[PATCH bpf-next v2 12/14] xdp: simplify xdp_return_{frame,frame_rx_napi,buff}

[Björn Töpel]

From: Björn Töpel <bjorn.to...@intel.com>

The xdp_return_{frame,frame_rx_napi,buff} function are never used,
except in xdp_convert_zc_to_xdp_frame(), by the MEM_TYPE_XSK_BUFF_POOL
memory type.

To simplify and reduce code, change so that
xdp_convert_zc_to_xdp_frame() calls xsk_buff_free() directly since the
type is know, and remove MEM_TYPE_XSK_BUFF_POOL from the switch
statement in __xdp_return() function.

Suggested-by: Maxim Mikityanskiy <maxi...@mellanox.com>
Signed-off-by: Björn Töpel <bjorn.to...@intel.com>
---
 net/core/xdp.c | 21 +++++++++------------
 1 file changed, 9 insertions(+), 12 deletions(-)

diff --git a/net/core/xdp.c b/net/core/xdp.c
index 11273c976e19..7ab1f9014c5e 100644
--- a/net/core/xdp.c
+++ b/net/core/xdp.c
@@ -334,10 +334,11 @@ EXPORT_SYMBOL_GPL(xdp_rxq_info_reg_mem_model);
  * scenarios (e.g. queue full), it is possible to return the xdp_frame
  * while still leveraging this protection.  The @napi_direct boolean
  * is used for those calls sites.  Thus, allowing for faster recycling
- * of xdp_frames/pages in those cases.
+ * of xdp_frames/pages in those cases. This path is never used by the
+ * MEM_TYPE_XSK_BUFF_POOL memory type, so it's explicitly not part of
+ * the switch-statement.
  */
-static void __xdp_return(void *data, struct xdp_mem_info *mem, bool 
napi_direct,
-                        struct xdp_buff *xdp)
+static void __xdp_return(void *data, struct xdp_mem_info *mem, bool 
napi_direct)
 {
        struct xdp_mem_allocator *xa;
        struct page *page;
@@ -359,33 +360,29 @@ static void __xdp_return(void *data, struct xdp_mem_info 
*mem, bool napi_direct,
                page = virt_to_page(data); /* Assumes order0 page*/
                put_page(page);
                break;
-       case MEM_TYPE_XSK_BUFF_POOL:
-               /* NB! Only valid from an xdp_buff! */
-               xsk_buff_free(xdp);
-               break;
        default:
                /* Not possible, checked in xdp_rxq_info_reg_mem_model() */
+               WARN(1, "Incorrect XDP memory type (%d) usage", mem->type);
                break;
        }
 }
 
 void xdp_return_frame(struct xdp_frame *xdpf)
 {
-       __xdp_return(xdpf->data, &xdpf->mem, false, NULL);
+       __xdp_return(xdpf->data, &xdpf->mem, false);
 }
 EXPORT_SYMBOL_GPL(xdp_return_frame);
 
 void xdp_return_frame_rx_napi(struct xdp_frame *xdpf)
 {
-       __xdp_return(xdpf->data, &xdpf->mem, true, NULL);
+       __xdp_return(xdpf->data, &xdpf->mem, true);
 }
 EXPORT_SYMBOL_GPL(xdp_return_frame_rx_napi);
 
 void xdp_return_buff(struct xdp_buff *xdp)
 {
-       __xdp_return(xdp->data, &xdp->rxq->mem, true, xdp);
+       __xdp_return(xdp->data, &xdp->rxq->mem, true);
 }
-EXPORT_SYMBOL_GPL(xdp_return_buff);
 
 /* Only called for MEM_TYPE_PAGE_POOL see xdp.h */
 void __xdp_release_frame(void *data, struct xdp_mem_info *mem)
@@ -466,7 +463,7 @@ struct xdp_frame *xdp_convert_zc_to_xdp_frame(struct 
xdp_buff *xdp)
        xdpf->metasize = metasize;
        xdpf->mem.type = MEM_TYPE_PAGE_ORDER0;
 
-       xdp_return_buff(xdp);
+       xsk_buff_free(xdp);
        return xdpf;
 }
 EXPORT_SYMBOL_GPL(xdp_convert_zc_to_xdp_frame);
-- 
2.25.1