Netdev List
 help / color / mirror / Atom feed
* [PATCH net-next V2 5/8] vhost: vhost_put_user() can accept metadata type
From: Jason Wang @ 2018-07-16  3:28 UTC (permalink / raw)
  To: mst, jasowang
  Cc: kvm, virtualization, netdev, linux-kernel, wexu, jfreimann,
	tiwei.bie, maxime.coquelin
In-Reply-To: <1531711691-6769-1-git-send-email-jasowang@redhat.com>

We assumes used ring update is the only user for vhost_put_user() in
the past. This may not be the case for the incoming packed ring which
may update the descriptor ring for used. So introduce a new type
parameter.

Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 drivers/vhost/vhost.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index af15bec..060a431 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -814,7 +814,7 @@ static inline void __user *__vhost_get_user(struct vhost_virtqueue *vq,
 	return __vhost_get_user_slow(vq, addr, size, type);
 }
 
-#define vhost_put_user(vq, x, ptr)		\
+#define vhost_put_user(vq, x, ptr, type)		\
 ({ \
 	int ret = -EFAULT; \
 	if (!vq->iotlb) { \
@@ -822,7 +822,7 @@ static inline void __user *__vhost_get_user(struct vhost_virtqueue *vq,
 	} else { \
 		__typeof__(ptr) to = \
 			(__typeof__(ptr)) __vhost_get_user(vq, ptr,	\
-					  sizeof(*ptr), VHOST_ADDR_USED); \
+					  sizeof(*ptr), type); \
 		if (to != NULL) \
 			ret = __put_user(x, to); \
 		else \
@@ -1687,7 +1687,7 @@ static int vhost_update_used_flags(struct vhost_virtqueue *vq)
 {
 	void __user *used;
 	if (vhost_put_user(vq, cpu_to_vhost16(vq, vq->used_flags),
-			   &vq->used->flags) < 0)
+			   &vq->used->flags, VHOST_ADDR_USED) < 0)
 		return -EFAULT;
 	if (unlikely(vq->log_used)) {
 		/* Make sure the flag is seen before log. */
@@ -1706,7 +1706,7 @@ static int vhost_update_used_flags(struct vhost_virtqueue *vq)
 static int vhost_update_avail_event(struct vhost_virtqueue *vq, u16 avail_event)
 {
 	if (vhost_put_user(vq, cpu_to_vhost16(vq, vq->avail_idx),
-			   vhost_avail_event(vq)))
+			   vhost_avail_event(vq), VHOST_ADDR_USED))
 		return -EFAULT;
 	if (unlikely(vq->log_used)) {
 		void __user *used;
@@ -2189,12 +2189,12 @@ static int __vhost_add_used_n(struct vhost_virtqueue *vq,
 	used = vq->used->ring + start;
 	for (i = 0; i < count; i++) {
 		if (unlikely(vhost_put_user(vq, heads[i].elem.id,
-					    &used[i].id))) {
+					    &used[i].id, VHOST_ADDR_USED))) {
 			vq_err(vq, "Failed to write used id");
 			return -EFAULT;
 		}
 		if (unlikely(vhost_put_user(vq, heads[i].elem.len,
-					    &used[i].len))) {
+					    &used[i].len, VHOST_ADDR_USED))) {
 			vq_err(vq, "Failed to write used len");
 			return -EFAULT;
 		}
@@ -2240,7 +2240,7 @@ int vhost_add_used_n(struct vhost_virtqueue *vq, struct vhost_used_elem *heads,
 	/* Make sure buffer is written before we update index. */
 	smp_wmb();
 	if (vhost_put_user(vq, cpu_to_vhost16(vq, vq->last_used_idx),
-			   &vq->used->idx)) {
+			   &vq->used->idx, VHOST_ADDR_USED)) {
 		vq_err(vq, "Failed to increment used idx");
 		return -EFAULT;
 	}
-- 
2.7.4

^ permalink raw reply related

* [PATCH] rxrpc: Reuse SKCIPHER_REQUEST_ON_STACK buffer
From: Kees Cook @ 2018-07-16  3:49 UTC (permalink / raw)
  To: David Howells
  Cc: Herbert Xu, Arnd Bergmann, Eric Biggers, Gustavo A. R. Silva,
	David S. Miller, netdev, linux-kernel

The use of SKCIPHER_REQUEST_ON_STACK() will trigger FRAME_WARN warnings
(when less than 2048) once the VLA is no longer hidden from the check:

net/rxrpc/rxkad.c:398:1: warning: the frame size of 1152 bytes is larger than 1024 bytes [-Wframe-larger-than=]
net/rxrpc/rxkad.c:242:1: warning: the frame size of 1152 bytes is larger than 1024 bytes [-Wframe-larger-than=]

This passes the initial SKCIPHER_REQUEST_ON_STACK allocation to the leaf
functions for reuse. Two requests allocated on the stack are not needed
when only one is used at a time.

Signed-off-by: Kees Cook <keescook@chromium.org>
---
 net/rxrpc/rxkad.c | 25 +++++++++++++------------
 1 file changed, 13 insertions(+), 12 deletions(-)

diff --git a/net/rxrpc/rxkad.c b/net/rxrpc/rxkad.c
index 278ac0807a60..6393391fac86 100644
--- a/net/rxrpc/rxkad.c
+++ b/net/rxrpc/rxkad.c
@@ -146,10 +146,10 @@ static int rxkad_prime_packet_security(struct rxrpc_connection *conn)
 static int rxkad_secure_packet_auth(const struct rxrpc_call *call,
 				    struct sk_buff *skb,
 				    u32 data_size,
-				    void *sechdr)
+				    void *sechdr,
+				    struct skcipher_request *req)
 {
 	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
-	SKCIPHER_REQUEST_ON_STACK(req, call->conn->cipher);
 	struct rxkad_level1_hdr hdr;
 	struct rxrpc_crypt iv;
 	struct scatterlist sg;
@@ -183,12 +183,12 @@ static int rxkad_secure_packet_auth(const struct rxrpc_call *call,
 static int rxkad_secure_packet_encrypt(const struct rxrpc_call *call,
 				       struct sk_buff *skb,
 				       u32 data_size,
-				       void *sechdr)
+				       void *sechdr,
+				       struct skcipher_request *req)
 {
 	const struct rxrpc_key_token *token;
 	struct rxkad_level2_hdr rxkhdr;
 	struct rxrpc_skb_priv *sp;
-	SKCIPHER_REQUEST_ON_STACK(req, call->conn->cipher);
 	struct rxrpc_crypt iv;
 	struct scatterlist sg[16];
 	struct sk_buff *trailer;
@@ -296,11 +296,12 @@ static int rxkad_secure_packet(struct rxrpc_call *call,
 		ret = 0;
 		break;
 	case RXRPC_SECURITY_AUTH:
-		ret = rxkad_secure_packet_auth(call, skb, data_size, sechdr);
+		ret = rxkad_secure_packet_auth(call, skb, data_size, sechdr,
+					       req);
 		break;
 	case RXRPC_SECURITY_ENCRYPT:
 		ret = rxkad_secure_packet_encrypt(call, skb, data_size,
-						  sechdr);
+						  sechdr, req);
 		break;
 	default:
 		ret = -EPERM;
@@ -316,10 +317,10 @@ static int rxkad_secure_packet(struct rxrpc_call *call,
  */
 static int rxkad_verify_packet_1(struct rxrpc_call *call, struct sk_buff *skb,
 				 unsigned int offset, unsigned int len,
-				 rxrpc_seq_t seq)
+				 rxrpc_seq_t seq,
+				 struct skcipher_request *req)
 {
 	struct rxkad_level1_hdr sechdr;
-	SKCIPHER_REQUEST_ON_STACK(req, call->conn->cipher);
 	struct rxrpc_crypt iv;
 	struct scatterlist sg[16];
 	struct sk_buff *trailer;
@@ -402,11 +403,11 @@ static int rxkad_verify_packet_1(struct rxrpc_call *call, struct sk_buff *skb,
  */
 static int rxkad_verify_packet_2(struct rxrpc_call *call, struct sk_buff *skb,
 				 unsigned int offset, unsigned int len,
-				 rxrpc_seq_t seq)
+				 rxrpc_seq_t seq,
+				 struct skcipher_request *req)
 {
 	const struct rxrpc_key_token *token;
 	struct rxkad_level2_hdr sechdr;
-	SKCIPHER_REQUEST_ON_STACK(req, call->conn->cipher);
 	struct rxrpc_crypt iv;
 	struct scatterlist _sg[4], *sg;
 	struct sk_buff *trailer;
@@ -549,9 +550,9 @@ static int rxkad_verify_packet(struct rxrpc_call *call, struct sk_buff *skb,
 	case RXRPC_SECURITY_PLAIN:
 		return 0;
 	case RXRPC_SECURITY_AUTH:
-		return rxkad_verify_packet_1(call, skb, offset, len, seq);
+		return rxkad_verify_packet_1(call, skb, offset, len, seq, req);
 	case RXRPC_SECURITY_ENCRYPT:
-		return rxkad_verify_packet_2(call, skb, offset, len, seq);
+		return rxkad_verify_packet_2(call, skb, offset, len, seq, req);
 	default:
 		return -ENOANO;
 	}
-- 
2.17.1


-- 
Kees Cook
Pixel Security

^ permalink raw reply related

* [PATCH net-next V2 8/8] vhost: enable packed virtqueues
From: Jason Wang @ 2018-07-16  3:28 UTC (permalink / raw)
  To: mst, jasowang
  Cc: kvm, virtualization, netdev, linux-kernel, wexu, jfreimann,
	tiwei.bie, maxime.coquelin
In-Reply-To: <1531711691-6769-1-git-send-email-jasowang@redhat.com>

Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 drivers/vhost/vhost.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
index 3a7fc4b..0dfe864 100644
--- a/drivers/vhost/vhost.h
+++ b/drivers/vhost/vhost.h
@@ -264,7 +264,8 @@ enum {
 			 (1ULL << VIRTIO_RING_F_EVENT_IDX) |
 			 (1ULL << VHOST_F_LOG_ALL) |
 			 (1ULL << VIRTIO_F_ANY_LAYOUT) |
-			 (1ULL << VIRTIO_F_VERSION_1)
+			 (1ULL << VIRTIO_F_VERSION_1) |
+			 (1ULL << VIRTIO_F_RING_PACKED)
 };
 
 static inline bool vhost_has_feature(struct vhost_virtqueue *vq, int bit)
-- 
2.7.4

^ permalink raw reply related

* [PATCH net-next V2 7/8] vhost: event suppression for packed ring
From: Jason Wang @ 2018-07-16  3:28 UTC (permalink / raw)
  To: mst, jasowang
  Cc: kvm, virtualization, netdev, linux-kernel, wexu, jfreimann,
	tiwei.bie, maxime.coquelin
In-Reply-To: <1531711691-6769-1-git-send-email-jasowang@redhat.com>

This patch introduces support for event suppression. This is done by
have a two areas: device area and driver area. One side could then try
to disable or enable (delayed) notification from other side by using a
boolean hint or event index interface in the areas.

For more information, please refer Virtio spec.

Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 drivers/vhost/vhost.c | 191 ++++++++++++++++++++++++++++++++++++++++++++++----
 drivers/vhost/vhost.h |  10 ++-
 2 files changed, 185 insertions(+), 16 deletions(-)

diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 63b79e8..0459f8b 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -1115,10 +1115,15 @@ static int vq_access_ok_packed(struct vhost_virtqueue *vq, unsigned int num,
 			       struct vring_used __user *used)
 {
 	struct vring_packed_desc *packed = (struct vring_packed_desc *)desc;
+	struct vring_packed_desc_event *driver_event =
+		(struct vring_packed_desc_event *)avail;
+	struct vring_packed_desc_event *device_event =
+		(struct vring_packed_desc_event *)used;
 
-	/* TODO: check device area and driver area */
 	return access_ok(VERIFY_READ, packed, num * sizeof(*packed)) &&
-	       access_ok(VERIFY_WRITE, packed, num * sizeof(*packed));
+	       access_ok(VERIFY_WRITE, packed, num * sizeof(*packed)) &&
+	       access_ok(VERIFY_READ, driver_event, sizeof(*driver_event)) &&
+	       access_ok(VERIFY_WRITE, device_event, sizeof(*device_event));
 }
 
 static int vq_access_ok_split(struct vhost_virtqueue *vq, unsigned int num,
@@ -1193,14 +1198,27 @@ static bool iotlb_access_ok(struct vhost_virtqueue *vq,
 	return true;
 }
 
-int vq_iotlb_prefetch(struct vhost_virtqueue *vq)
+int vq_iotlb_prefetch_packed(struct vhost_virtqueue *vq)
+{
+	int num = vq->num;
+
+	return iotlb_access_ok(vq, VHOST_ACCESS_RO, (u64)(uintptr_t)vq->desc,
+			       num * sizeof(*vq->desc), VHOST_ADDR_DESC) &&
+	       iotlb_access_ok(vq, VHOST_ACCESS_WO, (u64)(uintptr_t)vq->desc,
+			       num * sizeof(*vq->desc), VHOST_ADDR_DESC) &&
+	       iotlb_access_ok(vq, VHOST_ACCESS_RO,
+			       (u64)(uintptr_t)vq->driver_event,
+			       sizeof(*vq->driver_event), VHOST_ADDR_AVAIL) &&
+	       iotlb_access_ok(vq, VHOST_ACCESS_WO,
+			       (u64)(uintptr_t)vq->device_event,
+			       sizeof(*vq->device_event), VHOST_ADDR_USED);
+}
+
+int vq_iotlb_prefetch_split(struct vhost_virtqueue *vq)
 {
 	size_t s = vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
 	unsigned int num = vq->num;
 
-	if (!vq->iotlb)
-		return 1;
-
 	return iotlb_access_ok(vq, VHOST_ACCESS_RO, (u64)(uintptr_t)vq->desc,
 			       num * sizeof(*vq->desc), VHOST_ADDR_DESC) &&
 	       iotlb_access_ok(vq, VHOST_ACCESS_RO, (u64)(uintptr_t)vq->avail,
@@ -1212,6 +1230,17 @@ int vq_iotlb_prefetch(struct vhost_virtqueue *vq)
 			       num * sizeof(*vq->used->ring) + s,
 			       VHOST_ADDR_USED);
 }
+
+int vq_iotlb_prefetch(struct vhost_virtqueue *vq)
+{
+	if (!vq->iotlb)
+		return 1;
+
+	if (vhost_has_feature(vq, VIRTIO_F_RING_PACKED))
+		return vq_iotlb_prefetch_packed(vq);
+	else
+		return vq_iotlb_prefetch_split(vq);
+}
 EXPORT_SYMBOL_GPL(vq_iotlb_prefetch);
 
 /* Can we log writes? */
@@ -1771,6 +1800,50 @@ static int vhost_update_used_flags(struct vhost_virtqueue *vq)
 	return 0;
 }
 
+static int vhost_update_device_flags(struct vhost_virtqueue *vq,
+				     __virtio16 device_flags)
+{
+	void __user *flags;
+
+	if (vhost_put_user(vq, device_flags, &vq->device_event->flags,
+			   VHOST_ADDR_USED) < 0)
+		return -EFAULT;
+	if (unlikely(vq->log_used)) {
+		/* Make sure the flag is seen before log. */
+		smp_wmb();
+		/* Log used flag write. */
+		flags = &vq->device_event->flags;
+		log_write(vq->log_base, vq->log_addr +
+			  (flags - (void __user *)vq->device_event),
+			  sizeof(vq->device_event->flags));
+		if (vq->log_ctx)
+			eventfd_signal(vq->log_ctx, 1);
+	}
+	return 0;
+}
+
+static int vhost_update_device_off_wrap(struct vhost_virtqueue *vq,
+					__virtio16 device_off_wrap)
+{
+	void __user *off_wrap;
+
+	if (vhost_put_user(vq, device_off_wrap, &vq->device_event->off_wrap,
+			   VHOST_ADDR_USED) < 0)
+		return -EFAULT;
+	if (unlikely(vq->log_used)) {
+		/* Make sure the flag is seen before log. */
+		smp_wmb();
+		/* Log used flag write. */
+		off_wrap = &vq->device_event->off_wrap;
+		log_write(vq->log_base, vq->log_addr +
+			  (off_wrap - (void __user *)vq->device_event),
+			  sizeof(vq->device_event->off_wrap));
+		if (vq->log_ctx)
+			eventfd_signal(vq->log_ctx, 1);
+	}
+	return 0;
+}
+
 static int vhost_update_avail_event(struct vhost_virtqueue *vq, u16 avail_event)
 {
 	if (vhost_put_user(vq, cpu_to_vhost16(vq, vq->avail_idx),
@@ -2754,16 +2827,13 @@ int vhost_add_used_n(struct vhost_virtqueue *vq,
 }
 EXPORT_SYMBOL_GPL(vhost_add_used_n);
 
