[S390] lockless get_user_pages_fast()

Implement get_user_pages_fast without locking in the fastpath on s390.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

3 files changed, 12 insertions, 6 deletions

diff --git a/arch/s390/include/asm/pgalloc.h b/arch/s390/include/asm/pgalloc.h
index 68940d0bad91..082eb4e50e8b 100644
--- a/arch/s390/include/asm/pgalloc.h
+++ b/arch/s390/include/asm/pgalloc.h
@@ -21,9 +21,11 @@
 
 unsigned long *crst_table_alloc(struct mm_struct *, int);
 void crst_table_free(struct mm_struct *, unsigned long *);
+void crst_table_free_rcu(struct mm_struct *, unsigned long *);
 
 unsigned long *page_table_alloc(struct mm_struct *);
 void page_table_free(struct mm_struct *, unsigned long *);
+void page_table_free_rcu(struct mm_struct *, unsigned long *);
 void disable_noexec(struct mm_struct *, struct task_struct *);
 
 static inline void clear_table(unsigned long *s, unsigned long val, size_t n)
@@ -176,4 +178,6 @@ static inline void pmd_populate(struct mm_struct *mm,
 #define pte_free_kernel(mm, pte) page_table_free(mm, (unsigned long *) pte)
 #define pte_free(mm, pte) page_table_free(mm, (unsigned long *) pte)
 
+extern void rcu_table_freelist_finish(void);
+
 #endif /* _S390_PGALLOC_H */
diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h
index 22a294571000..785229ae39cb 100644
--- a/arch/s390/include/asm/pgtable.h
+++ b/arch/s390/include/asm/pgtable.h
@@ -316,6 +316,7 @@ extern unsigned long VMALLOC_START;
 
 /* Bits in the segment table entry */
 #define _SEGMENT_ENTRY_ORIGIN   0x7fffffc0UL    /* page table origin        */
+#define _SEGMENT_ENTRY_RO       0x200   /* page protection bit              */
 #define _SEGMENT_ENTRY_INV      0x20    /* invalid segment table entry      */
 #define _SEGMENT_ENTRY_COMMON   0x10    /* common segment bit               */
 #define _SEGMENT_ENTRY_PTL      0x0f    /* page table length                */
diff --git a/arch/s390/include/asm/tlb.h b/arch/s390/include/asm/tlb.h
index fd1c00d08bf5..f1f644f2240a 100644
--- a/arch/s390/include/asm/tlb.h
+++ b/arch/s390/include/asm/tlb.h
@@ -64,10 +64,9 @@ static inline void tlb_flush_mmu(struct mmu_gather *tlb,
         if (!tlb->fullmm && (tlb->nr_ptes > 0 || tlb->nr_pxds < TLB_NR_PTRS))
                 __tlb_flush_mm(tlb->mm);
         while (tlb->nr_ptes > 0)
-                pte_free(tlb->mm, tlb->array[--tlb->nr_ptes]);
+                page_table_free_rcu(tlb->mm, tlb->array[--tlb->nr_ptes]);
         while (tlb->nr_pxds < TLB_NR_PTRS)
-                /* pgd_free frees the pointer as region or segment table */
-                pgd_free(tlb->mm, tlb->array[tlb->nr_pxds++]);
+                crst_table_free_rcu(tlb->mm, tlb->array[tlb->nr_pxds++]);
 }
 
 static inline void tlb_finish_mmu(struct mmu_gather *tlb,
@@ -75,6 +74,8 @@ static inline void tlb_finish_mmu(struct mmu_gather *tlb,
 {
         tlb_flush_mmu(tlb, start, end);
 
+        rcu_table_freelist_finish();
+
         /* keep the page table cache within bounds */
         check_pgt_cache();
 
@@ -103,7 +104,7 @@ static inline void pte_free_tlb(struct mmu_gather *tlb, pgtable_t pte,
                 if (tlb->nr_ptes >= tlb->nr_pxds)
                         tlb_flush_mmu(tlb, 0, 0);
         } else
-                pte_free(tlb->mm, pte);
+                page_table_free(tlb->mm, (unsigned long *) pte);
 }
 
 /*
@@ -124,7 +125,7 @@ static inline void pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmd,
                 if (tlb->nr_ptes >= tlb->nr_pxds)
                         tlb_flush_mmu(tlb, 0, 0);
         } else
-                pmd_free(tlb->mm, pmd);
+                crst_table_free(tlb->mm, (unsigned long *) pmd);
 #endif
 }
 
@@ -146,7 +147,7 @@ static inline void pud_free_tlb(struct mmu_gather *tlb, pud_t *pud,
                 if (tlb->nr_ptes >= tlb->nr_pxds)
                         tlb_flush_mmu(tlb, 0, 0);
         } else
-                pud_free(tlb->mm, pud);
+                crst_table_free(tlb->mm, (unsigned long *) pud);
 #endif
 }