[PATCH net-next v2 05/18] xdp, xsk: constify read-only arguments of some static inline helpers

[Alexander Lobakin <aleksander.lobakin@intel.com>]

Lots of read-only helpers for &xdp_buff and &xdp_frame, such as getting
the frame length, skb_shared_info etc., don't have their arguments
marked with `const` for no reason. Add the missing annotations to leave
less place for mistakes and more for optimization.

Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
---
 include/net/xdp.h           | 29 +++++++++++++++++------------
 include/net/xdp_sock_drv.h  | 11 ++++++-----
 include/net/xsk_buff_pool.h |  2 +-
 3 files changed, 24 insertions(+), 18 deletions(-)

diff --git a/include/net/xdp.h b/include/net/xdp.h
index e6770dd40c91..197808df1ee1 100644
--- a/include/net/xdp.h
+++ b/include/net/xdp.h
@@ -88,7 +88,7 @@ struct xdp_buff {
 	u32 flags; /* supported values defined in xdp_buff_flags */
 };
 
-static __always_inline bool xdp_buff_has_frags(struct xdp_buff *xdp)
+static __always_inline bool xdp_buff_has_frags(const struct xdp_buff *xdp)
 {
 	return !!(xdp->flags & XDP_FLAGS_HAS_FRAGS);
 }
@@ -103,7 +103,8 @@ static __always_inline void xdp_buff_clear_frags_flag(struct xdp_buff *xdp)
 	xdp->flags &= ~XDP_FLAGS_HAS_FRAGS;
 }
 
-static __always_inline bool xdp_buff_is_frag_pfmemalloc(struct xdp_buff *xdp)
+static __always_inline bool
+xdp_buff_is_frag_pfmemalloc(const struct xdp_buff *xdp)
 {
 	return !!(xdp->flags & XDP_FLAGS_FRAGS_PF_MEMALLOC);
 }
@@ -144,15 +145,16 @@ xdp_prepare_buff(struct xdp_buff *xdp, unsigned char *hard_start,
 	 SKB_DATA_ALIGN(sizeof(struct skb_shared_info)))
 
 static inline struct skb_shared_info *
-xdp_get_shared_info_from_buff(struct xdp_buff *xdp)
+xdp_get_shared_info_from_buff(const struct xdp_buff *xdp)
 {
 	return (struct skb_shared_info *)xdp_data_hard_end(xdp);
 }
 
-static __always_inline unsigned int xdp_get_buff_len(struct xdp_buff *xdp)
+static __always_inline unsigned int
+xdp_get_buff_len(const struct xdp_buff *xdp)
 {
 	unsigned int len = xdp->data_end - xdp->data;
-	struct skb_shared_info *sinfo;
+	const struct skb_shared_info *sinfo;
 
 	if (likely(!xdp_buff_has_frags(xdp)))
 		goto out;
@@ -177,12 +179,13 @@ struct xdp_frame {
 	u32 flags; /* supported values defined in xdp_buff_flags */
 };
 
-static __always_inline bool xdp_frame_has_frags(struct xdp_frame *frame)
+static __always_inline bool xdp_frame_has_frags(const struct xdp_frame *frame)
 {
 	return !!(frame->flags & XDP_FLAGS_HAS_FRAGS);
 }
 
-static __always_inline bool xdp_frame_is_frag_pfmemalloc(struct xdp_frame *frame)
+static __always_inline bool
+xdp_frame_is_frag_pfmemalloc(const struct xdp_frame *frame)
 {
 	return !!(frame->flags & XDP_FLAGS_FRAGS_PF_MEMALLOC);
 }
@@ -201,7 +204,7 @@ static __always_inline void xdp_frame_bulk_init(struct xdp_frame_bulk *bq)
 }
 
 static inline struct skb_shared_info *
-xdp_get_shared_info_from_frame(struct xdp_frame *frame)
+xdp_get_shared_info_from_frame(const struct xdp_frame *frame)
 {
 	void *data_hard_start = frame->data - frame->headroom - sizeof(*frame);
 