-static bool vhost_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
+static bool vhost_notify_split(struct vhost_dev *dev,
+			       struct vhost_virtqueue *vq)
 {
 	__u16 old, new;
 	__virtio16 event;
 	bool v;
 
-	/* TODO: check driver area */
-	if (vhost_has_feature(vq, VIRTIO_F_RING_PACKED))
-		return true;
-
 	/* Flush out used index updates. This is paired
 	 * with the barrier that the Guest executes when enabling
 	 * interrupts. */
@@ -2796,6 +2866,64 @@ static bool vhost_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
 	return vring_need_event(vhost16_to_cpu(vq, event), new, old);
 }
 
+static bool vhost_notify_packed(struct vhost_dev *dev,
+				struct vhost_virtqueue *vq)
+{
+	__virtio16 event_off_wrap, event_flags;
+	__u16 old, new, off_wrap;
+	bool v;
+
+	/* Flush out used descriptors updates. This is paired
+	 * with the barrier that the Guest executes when enabling
+	 * interrupts.
+	 */
+	smp_mb();
+
+	if (vhost_get_avail(vq, event_flags,
+			   &vq->driver_event->flags) < 0) {
+		vq_err(vq, "Failed to get driver desc_event_flags");
+		return true;
+	}
+
+	if (!vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX))
+		return event_flags !=
+		       cpu_to_vhost16(vq, VRING_EVENT_F_DISABLE);
+
+	old = vq->signalled_used;
+	v = vq->signalled_used_valid;
+	new = vq->signalled_used = vq->last_used_idx;
+	vq->signalled_used_valid = true;
+
+	if (event_flags != cpu_to_vhost16(vq, VRING_EVENT_F_DESC))
+		return event_flags !=
+		       cpu_to_vhost16(vq, VRING_EVENT_F_DISABLE);
+
+	/* Read desc event flags before event_off and event_wrap */
+	smp_rmb();
+
+	if (vhost_get_avail(vq, event_off_wrap,
+			    &vq->driver_event->off_wrap) < 0) {
+		vq_err(vq, "Failed to get driver desc_event_off/wrap");
+		return true;
+	}
+
+	off_wrap = vhost16_to_cpu(vq, event_off_wrap);
+
+	if (unlikely(!v))
+		return true;
+
+	return vhost_vring_packed_need_event(vq, vq->last_used_wrap_counter,
+					     off_wrap, new, old);
+}
+
+static bool vhost_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
+{
+	if (vhost_has_feature(vq, VIRTIO_F_RING_PACKED))
+		return vhost_notify_packed(dev, vq);
+	else
+		return vhost_notify_split(dev, vq);
+}
+
 /* This actually signals the guest, using eventfd. */
 void vhost_signal(struct vhost_dev *dev, struct vhost_virtqueue *vq)
 {
@@ -2873,10 +3001,34 @@ static bool vhost_enable_notify_packed(struct vhost_dev *dev,
 				       struct vhost_virtqueue *vq)
 {
 	struct vring_packed_desc *d = vq->desc_packed + vq->avail_idx;
-	__virtio16 flags;
+	__virtio16 flags = cpu_to_vhost16(vq, VRING_EVENT_F_ENABLE);
 	int ret;
 
-	/* TODO: enable notification through device area */
+	if (!(vq->used_flags & VRING_USED_F_NO_NOTIFY))
+		return false;
+	vq->used_flags &= ~VRING_USED_F_NO_NOTIFY;
+
+	if (vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX)) {
+		__virtio16 off_wrap = cpu_to_vhost16(vq, vq->avail_idx |
+				      vq->avail_wrap_counter << 15);
+
+		ret = vhost_update_device_off_wrap(vq, off_wrap);
+		if (ret) {
+			vq_err(vq, "Failed to write to off warp at %p: %d\n",
+			       &vq->device_event->off_wrap, ret);
+			return false;
+		}
+		/* Make sure off_wrap is wrote before flags */
+		smp_wmb();
+		flags = cpu_to_vhost16(vq, VRING_EVENT_F_DESC);
+	}
+
+	ret = vhost_update_device_flags(vq, flags);
+	if (ret) {
+		vq_err(vq, "Failed to enable notification at %p: %d\n",
+			&vq->device_event->flags, ret);
+		return false;
+	}
 
 	/* They could have slipped one in as we were doing that: make
 	 * sure it's written, then check again.
@@ -2943,7 +3095,18 @@ EXPORT_SYMBOL_GPL(vhost_enable_notify);
 static void vhost_disable_notify_packed(struct vhost_dev *dev,
 					struct vhost_virtqueue *vq)
 {
-	/* TODO: disable notification through device area */
+	__virtio16 flags;
+	int r;
+
+	if (vq->used_flags & VRING_USED_F_NO_NOTIFY)
+		return;
+	vq->used_flags |= VRING_USED_F_NO_NOTIFY;
+
+	flags = cpu_to_vhost16(vq, VRING_EVENT_F_DISABLE);
+	r = vhost_update_device_flags(vq, flags);
+	if (r)
+		vq_err(vq, "Failed to enable notification at %p: %d\n",
+		       &vq->device_event->flags, r);
 }
 
 static void vhost_disable_notify_split(struct vhost_dev *dev,
diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
index 73c2a78..3a7fc4b 100644
--- a/drivers/vhost/vhost.h
+++ b/drivers/vhost/vhost.h
@@ -96,8 +96,14 @@ struct vhost_virtqueue {
 		struct vring_desc __user *desc;
 		struct vring_packed_desc __user *desc_packed;
 	};
-	struct vring_avail __user *avail;
-	struct vring_used __user *used;
+	union {
+		struct vring_avail __user *avail;
+		struct vring_packed_desc_event __user *driver_event;
+	};
+	union {
+		struct vring_used __user *used;
+		struct vring_packed_desc_event __user *device_event;
+	};
 	const struct vhost_umem_node *meta_iotlb[VHOST_NUM_ADDRS];
 	struct file *kick;
 	struct eventfd_ctx *call_ctx;
-- 
2.7.4

^ permalink raw reply related

* [PATCH net-next V2 4/8] vhost_net: do not explicitly manipulate vhost_used_elem
From: Jason Wang @ 2018-07-16  3:28 UTC (permalink / raw)
  To: mst, jasowang
  Cc: kvm, virtualization, netdev, linux-kernel, wexu, jfreimann,
	tiwei.bie, maxime.coquelin
In-Reply-To: <1531711691-6769-1-git-send-email-jasowang@redhat.com>

Two helpers of setting/getting used len were introduced to avoid
explicitly manipulating vhost_used_elem in zerocopy code. This will be
used to hide used_elem internals and simplify packed ring
implementation.

Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 drivers/vhost/net.c   | 11 +++++------
 drivers/vhost/vhost.c | 12 ++++++++++--
 drivers/vhost/vhost.h |  5 +++++
 3 files changed, 20 insertions(+), 8 deletions(-)

diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index 2f1395a..2432002 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -348,9 +348,10 @@ static void vhost_zerocopy_signal_used(struct vhost_net *net,
 	int j = 0;
 
 	for (i = nvq->done_idx; i != nvq->upend_idx; i = (i + 1) % UIO_MAXIOV) {
-		if (vq->heads[i].elem.len == VHOST_DMA_FAILED_LEN)
+		if (vhost_get_used_len(vq, &vq->heads[i]) ==
+		    VHOST_DMA_FAILED_LEN)
 			vhost_net_tx_err(net);
-		if (VHOST_DMA_IS_DONE(vq->heads[i].elem.len)) {
+		if (VHOST_DMA_IS_DONE(vhost_get_used_len(vq, &vq->heads[i]))) {
 			vq->heads[i].elem.len = VHOST_DMA_CLEAR_LEN;
 			++j;
 		} else
@@ -557,10 +558,8 @@ static void handle_tx(struct vhost_net *net)
 			struct ubuf_info *ubuf;
 			ubuf = nvq->ubuf_info + nvq->upend_idx;
 
-			vq->heads[nvq->upend_idx].elem.id =
-				cpu_to_vhost32(vq, used.elem.id);
-			vq->heads[nvq->upend_idx].elem.len =
-				VHOST_DMA_IN_PROGRESS;
+			vhost_set_used_len(vq, &used, VHOST_DMA_IN_PROGRESS);
+			vq->heads[nvq->upend_idx] = used;
 			ubuf->callback = vhost_zerocopy_callback;
 			ubuf->ctx = nvq->ubufs;
 			ubuf->desc = nvq->upend_idx;
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 641f4c6..af15bec 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -2071,11 +2071,19 @@ int vhost_get_vq_desc(struct vhost_virtqueue *vq,
 }
 EXPORT_SYMBOL_GPL(vhost_get_vq_desc);
 
-static void vhost_set_used_len(struct vhost_virtqueue *vq,
-			       struct vhost_used_elem *used, int len)
+void vhost_set_used_len(struct vhost_virtqueue *vq,
+			struct vhost_used_elem *used, int len)
 {
 	used->elem.len = cpu_to_vhost32(vq, len);
 }
+EXPORT_SYMBOL_GPL(vhost_set_used_len);
+
+int vhost_get_used_len(struct vhost_virtqueue *vq,
+		       struct vhost_used_elem *used)
+{
+	return vhost32_to_cpu(vq, used->elem.len);
+}
+EXPORT_SYMBOL_GPL(vhost_get_used_len);
 
 /* This is a multi-buffer version of vhost_get_desc, that works if
  *	vq has read descriptors only.
diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
index 8dea44b..604821b 100644
--- a/drivers/vhost/vhost.h
+++ b/drivers/vhost/vhost.h
@@ -198,6 +198,11 @@ int vhost_get_bufs(struct vhost_virtqueue *vq,
 		   unsigned *log_num,
 		   unsigned int quota,
 		   s16 *count);
+void vhost_set_used_len(struct vhost_virtqueue *vq,
+			struct vhost_used_elem *used,
+			int len);
+int vhost_get_used_len(struct vhost_virtqueue *vq,
+		       struct vhost_used_elem *used);
 void vhost_discard_vq_desc(struct vhost_virtqueue *, int n);
 
 int vhost_vq_init_access(struct vhost_virtqueue *);
-- 
2.7.4

^ permalink raw reply related

* [PATCH net-next V2 3/8] vhost: do not use vring_used_elem
From: Jason Wang @ 2018-07-16  3:28 UTC (permalink / raw)
  To: mst, jasowang
  Cc: kvm, virtualization, netdev, linux-kernel, wexu, jfreimann,
	tiwei.bie, maxime.coquelin
In-Reply-To: <1531711691-6769-1-git-send-email-jasowang@redhat.com>

Instead of depending on the exported vring_used_elem, this patch
switches to use a new internal structure vhost_used_elem which embed
vring_used_elem in itself. This could be used to let vhost to record
extra metadata for the incoming packed ring layout.

Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 drivers/vhost/net.c   | 19 +++++++-------
 drivers/vhost/scsi.c  | 10 ++++----
 drivers/vhost/vhost.c | 68 ++++++++++++---------------------------------------
 drivers/vhost/vhost.h | 18 ++++++++------
 drivers/vhost/vsock.c |  6 ++---
 5 files changed, 45 insertions(+), 76 deletions(-)

diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index a8c9506..2f1395a 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -348,10 +348,10 @@ static void vhost_zerocopy_signal_used(struct vhost_net *net,
 	int j = 0;
 
 	for (i = nvq->done_idx; i != nvq->upend_idx; i = (i + 1) % UIO_MAXIOV) {
-		if (vq->heads[i].len == VHOST_DMA_FAILED_LEN)
+		if (vq->heads[i].elem.len == VHOST_DMA_FAILED_LEN)
 			vhost_net_tx_err(net);
-		if (VHOST_DMA_IS_DONE(vq->heads[i].len)) {
-			vq->heads[i].len = VHOST_DMA_CLEAR_LEN;
+		if (VHOST_DMA_IS_DONE(vq->heads[i].elem.len)) {
+			vq->heads[i].elem.len = VHOST_DMA_CLEAR_LEN;
 			++j;
 		} else
 			break;
@@ -374,7 +374,7 @@ static void vhost_zerocopy_callback(struct ubuf_info *ubuf, bool success)
 	rcu_read_lock_bh();
 
 	/* set len to mark this desc buffers done DMA */
-	vq->heads[ubuf->desc].len = success ?
+	vq->heads[ubuf->desc].elem.len = success ?
 		VHOST_DMA_DONE_LEN : VHOST_DMA_FAILED_LEN;
 	cnt = vhost_net_ubuf_put(ubufs);
 
@@ -430,7 +430,7 @@ static int vhost_net_enable_vq(struct vhost_net *n,
 
 static int vhost_net_tx_get_vq_desc(struct vhost_net *net,
 				    struct vhost_virtqueue *vq,
-				    struct vring_used_elem *used_elem,
+				    struct vhost_used_elem *used_elem,
 				    struct iovec iov[], unsigned int iov_size,
 				    unsigned int *out_num, unsigned int *in_num,
 				    bool *busyloop_intr)
@@ -488,7 +488,7 @@ static void handle_tx(struct vhost_net *net)
 	size_t hdr_size;
 	struct socket *sock;
 	struct vhost_net_ubuf_ref *uninitialized_var(ubufs);
-	struct vring_used_elem used;
+	struct vhost_used_elem used;
 	bool zcopy, zcopy_used;
 	int sent_pkts = 0;
 
@@ -557,9 +557,10 @@ static void handle_tx(struct vhost_net *net)
 			struct ubuf_info *ubuf;
 			ubuf = nvq->ubuf_info + nvq->upend_idx;
 
-			vq->heads[nvq->upend_idx].id =
-				cpu_to_vhost32(vq, used.id);
-			vq->heads[nvq->upend_idx].len = VHOST_DMA_IN_PROGRESS;
+			vq->heads[nvq->upend_idx].elem.id =
+				cpu_to_vhost32(vq, used.elem.id);
+			vq->heads[nvq->upend_idx].elem.len =
+				VHOST_DMA_IN_PROGRESS;
 			ubuf->callback = vhost_zerocopy_callback;
 			ubuf->ctx = nvq->ubufs;
 			ubuf->desc = nvq->upend_idx;
diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c
index 013464c..149c38c 100644
--- a/drivers/vhost/scsi.c
+++ b/drivers/vhost/scsi.c
@@ -67,7 +67,7 @@ struct vhost_scsi_inflight {
 
 struct vhost_scsi_cmd {
 	/* Descriptor from vhost_get_vq_desc() for virt_queue segment */
-	struct vring_used_elem tvc_vq_used;
+	struct vhost_used_elem tvc_vq_used;
 	/* virtio-scsi initiator task attribute */
 	int tvc_task_attr;
 	/* virtio-scsi response incoming iovecs */
@@ -441,7 +441,7 @@ vhost_scsi_do_evt_work(struct vhost_scsi *vs, struct vhost_scsi_evt *evt)
 	struct vhost_virtqueue *vq = &vs->vqs[VHOST_SCSI_VQ_EVT].vq;
 	struct virtio_scsi_event *event = &evt->event;
 	struct virtio_scsi_event __user *eventp;
-	struct vring_used_elem used;
+	struct vhost_used_elem used;
 	unsigned out, in;
 	int ret;
 
@@ -785,7 +785,7 @@ static void vhost_scsi_submission_work(struct work_struct *work)
 static void
 vhost_scsi_send_bad_target(struct vhost_scsi *vs,
 			   struct vhost_virtqueue *vq,
-			   struct vring_used_elem *used, unsigned out)
+			   struct vhost_used_elem *used, unsigned out)
 {
 	struct virtio_scsi_cmd_resp __user *resp;
 	struct virtio_scsi_cmd_resp rsp;
@@ -808,7 +808,7 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
 	struct virtio_scsi_cmd_req v_req;
 	struct virtio_scsi_cmd_req_pi v_req_pi;
 	struct vhost_scsi_cmd *cmd;
-	struct vring_used_elem used;
+	struct vhost_used_elem used;
 	struct iov_iter out_iter, in_iter, prot_iter, data_iter;
 	u64 tag;
 	u32 exp_data_len, data_direction;
@@ -837,7 +837,7 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
 					ARRAY_SIZE(vq->iov), &out, &in,
 					NULL, NULL);
 		pr_debug("vhost_get_vq_desc: head: %d, out: %u in: %u\n",
-			 used.id, out, in);
+			 used.elem.id, out, in);
 		/* Nothing new?  Wait for eventfd to tell us they refilled. */
 		if (ret == -ENOSPC) {
 			if (unlikely(vhost_enable_notify(&vs->dev, vq))) {
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 9572c4f..641f4c6 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -731,41 +731,6 @@ static bool memory_access_ok(struct vhost_dev *d, struct vhost_umem *umem,
 static int translate_desc(struct vhost_virtqueue *vq, u64 addr, u32 len,
 			  struct iovec iov[], int iov_size, int access);
 
