From: Jakub Kicinski <jakub.kicinski@netronome.com>
Date: Wed, 27 Nov 2019 12:16:44 -0800
Subject: net/tls: use sg_next() to walk sg entries
Git-commit: c5daa6cccdc2f94aca2c9b3fa5f94e4469997293
Patch-mainline: v5.5-rc1
References: bnc#1151927 5.3.15

Partially sent record cleanup path increments an SG entry
directly instead of using sg_next(). This should not be a
problem today, as encrypted messages should be always
allocated as arrays. But given this is a cleanup path it's
easy to miss was this ever to change. Use sg_next(), and
simplify the code.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Simon Horman <simon.horman@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
 include/net/tls.h  |    2 +-
 net/tls/tls_main.c |   13 ++-----------
 net/tls/tls_sw.c   |    3 ++-
 3 files changed, 5 insertions(+), 13 deletions(-)

--- a/include/net/tls.h
+++ b/include/net/tls.h
@@ -395,7 +395,7 @@ int tls_push_sg(struct sock *sk, struct
 		int flags);
 int tls_push_partial_record(struct sock *sk, struct tls_context *ctx,
 			    int flags);
-bool tls_free_partial_record(struct sock *sk, struct tls_context *ctx);
+void tls_free_partial_record(struct sock *sk, struct tls_context *ctx);
 
 static inline struct tls_msg *tls_msg(struct sk_buff *skb)
 {
--- a/net/tls/tls_main.c
+++ b/net/tls/tls_main.c
@@ -209,24 +209,15 @@ int tls_push_partial_record(struct sock
 	return tls_push_sg(sk, ctx, sg, offset, flags);
 }
 
-bool tls_free_partial_record(struct sock *sk, struct tls_context *ctx)
+void tls_free_partial_record(struct sock *sk, struct tls_context *ctx)
 {
 	struct scatterlist *sg;
 
-	sg = ctx->partially_sent_record;
-	if (!sg)
-		return false;
-
-	while (1) {
+	for (sg = ctx->partially_sent_record; sg; sg = sg_next(sg)) {
 		put_page(sg_page(sg));
 		sk_mem_uncharge(sk, sg->length);
-
-		if (sg_is_last(sg))
-			break;
-		sg++;
 	}
 	ctx->partially_sent_record = NULL;
-	return true;
 }
 
 static void tls_write_space(struct sock *sk)
--- a/net/tls/tls_sw.c
+++ b/net/tls/tls_sw.c
@@ -2084,7 +2084,8 @@ void tls_sw_release_resources_tx(struct
 	/* Free up un-sent records in tx_list. First, free
 	 * the partially sent record if any at head of tx_list.
 	 */
-	if (tls_free_partial_record(sk, tls_ctx)) {
+	if (tls_ctx->partially_sent_record) {
+		tls_free_partial_record(sk, tls_ctx);
 		rec = list_first_entry(&ctx->tx_list,
 				       struct tls_rec, list);
 		list_del(&rec->list);