netdev - [PATCH bpf-next v2 2/8] xsk: remove explicit_free parameter from __xsk

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Date:   Tue, 19 Jan 2021 16:50:07 +0100
From:   Björn Töpel <bjorn.topel@...il.com>
To:     ast@...nel.org, daniel@...earbox.net, netdev@...r.kernel.org,
        bpf@...r.kernel.org
Cc:     Björn Töpel <bjorn.topel@...el.com>,
        magnus.karlsson@...el.com, maciej.fijalkowski@...el.com,
        kuba@...nel.org, jonathan.lemon@...il.com, maximmi@...dia.com,
        davem@...emloft.net, hawk@...nel.org, john.fastabend@...il.com,
        ciara.loftus@...el.com, weqaar.a.janjua@...el.com
Subject: [PATCH bpf-next v2 2/8] xsk: remove explicit_free parameter from __xsk_rcv()

From: Björn Töpel <bjorn.topel@...el.com>

The explicit_free parameter of the __xsk_rcv() function was used to
mark whether the call was via the generic XDP or the native XDP
path. Instead of clutter the code with if-statements and "true/false"
parameters which are hard to understand, simply move the explicit free
to the __xsk_map_redirect() which is always called from the native XDP
path.

Reviewed-by: Maciej Fijalkowski <maciej.fijalkowski@...el.com>
Signed-off-by: Björn Töpel <bjorn.topel@...el.com>
---
 net/xdp/xsk.c | 47 +++++++++++++++++++++++++++++++----------------
 1 file changed, 31 insertions(+), 16 deletions(-)

diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
index 8037b04a9edd..5820de65060b 100644
--- a/net/xdp/xsk.c
+++ b/net/xdp/xsk.c
@@ -184,12 +184,13 @@ static void xsk_copy_xdp(struct xdp_buff *to, struct xdp_buff *from, u32 len)
 	memcpy(to_buf, from_buf, len + metalen);
 }
 
-static int __xsk_rcv(struct xdp_sock *xs, struct xdp_buff *xdp, u32 len,
-		     bool explicit_free)
+static int __xsk_rcv(struct xdp_sock *xs, struct xdp_buff *xdp)
 {
 	struct xdp_buff *xsk_xdp;
 	int err;
+	u32 len;
 
+	len = xdp->data_end - xdp->data;
 	if (len > xsk_pool_get_rx_frame_size(xs->pool)) {
 		xs->rx_dropped++;
 		return -ENOSPC;
@@ -207,8 +208,6 @@ static int __xsk_rcv(struct xdp_sock *xs, struct xdp_buff *xdp, u32 len,
 		xsk_buff_free(xsk_xdp);
 		return err;
 	}
-	if (explicit_free)
-		xdp_return_buff(xdp);
 	return 0;
 }
 
@@ -230,11 +229,8 @@ static bool xsk_is_bound(struct xdp_sock *xs)
 	return false;
 }
 
-static int xsk_rcv(struct xdp_sock *xs, struct xdp_buff *xdp,
-		   bool explicit_free)
+static int xsk_rcv_check(struct xdp_sock *xs, struct xdp_buff *xdp)
 {
-	u32 len;
-
 	if (!xsk_is_bound(xs))
 		return -EINVAL;
 
@@ -242,11 +238,7 @@ static int xsk_rcv(struct xdp_sock *xs, struct xdp_buff *xdp,
 		return -EINVAL;
 
 	sk_mark_napi_id_once_xdp(&xs->sk, xdp);
-	len = xdp->data_end - xdp->data;
-
-	return xdp->rxq->mem.type == MEM_TYPE_XSK_BUFF_POOL ?
-		__xsk_rcv_zc(xs, xdp, len) :
-		__xsk_rcv(xs, xdp, len, explicit_free);
+	return 0;
 }
 
 static void xsk_flush(struct xdp_sock *xs)
@@ -261,18 +253,41 @@ int xsk_generic_rcv(struct xdp_sock *xs, struct xdp_buff *xdp)
 	int err;
 
 	spin_lock_bh(&xs->rx_lock);
-	err = xsk_rcv(xs, xdp, false);
-	xsk_flush(xs);
+	err = xsk_rcv_check(xs, xdp);
+	if (!err) {
+		err = __xsk_rcv(xs, xdp);
+		xsk_flush(xs);
+	}
 	spin_unlock_bh(&xs->rx_lock);
 	return err;
 }
 
+static int xsk_rcv(struct xdp_sock *xs, struct xdp_buff *xdp)
+{
+	int err;
+	u32 len;
+
+	err = xsk_rcv_check(xs, xdp);
+	if (err)
+		return err;
+
+	if (xdp->rxq->mem.type == MEM_TYPE_XSK_BUFF_POOL) {
+		len = xdp->data_end - xdp->data;
+		return __xsk_rcv_zc(xs, xdp, len);
+	}
+
+	err = __xsk_rcv(xs, xdp);
+	if (!err)
+		xdp_return_buff(xdp);
+	return err;
+}
+
 int __xsk_map_redirect(struct xdp_sock *xs, struct xdp_buff *xdp)
 {
 	struct list_head *flush_list = this_cpu_ptr(&xskmap_flush_list);
 	int err;
 
-	err = xsk_rcv(xs, xdp, true);
+	err = xsk_rcv(xs, xdp);
 	if (err)
 		return err;
 
-- 
2.27.0