-static int vhost_copy_to_user(struct vhost_virtqueue *vq, void __user *to,
-			      const void *from, unsigned size)
-{
-	int ret;
-
-	if (!vq->iotlb)
-		return __copy_to_user(to, from, size);
-	else {
-		/* This function should be called after iotlb
-		 * prefetch, which means we're sure that all vq
-		 * could be access through iotlb. So -EAGAIN should
-		 * not happen in this case.
-		 */
-		struct iov_iter t;
-		void __user *uaddr = vhost_vq_meta_fetch(vq,
-				     (u64)(uintptr_t)to, size,
-				     VHOST_ADDR_USED);
-
-		if (uaddr)
-			return __copy_to_user(uaddr, from, size);
-
-		ret = translate_desc(vq, (u64)(uintptr_t)to, size, vq->iotlb_iov,
-				     ARRAY_SIZE(vq->iotlb_iov),
-				     VHOST_ACCESS_WO);
-		if (ret < 0)
-			goto out;
-		iov_iter_init(&t, WRITE, vq->iotlb_iov, ret, size);
-		ret = copy_to_iter(from, size, &t);
-		if (ret == size)
-			ret = 0;
-	}
-out:
-	return ret;
-}
-
 static int vhost_copy_from_user(struct vhost_virtqueue *vq, void *to,
 				void __user *from, unsigned size)
 {
@@ -1962,7 +1927,7 @@ static int get_indirect(struct vhost_virtqueue *vq,
  * never a valid descriptor number) if none was found.  A negative code is
  * returned on error. */
 int vhost_get_vq_desc(struct vhost_virtqueue *vq,
-		      struct vring_used_elem *used,
+		      struct vhost_used_elem *used,
 		      struct iovec iov[], unsigned int iov_size,
 		      unsigned int *out_num, unsigned int *in_num,
 		      struct vhost_log *log, unsigned int *log_num)
@@ -2013,7 +1978,7 @@ int vhost_get_vq_desc(struct vhost_virtqueue *vq,
 		return -EFAULT;
 	}
 
-	used->id = ring_head;
+	used->elem.id = ring_head;
 	head = vhost16_to_cpu(vq, ring_head);
 
 	/* If their number is silly, that's an error. */
@@ -2107,9 +2072,9 @@ int vhost_get_vq_desc(struct vhost_virtqueue *vq,
 EXPORT_SYMBOL_GPL(vhost_get_vq_desc);
 
 static void vhost_set_used_len(struct vhost_virtqueue *vq,
-			       struct vring_used_elem *used, int len)
+			       struct vhost_used_elem *used, int len)
 {
-	used->len = cpu_to_vhost32(vq, len);
+	used->elem.len = cpu_to_vhost32(vq, len);
 }
 
 /* This is a multi-buffer version of vhost_get_desc, that works if
@@ -2123,7 +2088,7 @@ static void vhost_set_used_len(struct vhost_virtqueue *vq,
  *	returns number of buffer heads allocated, negative on error
  */
 int vhost_get_bufs(struct vhost_virtqueue *vq,
-		   struct vring_used_elem *heads,
+		   struct vhost_used_elem *heads,
 		   int datalen,
 		   unsigned *iovcount,
 		   struct vhost_log *log,
@@ -2196,7 +2161,7 @@ EXPORT_SYMBOL_GPL(vhost_discard_vq_desc);
 
 /* After we've used one of their buffers, we tell them about it.  We'll then
  * want to notify the guest, using eventfd. */
-int vhost_add_used(struct vhost_virtqueue *vq, struct vring_used_elem *used,
+int vhost_add_used(struct vhost_virtqueue *vq, struct vhost_used_elem *used,
 		   int len)
 {
 	vhost_set_used_len(vq, used, len);
@@ -2205,27 +2170,26 @@ int vhost_add_used(struct vhost_virtqueue *vq, struct vring_used_elem *used,
 EXPORT_SYMBOL_GPL(vhost_add_used);
 
 static int __vhost_add_used_n(struct vhost_virtqueue *vq,
-			    struct vring_used_elem *heads,
+			    struct vhost_used_elem *heads,
 			    unsigned count)
 {
 	struct vring_used_elem __user *used;
 	u16 old, new;
-	int start;
+	int start, i;
 
 	start = vq->last_used_idx & (vq->num - 1);
 	used = vq->used->ring + start;
-	if (count == 1) {
-		if (vhost_put_user(vq, heads[0].id, &used->id)) {
+	for (i = 0; i < count; i++) {
+		if (unlikely(vhost_put_user(vq, heads[i].elem.id,
+					    &used[i].id))) {
 			vq_err(vq, "Failed to write used id");
 			return -EFAULT;
 		}
-		if (vhost_put_user(vq, heads[0].len, &used->len)) {
+		if (unlikely(vhost_put_user(vq, heads[i].elem.len,
+					    &used[i].len))) {
 			vq_err(vq, "Failed to write used len");
 			return -EFAULT;
 		}
-	} else if (vhost_copy_to_user(vq, used, heads, count * sizeof *used)) {
-		vq_err(vq, "Failed to write used");
-		return -EFAULT;
 	}
 	if (unlikely(vq->log_used)) {
 		/* Make sure data is seen before log. */
@@ -2249,7 +2213,7 @@ static int __vhost_add_used_n(struct vhost_virtqueue *vq,
 
 /* After we've used one of their buffers, we tell them about it.  We'll then
  * want to notify the guest, using eventfd. */
-int vhost_add_used_n(struct vhost_virtqueue *vq, struct vring_used_elem *heads,
+int vhost_add_used_n(struct vhost_virtqueue *vq, struct vhost_used_elem *heads,
 		     unsigned count)
 {
 	int start, n, r;
@@ -2333,7 +2297,7 @@ EXPORT_SYMBOL_GPL(vhost_signal);
 /* And here's the combo meal deal.  Supersize me! */
 void vhost_add_used_and_signal(struct vhost_dev *dev,
 			       struct vhost_virtqueue *vq,
-			       struct vring_used_elem *used, int len)
+			       struct vhost_used_elem *used, int len)
 {
 	vhost_add_used(vq, used, len);
 	vhost_signal(dev, vq);
@@ -2343,7 +2307,7 @@ EXPORT_SYMBOL_GPL(vhost_add_used_and_signal);
 /* multi-buffer version of vhost_add_used_and_signal */
 void vhost_add_used_and_signal_n(struct vhost_dev *dev,
 				 struct vhost_virtqueue *vq,
-				 struct vring_used_elem *heads, unsigned count)
+				 struct vhost_used_elem *heads, unsigned count)
 {
 	vhost_add_used_n(vq, heads, count);
 	vhost_signal(dev, vq);
diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
index a7cc7e7..8dea44b 100644
--- a/drivers/vhost/vhost.h
+++ b/drivers/vhost/vhost.h
@@ -34,6 +34,10 @@ struct vhost_poll {
 	struct vhost_dev	 *dev;
 };
 
+struct vhost_used_elem {
+	struct vring_used_elem elem;
+};
+
 void vhost_work_init(struct vhost_work *work, vhost_work_fn_t fn);
 void vhost_work_queue(struct vhost_dev *dev, struct vhost_work *work);
 bool vhost_has_work(struct vhost_dev *dev);
@@ -126,7 +130,7 @@ struct vhost_virtqueue {
 	struct iovec iov[UIO_MAXIOV];
 	struct iovec iotlb_iov[64];
 	struct iovec *indirect;
-	struct vring_used_elem *heads;
+	struct vhost_used_elem *heads;
 	/* Protected by virtqueue mutex. */
 	struct vhost_umem *umem;
 	struct vhost_umem *iotlb;
@@ -182,12 +186,12 @@ bool vhost_vq_access_ok(struct vhost_virtqueue *vq);
 bool vhost_log_access_ok(struct vhost_dev *);
 
 int vhost_get_vq_desc(struct vhost_virtqueue *,
-		      struct vring_used_elem *used_elem,
+		      struct vhost_used_elem *used_elem,
 		      struct iovec iov[], unsigned int iov_count,
 		      unsigned int *out_num, unsigned int *in_num,
 		      struct vhost_log *log, unsigned int *log_num);
 int vhost_get_bufs(struct vhost_virtqueue *vq,
-		   struct vring_used_elem *heads,
+		   struct vhost_used_elem *heads,
 		   int datalen,
 		   unsigned *iovcount,
 		   struct vhost_log *log,
@@ -198,13 +202,13 @@ void vhost_discard_vq_desc(struct vhost_virtqueue *, int n);
 
 int vhost_vq_init_access(struct vhost_virtqueue *);
 int vhost_add_used(struct vhost_virtqueue *vq,
-		   struct vring_used_elem *elem, int len);
-int vhost_add_used_n(struct vhost_virtqueue *, struct vring_used_elem *heads,
+		   struct vhost_used_elem *elem, int len);
+int vhost_add_used_n(struct vhost_virtqueue *vq, struct vhost_used_elem *heads,
 		     unsigned count);
 void vhost_add_used_and_signal(struct vhost_dev *, struct vhost_virtqueue *,
-			       struct vring_used_elem *, int len);
+			       struct vhost_used_elem *, int len);
 void vhost_add_used_and_signal_n(struct vhost_dev *, struct vhost_virtqueue *,
-			       struct vring_used_elem *heads, unsigned count);
+			       struct vhost_used_elem *heads, unsigned count);
 void vhost_signal(struct vhost_dev *, struct vhost_virtqueue *);
 void vhost_disable_notify(struct vhost_dev *, struct vhost_virtqueue *);
 bool vhost_vq_avail_empty(struct vhost_dev *, struct vhost_virtqueue *);
diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
index 59a01cd..695694f 100644
--- a/drivers/vhost/vsock.c
+++ b/drivers/vhost/vsock.c
@@ -98,7 +98,7 @@ vhost_transport_do_send_pkt(struct vhost_vsock *vsock,
 
 	for (;;) {
 		struct virtio_vsock_pkt *pkt;
-		struct vring_used_elem used;
+		struct vhost_used_elem used;
 		struct iov_iter iov_iter;
 		unsigned out, in;
 		size_t nbytes;
@@ -146,7 +146,7 @@ vhost_transport_do_send_pkt(struct vhost_vsock *vsock,
 			break;
 		}
 
-		len = vhost32_to_cpu(vq, used.len);
+		len = vhost32_to_cpu(vq, used.elem.len);
 		iov_iter_init(&iov_iter, READ, &vq->iov[out], in, len);
 
 		nbytes = copy_to_iter(&pkt->hdr, sizeof(pkt->hdr), &iov_iter);
@@ -346,7 +346,7 @@ static void vhost_vsock_handle_tx_kick(struct vhost_work *work)
 	struct vhost_vsock *vsock = container_of(vq->dev, struct vhost_vsock,
 						 dev);
 	struct virtio_vsock_pkt *pkt;
-	struct vring_used_elem used;
+	struct vhost_used_elem used;
 	int ret;
 	unsigned int out, in;
 	bool added = false;
-- 
2.7.4

^ permalink raw reply related

* [PATCH net-next V2 2/8] vhost: hide used ring layout from device
From: Jason Wang @ 2018-07-16  3:28 UTC (permalink / raw)
  To: mst, jasowang
  Cc: kvm, virtualization, netdev, linux-kernel, wexu, jfreimann,
	tiwei.bie, maxime.coquelin
In-Reply-To: <1531711691-6769-1-git-send-email-jasowang@redhat.com>

We used to return descriptor head by vhost_get_vq_desc() to device and
pass it back to vhost_add_used() and its friends. This exposes the
internal used ring layout to device which makes it hard to be extended for
e.g packed ring layout.

So this patch tries to hide the used ring layout by

- letting vhost_get_vq_desc() return pointer to struct vring_used_elem
- accepting pointer to struct vring_used_elem in vhost_add_used() and
  vhost_add_used_and_signal()

This could help to hide used ring layout and make it easier to
implement packed ring on top.

Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 drivers/vhost/net.c   | 48 +++++++++++++++++++++------------------
 drivers/vhost/scsi.c  | 62 +++++++++++++++++++++++++++------------------------
 drivers/vhost/vhost.c | 52 +++++++++++++++++++++---------------------
 drivers/vhost/vhost.h |  9 +++++---
 drivers/vhost/vsock.c | 42 +++++++++++++++++-----------------
 5 files changed, 113 insertions(+), 100 deletions(-)

diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index 03dd1de..a8c9506 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -430,15 +430,16 @@ static int vhost_net_enable_vq(struct vhost_net *n,
 
 static int vhost_net_tx_get_vq_desc(struct vhost_net *net,
 				    struct vhost_virtqueue *vq,
+				    struct vring_used_elem *used_elem,
 				    struct iovec iov[], unsigned int iov_size,
 				    unsigned int *out_num, unsigned int *in_num,
 				    bool *busyloop_intr)
 {
 	unsigned long uninitialized_var(endtime);
-	int r = vhost_get_vq_desc(vq, vq->iov, ARRAY_SIZE(vq->iov),
+	int r = vhost_get_vq_desc(vq, used_elem, vq->iov, ARRAY_SIZE(vq->iov),
 				  out_num, in_num, NULL, NULL);
 
-	if (r == vq->num && vq->busyloop_timeout) {
+	if (r == -ENOSPC && vq->busyloop_timeout) {
 		preempt_disable();
 		endtime = busy_clock() + vq->busyloop_timeout;
 		while (vhost_can_busy_poll(endtime)) {
@@ -451,8 +452,9 @@ static int vhost_net_tx_get_vq_desc(struct vhost_net *net,
 			cpu_relax();
 		}
 		preempt_enable();
-		r = vhost_get_vq_desc(vq, vq->iov, ARRAY_SIZE(vq->iov),
-				      out_num, in_num, NULL, NULL);
+		r = vhost_get_vq_desc(vq, used_elem, vq->iov,
+				      ARRAY_SIZE(vq->iov), out_num, in_num,
+				      NULL, NULL);
 	}
 
 	return r;
@@ -474,7 +476,6 @@ static void handle_tx(struct vhost_net *net)
 	struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX];
 	struct vhost_virtqueue *vq = &nvq->vq;
 	unsigned out, in;
-	int head;
 	struct msghdr msg = {
 		.msg_name = NULL,
 		.msg_namelen = 0,
@@ -487,6 +488,7 @@ static void handle_tx(struct vhost_net *net)
 	size_t hdr_size;
 	struct socket *sock;
 	struct vhost_net_ubuf_ref *uninitialized_var(ubufs);
+	struct vring_used_elem used;
 	bool zcopy, zcopy_used;
 	int sent_pkts = 0;
 
@@ -512,14 +514,11 @@ static void handle_tx(struct vhost_net *net)
 			vhost_zerocopy_signal_used(net, vq);
 
 		busyloop_intr = false;
-		head = vhost_net_tx_get_vq_desc(net, vq, vq->iov,
-						ARRAY_SIZE(vq->iov),
-						&out, &in, &busyloop_intr);
-		/* On error, stop handling until the next kick. */
-		if (unlikely(head < 0))
-			break;
+		err = vhost_net_tx_get_vq_desc(net, vq, &used, vq->iov,
+					       ARRAY_SIZE(vq->iov),
+					       &out, &in, &busyloop_intr);
 		/* Nothing new?  Wait for eventfd to tell us they refilled. */
-		if (head == vq->num) {
+		if (err == -ENOSPC) {
 			if (unlikely(busyloop_intr)) {
 				vhost_poll_queue(&vq->poll);
 			} else if (unlikely(vhost_enable_notify(&net->dev, vq))) {
@@ -528,6 +527,9 @@ static void handle_tx(struct vhost_net *net)
 			}
 			break;
 		}
+		/* On error, stop handling until the next kick. */
+		if (unlikely(err < 0))
+			break;
 		if (in) {
 			vq_err(vq, "Unexpected descriptor format for TX: "
 			       "out %d, int %d\n", out, in);
@@ -555,7 +557,8 @@ static void handle_tx(struct vhost_net *net)
 			struct ubuf_info *ubuf;
 			ubuf = nvq->ubuf_info + nvq->upend_idx;
 
