Thread (20 messages) 20 messages, 2 authors, 2021-12-14

[PATCH bpf-next v3 1/8] xdp: Allow registering memory model without rxq reference

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From: Toke Høiland-Jørgensen <hidden>
Date: 2021-12-11 18:43:41
Also in: bpf
Subsystem: networking [general], the rest, xdp (express data path) · Maintainers: "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds, Alexei Starovoitov, Daniel Borkmann, Jesper Dangaard Brouer, John Fastabend

Revision v3 of 11 in this series.

Revisions (11)
  1. v1 [diff vs current]
  2. v2 [diff vs current]
  3. v3 current
  4. v4 [diff vs current]
  5. v5 [diff vs current]
  6. v6 [diff vs current]
  7. v7 [diff vs current]
  8. v8 [diff vs current]
  9. v9 [diff vs current]
  10. v10 [diff vs current]
  11. v11 [diff vs current]
The functions that register an XDP memory model take a struct xdp_rxq as
parameter, but the RXQ is not actually used for anything other than pulling
out the struct xdp_mem_info that it embeds. So refactor the register
functions and export variants that just take a pointer to the xdp_mem_info.

This is in preparation for enabling XDP_REDIRECT in bpf_prog_run(), using a
page_pool instance that is not connected to any network device.

Signed-off-by: Toke Høiland-Jørgensen <redacted>
---
 include/net/xdp.h |  3 ++
 net/core/xdp.c    | 92 +++++++++++++++++++++++++++++++----------------
 2 files changed, 65 insertions(+), 30 deletions(-)
diff --git a/include/net/xdp.h b/include/net/xdp.h
index 447f9b1578f3..8f0812e4996d 100644
--- a/include/net/xdp.h
+++ b/include/net/xdp.h
@@ -260,6 +260,9 @@ bool xdp_rxq_info_is_reg(struct xdp_rxq_info *xdp_rxq);
 int xdp_rxq_info_reg_mem_model(struct xdp_rxq_info *xdp_rxq,
 			       enum xdp_mem_type type, void *allocator);
 void xdp_rxq_info_unreg_mem_model(struct xdp_rxq_info *xdp_rxq);
+int xdp_reg_mem_model(struct xdp_mem_info *mem,
+		      enum xdp_mem_type type, void *allocator);
+void xdp_unreg_mem_model(struct xdp_mem_info *mem);
 
 /* Drivers not supporting XDP metadata can use this helper, which
  * rejects any room expansion for metadata as a result.
diff --git a/net/core/xdp.c b/net/core/xdp.c
index 5ddc29f29bad..ac476c84a986 100644
--- a/net/core/xdp.c
+++ b/net/core/xdp.c
@@ -110,20 +110,15 @@ static void mem_allocator_disconnect(void *allocator)
 	mutex_unlock(&mem_id_lock);
 }
 
-void xdp_rxq_info_unreg_mem_model(struct xdp_rxq_info *xdp_rxq)
+void xdp_unreg_mem_model(struct xdp_mem_info *mem)
 {
 	struct xdp_mem_allocator *xa;
-	int type = xdp_rxq->mem.type;
-	int id = xdp_rxq->mem.id;
+	int type = mem->type;
+	int id = mem->id;
 
 	/* Reset mem info to defaults */
-	xdp_rxq->mem.id = 0;
-	xdp_rxq->mem.type = 0;
-
-	if (xdp_rxq->reg_state != REG_STATE_REGISTERED) {
-		WARN(1, "Missing register, driver bug");
-		return;
-	}
+	mem->id = 0;
+	mem->type = 0;
 
 	if (id == 0)
 		return;
@@ -135,6 +130,17 @@ void xdp_rxq_info_unreg_mem_model(struct xdp_rxq_info *xdp_rxq)
 		rcu_read_unlock();
 	}
 }
+EXPORT_SYMBOL_GPL(xdp_unreg_mem_model);
+
+void xdp_rxq_info_unreg_mem_model(struct xdp_rxq_info *xdp_rxq)
+{
+	if (xdp_rxq->reg_state != REG_STATE_REGISTERED) {
+		WARN(1, "Missing register, driver bug");
+		return;
+	}
+
+	xdp_unreg_mem_model(&xdp_rxq->mem);
+}
 EXPORT_SYMBOL_GPL(xdp_rxq_info_unreg_mem_model);
 
 void xdp_rxq_info_unreg(struct xdp_rxq_info *xdp_rxq)
@@ -259,28 +265,24 @@ static bool __is_supported_mem_type(enum xdp_mem_type type)
 	return true;
 }
 
