[PATCH 6.18 501/614] smb: smbdirect: introduce SMBDIRECT_DEBUG_ERR_PTR() helper

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

6.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Stefan Metzmacher <metze@samba.org>

[ Upstream commit 1f3fd108c5c5a9885c6c276a2489c49b60a6b90d ]

This can be used like this:

  int err = somefunc();
  pr_warn("err=%1pe\n", SMBDIRECT_DEBUG_ERR_PTR(err));

This will be used in the following fixes in order
to be prepared to identify real world problems
more easily.

Cc: Steve French <smfrench@gmail.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Long Li <longli@microsoft.com>
Cc: Namjae Jeon <linkinjeon@kernel.org>
Cc: Paulo Alcantara <pc@manguebit.org>
Cc: linux-cifs@vger.kernel.org
Cc: samba-technical@lists.samba.org
Signed-off-by: Stefan Metzmacher <metze@samba.org>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Stable-dep-of: 425c32750b48 ("smb: server: relax WARN_ON_ONCE(SMBDIRECT_SOCKET_*) checks in recv_done() and smb_direct_cm_handler()")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/smb/common/smbdirect/smbdirect_socket.h | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/fs/smb/common/smbdirect/smbdirect_socket.h b/fs/smb/common/smbdirect/smbdirect_socket.h
index ee5a90d691c89..611986827a5e2 100644
--- a/fs/smb/common/smbdirect/smbdirect_socket.h
+++ b/fs/smb/common/smbdirect/smbdirect_socket.h
@@ -74,6 +74,19 @@ const char *smbdirect_socket_status_string(enum smbdirect_socket_status status)
 	return "<unknown>";
 }
 
+/*
+ * This can be used with %1pe to print errors as strings or '0'
+ * And it avoids warnings like: warn: passing zero to 'ERR_PTR'
+ * from smatch -p=kernel --pedantic
+ */
+static __always_inline
+const void * __must_check SMBDIRECT_DEBUG_ERR_PTR(long error)
+{
+	if (error == 0)
+		return NULL;
+	return ERR_PTR(error);
+}
+
 enum smbdirect_keepalive_status {
 	SMBDIRECT_KEEPALIVE_NONE,
 	SMBDIRECT_KEEPALIVE_PENDING,
-- 
2.51.0