-			vq->heads[nvq->upend_idx].id = cpu_to_vhost32(vq, head);
+			vq->heads[nvq->upend_idx].id =
+				cpu_to_vhost32(vq, used.id);
 			vq->heads[nvq->upend_idx].len = VHOST_DMA_IN_PROGRESS;
 			ubuf->callback = vhost_zerocopy_callback;
 			ubuf->ctx = nvq->ubufs;
@@ -596,7 +599,7 @@ static void handle_tx(struct vhost_net *net)
 			pr_debug("Truncated TX packet: "
 				 " len %d != %zd\n", err, len);
 		if (!zcopy_used)
-			vhost_add_used_and_signal(&net->dev, vq, head, 0);
+			vhost_add_used_and_signal(&net->dev, vq, &used, 0);
 		else
 			vhost_zerocopy_signal_used(net, vq);
 		vhost_net_tx_packet(net);
@@ -754,17 +757,15 @@ static void handle_rx(struct vhost_net *net)
 						      &busyloop_intr))) {
 		sock_len += sock_hlen;
 		vhost_len = sock_len + vhost_hlen;
-		headcount = vhost_get_bufs(vq, vq->heads + nvq->done_idx,
-					   vhost_len, &in, vq_log, &log,
-					   likely(mergeable) ? UIO_MAXIOV : 1);
-		/* On error, stop handling until the next kick. */
-		if (unlikely(headcount < 0))
-			goto out;
+		err = vhost_get_bufs(vq, vq->heads + nvq->done_idx,
+				     vhost_len, &in, vq_log, &log,
+				     likely(mergeable) ? UIO_MAXIOV : 1,
+				     &headcount);
 		/* OK, now we need to know about added descriptors. */
-		if (!headcount) {
+		if (err == -ENOSPC) {
 			if (unlikely(busyloop_intr)) {
 				vhost_poll_queue(&vq->poll);
-			} else if (unlikely(vhost_enable_notify(&net->dev, vq))) {
+			}else if (unlikely(vhost_enable_notify(&net->dev, vq))) {
 				/* They have slipped one in as we were
 				 * doing that: check again. */
 				vhost_disable_notify(&net->dev, vq);
@@ -775,6 +776,9 @@ static void handle_rx(struct vhost_net *net)
 			goto out;
 		}
 		busyloop_intr = false;
+		/* On error, stop handling until the next kick. */
+		if (unlikely(err < 0))
+			goto out;
 		if (nvq->rx_ring)
 			msg.msg_control = vhost_net_buf_consume(&nvq->rxq);
 		/* On overrun, truncate and discard */
diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c
index 17fcd3b..013464c 100644
--- a/drivers/vhost/scsi.c
+++ b/drivers/vhost/scsi.c
@@ -67,7 +67,7 @@ struct vhost_scsi_inflight {
 
 struct vhost_scsi_cmd {
 	/* Descriptor from vhost_get_vq_desc() for virt_queue segment */
-	int tvc_vq_desc;
+	struct vring_used_elem tvc_vq_used;
 	/* virtio-scsi initiator task attribute */
 	int tvc_task_attr;
 	/* virtio-scsi response incoming iovecs */
@@ -441,8 +441,9 @@ vhost_scsi_do_evt_work(struct vhost_scsi *vs, struct vhost_scsi_evt *evt)
 	struct vhost_virtqueue *vq = &vs->vqs[VHOST_SCSI_VQ_EVT].vq;
 	struct virtio_scsi_event *event = &evt->event;
 	struct virtio_scsi_event __user *eventp;
+	struct vring_used_elem used;
 	unsigned out, in;
-	int head, ret;
+	int ret;
 
 	if (!vq->private_data) {
 		vs->vs_events_missed = true;
@@ -451,16 +452,16 @@ vhost_scsi_do_evt_work(struct vhost_scsi *vs, struct vhost_scsi_evt *evt)
 
 again:
 	vhost_disable_notify(&vs->dev, vq);
-	head = vhost_get_vq_desc(vq, vq->iov,
+	ret = vhost_get_vq_desc(vq, &used, vq->iov,
 			ARRAY_SIZE(vq->iov), &out, &in,
 			NULL, NULL);
-	if (head < 0) {
+	if (ret == -ENOSPC) {
+		if (vhost_enable_notify(&vs->dev, vq))
+			goto again;
 		vs->vs_events_missed = true;
 		return;
 	}
-	if (head == vq->num) {
-		if (vhost_enable_notify(&vs->dev, vq))
-			goto again;
+	if (ret < 0) {
 		vs->vs_events_missed = true;
 		return;
 	}
@@ -480,7 +481,7 @@ vhost_scsi_do_evt_work(struct vhost_scsi *vs, struct vhost_scsi_evt *evt)
 	eventp = vq->iov[out].iov_base;
 	ret = __copy_to_user(eventp, event, sizeof(*event));
 	if (!ret)
-		vhost_add_used_and_signal(&vs->dev, vq, head, 0);
+		vhost_add_used_and_signal(&vs->dev, vq, &used, 0);
 	else
 		vq_err(vq, "Faulted on vhost_scsi_send_event\n");
 }
@@ -541,7 +542,7 @@ static void vhost_scsi_complete_cmd_work(struct vhost_work *work)
 		ret = copy_to_iter(&v_rsp, sizeof(v_rsp), &iov_iter);
 		if (likely(ret == sizeof(v_rsp))) {
 			struct vhost_scsi_virtqueue *q;
-			vhost_add_used(cmd->tvc_vq, cmd->tvc_vq_desc, 0);
+			vhost_add_used(cmd->tvc_vq, &cmd->tvc_vq_used, 0);
 			q = container_of(cmd->tvc_vq, struct vhost_scsi_virtqueue, vq);
 			vq = q - vs->vqs;
 			__set_bit(vq, signal);
@@ -784,7 +785,7 @@ static void vhost_scsi_submission_work(struct work_struct *work)
 static void
 vhost_scsi_send_bad_target(struct vhost_scsi *vs,
 			   struct vhost_virtqueue *vq,
-			   int head, unsigned out)
+			   struct vring_used_elem *used, unsigned out)
 {
 	struct virtio_scsi_cmd_resp __user *resp;
 	struct virtio_scsi_cmd_resp rsp;
@@ -795,7 +796,7 @@ vhost_scsi_send_bad_target(struct vhost_scsi *vs,
 	resp = vq->iov[out].iov_base;
 	ret = __copy_to_user(resp, &rsp, sizeof(rsp));
 	if (!ret)
-		vhost_add_used_and_signal(&vs->dev, vq, head, 0);
+		vhost_add_used_and_signal(&vs->dev, vq, used, 0);
 	else
 		pr_err("Faulted on virtio_scsi_cmd_resp\n");
 }
@@ -807,11 +808,12 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
 	struct virtio_scsi_cmd_req v_req;
 	struct virtio_scsi_cmd_req_pi v_req_pi;
 	struct vhost_scsi_cmd *cmd;
+	struct vring_used_elem used;
 	struct iov_iter out_iter, in_iter, prot_iter, data_iter;
 	u64 tag;
 	u32 exp_data_len, data_direction;
 	unsigned int out = 0, in = 0;
-	int head, ret, prot_bytes;
+	int ret, prot_bytes;
 	size_t req_size, rsp_size = sizeof(struct virtio_scsi_cmd_resp);
 	size_t out_size, in_size;
 	u16 lun;
@@ -831,22 +833,22 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
 	vhost_disable_notify(&vs->dev, vq);
 
 	for (;;) {
-		head = vhost_get_vq_desc(vq, vq->iov,
-					 ARRAY_SIZE(vq->iov), &out, &in,
-					 NULL, NULL);
+		ret = vhost_get_vq_desc(vq, &used, vq->iov,
+					ARRAY_SIZE(vq->iov), &out, &in,
+					NULL, NULL);
 		pr_debug("vhost_get_vq_desc: head: %d, out: %u in: %u\n",
-			 head, out, in);
-		/* On error, stop handling until the next kick. */
-		if (unlikely(head < 0))
-			break;
+			 used.id, out, in);
 		/* Nothing new?  Wait for eventfd to tell us they refilled. */
-		if (head == vq->num) {
+		if (ret == -ENOSPC) {
 			if (unlikely(vhost_enable_notify(&vs->dev, vq))) {
 				vhost_disable_notify(&vs->dev, vq);
 				continue;
 			}
 			break;
 		}
+		/* On error, stop handling until the next kick. */
+		if (unlikely(ret < 0))
+			break;
 		/*
 		 * Check for a sane response buffer so we can report early
 		 * errors back to the guest.
@@ -891,20 +893,20 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
 
 		if (unlikely(!copy_from_iter_full(req, req_size, &out_iter))) {
 			vq_err(vq, "Faulted on copy_from_iter\n");
-			vhost_scsi_send_bad_target(vs, vq, head, out);
+			vhost_scsi_send_bad_target(vs, vq, &used, out);
 			continue;
 		}
 		/* virtio-scsi spec requires byte 0 of the lun to be 1 */
 		if (unlikely(*lunp != 1)) {
 			vq_err(vq, "Illegal virtio-scsi lun: %u\n", *lunp);
-			vhost_scsi_send_bad_target(vs, vq, head, out);
+			vhost_scsi_send_bad_target(vs, vq, &used, out);
 			continue;
 		}
 
 		tpg = READ_ONCE(vs_tpg[*target]);
 		if (unlikely(!tpg)) {
 			/* Target does not exist, fail the request */
-			vhost_scsi_send_bad_target(vs, vq, head, out);
+			vhost_scsi_send_bad_target(vs, vq, &used, out);
 			continue;
 		}
 		/*
@@ -950,7 +952,8 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
 				if (data_direction != DMA_TO_DEVICE) {
 					vq_err(vq, "Received non zero pi_bytesout,"
 						" but wrong data_direction\n");
-					vhost_scsi_send_bad_target(vs, vq, head, out);
+					vhost_scsi_send_bad_target(vs, vq,
+								   &used, out);
 					continue;
 				}
 				prot_bytes = vhost32_to_cpu(vq, v_req_pi.pi_bytesout);
@@ -958,7 +961,8 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
 				if (data_direction != DMA_FROM_DEVICE) {
 					vq_err(vq, "Received non zero pi_bytesin,"
 						" but wrong data_direction\n");
-					vhost_scsi_send_bad_target(vs, vq, head, out);
+					vhost_scsi_send_bad_target(vs, vq,
+								   &used, out);
 					continue;
 				}
 				prot_bytes = vhost32_to_cpu(vq, v_req_pi.pi_bytesin);
@@ -996,7 +1000,7 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
 			vq_err(vq, "Received SCSI CDB with command_size: %d that"
 				" exceeds SCSI_MAX_VARLEN_CDB_SIZE: %d\n",
 				scsi_command_size(cdb), VHOST_SCSI_MAX_CDB_SIZE);
-			vhost_scsi_send_bad_target(vs, vq, head, out);
+			vhost_scsi_send_bad_target(vs, vq, &used, out);
 			continue;
 		}
 		cmd = vhost_scsi_get_tag(vq, tpg, cdb, tag, lun, task_attr,
@@ -1005,7 +1009,7 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
 		if (IS_ERR(cmd)) {
 			vq_err(vq, "vhost_scsi_get_tag failed %ld\n",
 			       PTR_ERR(cmd));
-			vhost_scsi_send_bad_target(vs, vq, head, out);
+			vhost_scsi_send_bad_target(vs, vq, &used, out);
 			continue;
 		}
 		cmd->tvc_vhost = vs;
@@ -1025,7 +1029,7 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
 			if (unlikely(ret)) {
 				vq_err(vq, "Failed to map iov to sgl\n");
 				vhost_scsi_release_cmd(&cmd->tvc_se_cmd);
-				vhost_scsi_send_bad_target(vs, vq, head, out);
+				vhost_scsi_send_bad_target(vs, vq, &used, out);
 				continue;
 			}
 		}
@@ -1034,7 +1038,7 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
 		 * complete the virtio-scsi request in TCM callback context via
 		 * vhost_scsi_queue_data_in() and vhost_scsi_queue_status()
 		 */
-		cmd->tvc_vq_desc = head;
+		cmd->tvc_vq_used = used;
 		/*
 		 * Dispatch cmd descriptor for cmwq execution in process
 		 * context provided by vhost_scsi_workqueue.  This also ensures
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 8814e5b..9572c4f 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -1962,6 +1962,7 @@ static int get_indirect(struct vhost_virtqueue *vq,
  * never a valid descriptor number) if none was found.  A negative code is
  * returned on error. */
 int vhost_get_vq_desc(struct vhost_virtqueue *vq,
+		      struct vring_used_elem *used,
 		      struct iovec iov[], unsigned int iov_size,
 		      unsigned int *out_num, unsigned int *in_num,
 		      struct vhost_log *log, unsigned int *log_num)
@@ -1994,7 +1995,7 @@ int vhost_get_vq_desc(struct vhost_virtqueue *vq,
 		 * invalid.
 		 */
 		if (vq->avail_idx == last_avail_idx)
-			return vq->num;
+			return -ENOSPC;
 
 		/* Only get avail ring entries after they have been
 		 * exposed by guest.
@@ -2012,6 +2013,7 @@ int vhost_get_vq_desc(struct vhost_virtqueue *vq,
 		return -EFAULT;
 	}
 
+	used->id = ring_head;
 	head = vhost16_to_cpu(vq, ring_head);
 
 	/* If their number is silly, that's an error. */
@@ -2100,10 +2102,16 @@ int vhost_get_vq_desc(struct vhost_virtqueue *vq,
 	/* Assume notifications from guest are disabled at this point,
 	 * if they aren't we would need to update avail_event index. */
 	BUG_ON(!(vq->used_flags & VRING_USED_F_NO_NOTIFY));
-	return head;
+	return 0;
 }
 EXPORT_SYMBOL_GPL(vhost_get_vq_desc);
 
+static void vhost_set_used_len(struct vhost_virtqueue *vq,
+			       struct vring_used_elem *used, int len)
+{
+	used->len = cpu_to_vhost32(vq, len);
+}
+
 /* This is a multi-buffer version of vhost_get_desc, that works if
  *	vq has read descriptors only.
  * @vq		- the relevant virtqueue
@@ -2120,13 +2128,13 @@ int vhost_get_bufs(struct vhost_virtqueue *vq,
 		   unsigned *iovcount,
 		   struct vhost_log *log,
 		   unsigned *log_num,
-		   unsigned int quota)
+		   unsigned int quota,
+		   s16 *count)
 {
 	unsigned int out, in;
 	int seg = 0;
 	int headcount = 0;
-	unsigned d;
-	int r, nlogs = 0;
+	int r = 0, nlogs = 0;
 	/* len is always initialized before use since we are always called with
 	 * datalen > 0.
 	 */
@@ -2137,17 +2145,12 @@ int vhost_get_bufs(struct vhost_virtqueue *vq,
 			r = -ENOBUFS;
 			goto err;
 		}
-		r = vhost_get_vq_desc(vq, vq->iov + seg,
+		r = vhost_get_vq_desc(vq, &heads[headcount], vq->iov + seg,
 				      ARRAY_SIZE(vq->iov) - seg, &out,
 				      &in, log, log_num);
 		if (unlikely(r < 0))
 			goto err;
 
-		d = r;
-		if (d == vq->num) {
-			r = 0;
-			goto err;
-		}
 		if (unlikely(out || in <= 0)) {
 			vq_err(vq, "unexpected descriptor format for RX: "
 				"out %d, in %d\n", out, in);
@@ -2158,24 +2161,26 @@ int vhost_get_bufs(struct vhost_virtqueue *vq,
 			nlogs += *log_num;
 			log += *log_num;
 		}
-		heads[headcount].id = cpu_to_vhost32(vq, d);
+
 		len = iov_length(vq->iov + seg, in);
-		heads[headcount].len = cpu_to_vhost32(vq, len);
+		vhost_set_used_len(vq, &heads[headcount], len);
 		datalen -= len;
 		++headcount;
 		seg += in;
 	}
-	heads[headcount - 1].len = cpu_to_vhost32(vq, len + datalen);
+	vhost_set_used_len(vq, &heads[headcount - 1], len + datalen);
 	*iovcount = seg;
 	if (unlikely(log))
 		*log_num = nlogs;
 
 	/* Detect overrun */
 	if (unlikely(datalen > 0)) {
-		r = UIO_MAXIOV + 1;
+		headcount = UIO_MAXIOV + 1;
 		goto err;
 	}
-	return headcount;
+
+	*count = headcount;
+	return 0;
 err:
 	vhost_discard_vq_desc(vq, headcount);
 	return r;
@@ -2191,14 +2196,11 @@ EXPORT_SYMBOL_GPL(vhost_discard_vq_desc);
 
