From: Davidlohr Bueso <d...@stgolabs.net>

This becomes quite straightforward with the mmrange in place.

Signed-off-by: Davidlohr Bueso <dbu...@suse.de>
---
 arch/m68k/kernel/sys_m68k.c | 18 +++++++++++-------
 arch/m68k/mm/fault.c        |  8 ++++----
 2 files changed, 15 insertions(+), 11 deletions(-)

diff --git a/arch/m68k/kernel/sys_m68k.c b/arch/m68k/kernel/sys_m68k.c
index 27e10af5153a..d151bd19385c 100644
--- a/arch/m68k/kernel/sys_m68k.c
+++ b/arch/m68k/kernel/sys_m68k.c
@@ -378,6 +378,7 @@ asmlinkage int
 sys_cacheflush (unsigned long addr, int scope, int cache, unsigned long len)
 {
        int ret = -EINVAL;
+       DEFINE_RANGE_LOCK_FULL(mmrange);
 
        if (scope < FLUSH_SCOPE_LINE || scope > FLUSH_SCOPE_ALL ||
            cache & ~FLUSH_CACHE_BOTH)
@@ -399,7 +400,7 @@ sys_cacheflush (unsigned long addr, int scope, int cache, 
unsigned long len)
                 * Verify that the specified address region actually belongs
                 * to this process.
                 */
-               down_read(&current->mm->mmap_sem);
+               mm_read_lock(current->mm, &mmrange);
                vma = find_vma(current->mm, addr);
                if (!vma || addr < vma->vm_start || addr + len > vma->vm_end)
                        goto out_unlock;
@@ -450,7 +451,7 @@ sys_cacheflush (unsigned long addr, int scope, int cache, 
unsigned long len)
            }
        }
 out_unlock:
-       up_read(&current->mm->mmap_sem);
+       mm_read_unlock(current->mm, &mmrange);
 out:
        return ret;
 }
@@ -461,6 +462,8 @@ asmlinkage int
 sys_atomic_cmpxchg_32(unsigned long newval, int oldval, int d3, int d4, int d5,
                      unsigned long __user * mem)
 {
+       DEFINE_RANGE_LOCK_FULL(mmrange);
+
        /* This was borrowed from ARM's implementation.  */
        for (;;) {
                struct mm_struct *mm = current->mm;
@@ -470,7 +473,7 @@ sys_atomic_cmpxchg_32(unsigned long newval, int oldval, int 
d3, int d4, int d5,
                spinlock_t *ptl;
                unsigned long mem_value;
 
-               down_read(&mm->mmap_sem);
+               mm_read_lock(mm, &mmrange);
                pgd = pgd_offset(mm, (unsigned long)mem);
                if (!pgd_present(*pgd))
                        goto bad_access;
@@ -493,11 +496,11 @@ sys_atomic_cmpxchg_32(unsigned long newval, int oldval, 
int d3, int d4, int d5,
                        __put_user(newval, mem);
 
                pte_unmap_unlock(pte, ptl);
-               up_read(&mm->mmap_sem);
+               mm_read_unlock(mm, &mmrange);
                return mem_value;
 
              bad_access:
-               up_read(&mm->mmap_sem);
+               mm_read_unlock(mm, &mmrange);
                /* This is not necessarily a bad access, we can get here if
                   a memory we're trying to write to should be copied-on-write.
                   Make the kernel do the necessary page stuff, then re-iterate.
@@ -536,14 +539,15 @@ sys_atomic_cmpxchg_32(unsigned long newval, int oldval, 
int d3, int d4, int d5,
 {
        struct mm_struct *mm = current->mm;
        unsigned long mem_value;
+       DEFINE_RANGE_LOCK_FULL(mmrange);
 
-       down_read(&mm->mmap_sem);
+       mm_read_lock(mm, &mmrange);
 
        mem_value = *mem;
        if (mem_value == oldval)
                *mem = newval;
 
-       up_read(&mm->mmap_sem);
+       mm_read_unlock(mm, &mmrange);
        return mem_value;
 }
 
diff --git a/arch/m68k/mm/fault.c b/arch/m68k/mm/fault.c
index ec32a193726f..426d22924852 100644
--- a/arch/m68k/mm/fault.c
+++ b/arch/m68k/mm/fault.c
@@ -90,7 +90,7 @@ int do_page_fault(struct pt_regs *regs, unsigned long address,
        if (user_mode(regs))
                flags |= FAULT_FLAG_USER;
 retry:
-       down_read(&mm->mmap_sem);
+       mm_read_lock(mm, &mmrange);
 
        vma = find_vma(mm, address);
        if (!vma)
@@ -181,7 +181,7 @@ int do_page_fault(struct pt_regs *regs, unsigned long 
address,
                }
        }
 
-       up_read(&mm->mmap_sem);
+       mm_read_unlock(mm, &mmrange);
        return 0;
 
 /*
@@ -189,7 +189,7 @@ int do_page_fault(struct pt_regs *regs, unsigned long 
address,
  * us unable to handle the page fault gracefully.
  */
 out_of_memory:
-       up_read(&mm->mmap_sem);
+       mm_read_unlock(mm, &mmrange);
        if (!user_mode(regs))
                goto no_context;
        pagefault_out_of_memory();
@@ -218,6 +218,6 @@ int do_page_fault(struct pt_regs *regs, unsigned long 
address,
        current->thread.faddr = address;
 
 send_sig:
-       up_read(&mm->mmap_sem);
+       mm_read_unlock(mm, &mmrange);
        return send_fault_sig(regs);
 }
-- 
2.13.6

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