Add bridged amplifiers to cs42l43

Merge series from Charles Keepax <ckeepax@opensource.cirrus.com>:

In some cs42l43 systems a couple of cs35l56 amplifiers are attached
to the cs42l43's SPI and I2S. On Windows the cs42l43 is controlled
by a SDCA class driver and these two amplifiers are controlled by
firmware running on the cs42l43. However, under Linux the decision
was made to interact with the cs42l43 directly, affording the user
greater control over the audio system. However, this has resulted
in an issue where these two bridged cs35l56 amplifiers are not
populated in ACPI and must be added manually. There is at least an
SDCA extension unit DT entry we can key off.

The process of adding this is handled using a software node, firstly the
ability to add native chip selects to software nodes must be added.
Secondly, an additional flag for naming the SPI devices is added this
allows the machine driver to key to the correct amplifier. Then finally,
the cs42l43 SPI driver adds the two amplifiers directly onto its SPI
bus.

An additional series will follow soon to add the audio machine driver
parts (in the sof-sdw driver), however that is fairly orthogonal to
this part of the process, getting the actual amplifiers registered.

1 files changed, 57 insertions, 13 deletions

diff --git a/net/ipv4/inet_fragment.c b/net/ipv4/inet_fragment.c
index 7072fc0783ef..c88c9034d630 100644
--- a/net/ipv4/inet_fragment.c
+++ b/net/ipv4/inet_fragment.c
@@ -24,6 +24,8 @@
 #include <net/ip.h>
 #include <net/ipv6.h>
 
+#include "../core/sock_destructor.h"
+
 /* Use skb->cb to track consecutive/adjacent fragments coming at
  * the end of the queue. Nodes in the rb-tree queue will
  * contain "runs" of one or more adjacent fragments.
@@ -39,6 +41,7 @@ struct ipfrag_skb_cb {
 	};
 	struct sk_buff		*next_frag;
 	int			frag_run_len;
+	int			ip_defrag_offset;
 };
 
 #define FRAG_CB(skb)		((struct ipfrag_skb_cb *)((skb)->cb))
@@ -396,12 +399,12 @@ int inet_frag_queue_insert(struct inet_frag_queue *q, struct sk_buff *skb,
 	 */
 	if (!last)
 		fragrun_create(q, skb);  /* First fragment. */
-	else if (last->ip_defrag_offset + last->len < end) {
+	else if (FRAG_CB(last)->ip_defrag_offset + last->len < end) {
 		/* This is the common case: skb goes to the end. */
 		/* Detect and discard overlaps. */
-		if (offset < last->ip_defrag_offset + last->len)
+		if (offset < FRAG_CB(last)->ip_defrag_offset + last->len)
 			return IPFRAG_OVERLAP;
-		if (offset == last->ip_defrag_offset + last->len)
+		if (offset == FRAG_CB(last)->ip_defrag_offset + last->len)
 			fragrun_append_to_last(q, skb);
 		else
 			fragrun_create(q, skb);
@@ -418,13 +421,13 @@ int inet_frag_queue_insert(struct inet_frag_queue *q, struct sk_buff *skb,
 
 			parent = *rbn;
 			curr = rb_to_skb(parent);
-			curr_run_end = curr->ip_defrag_offset +
+			curr_run_end = FRAG_CB(curr)->ip_defrag_offset +
 					FRAG_CB(curr)->frag_run_len;
-			if (end <= curr->ip_defrag_offset)
+			if (end <= FRAG_CB(curr)->ip_defrag_offset)
 				rbn = &parent->rb_left;
 			else if (offset >= curr_run_end)
 				rbn = &parent->rb_right;
-			else if (offset >= curr->ip_defrag_offset &&
+			else if (offset >= FRAG_CB(curr)->ip_defrag_offset &&
 				 end <= curr_run_end)
 				return IPFRAG_DUP;
 			else
@@ -438,7 +441,7 @@ int inet_frag_queue_insert(struct inet_frag_queue *q, struct sk_buff *skb,
 		rb_insert_color(&skb->rbnode, &q->rb_fragments);
 	}
 
-	skb->ip_defrag_offset = offset;
+	FRAG_CB(skb)->ip_defrag_offset = offset;
 
 	return IPFRAG_OK;
 }
@@ -448,13 +451,28 @@ void *inet_frag_reasm_prepare(struct inet_frag_queue *q, struct sk_buff *skb,
 			      struct sk_buff *parent)
 {
 	struct sk_buff *fp, *head = skb_rb_first(&q->rb_fragments);
-	struct sk_buff **nextp;
+	void (*destructor)(struct sk_buff *);
+	unsigned int orig_truesize = 0;
+	struct sk_buff **nextp = NULL;
+	struct sock *sk = skb->sk;
 	int delta;
 