 /* After we've used one of their buffers, we tell them about it.  We'll then
  * want to notify the guest, using eventfd. */
-int vhost_add_used(struct vhost_virtqueue *vq, unsigned int head, int len)
+int vhost_add_used(struct vhost_virtqueue *vq, struct vring_used_elem *used,
+		   int len)
 {
-	struct vring_used_elem heads = {
-		cpu_to_vhost32(vq, head),
-		cpu_to_vhost32(vq, len)
-	};
-
-	return vhost_add_used_n(vq, &heads, 1);
+	vhost_set_used_len(vq, used, len);
+	return vhost_add_used_n(vq, used, 1);
 }
 EXPORT_SYMBOL_GPL(vhost_add_used);
 
@@ -2331,9 +2333,9 @@ EXPORT_SYMBOL_GPL(vhost_signal);
 /* And here's the combo meal deal.  Supersize me! */
 void vhost_add_used_and_signal(struct vhost_dev *dev,
 			       struct vhost_virtqueue *vq,
-			       unsigned int head, int len)
+			       struct vring_used_elem *used, int len)
 {
-	vhost_add_used(vq, head, len);
+	vhost_add_used(vq, used, len);
 	vhost_signal(dev, vq);
 }
 EXPORT_SYMBOL_GPL(vhost_add_used_and_signal);
diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
index 52edd242..a7cc7e7 100644
--- a/drivers/vhost/vhost.h
+++ b/drivers/vhost/vhost.h
@@ -182,6 +182,7 @@ bool vhost_vq_access_ok(struct vhost_virtqueue *vq);
 bool vhost_log_access_ok(struct vhost_dev *);
 
 int vhost_get_vq_desc(struct vhost_virtqueue *,
+		      struct vring_used_elem *used_elem,
 		      struct iovec iov[], unsigned int iov_count,
 		      unsigned int *out_num, unsigned int *in_num,
 		      struct vhost_log *log, unsigned int *log_num);
@@ -191,15 +192,17 @@ int vhost_get_bufs(struct vhost_virtqueue *vq,
 		   unsigned *iovcount,
 		   struct vhost_log *log,
 		   unsigned *log_num,
-		   unsigned int quota);
+		   unsigned int quota,
+		   s16 *count);
 void vhost_discard_vq_desc(struct vhost_virtqueue *, int n);
 
 int vhost_vq_init_access(struct vhost_virtqueue *);
-int vhost_add_used(struct vhost_virtqueue *, unsigned int head, int len);
+int vhost_add_used(struct vhost_virtqueue *vq,
+		   struct vring_used_elem *elem, int len);
 int vhost_add_used_n(struct vhost_virtqueue *, struct vring_used_elem *heads,
 		     unsigned count);
 void vhost_add_used_and_signal(struct vhost_dev *, struct vhost_virtqueue *,
-			       unsigned int id, int len);
+			       struct vring_used_elem *, int len);
 void vhost_add_used_and_signal_n(struct vhost_dev *, struct vhost_virtqueue *,
 			       struct vring_used_elem *heads, unsigned count);
 void vhost_signal(struct vhost_dev *, struct vhost_virtqueue *);
diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
index 34bc3ab..59a01cd 100644
--- a/drivers/vhost/vsock.c
+++ b/drivers/vhost/vsock.c
@@ -98,11 +98,12 @@ vhost_transport_do_send_pkt(struct vhost_vsock *vsock,
 
 	for (;;) {
 		struct virtio_vsock_pkt *pkt;
+		struct vring_used_elem used;
 		struct iov_iter iov_iter;
 		unsigned out, in;
 		size_t nbytes;
 		size_t len;
-		int head;
+		int ret;
 
 		spin_lock_bh(&vsock->send_pkt_list_lock);
 		if (list_empty(&vsock->send_pkt_list)) {
@@ -116,16 +117,9 @@ vhost_transport_do_send_pkt(struct vhost_vsock *vsock,
 		list_del_init(&pkt->list);
 		spin_unlock_bh(&vsock->send_pkt_list_lock);
 
-		head = vhost_get_vq_desc(vq, vq->iov, ARRAY_SIZE(vq->iov),
-					 &out, &in, NULL, NULL);
-		if (head < 0) {
-			spin_lock_bh(&vsock->send_pkt_list_lock);
-			list_add(&pkt->list, &vsock->send_pkt_list);
-			spin_unlock_bh(&vsock->send_pkt_list_lock);
-			break;
-		}
-
-		if (head == vq->num) {
+		ret = vhost_get_vq_desc(vq, &used, vq->iov, ARRAY_SIZE(vq->iov),
+					&out, &in, NULL, NULL);
+		if (ret == -ENOSPC) {
 			spin_lock_bh(&vsock->send_pkt_list_lock);
 			list_add(&pkt->list, &vsock->send_pkt_list);
 			spin_unlock_bh(&vsock->send_pkt_list_lock);
@@ -139,6 +133,12 @@ vhost_transport_do_send_pkt(struct vhost_vsock *vsock,
 			}
 			break;
 		}
+		if (ret < 0) {
+			spin_lock_bh(&vsock->send_pkt_list_lock);
+			list_add(&pkt->list, &vsock->send_pkt_list);
+			spin_unlock_bh(&vsock->send_pkt_list_lock);
+			break;
+		}
 
 		if (out) {
 			virtio_transport_free_pkt(pkt);
@@ -146,7 +146,7 @@ vhost_transport_do_send_pkt(struct vhost_vsock *vsock,
 			break;
 		}
 
-		len = iov_length(&vq->iov[out], in);
+		len = vhost32_to_cpu(vq, used.len);
 		iov_iter_init(&iov_iter, READ, &vq->iov[out], in, len);
 
 		nbytes = copy_to_iter(&pkt->hdr, sizeof(pkt->hdr), &iov_iter);
@@ -163,7 +163,7 @@ vhost_transport_do_send_pkt(struct vhost_vsock *vsock,
 			break;
 		}
 
-		vhost_add_used(vq, head, sizeof(pkt->hdr) + pkt->len);
+		vhost_add_used(vq, &used, sizeof(pkt->hdr) + pkt->len);
 		added = true;
 
 		if (pkt->reply) {
@@ -346,7 +346,8 @@ static void vhost_vsock_handle_tx_kick(struct vhost_work *work)
 	struct vhost_vsock *vsock = container_of(vq->dev, struct vhost_vsock,
 						 dev);
 	struct virtio_vsock_pkt *pkt;
-	int head;
+	struct vring_used_elem used;
+	int ret;
 	unsigned int out, in;
 	bool added = false;
 
@@ -367,18 +368,17 @@ static void vhost_vsock_handle_tx_kick(struct vhost_work *work)
 			goto no_more_replies;
 		}
 
-		head = vhost_get_vq_desc(vq, vq->iov, ARRAY_SIZE(vq->iov),
-					 &out, &in, NULL, NULL);
-		if (head < 0)
-			break;
-
-		if (head == vq->num) {
+		ret = vhost_get_vq_desc(vq, &used, vq->iov, ARRAY_SIZE(vq->iov),
+					&out, &in, NULL, NULL);
+		if (ret == -ENOSPC) {
 			if (unlikely(vhost_enable_notify(&vsock->dev, vq))) {
 				vhost_disable_notify(&vsock->dev, vq);
 				continue;
 			}
 			break;
 		}
+		if (ret < 0)
+			break;
 
 		pkt = vhost_vsock_alloc_pkt(vq, out, in);
 		if (!pkt) {
@@ -397,7 +397,7 @@ static void vhost_vsock_handle_tx_kick(struct vhost_work *work)
 		else
 			virtio_transport_free_pkt(pkt);
 
-		vhost_add_used(vq, head, sizeof(pkt->hdr) + len);
+		vhost_add_used(vq, &used, sizeof(pkt->hdr) + len);
 		added = true;
 	}
 
-- 
2.7.4

^ permalink raw reply related

* [PATCH net-next V2 1/8] vhost: move get_rx_bufs to vhost.c
From: Jason Wang @ 2018-07-16  3:28 UTC (permalink / raw)
  To: mst, jasowang
  Cc: kvm, virtualization, netdev, linux-kernel, wexu, jfreimann,
	tiwei.bie, maxime.coquelin
In-Reply-To: <1531711691-6769-1-git-send-email-jasowang@redhat.com>

Move get_rx_bufs() to vhost.c and rename it to
vhost_get_bufs(). This helps to hide vring internal layout from
specific device implementation. Packed ring implementation will
benefit from this.

Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 drivers/vhost/net.c   | 83 ++-------------------------------------------------
 drivers/vhost/vhost.c | 78 +++++++++++++++++++++++++++++++++++++++++++++++
 drivers/vhost/vhost.h |  7 +++++
 3 files changed, 88 insertions(+), 80 deletions(-)

diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index b224036..03dd1de 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -702,83 +702,6 @@ static int vhost_net_rx_peek_head_len(struct vhost_net *net, struct sock *sk,
 	return len;
 }
 
-/* This is a multi-buffer version of vhost_get_desc, that works if
- *	vq has read descriptors only.
- * @vq		- the relevant virtqueue
- * @datalen	- data length we'll be reading
- * @iovcount	- returned count of io vectors we fill
- * @log		- vhost log
- * @log_num	- log offset
- * @quota       - headcount quota, 1 for big buffer
- *	returns number of buffer heads allocated, negative on error
- */
-static int get_rx_bufs(struct vhost_virtqueue *vq,
-		       struct vring_used_elem *heads,
-		       int datalen,
-		       unsigned *iovcount,
-		       struct vhost_log *log,
-		       unsigned *log_num,
-		       unsigned int quota)
-{
-	unsigned int out, in;
-	int seg = 0;
-	int headcount = 0;
-	unsigned d;
-	int r, nlogs = 0;
-	/* len is always initialized before use since we are always called with
-	 * datalen > 0.
-	 */
-	u32 uninitialized_var(len);
-
-	while (datalen > 0 && headcount < quota) {
-		if (unlikely(seg >= UIO_MAXIOV)) {
-			r = -ENOBUFS;
-			goto err;
-		}
-		r = vhost_get_vq_desc(vq, vq->iov + seg,
-				      ARRAY_SIZE(vq->iov) - seg, &out,
-				      &in, log, log_num);
-		if (unlikely(r < 0))
-			goto err;
-
-		d = r;
-		if (d == vq->num) {
-			r = 0;
-			goto err;
-		}
-		if (unlikely(out || in <= 0)) {
-			vq_err(vq, "unexpected descriptor format for RX: "
-				"out %d, in %d\n", out, in);
-			r = -EINVAL;
-			goto err;
-		}
-		if (unlikely(log)) {
-			nlogs += *log_num;
-			log += *log_num;
-		}
-		heads[headcount].id = cpu_to_vhost32(vq, d);
-		len = iov_length(vq->iov + seg, in);
-		heads[headcount].len = cpu_to_vhost32(vq, len);
-		datalen -= len;
-		++headcount;
-		seg += in;
-	}
-	heads[headcount - 1].len = cpu_to_vhost32(vq, len + datalen);
-	*iovcount = seg;
-	if (unlikely(log))
-		*log_num = nlogs;
-
-	/* Detect overrun */
-	if (unlikely(datalen > 0)) {
-		r = UIO_MAXIOV + 1;
-		goto err;
-	}
-	return headcount;
-err:
-	vhost_discard_vq_desc(vq, headcount);
-	return r;
-}
-
 /* Expects to be always run from workqueue - which acts as
  * read-size critical section for our kind of RCU. */
 static void handle_rx(struct vhost_net *net)
@@ -831,9 +754,9 @@ static void handle_rx(struct vhost_net *net)
 						      &busyloop_intr))) {
 		sock_len += sock_hlen;
 		vhost_len = sock_len + vhost_hlen;
-		headcount = get_rx_bufs(vq, vq->heads + nvq->done_idx,
-					vhost_len, &in, vq_log, &log,
-					likely(mergeable) ? UIO_MAXIOV : 1);
+		headcount = vhost_get_bufs(vq, vq->heads + nvq->done_idx,
+					   vhost_len, &in, vq_log, &log,
+					   likely(mergeable) ? UIO_MAXIOV : 1);
 		/* On error, stop handling until the next kick. */
 		if (unlikely(headcount < 0))
 			goto out;
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index a502f1a..8814e5b 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -2104,6 +2104,84 @@ int vhost_get_vq_desc(struct vhost_virtqueue *vq,
 }
 EXPORT_SYMBOL_GPL(vhost_get_vq_desc);
 
+/* This is a multi-buffer version of vhost_get_desc, that works if
+ *	vq has read descriptors only.
+ * @vq		- the relevant virtqueue
+ * @datalen	- data length we'll be reading
+ * @iovcount	- returned count of io vectors we fill
+ * @log		- vhost log
+ * @log_num	- log offset
+ * @quota       - headcount quota, 1 for big buffer
+ *	returns number of buffer heads allocated, negative on error
+ */
+int vhost_get_bufs(struct vhost_virtqueue *vq,
+		   struct vring_used_elem *heads,
+		   int datalen,
+		   unsigned *iovcount,
+		   struct vhost_log *log,
+		   unsigned *log_num,
+		   unsigned int quota)
+{
+	unsigned int out, in;
+	int seg = 0;
+	int headcount = 0;
+	unsigned d;
+	int r, nlogs = 0;
+	/* len is always initialized before use since we are always called with
+	 * datalen > 0.
+	 */
+	u32 uninitialized_var(len);
+
+	while (datalen > 0 && headcount < quota) {
+		if (unlikely(seg >= UIO_MAXIOV)) {
+			r = -ENOBUFS;
+			goto err;
+		}
+		r = vhost_get_vq_desc(vq, vq->iov + seg,
+				      ARRAY_SIZE(vq->iov) - seg, &out,
+				      &in, log, log_num);
+		if (unlikely(r < 0))
+			goto err;
+
+		d = r;
+		if (d == vq->num) {
+			r = 0;
+			goto err;
+		}
+		if (unlikely(out || in <= 0)) {
+			vq_err(vq, "unexpected descriptor format for RX: "
+				"out %d, in %d\n", out, in);
+			r = -EINVAL;
+			goto err;
+		}
+		if (unlikely(log)) {
+			nlogs += *log_num;
+			log += *log_num;
+		}
+		heads[headcount].id = cpu_to_vhost32(vq, d);
+		len = iov_length(vq->iov + seg, in);
+		heads[headcount].len = cpu_to_vhost32(vq, len);
+		datalen -= len;
+		++headcount;
+		seg += in;
+	}
+	heads[headcount - 1].len = cpu_to_vhost32(vq, len + datalen);
+	*iovcount = seg;
+	if (unlikely(log))
+		*log_num = nlogs;
+
+	/* Detect overrun */
+	if (unlikely(datalen > 0)) {
+		r = UIO_MAXIOV + 1;
+		goto err;
+	}
+	return headcount;
+err:
+	vhost_discard_vq_desc(vq, headcount);
+	return r;
+}
+EXPORT_SYMBOL_GPL(vhost_get_bufs);
+
 /* Reverse the effect of vhost_get_vq_desc. Useful for error handling. */
 void vhost_discard_vq_desc(struct vhost_virtqueue *vq, int n)
 {
diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
index 6c844b9..52edd242 100644
--- a/drivers/vhost/vhost.h
+++ b/drivers/vhost/vhost.h
@@ -185,6 +185,13 @@ int vhost_get_vq_desc(struct vhost_virtqueue *,
 		      struct iovec iov[], unsigned int iov_count,
 		      unsigned int *out_num, unsigned int *in_num,
 		      struct vhost_log *log, unsigned int *log_num);
+int vhost_get_bufs(struct vhost_virtqueue *vq,
+		   struct vring_used_elem *heads,
+		   int datalen,
+		   unsigned *iovcount,
+		   struct vhost_log *log,
+		   unsigned *log_num,
+		   unsigned int quota);
 void vhost_discard_vq_desc(struct vhost_virtqueue *, int n);
 
 int vhost_vq_init_access(struct vhost_virtqueue *);
-- 
2.7.4

^ permalink raw reply related

* [PATCH net-next V2 0/8] Packed virtqueue support for vhost
From: Jason Wang @ 2018-07-16  3:28 UTC (permalink / raw)
  To: mst, jasowang
  Cc: kvm, netdev, linux-kernel, virtualization, maxime.coquelin, wexu

Hi all:

This series implements packed virtqueues. The code were tested with
Tiwei's guest driver series at https://patchwork.ozlabs.org/cover/942297/


Pktgen test for both RX and TX does not show obvious difference with
split virtqueues. The main bottleneck is the guest Linux driver, since
it can not stress vhost for a 100% CPU utilization. A full TCP
benchmark is ongoing. Will test virtio-net pmd as well when it was
ready.