@@ -249,7 +252,8 @@ int xdp_alloc_skb_bulk(void **skbs, int n_skb, gfp_t gfp);
 struct xdp_frame *xdpf_clone(struct xdp_frame *xdpf);
 
 static inline
-void xdp_convert_frame_to_buff(struct xdp_frame *frame, struct xdp_buff *xdp)
+void xdp_convert_frame_to_buff(const struct xdp_frame *frame,
+			       struct xdp_buff *xdp)
 {
 	xdp->data_hard_start = frame->data - frame->headroom - sizeof(*frame);
 	xdp->data = frame->data;
@@ -260,7 +264,7 @@ void xdp_convert_frame_to_buff(struct xdp_frame *frame, struct xdp_buff *xdp)
 }
 
 static inline
-int xdp_update_frame_from_buff(struct xdp_buff *xdp,
+int xdp_update_frame_from_buff(const struct xdp_buff *xdp,
 			       struct xdp_frame *xdp_frame)
 {
 	int metasize, headroom;
@@ -317,9 +321,10 @@ void xdp_flush_frame_bulk(struct xdp_frame_bulk *bq);
 void xdp_return_frame_bulk(struct xdp_frame *xdpf,
 			   struct xdp_frame_bulk *bq);
 
-static __always_inline unsigned int xdp_get_frame_len(struct xdp_frame *xdpf)
+static __always_inline unsigned int
+xdp_get_frame_len(const struct xdp_frame *xdpf)
 {
-	struct skb_shared_info *sinfo;
+	const struct skb_shared_info *sinfo;
 	unsigned int len = xdpf->len;
 
 	if (likely(!xdp_frame_has_frags(xdpf)))
diff --git a/include/net/xdp_sock_drv.h b/include/net/xdp_sock_drv.h
index 40085afd9160..f3175a5d28f7 100644
--- a/include/net/xdp_sock_drv.h
+++ b/include/net/xdp_sock_drv.h
@@ -101,7 +101,7 @@ static inline struct xdp_buff *xsk_buff_alloc(struct xsk_buff_pool *pool)
 	return xp_alloc(pool);
 }
 
-static inline bool xsk_is_eop_desc(struct xdp_desc *desc)
+static inline bool xsk_is_eop_desc(const struct xdp_desc *desc)
 {
 	return !xp_mb_desc(desc);
 }
@@ -143,7 +143,7 @@ static inline void xsk_buff_add_frag(struct xdp_buff *xdp)
 	list_add_tail(&frag->list_node, &frag->pool->xskb_list);
 }
 
-static inline struct xdp_buff *xsk_buff_get_frag(struct xdp_buff *first)
+static inline struct xdp_buff *xsk_buff_get_frag(const struct xdp_buff *first)
 {
 	struct xdp_buff_xsk *xskb = container_of(first, struct xdp_buff_xsk, xdp);
 	struct xdp_buff *ret = NULL;
@@ -200,7 +200,8 @@ static inline void *xsk_buff_raw_get_data(struct xsk_buff_pool *pool, u64 addr)
 		XDP_TXMD_FLAGS_CHECKSUM | \
 	0)
 
-static inline bool xsk_buff_valid_tx_metadata(struct xsk_tx_metadata *meta)
+static inline bool
+xsk_buff_valid_tx_metadata(const struct xsk_tx_metadata *meta)
 {
 	return !(meta->flags & ~XDP_TXMD_FLAGS_VALID);
 }
@@ -337,7 +338,7 @@ static inline struct xdp_buff *xsk_buff_alloc(struct xsk_buff_pool *pool)
 	return NULL;
 }
 
-static inline bool xsk_is_eop_desc(struct xdp_desc *desc)
+static inline bool xsk_is_eop_desc(const struct xdp_desc *desc)
 {
 	return false;
 }
@@ -360,7 +361,7 @@ static inline void xsk_buff_add_frag(struct xdp_buff *xdp)
 {
 }
 
-static inline struct xdp_buff *xsk_buff_get_frag(struct xdp_buff *first)
+static inline struct xdp_buff *xsk_buff_get_frag(const struct xdp_buff *first)
 {
 	return NULL;
 }
diff --git a/include/net/xsk_buff_pool.h b/include/net/xsk_buff_pool.h
index bb03cee716b3..3832997cc605 100644
--- a/include/net/xsk_buff_pool.h
+++ b/include/net/xsk_buff_pool.h
@@ -183,7 +183,7 @@ static inline bool xp_desc_crosses_non_contig_pg(struct xsk_buff_pool *pool,
 	       !(pool->dma_pages[addr >> PAGE_SHIFT] & XSK_NEXT_PG_CONTIG_MASK);
 }
 
-static inline bool xp_mb_desc(struct xdp_desc *desc)
+static inline bool xp_mb_desc(const struct xdp_desc *desc)
 {
 	return desc->options & XDP_PKT_CONTD;
 }
-- 
2.46.2