packet: switch kvzalloc to allocate memory

The patches includes following change:

*Use modern kvzalloc()/kvfree() instead of custom allocations.

*Remove order argument for alloc_pg_vec, it can get from req.

*Remove order argument for free_pg_vec, free_pg_vec now uses
kvfree which does not need order argument.

*Remove pg_vec_order from struct packet_ring_buffer, no longer
need to save/restore 'order'

*Remove variable 'order' for packet_set_ring, it is now unused
Signed-off-by: Zhang Yu <zhangyu31@baidu.com>
Signed-off-by: Li RongQing <lirongqing@baidu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/packet/af_packet.c

@@ -4137,52 +4137,36 @@ static const struct vm_operations_struct packet_mmap_ops = {
 	.close	=	packet_mm_close,
 };
 
-static void free_pg_vec(struct pgv *pg_vec, unsigned int order,
-			unsigned int len)
+static void free_pg_vec(struct pgv *pg_vec, unsigned int len)
 {
 	int i;
 
 	for (i = 0; i < len; i++) {
 		if (likely(pg_vec[i].buffer)) {
-			if (is_vmalloc_addr(pg_vec[i].buffer))
-				vfree(pg_vec[i].buffer);
-			else
-				free_pages((unsigned long)pg_vec[i].buffer,
-					   order);
+			kvfree(pg_vec[i].buffer);
 			pg_vec[i].buffer = NULL;
 		}
 	}
 	kfree(pg_vec);
 }
 
-static char *alloc_one_pg_vec_page(unsigned long order)
+static char *alloc_one_pg_vec_page(unsigned long size)
 {
 	char *buffer;
-	gfp_t gfp_flags = GFP_KERNEL | __GFP_COMP |
-			  __GFP_ZERO | __GFP_NOWARN | __GFP_NORETRY;
 
-	buffer = (char *) __get_free_pages(gfp_flags, order);
+	buffer = kvzalloc(size, GFP_KERNEL);
 	if (buffer)
 		return buffer;
 
-	/* __get_free_pages failed, fall back to vmalloc */
-	buffer = vzalloc(array_size((1 << order), PAGE_SIZE));
-	if (buffer)
-		return buffer;
+	buffer = kvzalloc(size, GFP_KERNEL | __GFP_RETRY_MAYFAIL);
 
-	/* vmalloc failed, lets dig into swap here */
-	gfp_flags &= ~__GFP_NORETRY;
-	buffer = (char *) __get_free_pages(gfp_flags, order);
-	if (buffer)
-		return buffer;
-
-	/* complete and utter failure */
-	return NULL;
+	return buffer;
 }
 
-static struct pgv *alloc_pg_vec(struct tpacket_req *req, int order)
+static struct pgv *alloc_pg_vec(struct tpacket_req *req)
 {
 	unsigned int block_nr = req->tp_block_nr;
+	unsigned long size = req->tp_block_size;
 	struct pgv *pg_vec;
 	int i;
 
@@ -4191,7 +4175,7 @@ static struct pgv *alloc_pg_vec(struct tpacket_req *req, int order)
 		goto out;
 
 	for (i = 0; i < block_nr; i++) {
-		pg_vec[i].buffer = alloc_one_pg_vec_page(order);
+		pg_vec[i].buffer = alloc_one_pg_vec_page(size);
 		if (unlikely(!pg_vec[i].buffer))
 			goto out_free_pgvec;
 	}
@@ -4200,7 +4184,7 @@ static struct pgv *alloc_pg_vec(struct tpacket_req *req, int order)
 	return pg_vec;
 
 out_free_pgvec:
-	free_pg_vec(pg_vec, order, block_nr);
+	free_pg_vec(pg_vec, block_nr);
 	pg_vec = NULL;
 	goto out;
 }
@@ -4210,9 +4194,9 @@ static int packet_set_ring(struct sock *sk, union tpacket_req_u *req_u,
 {
 	struct pgv *pg_vec = NULL;
 	struct packet_sock *po = pkt_sk(sk);
-	int was_running, order = 0;
 	struct packet_ring_buffer *rb;
 	struct sk_buff_head *rb_queue;
+	int was_running;
 	__be16 num;
 	int err = -EINVAL;
 	/* Added to avoid minimal code churn */
@@ -4274,8 +4258,7 @@ static int packet_set_ring(struct sock *sk, union tpacket_req_u *req_u,
 			goto out;
 
 		err = -ENOMEM;
-		order = get_order(req->tp_block_size);
-		pg_vec = alloc_pg_vec(req, order);
+		pg_vec = alloc_pg_vec(req);
 		if (unlikely(!pg_vec))
 			goto out;
 		switch (po->tp_version) {
@@ -4329,7 +4312,6 @@ static int packet_set_ring(struct sock *sk, union tpacket_req_u *req_u,
 		rb->frame_size = req->tp_frame_size;
 		spin_unlock_bh(&rb_queue->lock);
 
-		swap(rb->pg_vec_order, order);
 		swap(rb->pg_vec_len, req->tp_block_nr);
 
 		rb->pg_vec_pages = req->tp_block_size/PAGE_SIZE;
@@ -4355,7 +4337,7 @@ static int packet_set_ring(struct sock *sk, union tpacket_req_u *req_u,
 	}
 
 	if (pg_vec)
-		free_pg_vec(pg_vec, order, req->tp_block_nr);
+		free_pg_vec(pg_vec, req->tp_block_nr);
 out:
 	return err;
 }

net/packet/internal.h

@@ -64,7 +64,6 @@ struct packet_ring_buffer {
 	unsigned int		frame_size;
 	unsigned int		frame_max;
 
-	unsigned int		pg_vec_order;
 	unsigned int		pg_vec_pages;
 	unsigned int		pg_vec_len;