Notes:
- This version depends on Tiwei's series at https://patchwork.ozlabs.org/cover/942297/

This version were tested with:

- Zerocopy (Out of Order) support
- vIOMMU support
- mergeable buffer on/off
- busy polling on/off
- vsock (nc-vsock)

Changes from V1:
- drop uapi patch and use Tiwei's
- split the enablement of packed virtqueue into a separate patch

Changes from RFC V5:

- save unnecessary barriers during vhost_add_used_packed_n()
- more compact math for event idx
- fix failure of SET_VRING_BASE when avail_wrap_counter is true
- fix not copy avail_wrap_counter during GET_VRING_BASE
- introduce SET_VRING_USED_BASE/GET_VRING_USED_BASE for syncing last_used_idx
- rename used_wrap_counter to last_used_wrap_counter
- rebase to net-next

Changes from RFC V4:

- fix signalled_used index recording
- track avail index correctly
- various minor fixes

Changes from RFC V3:

- Fix math on event idx checking
- Sync last avail wrap counter through GET/SET_VRING_BASE
- remove desc_event prefix in the driver/device structure

Changes from RFC V2:

- do not use & in checking desc_event_flags
- off should be most significant bit
- remove the workaround of mergeable buffer for dpdk prototype
- id should be in the last descriptor in the chain
- keep _F_WRITE for write descriptor when adding used
- device flags updating should use ADDR_USED type
- return error on unexpected unavail descriptor in a chain
- return false in vhost_ve_avail_empty is descriptor is available
- track last seen avail_wrap_counter
- correctly examine available descriptor in get_indirect_packed()
- vhost_idx_diff should return u16 instead of bool

Changes from RFC V1:

- Refactor vhost used elem code to avoid open coding on used elem
- Event suppression support (compile test only).
- Indirect descriptor support (compile test only).
- Zerocopy support.
- vIOMMU support.
- SCSI/VSOCK support (compile test only).
- Fix several bugs

Jason Wang (8):
  vhost: move get_rx_bufs to vhost.c
  vhost: hide used ring layout from device
  vhost: do not use vring_used_elem
  vhost_net: do not explicitly manipulate vhost_used_elem
  vhost: vhost_put_user() can accept metadata type
  vhost: packed ring support
  vhost: event suppression for packed ring
  vhost: enable packed virtqueues

 drivers/vhost/net.c        | 143 ++-----
 drivers/vhost/scsi.c       |  62 +--
 drivers/vhost/vhost.c      | 994 ++++++++++++++++++++++++++++++++++++++++-----
 drivers/vhost/vhost.h      |  55 ++-
 drivers/vhost/vsock.c      |  42 +-
 include/uapi/linux/vhost.h |   7 +
 6 files changed, 1035 insertions(+), 268 deletions(-)

-- 
2.7.4

^ permalink raw reply

* Re: [PATCH - revised] rhashtable: detect when object movement might have invalidated a lookup
From: NeilBrown @ 2018-07-16  3:26 UTC (permalink / raw)
  To: Herbert Xu; +Cc: David Miller, tgraf, netdev, linux-kernel, eric.dumazet
In-Reply-To: <20180716021653.xtbyetdfc2uzxub3@gondor.apana.org.au>

[-- Attachment #1: Type: text/plain, Size: 1603 bytes --]

On Mon, Jul 16 2018, Herbert Xu wrote:

> On Mon, Jul 16, 2018 at 11:23:43AM +1000, NeilBrown wrote:
>>
>> kmem_cache_free() directly.  For this, I need rhashtable to be safe if
>> an object is deleted and immediately re-inserted into the same hash
>> chain.
>
> This means that
>
> 	rcu_read_lock();
> 	A = rhashtable_lookup();
> 	use(A);
> 	rcu_read_unlock();
>
> A can turn into object B when it is used.  That is just too strange
> for words.  Can we see some actual code on how this works?

Look in Documenation/RCU/rculist_nulls.txt.
The very first example is a typical lookup for a nulls list.
The above sample code would read:

	rcu_read_lock();
    begin:
        A = rhashtable_lookup(table, key);
        if (IS_ERR(A)) {
        	rcu_read_unlock();
        	goto not_found;
        }
        if (!try_get_ref(A))
        	goto again;
        if (A->key != key) {
        	put_ref(A);
        	goto again;
        }
        rcu_read_unlock();
        use(A);

If you particularly need to see real code rather than sample code, I can
have something for you in a day or so.

Thanks,
NeilBrown

>
> For comparison, the existing net code where this happens A doesn't
> actually change and it simply moves from one hashtable to another.
>
> I'm relucant to add semantics that would restrain on how rhashtable
> works unless we have real and valid use-cases for it.
>
> Cheers,
> -- 
> Email: Herbert Xu <herbert@gondor.apana.org.au>
> Home Page: http://gondor.apana.org.au/~herbert/
> PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 832 bytes --]

^ permalink raw reply

* Re: [PATCH - revised] rhashtable: detect when object movement might have invalidated a lookup
From: Herbert Xu @ 2018-07-16  2:16 UTC (permalink / raw)
  To: NeilBrown; +Cc: David Miller, tgraf, netdev, linux-kernel, eric.dumazet
In-Reply-To: <874lh0t1ls.fsf@notabene.neil.brown.name>

On Mon, Jul 16, 2018 at 11:23:43AM +1000, NeilBrown wrote:
>
> kmem_cache_free() directly.  For this, I need rhashtable to be safe if
> an object is deleted and immediately re-inserted into the same hash
> chain.

This means that

	rcu_read_lock();
	A = rhashtable_lookup();
	use(A);
	rcu_read_unlock();

A can turn into object B when it is used.  That is just too strange
for words.  Can we see some actual code on how this works?

For comparison, the existing net code where this happens A doesn't
actually change and it simply moves from one hashtable to another.

I'm relucant to add semantics that would restrain on how rhashtable
works unless we have real and valid use-cases for it.

Cheers,
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

^ permalink raw reply

* tc mqprio offload command error
From: Chopra, Manish @ 2018-07-16  1:30 UTC (permalink / raw)
  To: Stephen Hemminger, David Miller, Jiri Pirko; +Cc: netdev@vger.kernel.org

Hello Folks,

I am trying to set below command to try mqprio offload on 4.18 kernel. It is throwing the flowing error.

# tc qdisc add dev eth0 root mqprio num_tc 2 map 1 1 1 1 0 0 0 0
RTNETLINK answers: Numerical result out of range

I can't really make out what's wrong with the above command, since this works fine with other OS kernels.
Any thoughts if it is something broken on upstream kernel ?

Thanks,
Manish

^ permalink raw reply

* [PATCH next] bonding: pass link-local packets to bonding master also.
From: Mahesh Bandewar @ 2018-07-16  1:12 UTC (permalink / raw)
  To: Jay Vosburgh, Andy Gospodarek, Veaceslav Falico, David Miller
  Cc: Netdev, Michal Soltys, Mahesh Bandewar, Mahesh Bandewar

From: Mahesh Bandewar <maheshb@google.com>

Commit b89f04c61efe ("bonding: deliver link-local packets with
skb->dev set to link that packets arrived on") changed the behavior
of how link-local-multicast packets are processed. The change in
the behavior broke some legacy use cases where these packets are
expected to arrive on bonding master device also.

This patch passes the packet to the stack with the link it arrived
on as well as passes to the bonding-master device to preserve the
legacy use case.

Reported-by: Michal Soltys <soltys@ziu.info>
Signed-off-by: Mahesh Bandewar <maheshb@google.com>
---
 drivers/net/bonding/bond_main.c | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 9a2ea3c1f949..1d3b7d8448f2 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -1177,9 +1177,22 @@ static rx_handler_result_t bond_handle_frame(struct sk_buff **pskb)
 		}
 	}
 
-	/* don't change skb->dev for link-local packets */
-	if (is_link_local_ether_addr(eth_hdr(skb)->h_dest))
+	/* Link-local multicast packets should be passed to the
+	 * stack on the link they arrive as well as pass them to the
+	 * bond-master device. These packets are mostly usable when
+	 * stack receives it with the link on which they arrive
+	 * (e.g. LLDP) but there may be some legacy behavior that
+	 * expects these packets to appear on bonding master too.
+	 */
+	if (is_link_local_ether_addr(eth_hdr(skb)->h_dest)) {
+		struct sk_buff *nskb = skb_clone(skb, GFP_ATOMIC);
+
+		if (nskb) {
+			nskb->dev = bond->dev;
+			netif_rx(nskb);
+		}
 		return RX_HANDLER_PASS;
+	}
 	if (bond_should_deliver_exact_match(skb, slave, bond))
 		return RX_HANDLER_EXACT;
 
-- 
2.18.0.203.gfac676dfb9-goog

^ permalink raw reply related

* Re: [PATCH - revised] rhashtable: detect when object movement might have invalidated a lookup
From: NeilBrown @ 2018-07-16  1:23 UTC (permalink / raw)
  To: Herbert Xu; +Cc: David Miller, tgraf, netdev, linux-kernel, eric.dumazet
In-Reply-To: <20180716005134.q4rfkfn3m5zzwt62@gondor.apana.org.au>

[-- Attachment #1: Type: text/plain, Size: 3024 bytes --]

On Mon, Jul 16 2018, Herbert Xu wrote:

> On Mon, Jul 16, 2018 at 09:57:11AM +1000, NeilBrown wrote:
>> 
>> Some users of rhashtable might need to change the key
>> of an object and move it to a different location in the table.
>> Other users might want to allocate objects using
>> SLAB_TYPESAFE_BY_RCU which can result in the same memory allocation
>> being used for a different (type-compatible) purpose and similarly
>> end up in a different hash-chain.
>> 
>> To support these, we store a unique NULLS_MARKER at the end of
>> each chain, and when a search fails to find a match, we check
>> if the NULLS marker found was the expected one.  If not,
>> the search is repeated.
>> 
>> The unique NULLS_MARKER is derived from the address of the
>> head of the chain.
>> 
>> If an object is removed and re-added to the same hash chain, we won't
>> notice by looking that the NULLS marker.  In this case we must be sure
>> that it was not re-added *after* its original location, or a lookup may
>> incorrectly fail.  The easiest solution is to ensure it is inserted at
>> the start of the chain.  insert_slow() already does that,
>> insert_fast() does not.  So this patch changes insert_fast to always
>> insert at the head of the chain.
>> 
>> Note that such a user must do their own double-checking of
>> the object found by rhashtable_lookup_fast() after ensuring
>> mutual exclusion which anything that might change the key, such as
>> successfully taking a new reference.
>> 
>> Signed-off-by: NeilBrown <neilb@suse.com>
>
> I still don't understand why we need this feature.  The only
> existing user of this (which currently doesn't use rhashtable)
> does not readd the reused entry to the same table.  IOW the flow
> is always from table A to table B.  After which the entry will
> be properly freed rather than reused.
>
> So who is going to use this?

I want it so I can use SLAB_TYPESAFE_BY_RCU slab caches in lustre.
lustre isn't in mainline any more so I cannot point at the code but the
concept is simple.
Without this, you need to use rcu_free to free any object added to an
rhashtable.
When kmalloc is used, kfree_rcu() can be used, which is fairly painless.
When a kmem_cache is used, you need to provide your own rcu free
function, which is clumsy.
With SLAB_TYPESAFE_BY_RCU, that isn't needed.  The object can be freed
immediately, providing you can cope with it being re-used (as the same
type) immediately.  Part of handling that is coping with the possibility
that it might be inserted into the same hash table, and possibly the
same chain, immediately it is freed.
lustre has 6 different resizable hashtables which I want to convert
to use rhashtable.
I currently need call_rcu handlers for 3 for these.  I want those
3 to use SLAB_TYPESAFE_BY_RCU instead so they can use
kmem_cache_free() directly.  For this, I need rhashtable to be safe if
an object is deleted and immediately re-inserted into the same hash
chain.

Thanks,
NeilBrown

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 832 bytes --]

^ permalink raw reply

* Re: [PATCH - revised] rhashtable: detect when object movement might have invalidated a lookup
From: Herbert Xu @ 2018-07-16  0:51 UTC (permalink / raw)
  To: NeilBrown; +Cc: David Miller, tgraf, netdev, linux-kernel, eric.dumazet
In-Reply-To: <87fu0kt5m0.fsf@notabene.neil.brown.name>

On Mon, Jul 16, 2018 at 09:57:11AM +1000, NeilBrown wrote:
> 
> Some users of rhashtable might need to change the key
> of an object and move it to a different location in the table.
> Other users might want to allocate objects using
> SLAB_TYPESAFE_BY_RCU which can result in the same memory allocation
> being used for a different (type-compatible) purpose and similarly
> end up in a different hash-chain.
> 
> To support these, we store a unique NULLS_MARKER at the end of
> each chain, and when a search fails to find a match, we check
> if the NULLS marker found was the expected one.  If not,
> the search is repeated.
> 
> The unique NULLS_MARKER is derived from the address of the
> head of the chain.
> 
> If an object is removed and re-added to the same hash chain, we won't
> notice by looking that the NULLS marker.  In this case we must be sure
> that it was not re-added *after* its original location, or a lookup may
> incorrectly fail.  The easiest solution is to ensure it is inserted at
> the start of the chain.  insert_slow() already does that,
> insert_fast() does not.  So this patch changes insert_fast to always
> insert at the head of the chain.
> 
> Note that such a user must do their own double-checking of
> the object found by rhashtable_lookup_fast() after ensuring
> mutual exclusion which anything that might change the key, such as
> successfully taking a new reference.
> 
> Signed-off-by: NeilBrown <neilb@suse.com>

I still don't understand why we need this feature.  The only
existing user of this (which currently doesn't use rhashtable)
does not readd the reused entry to the same table.  IOW the flow
is always from table A to table B.  After which the entry will
be properly freed rather than reused.

So who is going to use this?

Cheers,
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

^ permalink raw reply

* Re: [PATCH 2/3] rhashtable: add rhashtable_walk_last_seen()
From: NeilBrown @ 2018-07-15 23:58 UTC (permalink / raw)
  To: David Miller; +Cc: tgraf, herbert, tom, netdev, linux-kernel
In-Reply-To: <20180710.165547.1599531889181336348.davem@davemloft.net>

[-- Attachment #1: Type: text/plain, Size: 504 bytes --]

On Tue, Jul 10 2018, David Miller wrote:

> From: NeilBrown <neilb@suse.com>
> Date: Fri, 06 Jul 2018 17:11:32 +1000
>
>> rhashtable_walk_last_seen() returns the object returned by
>> the previous rhashtable_walk_next(), providing it is still in the
>> table (or was during this grace period).
>> This works even if rhashtable_walk_stop() and rhashtable_talk_start()
>                                                            ^^^^
>
> "walk"

Thanks :-)  Fixed for when I next post.

Thanks,
NeilBrown

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 832 bytes --]

^ permalink raw reply

* [PATCH - revised] rhashtable: detect when object movement might have invalidated a lookup
From: NeilBrown @ 2018-07-15 23:57 UTC (permalink / raw)
  To: David Miller; +Cc: herbert, tgraf, netdev, linux-kernel, eric.dumazet
In-Reply-To: <20180711.224801.1129067473269289703.davem@davemloft.net>

[-- Attachment #1: Type: text/plain, Size: 5355 bytes --]


Some users of rhashtable might need to change the key
of an object and move it to a different location in the table.
Other users might want to allocate objects using
SLAB_TYPESAFE_BY_RCU which can result in the same memory allocation
being used for a different (type-compatible) purpose and similarly
end up in a different hash-chain.

To support these, we store a unique NULLS_MARKER at the end of
each chain, and when a search fails to find a match, we check
if the NULLS marker found was the expected one.  If not,
the search is repeated.

The unique NULLS_MARKER is derived from the address of the
head of the chain.

If an object is removed and re-added to the same hash chain, we won't
notice by looking that the NULLS marker.  In this case we must be sure
that it was not re-added *after* its original location, or a lookup may
incorrectly fail.  The easiest solution is to ensure it is inserted at
the start of the chain.  insert_slow() already does that,
insert_fast() does not.  So this patch changes insert_fast to always
insert at the head of the chain.

Note that such a user must do their own double-checking of
the object found by rhashtable_lookup_fast() after ensuring
mutual exclusion which anything that might change the key, such as
successfully taking a new reference.

