[PATCH bpf-next 1/5] xsk: Convert bool 'zc' field in struct xdp_umem to a u32 bitmap

[Sridhar Samudrala <sridhar.samudrala@intel.com>]

The bool 'zc' field in struct xdp_uem is replaced with a u32 flags
field and a bit within flags is used to indicate zerocopy. This flags
field will be used in later patches for other bit fields.

Also, removed the bool 'zc' field from struct xdp_sock as it can be
accessed via flags in xs->umem.

Signed-off-by: Sridhar Samudrala <sridhar.samudrala@intel.com>
---
 include/net/xdp_sock.h | 12 ++++++++++--
 net/xdp/xdp_umem.c     |  6 +++---
 net/xdp/xsk.c          | 12 +++++++++---
 net/xdp/xsk_diag.c     |  3 ++-
 4 files changed, 24 insertions(+), 9 deletions(-)

diff --git a/include/net/xdp_sock.h b/include/net/xdp_sock.h
index 69796d264f06..b6716dbdce1a 100644
--- a/include/net/xdp_sock.h
+++ b/include/net/xdp_sock.h
@@ -27,6 +27,9 @@ struct xdp_umem_fq_reuse {
 	u64 handles[];
 };
 
+/* Bits for the umem flags field. */
+#define XDP_UMEM_F_ZEROCOPY	(1 << 0)
+
 struct xdp_umem {
 	struct xsk_queue *fq;
 	struct xsk_queue *cq;
@@ -45,7 +48,7 @@ struct xdp_umem {
 	struct net_device *dev;
 	struct xdp_umem_fq_reuse *fq_reuse;
 	u16 queue_id;
-	bool zc;
+	u32 flags;
 	spinlock_t xsk_list_lock;
 	struct list_head xsk_list;
 };
@@ -58,7 +61,6 @@ struct xdp_sock {
 	struct xdp_umem *umem;
 	struct list_head flush_node;
 	u16 queue_id;
-	bool zc;
 	enum {
 		XSK_READY = 0,
 		XSK_BOUND,
@@ -95,6 +97,7 @@ struct xdp_umem_fq_reuse *xsk_reuseq_swap(struct xdp_umem *umem,
 					  struct xdp_umem_fq_reuse *newq);
 void xsk_reuseq_free(struct xdp_umem_fq_reuse *rq);
 struct xdp_umem *xdp_get_umem_from_qid(struct net_device *dev, u16 queue_id);
+bool xsk_umem_zerocopy(struct xdp_umem *umem);
 
 static inline char *xdp_umem_get_data(struct xdp_umem *umem, u64 addr)
 {
@@ -213,6 +216,11 @@ static inline struct xdp_umem *xdp_get_umem_from_qid(struct net_device *dev,
 	return NULL;
 }
 
+static inline bool xsk_umem_zerocopy(struct xdp_umem *umem)
+{
+	return false;
+}
+
 static inline char *xdp_umem_get_data(struct xdp_umem *umem, u64 addr)
 {
 	return NULL;
diff --git a/net/xdp/xdp_umem.c b/net/xdp/xdp_umem.c
index a0607969f8c0..411b3e3498c4 100644
--- a/net/xdp/xdp_umem.c
+++ b/net/xdp/xdp_umem.c
@@ -126,7 +126,7 @@ int xdp_umem_assign_dev(struct xdp_umem *umem, struct net_device *dev,
 	if (err)
 		goto err_unreg_umem;
 
-	umem->zc = true;
+	umem->flags |= XDP_UMEM_F_ZEROCOPY;
 	return 0;
 
 err_unreg_umem:
@@ -147,7 +147,7 @@ void xdp_umem_clear_dev(struct xdp_umem *umem)
 	if (!umem->dev)
 		return;
 
-	if (umem->zc) {
+	if (xsk_umem_zerocopy(umem)) {
 		bpf.command = XDP_SETUP_XSK_UMEM;
 		bpf.xsk.umem = NULL;
 		bpf.xsk.queue_id = umem->queue_id;
@@ -162,7 +162,7 @@ void xdp_umem_clear_dev(struct xdp_umem *umem)
 
 	dev_put(umem->dev);
 	umem->dev = NULL;
-	umem->zc = false;
+	umem->flags &= ~XDP_UMEM_F_ZEROCOPY;
 }
 
 static void xdp_umem_unmap_pages(struct xdp_umem *umem)
diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
index 59b57d708697..ca95676ef75d 100644
--- a/net/xdp/xsk.c
+++ b/net/xdp/xsk.c
@@ -295,6 +295,12 @@ static int xsk_generic_xmit(struct sock *sk, struct msghdr *m,
 	return err;
 }
 
+bool xsk_umem_zerocopy(struct xdp_umem *umem)
+{
+	return (umem && (umem->flags & XDP_UMEM_F_ZEROCOPY));
+}
+EXPORT_SYMBOL(xsk_umem_zerocopy);
+
 static int xsk_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
 {
 	bool need_wait = !(m->msg_flags & MSG_DONTWAIT);
@@ -310,7 +316,8 @@ static int xsk_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
 	if (need_wait)
 		return -EOPNOTSUPP;
 
-	return (xs->zc) ? xsk_zc_xmit(sk) : xsk_generic_xmit(sk, m, total_len);
+	return xsk_umem_zerocopy(xs->umem) ? xsk_zc_xmit(sk) :
+					     xsk_generic_xmit(sk, m, total_len);
 }
 
 static unsigned int xsk_poll(struct file *file, struct socket *sock,
@@ -503,7 +510,6 @@ static int xsk_bind(struct socket *sock, struct sockaddr *addr, int addr_len)
 	}
 
 	xs->dev = dev;
-	xs->zc = xs->umem->zc;
 	xs->queue_id = qid;
 	xskq_set_umem(xs->rx, xs->umem->size, xs->umem->chunk_mask);
 	xskq_set_umem(xs->tx, xs->umem->size, xs->umem->chunk_mask);
@@ -683,7 +689,7 @@ static int xsk_getsockopt(struct socket *sock, int level, int optname,
 			return -EINVAL;
 
 		mutex_lock(&xs->mutex);
-		if (xs->zc)
+		if (xsk_umem_zerocopy(xs->umem))
 			opts.flags |= XDP_OPTIONS_ZEROCOPY;
 		mutex_unlock(&xs->mutex);
 
diff --git a/net/xdp/xsk_diag.c b/net/xdp/xsk_diag.c
index d5e06c8e0cbf..8a19b7e87cfb 100644
--- a/net/xdp/xsk_diag.c
+++ b/net/xdp/xsk_diag.c
@@ -10,6 +10,7 @@
 #include <net/xdp_sock.h>
 #include <linux/xdp_diag.h>
 #include <linux/sock_diag.h>
+#include <net/xdp_sock.h>
 
 #include "xsk_queue.h"
 #include "xsk.h"
@@ -61,7 +62,7 @@ static int xsk_diag_put_umem(const struct xdp_sock *xs, struct sk_buff *nlskb)
 	du.ifindex = umem->dev ? umem->dev->ifindex : 0;
 	du.queue_id = umem->queue_id;
 	du.flags = 0;
-	if (umem->zc)
+	if (xsk_umem_zerocopy(umem))
 		du.flags |= XDP_DU_F_ZEROCOPY;
 	du.refs = refcount_read(&umem->users);
 
-- 
2.20.1