drbd/bsc-1206791-02-drbd-fix-static-analysis-warnings.patch

From f465ef1a70c7b559fcf3924e450bc5e836e448de Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Christoph=20B=C3=B6hmwalder?=
 <christoph.boehmwalder@linbit.com>
Date: Mon, 3 Oct 2022 15:56:44 +0200
Subject: [PATCH] drbd: fix static analysis warnings
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GCC now does some pretty impressive static analysis, and it spits out
some warnings when compiling DRBD. Newer kernels "unfortunately" set
-Werror, which forces us to stop sweeping these under the rug.

This commits fixes two distinct classes of warning.

First, if a netlink field is declared with DRBD_GENLA_F_MANDATORY, it
can never be NULL. The compiler catches this and complains:

drbd_nl.c:3490:53: warning: the comparison will always evaluate
		   as ‘true’ for the address of ‘integrity_alg’
		   will never be NULL [-Waddress]
 3490 | if (!new_net_conf->integrity_alg != !old_net_conf->integrity_alg)
      |     ^

And similarly for net_conf->name. The fix is simple: just remove the
checks.

The other warning that is fixed is:

drbd_main.c:421:55: warning: unused variable ‘ddm’ [-Wunused-variable]
  421 | DEFINE_DYNAMIC_DEBUG_METADATA(ddm, "Bad barrier ack dump");
      |                               ^~~

Which happens when dynamic debug is not enabled, erasing the
DYNAMIC_DEBUG_BRANCH(ddm) below.
This is easily fixed by "accessing" the declared variable by doing a
dummy cast to void.

Finally, the compiler complains that the DYNAMIC_DEBUG macros are
redefined in drbd_polymorph_printk.h, so #undef them before #defining
them.
---
 drbd/drbd_nl.c               | 5 +----
 drbd/drbd_polymorph_printk.h | 5 ++++-
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/drbd/drbd_nl.c b/drbd/drbd_nl.c
index 6a2afd184ae6..de064215b638 100644
--- a/drbd/drbd_nl.c
+++ b/drbd/drbd_nl.c
@@ -3553,9 +3553,6 @@ _check_net_options(struct drbd_connection *connection, struct net_conf *old_net_
 		if (new_net_conf->two_primaries != old_net_conf->two_primaries)
 			return ERR_NEED_APV_100;
 
-		if (!new_net_conf->integrity_alg != !old_net_conf->integrity_alg)
-			return ERR_NEED_APV_100;
-
 		if (strcmp(new_net_conf->integrity_alg, old_net_conf->integrity_alg))
 			return ERR_NEED_APV_100;
 	}
@@ -5398,7 +5395,7 @@ static int nla_put_drbd_cfg_context(struct sk_buff *skb,
 	if (connection) {
 		nla_put_u32(skb, T_ctx_peer_node_id, connection->peer_node_id);
 		rcu_read_lock();
-		if (connection->transport.net_conf && connection->transport.net_conf->name)
+		if (connection->transport.net_conf)
 			nla_put_string(skb, T_ctx_conn_name, connection->transport.net_conf->name);
 		rcu_read_unlock();
 	}
diff --git a/drbd/drbd_polymorph_printk.h b/drbd/drbd_polymorph_printk.h
index 1ce6cc2e6f74..4e7f2f17014e 100644
--- a/drbd/drbd_polymorph_printk.h
+++ b/drbd/drbd_polymorph_printk.h
@@ -2,7 +2,10 @@
 #define DRBD_POLYMORPH_PRINTK_H
 
 #if !defined(CONFIG_DYNAMIC_DEBUG)
-#define DEFINE_DYNAMIC_DEBUG_METADATA(D, F) const char *D = F
+#undef DEFINE_DYNAMIC_DEBUG_METADATA
+#undef __dynamic_pr_debug
+#undef DYNAMIC_DEBUG_BRANCH
+#define DEFINE_DYNAMIC_DEBUG_METADATA(D, F) const char *D = F; ((void)D)
 #define __dynamic_pr_debug(D, F, args...) do { (void)(D); if (0) printk(F, ## args); } while(0)
 #define DYNAMIC_DEBUG_BRANCH(D) false
 #endif
-- 
2.26.2