Signed-off-by: NeilBrown <neilb@suse.com>
---
 include/linux/rhashtable.h | 35 +++++++++++++++++++++++------------
 lib/rhashtable.c           |  8 +++++---
 2 files changed, 28 insertions(+), 15 deletions(-)

diff --git a/include/linux/rhashtable.h b/include/linux/rhashtable.h
index eb7111039247..10435a77b156 100644
--- a/include/linux/rhashtable.h
+++ b/include/linux/rhashtable.h
@@ -75,8 +75,10 @@ struct bucket_table {
 	struct rhash_head __rcu *buckets[] ____cacheline_aligned_in_smp;
 };
 
+#define	RHT_NULLS_MARKER(ptr)	\
+	((void *)NULLS_MARKER(((unsigned long) (ptr)) >> 1))
 #define INIT_RHT_NULLS_HEAD(ptr)	\
-	((ptr) = (typeof(ptr)) NULLS_MARKER(0))
+	((ptr) = RHT_NULLS_MARKER(&(ptr)))
 
 static inline bool rht_is_a_nulls(const struct rhash_head *ptr)
 {
@@ -471,6 +473,7 @@ static inline struct rhash_head *__rhashtable_lookup(
 		.ht = ht,
 		.key = key,
 	};
+	struct rhash_head __rcu * const *head;
 	struct bucket_table *tbl;
 	struct rhash_head *he;
 	unsigned int hash;
@@ -478,13 +481,19 @@ static inline struct rhash_head *__rhashtable_lookup(
 	tbl = rht_dereference_rcu(ht->tbl, ht);
 restart:
 	hash = rht_key_hashfn(ht, tbl, key, params);
-	rht_for_each_rcu(he, tbl, hash) {
-		if (params.obj_cmpfn ?
-		    params.obj_cmpfn(&arg, rht_obj(ht, he)) :
-		    rhashtable_compare(&arg, rht_obj(ht, he)))
-			continue;
-		return he;
-	}
+	head = rht_bucket(tbl, hash);
+	do {
+		rht_for_each_rcu_continue(he, *head, tbl, hash) {
+			if (params.obj_cmpfn ?
+			    params.obj_cmpfn(&arg, rht_obj(ht, he)) :
+			    rhashtable_compare(&arg, rht_obj(ht, he)))
+				continue;
+			return he;
+		}
+		/* An object might have been moved to a different hash chain,
+		 * while we walk along it - better check and retry.
+		 */
+	} while (he != RHT_NULLS_MARKER(head));
 
 	/* Ensure we see any new tables. */
 	smp_rmb();
@@ -580,6 +589,7 @@ static inline void *__rhashtable_insert_fast(
 		.ht = ht,
 		.key = key,
 	};
+	struct rhash_head __rcu **headp;
 	struct rhash_head __rcu **pprev;
 	struct bucket_table *tbl;
 	struct rhash_head *head;
@@ -603,12 +613,13 @@ static inline void *__rhashtable_insert_fast(
 	}
 
 	elasticity = RHT_ELASTICITY;
-	pprev = rht_bucket_insert(ht, tbl, hash);
+	headp = rht_bucket_insert(ht, tbl, hash);
+	pprev = headp;
 	data = ERR_PTR(-ENOMEM);
 	if (!pprev)
 		goto out;
 
-	rht_for_each_continue(head, *pprev, tbl, hash) {
+	rht_for_each_continue(head, *headp, tbl, hash) {
 		struct rhlist_head *plist;
 		struct rhlist_head *list;
 
@@ -648,7 +659,7 @@ static inline void *__rhashtable_insert_fast(
 	if (unlikely(rht_grow_above_100(ht, tbl)))
 		goto slow_path;
 
-	head = rht_dereference_bucket(*pprev, tbl, hash);
+	head = rht_dereference_bucket(*headp, tbl, hash);
 
 	RCU_INIT_POINTER(obj->next, head);
 	if (rhlist) {
@@ -658,7 +669,7 @@ static inline void *__rhashtable_insert_fast(
 		RCU_INIT_POINTER(list->next, NULL);
 	}
 
-	rcu_assign_pointer(*pprev, obj);
+	rcu_assign_pointer(*headp, obj);
 
 	atomic_inc(&ht->nelems);
 	if (rht_grow_above_75(ht, tbl))
diff --git a/lib/rhashtable.c b/lib/rhashtable.c
index 0e04947b7e0c..1737fbd049da 100644
--- a/lib/rhashtable.c
+++ b/lib/rhashtable.c
@@ -1164,8 +1164,7 @@ struct rhash_head __rcu **rht_bucket_nested(const struct bucket_table *tbl,
 					    unsigned int hash)
 {
 	const unsigned int shift = PAGE_SHIFT - ilog2(sizeof(void *));
-	static struct rhash_head __rcu *rhnull =
-		(struct rhash_head __rcu *)NULLS_MARKER(0);
+	static struct rhash_head __rcu *rhnull;
 	unsigned int index = hash & ((1 << tbl->nest) - 1);
 	unsigned int size = tbl->size >> tbl->nest;
 	unsigned int subhash = hash;
@@ -1183,8 +1182,11 @@ struct rhash_head __rcu **rht_bucket_nested(const struct bucket_table *tbl,
 		subhash >>= shift;
 	}
 
-	if (!ntbl)
+	if (!ntbl) {
+		if (!rhnull)
+			INIT_RHT_NULLS_HEAD(rhnull);
 		return &rhnull;
+	}
 
 	return &ntbl[subhash].bucket;
 
-- 
2.14.0.rc0.dirty


[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 832 bytes --]

^ permalink raw reply related

* Re: [PATCH resend] rhashtable: detect when object movement might have invalidated a lookup
From: NeilBrown @ 2018-07-15 23:55 UTC (permalink / raw)
  To: David Miller; +Cc: herbert, tgraf, netdev, linux-kernel, eric.dumazet
In-Reply-To: <20180711.224801.1129067473269289703.davem@davemloft.net>

[-- Attachment #1: Type: text/plain, Size: 2534 bytes --]

On Wed, Jul 11 2018, David Miller wrote:

> From: David Miller <davem@davemloft.net>
> Date: Wed, 11 Jul 2018 22:46:58 -0700 (PDT)
>
>> From: NeilBrown <neilb@suse.com>
>> Date: Fri, 06 Jul 2018 17:08:35 +1000
>> 
>>> 
>>> Some users of rhashtable might need to change the key
>>> of an object and move it to a different location in the table.
>>> Other users might want to allocate objects using
>>> SLAB_TYPESAFE_BY_RCU which can result in the same memory allocation
>>> being used for a different (type-compatible) purpose and similarly
>>> end up in a different hash-chain.
>>> 
>>> To support these, we store a unique NULLS_MARKER at the end of
>>> each chain, and when a search fails to find a match, we check
>>> if the NULLS marker found was the expected one.  If not,
>>> the search is repeated.
>>> 
>>> The unique NULLS_MARKER is derived from the address of the
>>> head of the chain.
>>> 
>>> If an object is removed and re-added to the same hash chain, we won't
>>> notice by looking that the NULLS marker.  In this case we must be sure
>>> that it was not re-added *after* its original location, or a lookup may
>>> incorrectly fail.  The easiest solution is to ensure it is inserted at
>>> the start of the chain.  insert_slow() already does that,
>>> insert_fast() does not.  So this patch changes insert_fast to always
>>> insert at the head of the chain.
>>> 
>>> Note that such a user must do their own double-checking of
>>> the object found by rhashtable_lookup_fast() after ensuring
>>> mutual exclusion which anything that might change the key, such as
>>> successfully taking a new reference.
>>> 
>>> Signed-off-by: NeilBrown <neilb@suse.com>
>> 
>> Applied to net-next.
>
> Actually, reverted, it doesn't even compile.
>
> lib/rhashtable.c: In function ‘rht_bucket_nested’:
> lib/rhashtable.c:1187:39: error: macro "INIT_RHT_NULLS_HEAD" passed 3 arguments, but takes just 1
>     INIT_RHT_NULLS_HEAD(rhnull, NULL, 0);
>                                        ^
> lib/rhashtable.c:1187:4: error: ‘INIT_RHT_NULLS_HEAD’ undeclared (first use in this function); did you mean ‘INIT_LIST_HEAD’?
>     INIT_RHT_NULLS_HEAD(rhnull, NULL, 0);
>     ^~~~~~~~~~~~~~~~~~~
>     INIT_LIST_HEAD
> lib/rhashtable.c:1187:4: note: each undeclared identifier is reported only once for each function it appears in

How embarrassing :-(
I had tested a series, but not each individual patch.  Sorry about that.
I'll post the correct patch.

Thanks,
NeilBrown

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 832 bytes --]

^ permalink raw reply

* Re: [PATCH] bpf: allow BPF programs access skb_shared_info->gso_segs field
From: Eddie Hao @ 2018-07-15 22:06 UTC (permalink / raw)
  To: ast, daniel; +Cc: davem, netdev, linux-kernel
In-Reply-To: <20180715084524.181717-1-eddieh@google.com>

Sorry, forgot to annotate the subject line with bpf-next.

On Sun, Jul 15, 2018 at 1:45 AM Eddie Hao <eddieh@google.com> wrote:
>
> This adds the ability to read gso_segs from a BPF program. This is useful
> for user space monitoring systems to get gso_segs statistics for each
> arbitrary group of flows defined by the BPF program.
>
> Signed-off-by: Eddie Hao <eddieh@google.com>
> ---
>  include/uapi/linux/bpf.h | 1 +
>  net/core/filter.c        | 9 +++++++++
>  2 files changed, 10 insertions(+)
>
> diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
> index b7db3261c62d..282085445616 100644
> --- a/include/uapi/linux/bpf.h
> +++ b/include/uapi/linux/bpf.h
> @@ -2266,6 +2266,7 @@ struct __sk_buff {
>         /* ... here. */
>
>         __u32 data_meta;
> +       unsigned short gso_segs;
>  };
>
>  struct bpf_tunnel_key {
> diff --git a/net/core/filter.c b/net/core/filter.c
> index b9ec916f4e3a..f17e249f3fbb 100644
> --- a/net/core/filter.c
> +++ b/net/core/filter.c
> @@ -5820,6 +5820,15 @@ static u32 bpf_convert_ctx_access(enum bpf_access_type type,
>                                       bpf_target_off(struct sock_common,
>                                                      skc_num, 2, target_size));
>                 break;
> +
> +       case offsetof(struct __sk_buff, gso_segs):
> +               BUILD_BUG_ON(FIELD_SIZEOF(struct skb_shared_info, gso_segs) !=
> +                                         sizeof(unsigned short));
> +               off = offsetof(struct sk_buff, end);
> +               off += offsetof(struct skb_shared_info, gso_segs);
> +               *insn++ = BPF_LDX_MEM(BPF_SIZEOF(unsigned short), si->dst_reg,
> +                                                si->src_reg, off);
> +               break;
>         }
>
>         return insn - insn_buf;
> --
> 2.18.0.203.gfac676dfb9-goog
>

^ permalink raw reply

* How are you doing today? Please read my email and reply me!!
From: Billy Wilfred @ 2018-07-14  5:08 UTC (permalink / raw)


Dear Sir/Madam,
How are you doing today? My name is Billy Wilfred. I am California, United States of America. I am a broker of Project Financing Firm who has cutting edge and group capital fund, they can finance any lucrative project and help you to enhance your business plan. Are you in need of a Loan to Finance and Fund your Project or Company? Are you an Investor, Real Estate developer, Construction Company, etc? or Do you need a loan to keep your investment or business going on in order to have a different look?  Have you been trying to obtain a Loan from Banks or Loan Companies and got Ripped off and they have refused to grant you the Loan because of bad credit? do not close your company and stop your project because of bankruptcy, we are here for you for real, please be happy, rejoice and celebrate 
 because your solution have come, we will end your financial worries now. Therefore come to us, we will grant you the loan you need without delay. We offer all types of non-recourse Loan and Funding 
 at a low Interest Rate of

The categories of Loan Financial Funding we offered include but not limited to: Business Loan, Personal Loan, Company Loan, Mortgage Loan, Debt Consolidation and Financial Funding for both Turnkey and mega projects etc from a minimum of Euro / US$1Million to Euro / US$5 Billion Max. Most importantly, Note that the loan company DO NOT charge any upfront fee or advance fee. This message is not scam for what so ever. This is 100% real, legal and legitimate loan company office in Turkey. Kindly get in touch for further details and procedures. Thanks for your cooperation with us. I will be waiting for your response. Further more details and directives contact me on my private email: bwilalessandro@gmail.com

Thank you & best regards,
Billy Wilfred.
Contact me on my private email: bwilalessandro@gmail.com

^ permalink raw reply

* Re: [PATCH iproute2-next v2] iplink: add support for reporting multiple XDP programs
From: David Ahern @ 2018-07-15 20:11 UTC (permalink / raw)
  To: Jakub Kicinski, alexei.starovoitov, daniel, stephen; +Cc: netdev, oss-drivers
In-Reply-To: <20180713225451.5689-1-jakub.kicinski@netronome.com>

On 7/13/18 4:54 PM, Jakub Kicinski wrote:
> Kernel now supports attaching XDP programs in the driver
> and hardware at the same time.  Print that information
> correctly.
> 
> In case there are multiple programs attached kernel will
> not provide IFLA_XDP_PROG_ID, so don't expect it to be
> there (this also improves the printing for very old kernels
> slightly, as it avoids unnecessary "prog/xdp" line).
> 
...

> 
> Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
> Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
> ---
> v2:
>  - const char * for constant string;
>  - add more compat for older kernels.
> ---
>  ip/iplink_xdp.c | 73 +++++++++++++++++++++++++++++++++++++++++--------
>  1 file changed, 61 insertions(+), 12 deletions(-)
> 

applied to iproute2-next. Thanks

^ permalink raw reply

* Re: [PATCH iproute2/net-next] tc: flower: Add support for QinQ
From: David Ahern @ 2018-07-15 20:09 UTC (permalink / raw)
  To: Jianbo Liu, netdev, davem, jiri
In-Reply-To: <20180630100133.14645-1-jianbol@mellanox.com>

On 6/30/18 4:01 AM, Jianbo Liu wrote:
> To support matching on both outer and inner vlan headers,
> we add new cvlan_id/cvlan_prio/cvlan_ethtype for inner vlan header.
> 
> Example:
> # tc filter add dev eth0 protocol 802.1ad parent ffff: \
>     flower vlan_id 1000 vlan_ethtype 802.1q \
>         cvlan_id 100 cvlan_ethtype ipv4 \
>     action vlan pop \
>     action vlan pop \
>     action mirred egress redirect dev eth1
> 
> # tc filter show dev eth0 ingress
> filter protocol 802.1ad pref 1 flower chain 0
> filter protocol 802.1ad pref 1 flower chain 0 handle 0x1
>   vlan_id 1000
>   vlan_ethtype 802.1Q
>   cvlan_id 100
>   cvlan_ethtype ip
>   eth_type ipv4
>   in_hw
> 
> Signed-off-by: Jianbo Liu <jianbol@mellanox.com>
> Acked-by: Jiri Pirko <jiri@mellanox.com>
> ---
>  include/uapi/linux/pkt_cls.h |   4 ++
>  man/man8/tc-flower.8         |  23 ++++++++++
>  tc/f_flower.c                | 103 ++++++++++++++++++++++++++++++++++++++-----
>  3 files changed, 118 insertions(+), 12 deletions(-)
> 

applied to iproute2-next. Thanks


> diff --git a/tc/f_flower.c b/tc/f_flower.c
> index ba8eb66..71f2bc1 100644
> --- a/tc/f_flower.c
> +++ b/tc/f_flower.c
> @@ -50,6 +50,9 @@ static void explain(void)
>  		"                       vlan_id VID |\n"
>  		"                       vlan_prio PRIORITY |\n"
>  		"                       vlan_ethtype [ ipv4 | ipv6 | ETH-TYPE ] |\n"
> +		"                       cvlan_id VID |\n"
> +		"                       cvlan_prio PRIORITY |\n"
> +		"                       cvlan_ethtype [ ipv4 | ipv6 | ETH-TYPE ] |\n"

This tendency for 1 option for line makes the output really long and is
not user friendly.

^ permalink raw reply

* [PATCH] net: lan78xx: Fix race in tx pending skb size calculation
From: Stefan Wahren @ 2018-07-15 19:53 UTC (permalink / raw)
  To: Woojung Huh, UNGLinuxDriver, David S. Miller
  Cc: Greg Kroah-Hartman, Dave Stevenson, netdev, linux-usb,
	Stefan Wahren, stable, Floris Bos

The skb size calculation in lan78xx_tx_bh is in race with the start_xmit,
which could lead to rare kernel oopses. So protect the whole skb walk with
a spin lock. As a benefit we can unlink the skb directly.