-int xdp_rxq_info_reg_mem_model(struct xdp_rxq_info *xdp_rxq,
-			       enum xdp_mem_type type, void *allocator)
+static struct xdp_mem_allocator *__xdp_reg_mem_model(struct xdp_mem_info *mem,
+						     enum xdp_mem_type type,
+						     void *allocator)
 {
 	struct xdp_mem_allocator *xdp_alloc;
 	gfp_t gfp = GFP_KERNEL;
 	int id, errno, ret;
 	void *ptr;
 
-	if (xdp_rxq->reg_state != REG_STATE_REGISTERED) {
-		WARN(1, "Missing register, driver bug");
-		return -EFAULT;
-	}
-
 	if (!__is_supported_mem_type(type))
-		return -EOPNOTSUPP;
+		return ERR_PTR(-EOPNOTSUPP);
 
-	xdp_rxq->mem.type = type;
+	mem->type = type;
 
 	if (!allocator) {
 		if (type == MEM_TYPE_PAGE_POOL)
-			return -EINVAL; /* Setup time check page_pool req */
-		return 0;
+			return ERR_PTR(-EINVAL); /* Setup time check page_pool req */
+		return NULL;
 	}
 
 	/* Delay init of rhashtable to save memory if feature isn't used */
@@ -290,13 +292,13 @@ int xdp_rxq_info_reg_mem_model(struct xdp_rxq_info *xdp_rxq,
 		mutex_unlock(&mem_id_lock);
 		if (ret < 0) {
 			WARN_ON(1);
-			return ret;
+			return ERR_PTR(ret);
 		}
 	}
 
 	xdp_alloc = kzalloc(sizeof(*xdp_alloc), gfp);
 	if (!xdp_alloc)
-		return -ENOMEM;
+		return ERR_PTR(-ENOMEM);
 
 	mutex_lock(&mem_id_lock);
 	id = __mem_id_cyclic_get(gfp);
@@ -304,15 +306,15 @@ int xdp_rxq_info_reg_mem_model(struct xdp_rxq_info *xdp_rxq,
 		errno = id;
 		goto err;
 	}
-	xdp_rxq->mem.id = id;
-	xdp_alloc->mem  = xdp_rxq->mem;
+	mem->id = id;
+	xdp_alloc->mem = *mem;
 	xdp_alloc->allocator = allocator;
 
 	/* Insert allocator into ID lookup table */
 	ptr = rhashtable_insert_slow(mem_id_ht, &id, &xdp_alloc->node);
 	if (IS_ERR(ptr)) {
-		ida_simple_remove(&mem_id_pool, xdp_rxq->mem.id);
-		xdp_rxq->mem.id = 0;
+		ida_simple_remove(&mem_id_pool, mem->id);
+		mem->id = 0;
 		errno = PTR_ERR(ptr);
 		goto err;
 	}
@@ -322,13 +324,43 @@ int xdp_rxq_info_reg_mem_model(struct xdp_rxq_info *xdp_rxq,
 
 	mutex_unlock(&mem_id_lock);
 
-	trace_mem_connect(xdp_alloc, xdp_rxq);
-	return 0;
+	return xdp_alloc;
 err:
 	mutex_unlock(&mem_id_lock);
 	kfree(xdp_alloc);
-	return errno;
+	return ERR_PTR(errno);
+}
+
+int xdp_reg_mem_model(struct xdp_mem_info *mem,
+		      enum xdp_mem_type type, void *allocator)
+{
+	struct xdp_mem_allocator *xdp_alloc;
+
+	xdp_alloc = __xdp_reg_mem_model(mem, type, allocator);
+	if (IS_ERR(xdp_alloc))
+		return PTR_ERR(xdp_alloc);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(xdp_reg_mem_model);
+
+int xdp_rxq_info_reg_mem_model(struct xdp_rxq_info *xdp_rxq,
+			       enum xdp_mem_type type, void *allocator)
+{
+	struct xdp_mem_allocator *xdp_alloc;
+
+	if (xdp_rxq->reg_state != REG_STATE_REGISTERED) {
+		WARN(1, "Missing register, driver bug");
+		return -EFAULT;
+	}
+
+	xdp_alloc = __xdp_reg_mem_model(&xdp_rxq->mem, type, allocator);
+	if (IS_ERR(xdp_alloc))
+		return PTR_ERR(xdp_alloc);
+
+	trace_mem_connect(xdp_alloc, xdp_rxq);
+	return 0;
 }
+
 EXPORT_SYMBOL_GPL(xdp_rxq_info_reg_mem_model);
 
 /* XDP RX runs under NAPI protection, and in different delivery error
-- 
2.34.0
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