[PATCH 48/64] arch/tile: use mm locking wrappers

[Davidlohr Bueso]

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

* THIS IS A HACK *

Breaks arch/um/. See comment in fix_range_common().

Signed-off-by: Davidlohr Bueso <dbu...@suse.de>
---
 arch/um/include/asm/mmu_context.h |  5 +++--
 arch/um/kernel/tlb.c              | 12 +++++++++++-
 arch/um/kernel/trap.c             |  6 +++---
 3 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/arch/um/include/asm/mmu_context.h 
b/arch/um/include/asm/mmu_context.h
index 98cc3e36385a..7dc202c611db 100644
--- a/arch/um/include/asm/mmu_context.h
+++ b/arch/um/include/asm/mmu_context.h
@@ -49,14 +49,15 @@ extern void force_flush_all(void);
 
 static inline void activate_mm(struct mm_struct *old, struct mm_struct *new)
 {
+       DEFINE_RANGE_LOCK_FULL(mmrange);
        /*
         * This is called by fs/exec.c and sys_unshare()
         * when the new ->mm is used for the first time.
         */
        __switch_mm(&new->context.id);
-       down_write(&new->mmap_sem);
+        mm_write_lock(new, &mmrange);
        uml_setup_stubs(new);
-       up_write(&new->mmap_sem);
+       mm_write_unlock(new, &mmrange);
 }
 
 static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next, 
diff --git a/arch/um/kernel/tlb.c b/arch/um/kernel/tlb.c
index 37508b190106..eeeeb048b6f4 100644
--- a/arch/um/kernel/tlb.c
+++ b/arch/um/kernel/tlb.c
@@ -297,10 +297,20 @@ void fix_range_common(struct mm_struct *mm, unsigned long 
start_addr,
 
        /* This is not an else because ret is modified above */
        if (ret) {
+               /*
+                * FIXME: this is _wrong_ and will break arch/um.
+                *
+                *  The right thing to do is modify the flush_tlb_range()
+                *  api, but that in turn would require file_operations
+                *  knowing about mmrange... Compiles cleanly, but sucks
+                *  otherwise.
+                */
+               DEFINE_RANGE_LOCK_FULL(mmrange);
+
                printk(KERN_ERR "fix_range_common: failed, killing current "
                       "process: %d\n", task_tgid_vnr(current));
                /* We are under mmap_sem, release it such that current can 
terminate */
-               up_write(&current->mm->mmap_sem);
+               mm_write_unlock(current->mm, &mmrange);
                force_sig(SIGKILL, current);
                do_signal(&current->thread.regs);
        }
diff --git a/arch/um/kernel/trap.c b/arch/um/kernel/trap.c
index e632a14e896e..14dcb83d00a9 100644
--- a/arch/um/kernel/trap.c
+++ b/arch/um/kernel/trap.c
@@ -47,7 +47,7 @@ int handle_page_fault(unsigned long address, unsigned long ip,
        if (is_user)
                flags |= FAULT_FLAG_USER;
 retry:
-       down_read(&mm->mmap_sem);
+       mm_read_lock(mm, &mmrange);
        vma = find_vma(mm, address);
        if (!vma)
                goto out;
@@ -123,7 +123,7 @@ int handle_page_fault(unsigned long address, unsigned long 
ip,
 #endif
        flush_tlb_page(vma, address);
 out:
-       up_read(&mm->mmap_sem);
+       mm_read_unlock(mm, &mmrange);
 out_nosemaphore:
        return err;
 
@@ -132,7 +132,7 @@ int handle_page_fault(unsigned long address, unsigned long 
ip,
         * We ran out of memory, call the OOM killer, and return the userspace
         * (which will retry the fault, or kill us if we got oom-killed).
         */
-       up_read(&mm->mmap_sem);
+       mm_read_unlock(mm, &mmrange);
        if (!is_user)
                goto out_nosemaphore;
        pagefault_out_of_memory();
-- 
2.13.6