[PATCH v9 6/8] Revert "x86/mm: Remove unused __set_memory_prot()"

[Coiby Xu <coxu@redhat.com>]

This reverts commit 693bbf2a50447353c6a47961e6a7240a823ace02 as kdump
LUKS support (CONFIG_CRASH_DM_CRYPT) depends on __set_memory_prot.

Signed-off-by: Coiby Xu <coxu@redhat.com>
---
 arch/x86/include/asm/set_memory.h |  1 +
 arch/x86/mm/pat/set_memory.c      | 13 +++++++++++++
 2 files changed, 14 insertions(+)

diff --git a/arch/x86/include/asm/set_memory.h b/arch/x86/include/asm/set_memory.h
index 8d9f1c9aaa4c..023994fe6115 100644
--- a/arch/x86/include/asm/set_memory.h
+++ b/arch/x86/include/asm/set_memory.h
@@ -37,6 +37,7 @@ int set_memory_rox(unsigned long addr, int numpages);
  * The caller is required to take care of these.
  */
 
+int __set_memory_prot(unsigned long addr, int numpages, pgprot_t prot);
 int _set_memory_uc(unsigned long addr, int numpages);
 int _set_memory_wc(unsigned long addr, int numpages);
 int _set_memory_wt(unsigned long addr, int numpages);
diff --git a/arch/x86/mm/pat/set_memory.c b/arch/x86/mm/pat/set_memory.c
index def3d9284254..df7502ad165c 100644
--- a/arch/x86/mm/pat/set_memory.c
+++ b/arch/x86/mm/pat/set_memory.c
@@ -2148,6 +2148,19 @@ static inline int cpa_clear_pages_array(struct page **pages, int numpages,
 		CPA_PAGES_ARRAY, pages);
 }
 
+/*
+ * __set_memory_prot is an internal helper for callers that have been passed
+ * a pgprot_t value from upper layers and a reservation has already been taken.
+ * If you want to set the pgprot to a specific page protocol, use the
+ * set_memory_xx() functions.
+ */
+int __set_memory_prot(unsigned long addr, int numpages, pgprot_t prot)
+{
+	return change_page_attr_set_clr(&addr, numpages, prot,
+					__pgprot(~pgprot_val(prot)), 0, 0,
+					NULL);
+}
+
 int _set_memory_uc(unsigned long addr, int numpages)
 {
 	/*
-- 
2.49.0