uml: customize tlb.h

Customize the hooks in tlb.h to optimize TLB flushing some more.

Add start and end fields to tlb_gather_mmu, which are used to limit
the address space range scanned when a region is unmapped.

The interfaces which just free page tables, without actually changing
mappings, don't need to cause a TLB flush.

Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 18 insertions, 7 deletions

diff --git a/arch/um/kernel/tlb.c b/arch/um/kernel/tlb.c
index 8127ca8d5957..0b6a77def311 100644
--- a/arch/um/kernel/tlb.c
+++ b/arch/um/kernel/tlb.c
@@ -193,18 +193,18 @@ static inline int update_pte_range(pmd_t *pmd, unsigned long addr,
                 if (!pte_young(*pte)) {
                         r = 0;
                         w = 0;
-                } else if (!pte_dirty(*pte)) {
+                } else if (!pte_dirty(*pte))
                         w = 0;
-                }
+
                 prot = ((r ? UM_PROT_READ : 0) | (w ? UM_PROT_WRITE : 0) |
                         (x ? UM_PROT_EXEC : 0));
                 if (hvc->force || pte_newpage(*pte)) {
                         if (pte_present(*pte))
                                 ret = add_mmap(addr, pte_val(*pte) & PAGE_MASK,
                                                PAGE_SIZE, prot, hvc);
-                        else ret = add_munmap(addr, PAGE_SIZE, hvc);
-                }
-                else if (pte_newprot(*pte))
+                        else
+                                ret = add_munmap(addr, PAGE_SIZE, hvc);
+                } else if (pte_newprot(*pte))
                         ret = add_mprotect(addr, PAGE_SIZE, prot, hvc);
                 *pte = pte_mkuptodate(*pte);
         } while (pte++, addr += PAGE_SIZE, ((addr < end) && !ret));
@@ -500,7 +500,8 @@ void flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
         else fix_range(vma->vm_mm, start, end, 0);
 }
 
-void flush_tlb_mm(struct mm_struct *mm)
+void flush_tlb_mm_range(struct mm_struct *mm, unsigned long start,
+                        unsigned long end)
 {
         /*
          * Don't bother flushing if this address space is about to be
@@ -509,7 +510,17 @@ void flush_tlb_mm(struct mm_struct *mm)
         if (atomic_read(&mm->mm_users) == 0)
                 return;
 
-        fix_range(mm, 0, TASK_SIZE, 0);
+        fix_range(mm, start, end, 0);
+}
+
+void flush_tlb_mm(struct mm_struct *mm)
+{
+        struct vm_area_struct *vma = mm->mmap;
+
+        while (vma != NULL) {
+                fix_range(mm, vma->vm_start, vma->vm_end, 0);
+                vma = vma->vm_next;
+        }
 }
 
 void force_flush_all(void)