This patch was tested on Raspberry Pi 3B+

Link: https://github.com/raspberrypi/linux/issues/2608
Fixes: 55d7de9de6c3 ("Microchip's LAN7800 family USB 2/3 to 10/100/1000 Ethernet")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Floris Bos <bos@je-eigen-domein.nl>
Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
---
 drivers/net/usb/lan78xx.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/net/usb/lan78xx.c b/drivers/net/usb/lan78xx.c
index 2e41307..ed10d49 100644
--- a/drivers/net/usb/lan78xx.c
+++ b/drivers/net/usb/lan78xx.c
@@ -3344,6 +3344,7 @@ static void lan78xx_tx_bh(struct lan78xx_net *dev)
 	pkt_cnt = 0;
 	count = 0;
 	length = 0;
+	spin_lock_irqsave(&tqp->lock, flags);
 	for (skb = tqp->next; pkt_cnt < tqp->qlen; skb = skb->next) {
 		if (skb_is_gso(skb)) {
 			if (pkt_cnt) {
@@ -3352,7 +3353,8 @@ static void lan78xx_tx_bh(struct lan78xx_net *dev)
 			}
 			count = 1;
 			length = skb->len - TX_OVERHEAD;
-			skb2 = skb_dequeue(tqp);
+			__skb_unlink(skb, tqp);
+			spin_unlock_irqrestore(&tqp->lock, flags);
 			goto gso_skb;
 		}
 
@@ -3361,6 +3363,7 @@ static void lan78xx_tx_bh(struct lan78xx_net *dev)
 		skb_totallen = skb->len + roundup(skb_totallen, sizeof(u32));
 		pkt_cnt++;
 	}
+	spin_unlock_irqrestore(&tqp->lock, flags);
 
 	/* copy to a single skb */
 	skb = alloc_skb(skb_totallen, GFP_ATOMIC);
-- 
2.7.4

^ permalink raw reply related

* [PATCH] Bluetooth: avoid killing an already killed socket
From: Sudip Mukherjee @ 2018-07-15 19:36 UTC (permalink / raw)
  To: Marcel Holtmann, Johan Hedberg, David S . Miller
  Cc: linux-kernel, linux-bluetooth, netdev, Sudip Mukherjee

slub debug reported:

[  440.648642] =============================================================================
[  440.648649] BUG kmalloc-1024 (Tainted: G    BU     O   ): Poison overwritten
[  440.648651] -----------------------------------------------------------------------------

[  440.648655] INFO: 0xe70f4bec-0xe70f4bec. First byte 0x6a instead of 0x6b
[  440.648665] INFO: Allocated in sk_prot_alloc+0x6b/0xc6 age=33155 cpu=1 pid=1047
[  440.648671] 	___slab_alloc.constprop.24+0x1fc/0x292
[  440.648675] 	__slab_alloc.isra.18.constprop.23+0x1c/0x25
[  440.648677] 	__kmalloc+0xb6/0x17f
[  440.648680] 	sk_prot_alloc+0x6b/0xc6
[  440.648683] 	sk_alloc+0x1e/0xa1
[  440.648700] 	sco_sock_alloc.constprop.6+0x26/0xaf [bluetooth]
[  440.648716] 	sco_connect_cfm+0x166/0x281 [bluetooth]
[  440.648731] 	hci_conn_request_evt.isra.53+0x258/0x281 [bluetooth]
[  440.648746] 	hci_event_packet+0x28b/0x2326 [bluetooth]
[  440.648759] 	hci_rx_work+0x161/0x291 [bluetooth]
[  440.648764] 	process_one_work+0x163/0x2b2
[  440.648767] 	worker_thread+0x1a9/0x25c
[  440.648770] 	kthread+0xf8/0xfd
[  440.648774] 	ret_from_fork+0x2e/0x38
[  440.648779] INFO: Freed in __sk_destruct+0xd3/0xdf age=3815 cpu=1 pid=1047
[  440.648782] 	__slab_free+0x4b/0x27a
[  440.648784] 	kfree+0x12e/0x155
[  440.648787] 	__sk_destruct+0xd3/0xdf
[  440.648790] 	sk_destruct+0x27/0x29
[  440.648793] 	__sk_free+0x75/0x91
[  440.648795] 	sk_free+0x1c/0x1e
[  440.648810] 	sco_sock_kill+0x5a/0x5f [bluetooth]
[  440.648825] 	sco_conn_del+0x8e/0xba [bluetooth]
[  440.648840] 	sco_disconn_cfm+0x3a/0x41 [bluetooth]
[  440.648855] 	hci_event_packet+0x45e/0x2326 [bluetooth]
[  440.648868] 	hci_rx_work+0x161/0x291 [bluetooth]
[  440.648872] 	process_one_work+0x163/0x2b2
[  440.648875] 	worker_thread+0x1a9/0x25c
[  440.648877] 	kthread+0xf8/0xfd
[  440.648880] 	ret_from_fork+0x2e/0x38
[  440.648884] INFO: Slab 0xf4718580 objects=27 used=27 fp=0x  (null) flags=0x40008100
[  440.648886] INFO: Object 0xe70f4b88 @offset=19336 fp=0xe70f54f8

When KASAN was enabled, it reported:

[  210.096613] ==================================================================
[  210.096634] BUG: KASAN: use-after-free in ex_handler_refcount+0x5b/0x127
[  210.096641] Write of size 4 at addr ffff880107e17160 by task kworker/u9:1/2040

[  210.096651] CPU: 1 PID: 2040 Comm: kworker/u9:1 Tainted: G     U     O    4.14.47-20180606+ #2
[  210.096654] Hardware name: , BIOS 2017.01-00087-g43e04de 08/30/2017
[  210.096693] Workqueue: hci0 hci_rx_work [bluetooth]
[  210.096698] Call Trace:
[  210.096711]  dump_stack+0x46/0x59
[  210.096722]  print_address_description+0x6b/0x23b
[  210.096729]  ? ex_handler_refcount+0x5b/0x127
[  210.096736]  kasan_report+0x220/0x246
[  210.096744]  ex_handler_refcount+0x5b/0x127
[  210.096751]  ? ex_handler_clear_fs+0x85/0x85
[  210.096757]  fixup_exception+0x8c/0x96
[  210.096766]  do_trap+0x66/0x2c1
[  210.096773]  do_error_trap+0x152/0x180
[  210.096781]  ? fixup_bug+0x78/0x78
[  210.096817]  ? hci_debugfs_create_conn+0x244/0x26a [bluetooth]
[  210.096824]  ? __schedule+0x113b/0x1453
[  210.096830]  ? sysctl_net_exit+0xe/0xe
[  210.096837]  ? __wake_up_common+0x343/0x343
[  210.096843]  ? insert_work+0x107/0x163
[  210.096850]  invalid_op+0x1b/0x40
[  210.096888] RIP: 0010:hci_debugfs_create_conn+0x244/0x26a [bluetooth]
[  210.096892] RSP: 0018:ffff880094a0f970 EFLAGS: 00010296
[  210.096898] RAX: 0000000000000000 RBX: ffff880107e170e8 RCX: ffff880107e17160
[  210.096902] RDX: 000000000000002f RSI: ffff88013b80ed40 RDI: ffffffffa058b940
[  210.096906] RBP: ffff88011b2b0578 R08: 00000000852f0ec9 R09: ffffffff81cfcf9b
[  210.096909] R10: 00000000d21bdad7 R11: 0000000000000001 R12: ffff8800967b0488
[  210.096913] R13: ffff880107e17168 R14: 0000000000000068 R15: ffff8800949c0008
[  210.096920]  ? __sk_destruct+0x2c6/0x2d4
[  210.096959]  hci_event_packet+0xff5/0x7de2 [bluetooth]
[  210.096969]  ? __local_bh_enable_ip+0x43/0x5b
[  210.097004]  ? l2cap_sock_recv_cb+0x158/0x166 [bluetooth]
[  210.097039]  ? hci_le_meta_evt+0x2bb3/0x2bb3 [bluetooth]
[  210.097075]  ? l2cap_ertm_init+0x94e/0x94e [bluetooth]
[  210.097093]  ? xhci_urb_enqueue+0xbd8/0xcf5 [xhci_hcd]
[  210.097102]  ? __accumulate_pelt_segments+0x24/0x33
[  210.097109]  ? __accumulate_pelt_segments+0x24/0x33
[  210.097115]  ? __update_load_avg_se.isra.2+0x217/0x3a4
[  210.097122]  ? set_next_entity+0x7c3/0x12cd
[  210.097128]  ? pick_next_entity+0x25e/0x26c
[  210.097135]  ? pick_next_task_fair+0x2ca/0xc1a
[  210.097141]  ? switch_mm_irqs_off+0x346/0xb4f
[  210.097147]  ? __switch_to+0x769/0xbc4
[  210.097153]  ? compat_start_thread+0x66/0x66
[  210.097188]  ? hci_conn_check_link_mode+0x1cd/0x1cd [bluetooth]
[  210.097195]  ? finish_task_switch+0x392/0x431
[  210.097228]  ? hci_rx_work+0x154/0x487 [bluetooth]
[  210.097260]  hci_rx_work+0x154/0x487 [bluetooth]
[  210.097269]  process_one_work+0x579/0x9e9
[  210.097277]  worker_thread+0x68f/0x804
[  210.097285]  kthread+0x31c/0x32b
[  210.097292]  ? rescuer_thread+0x70c/0x70c
[  210.097299]  ? kthread_create_on_node+0xa3/0xa3
[  210.097306]  ret_from_fork+0x35/0x40

[  210.097314] Allocated by task 2040:
[  210.097323]  kasan_kmalloc.part.1+0x51/0xc7
[  210.097328]  __kmalloc+0x17f/0x1b6
[  210.097335]  sk_prot_alloc+0xf2/0x1a3
[  210.097340]  sk_alloc+0x22/0x297
[  210.097375]  sco_sock_alloc.constprop.7+0x23/0x202 [bluetooth]
[  210.097410]  sco_connect_cfm+0x2d0/0x566 [bluetooth]
[  210.097443]  hci_conn_request_evt.isra.53+0x6d3/0x762 [bluetooth]
[  210.097476]  hci_event_packet+0x85e/0x7de2 [bluetooth]
[  210.097507]  hci_rx_work+0x154/0x487 [bluetooth]
[  210.097512]  process_one_work+0x579/0x9e9
[  210.097517]  worker_thread+0x68f/0x804
[  210.097523]  kthread+0x31c/0x32b
[  210.097529]  ret_from_fork+0x35/0x40

[  210.097533] Freed by task 2040:
[  210.097539]  kasan_slab_free+0xb3/0x15e
[  210.097544]  kfree+0x103/0x1a9
[  210.097549]  __sk_destruct+0x2c6/0x2d4
[  210.097584]  sco_conn_del.isra.1+0xba/0x10e [bluetooth]
[  210.097617]  hci_event_packet+0xff5/0x7de2 [bluetooth]
[  210.097648]  hci_rx_work+0x154/0x487 [bluetooth]
[  210.097653]  process_one_work+0x579/0x9e9
[  210.097658]  worker_thread+0x68f/0x804
[  210.097663]  kthread+0x31c/0x32b
[  210.097670]  ret_from_fork+0x35/0x40

[  210.097676] The buggy address belongs to the object at ffff880107e170e8
 which belongs to the cache kmalloc-1024 of size 1024
[  210.097681] The buggy address is located 120 bytes inside of
 1024-byte region [ffff880107e170e8, ffff880107e174e8)
[  210.097683] The buggy address belongs to the page:
[  210.097689] page:ffffea00041f8400 count:1 mapcount:0 mapping:          (null) index:0xffff880107e15b68 compound_mapcount: 0
[  210.110194] flags: 0x8000000000008100(slab|head)
[  210.115441] raw: 8000000000008100 0000000000000000 ffff880107e15b68 0000000100170016
[  210.115448] raw: ffffea0004a47620 ffffea0004b48e20 ffff88013b80ed40 0000000000000000
[  210.115451] page dumped because: kasan: bad access detected

[  210.115454] Memory state around the buggy address:
[  210.115460]  ffff880107e17000: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[  210.115465]  ffff880107e17080: fc fc fc fc fc fc fc fc fc fc fc fc fc fb fb fb
[  210.115469] >ffff880107e17100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[  210.115472]                                                        ^
[  210.115477]  ffff880107e17180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[  210.115481]  ffff880107e17200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[  210.115483] ==================================================================

And finally when BT_DBG() and ftrace was enabled it showed:

       <...>-14979 [001] ....   186.104191: sco_sock_kill <-sco_sock_close
       <...>-14979 [001] ....   186.104191: sco_sock_kill <-sco_sock_release
       <...>-14979 [001] ....   186.104192: sco_sock_kill: sk ef0497a0 state 9
       <...>-14979 [001] ....   186.104193: bt_sock_unlink <-sco_sock_kill
kworker/u9:2-792   [001] ....   186.104246: sco_sock_kill <-sco_conn_del
kworker/u9:2-792   [001] ....   186.104248: sco_sock_kill: sk ef0497a0 state 9
kworker/u9:2-792   [001] ....   186.104249: bt_sock_unlink <-sco_sock_kill
kworker/u9:2-792   [001] ....   186.104250: sco_sock_destruct <-__sk_destruct
kworker/u9:2-792   [001] ....   186.104250: sco_sock_destruct: sk ef0497a0
kworker/u9:2-792   [001] ....   186.104860: hci_conn_del <-hci_event_packet
kworker/u9:2-792   [001] ....   186.104864: hci_conn_del: hci0 hcon ef0484c0 handle 266

Only in the failed case, sco_sock_kill() gets called with the same sock
pointer two times. Add a check for SOCK_DEAD to avoid continue killing
a socket which has already been killed.

Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
---
 net/bluetooth/sco.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/bluetooth/sco.c b/net/bluetooth/sco.c
index 413b8ee49fec..8f0f9279eac9 100644
--- a/net/bluetooth/sco.c
+++ b/net/bluetooth/sco.c
@@ -393,7 +393,8 @@ static void sco_sock_cleanup_listen(struct sock *parent)
  */
 static void sco_sock_kill(struct sock *sk)
 {
-	if (!sock_flag(sk, SOCK_ZAPPED) || sk->sk_socket)
+	if (!sock_flag(sk, SOCK_ZAPPED) || sk->sk_socket ||
+	    sock_flag(sk, SOCK_DEAD))
 		return;
 
 	BT_DBG("sk %p state %d", sk, sk->sk_state);
-- 
2.11.0

^ permalink raw reply related

* [PATCH net] net/mlx5e: Move mlx5e_priv_flags into en_ethtool.c
From: Kamal Heib @ 2018-07-15 19:06 UTC (permalink / raw)
  To: David S . Miller, Saeed Mahameed; +Cc: netdev, Kamal Heib

Move the definition of mlx5e_priv_flags into en_ethtool.c because it's
only used there.

Fixes: 4e59e2888139 ("net/mlx5e: Introduce net device priv flags infrastructure")
Signed-off-by: Kamal Heib <kamalheib1@gmail.com>
---
 drivers/net/ethernet/mellanox/mlx5/core/en.h         | 7 -------
 drivers/net/ethernet/mellanox/mlx5/core/en_ethtool.c | 7 +++++++
 2 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en.h b/drivers/net/ethernet/mellanox/mlx5/core/en.h
index eb9eb7aa953a..84e6a5b42286 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en.h
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en.h
@@ -208,13 +208,6 @@ struct mlx5e_umr_wqe {
 
 extern const char mlx5e_self_tests[][ETH_GSTRING_LEN];
 
-static const char mlx5e_priv_flags[][ETH_GSTRING_LEN] = {
-	"rx_cqe_moder",
-	"tx_cqe_moder",
-	"rx_cqe_compress",
-	"rx_striding_rq",
-};
-
 enum mlx5e_priv_flag {
 	MLX5E_PFLAG_RX_CQE_BASED_MODER = (1 << 0),
 	MLX5E_PFLAG_TX_CQE_BASED_MODER = (1 << 1),
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_ethtool.c b/drivers/net/ethernet/mellanox/mlx5/core/en_ethtool.c
index fffe514ba855..2a1c35d82c2e 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_ethtool.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_ethtool.c
@@ -33,6 +33,13 @@
 #include "en.h"
 #include "en/port.h"
 
+static const char mlx5e_priv_flags[][ETH_GSTRING_LEN] = {
+	"rx_cqe_moder",
+	"tx_cqe_moder",
+	"rx_cqe_compress",
+	"rx_striding_rq",
+};
+
 void mlx5e_ethtool_get_drvinfo(struct mlx5e_priv *priv,
 			       struct ethtool_drvinfo *drvinfo)
 {
-- 
2.14.4

^ permalink raw reply related


This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox