From cfe8f3cfc190feac51169a86ed6c35bc7a286576 Mon Sep 17 00:00:00 2001
From: Bart Van Assche <bvanassche@acm.org>
Date: Thu, 19 Jul 2018 18:00:42 +0000
Subject: [PATCH] scst: Introduce a backport of kmem_cache_create_usercopy()

This patch does not change any functionality.


git-svn-id: http://svn.code.sf.net/p/scst/svn/trunk@7427 d57e44dd-8a1f-0410-8b47-8ef2f437770f
---
 scst/include/backport.h | 24 ++++++++++++++++++++++++
 scst/src/scst_main.c    |  4 ----
 2 files changed, 24 insertions(+), 4 deletions(-)

diff --git a/scst/include/backport.h b/scst/include/backport.h
index 2f65a9061..02372f453 100644
--- a/scst/include/backport.h
+++ b/scst/include/backport.h
@@ -671,6 +671,30 @@ static inline void *kmalloc_array(size_t n, size_t size, gfp_t flags)
 }
 #endif
 
+/*
+ * See also commit 8eb8284b4129 ("usercopy: Prepare for usercopy
+ * whitelisting").
+ */
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 23)
+static inline struct kmem_cache *kmem_cache_create_usercopy(const char *name,
+			unsigned int size, unsigned int align,
+			slab_flags_t flags,
+			unsigned int useroffset, unsigned int usersize,
+			void (*ctor)(void *))
+{
+	return kmem_cache_create(name, size, align, flags, ctor, NULL);
+}
+#elif LINUX_VERSION_CODE < KERNEL_VERSION(4, 16, 0)
+static inline struct kmem_cache *kmem_cache_create_usercopy(const char *name,
+			unsigned int size, unsigned int align,
+			slab_flags_t flags,
+			unsigned int useroffset, unsigned int usersize,
+			void (*ctor)(void *))
+{
+	return kmem_cache_create(name, size, align, flags, ctor);
+}
+#endif
+
 /* <linux/t10-pi.h> */
 
 #if LINUX_VERSION_CODE < KERNEL_VERSION(3, 18, 0)
diff --git a/scst/src/scst_main.c b/scst/src/scst_main.c
index 2573759e7..0ef90e6ea 100644
--- a/scst/src/scst_main.c
+++ b/scst/src/scst_main.c
@@ -2583,7 +2583,6 @@ static int __init init_scst(void)
  * Used for structures with fast path write access accessed from user space.
  * See also commit 8eb8284b4129 ("usercopy: Prepare for usercopy whitelisting").
  */
-#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 16, 0)
 #define INIT_CACHEP_ALIGN_USERCOPY(p, s) ({				\
 		(p) = kmem_cache_create_usercopy(#s, sizeof(struct s), 	\
 			__alignof__(struct s),				\
@@ -2593,9 +2592,6 @@ static int __init init_scst(void)
 			  sizeof(struct s));				\
 		(p);							\
 	})
-#else
-#define INIT_CACHEP_ALIGN_USERCOPY(p, s) INIT_CACHEP_ALIGN(p, s)
-#endif
 
 	res = -ENOMEM;
 	if (!INIT_CACHEP(scst_mgmt_cachep, scst_mgmt_cmd))