+	if (sk && is_skb_wmem(skb)) {
+		/* TX: skb->sk might have been passed as argument to
+		 * dst->output and must remain valid until tx completes.
+		 *
+		 * Move sk to reassembled skb and fix up wmem accounting.
+		 */
+		orig_truesize = skb->truesize;
+		destructor = skb->destructor;
+	}
+
 	if (head != skb) {
 		fp = skb_clone(skb, GFP_ATOMIC);
-		if (!fp)
-			return NULL;
+		if (!fp) {
+			head = skb;
+			goto out_restore_sk;
+		}
 		FRAG_CB(fp)->next_frag = FRAG_CB(skb)->next_frag;
 		if (RB_EMPTY_NODE(&skb->rbnode))
 			FRAG_CB(parent)->next_frag = fp;
@@ -463,6 +481,12 @@ void *inet_frag_reasm_prepare(struct inet_frag_queue *q, struct sk_buff *skb,
 					&q->rb_fragments);
 		if (q->fragments_tail == skb)
 			q->fragments_tail = fp;
+
+		if (orig_truesize) {
+			/* prevent skb_morph from releasing sk */
+			skb->sk = NULL;
+			skb->destructor = NULL;
+		}
 		skb_morph(skb, head);
 		FRAG_CB(skb)->next_frag = FRAG_CB(head)->next_frag;
 		rb_replace_node(&head->rbnode, &skb->rbnode,
@@ -470,13 +494,13 @@ void *inet_frag_reasm_prepare(struct inet_frag_queue *q, struct sk_buff *skb,
 		consume_skb(head);
 		head = skb;
 	}
-	WARN_ON(head->ip_defrag_offset != 0);
+	WARN_ON(FRAG_CB(head)->ip_defrag_offset != 0);
 
 	delta = -head->truesize;
 
 	/* Head of list must not be cloned. */
 	if (skb_unclone(head, GFP_ATOMIC))
-		return NULL;
+		goto out_restore_sk;
 
 	delta += head->truesize;
 	if (delta)
@@ -492,7 +516,7 @@ void *inet_frag_reasm_prepare(struct inet_frag_queue *q, struct sk_buff *skb,
 
 		clone = alloc_skb(0, GFP_ATOMIC);
 		if (!clone)
-			return NULL;
+			goto out_restore_sk;
 		skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list;
 		skb_frag_list_init(head);
 		for (i = 0; i < skb_shinfo(head)->nr_frags; i++)
@@ -509,6 +533,21 @@ void *inet_frag_reasm_prepare(struct inet_frag_queue *q, struct sk_buff *skb,
 		nextp = &skb_shinfo(head)->frag_list;
 	}
 
+out_restore_sk:
+	if (orig_truesize) {
+		int ts_delta = head->truesize - orig_truesize;
+
+		/* if this reassembled skb is fragmented later,
+		 * fraglist skbs will get skb->sk assigned from head->sk,
+		 * and each frag skb will be released via sock_wfree.
+		 *
+		 * Update sk_wmem_alloc.
+		 */
+		head->sk = sk;
+		head->destructor = destructor;
+		refcount_add(ts_delta, &sk->sk_wmem_alloc);
+	}
+
 	return nextp;
 }
 EXPORT_SYMBOL(inet_frag_reasm_prepare);
@@ -516,6 +555,8 @@ EXPORT_SYMBOL(inet_frag_reasm_prepare);
 void inet_frag_reasm_finish(struct inet_frag_queue *q, struct sk_buff *head,
 			    void *reasm_data, bool try_coalesce)
 {
+	struct sock *sk = is_skb_wmem(head) ? head->sk : NULL;
+	const unsigned int head_truesize = head->truesize;
 	struct sk_buff **nextp = reasm_data;
 	struct rb_node *rbn;
 	struct sk_buff *fp;
@@ -579,6 +620,9 @@ void inet_frag_reasm_finish(struct inet_frag_queue *q, struct sk_buff *head,
 	head->prev = NULL;
 	head->tstamp = q->stamp;
 	head->mono_delivery_time = q->mono_delivery_time;
+
+	if (sk)
+		refcount_add(sum_truesize - head_truesize, &sk->sk_wmem_alloc);
 }
 EXPORT_SYMBOL(inet_frag_reasm_finish);