdp: a fistful of generic changes pt. III

XDP for idpf is currently 5.(6) chapters:
* convert Rx to libeth;
* convert Tx and stats to libeth;
* generic XDP and XSk code changes;
* generic XDP and XSk code additions pt. 1;
* generic XDP and XSk code additions pt. 2 (you are here);
* actual XDP for idpf via new libeth_xdp;
* XSk for idpf (via ^).

Part III.3 does the following:
* adds generic functions to build skbs from xdp_buffs (regular and
  XSk) and attach frags to xdp_buffs (regular and XSk);
* adds helper to optimize XSk xmit in drivers.

Everything is prereq for libeth_xdp, but will be useful standalone
as well: less code in drivers, faster XSk XDP_PASS, smaller object
code.
====================

Link: https://patch.msgid.link/20241218174435.1445282-1-aleksander.lobakin@intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 12 insertions, 4 deletions

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index b2509cd0b930..bb2b751d274a 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -608,11 +608,19 @@ struct skb_shared_info {
 	 * Warning : all fields before dataref are cleared in __alloc_skb()
 	 */
 	atomic_t	dataref;
-	unsigned int	xdp_frags_size;
 
-	/* Intermediate layers must ensure that destructor_arg
-	 * remains valid until skb destructor */
-	void *		destructor_arg;
+	union {
+		struct {
+			u32		xdp_frags_size;
+			u32		xdp_frags_truesize;
+		};
+
+		/*
+		 * Intermediate layers must ensure that destructor_arg
+		 * remains valid until skb destructor.
+		 */
+		void		*destructor_arg;
+	};
 
 	/* must be last field, see pskb_expand_head() */
 	skb_frag_t	frags[MAX_SKB_FRAGS];