From 7dc56a07bf9318ea3cfa281021b3b919fc09741a Mon Sep 17 00:00:00 2001
From: Gleb Chesnokov <gleb.chesnokov@scst.dev>
Date: Tue, 27 Dec 2022 10:53:46 +0300
Subject: [PATCH] scst: Backport the PTR_ERR_OR_ZERO() function

Unbreak the build for the previous commit against kernel versions
before v3.12.

Fixes: ee6312ac5a30 ("scst_vdisk, qla2x00t-32gbit: Use PTR_ERR_OR_ZERO
instead of IS_ERR and PTR_ERR")
---
 scst/include/backport.h | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/scst/include/backport.h b/scst/include/backport.h
index 764cdef8a..6bf06a503 100644
--- a/scst/include/backport.h
+++ b/scst/include/backport.h
@@ -77,6 +77,15 @@ static __always_inline unsigned long long rdtsc(void)
 #define tsc_khz 1000
 #endif
 
+/* <linux/err.h> */
+
+/*
+ * See also commit 6e8b8726ad50 ("PTR_RET is now PTR_ERR_OR_ZERO") # v3.12
+ */
+#if LINUX_VERSION_CODE < KERNEL_VERSION(3, 12, 0) && !defined(RHEL_RELEASE_CODE)
+#define PTR_ERR_OR_ZERO(p) PTR_RET(p)
+#endif
+
 /* <linux/bio.h> */
 
 #if LINUX_VERSION_CODE < KERNEL_VERSION(4, 13, 0) &&	\