[withdrawn] hugetlb-avoid-taking-i_mmap_mutex-in-unmap_single_vma-for-hugetlb.patch removed from -mm tree

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The patch titled
     Subject: hugetlb: avoid taking i_mmap_mutex in unmap_single_vma() for hugetlb
has been removed from the -mm tree.  Its filename was
     hugetlb-avoid-taking-i_mmap_mutex-in-unmap_single_vma-for-hugetlb.patch

This patch was dropped because it was withdrawn

------------------------------------------------------
From: "Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
Subject: hugetlb: avoid taking i_mmap_mutex in unmap_single_vma() for hugetlb

i_mmap_mutex lock was added in unmap_single_vma by 502717f4e ("hugetlb:
fix linked list corruption in unmap_hugepage_range()") but we don't use
page->lru in unmap_hugepage_range any more.  Also the lock was taken
higher up in the stack in some code path.  That would result in deadlock.

unmap_mapping_range (i_mmap_mutex)
 -> unmap_mapping_range_tree
    -> unmap_mapping_range_vma
       -> zap_page_range_single
         -> unmap_single_vma
	      -> unmap_hugepage_range (i_mmap_mutex)

For shared pagetable support for huge pages, since pagetable pages are ref
counted we don't need any lock during huge_pmd_unshare.  We do take
i_mmap_mutex in huge_pmd_share while walking the vma_prio_tree in mapping.
(39dde65c9940c97f ("shared page table for hugetlb page")).

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Cc: Hillf Danton <dhillf@xxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxx>
Cc: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---

 mm/memory.c |    5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff -puN mm/memory.c~hugetlb-avoid-taking-i_mmap_mutex-in-unmap_single_vma-for-hugetlb mm/memory.c
--- a/mm/memory.c~hugetlb-avoid-taking-i_mmap_mutex-in-unmap_single_vma-for-hugetlb
+++ a/mm/memory.c
@@ -1335,11 +1335,8 @@ static void unmap_single_vma(struct mmu_
 			 * Since no pte has actually been setup, it is
 			 * safe to do nothing in this case.
 			 */
-			if (vma->vm_file) {
-				mutex_lock(&vma->vm_file->f_mapping->i_mmap_mutex);
+			if (vma->vm_file)
 				__unmap_hugepage_range(tlb, vma, start, end, NULL);
-				mutex_unlock(&vma->vm_file->f_mapping->i_mmap_mutex);
-			}
 		} else
 			unmap_page_range(tlb, vma, start, end, details);
 	}
_

Patches currently in -mm which might be from aneesh.kumar@xxxxxxxxxxxxxxxxxx are

origin.patch
hugetlb-rename-max_hstate-to-hugetlb_max_hstate.patch
hugetlb-dont-use-err_ptr-with-vm_fault-values.patch
hugetlb-add-an-inline-helper-for-finding-hstate-index.patch
hugetlb-use-mmu_gather-instead-of-a-temporary-linked-list-for-accumulating-pages.patch
hugetlb-avoid-taking-i_mmap_mutex-in-unmap_single_vma-for-hugetlb-revert.patch
hugetlb-simplify-migrate_huge_page.patch
hugetlb-add-a-list-for-tracking-in-use-hugetlb-pages.patch
hugetlb-make-some-static-variables-global.patch
hugetlb-make-some-static-variables-global-mark-hugelb_max_hstate-__read_mostly.patch
mm-hugetlb-add-new-hugetlb-cgroup.patch
mm-hugetlb-add-new-hugetlb-cgroup-fix.patch
mm-hugetlb-add-new-hugetlb-cgroup-fix-fix.patch
mm-hugetlb-add-new-hugetlb-cgroup-fix-3.patch
mm-hugetlb-add-new-hugetlb-cgroup-mark-root_h_cgroup-static.patch
hugetlb-cgroup-add-the-cgroup-pointer-to-page-lru.patch
hugetlb-cgroup-add-charge-uncharge-routines-for-hugetlb-cgroup.patch
hugetlb-cgroup-add-charge-uncharge-routines-for-hugetlb-cgroup-fix.patch
hugetlb-cgroup-add-charge-uncharge-routines-for-hugetlb-cgroup-add-huge_page_order-check-to-avoid-incorrectly-uncharge.patch
hugetlb-cgroup-add-support-for-cgroup-removal.patch
hugetlb-cgroup-add-hugetlb-cgroup-control-files.patch
hugetlb-cgroup-add-hugetlb-cgroup-control-files-fix.patch
hugetlb-cgroup-add-hugetlb-cgroup-control-files-fix-fix.patch
hugetlb-cgroup-migrate-hugetlb-cgroup-info-from-oldpage-to-new-page-during-migration.patch
hugetlb-cgroup-add-hugetlb-controller-documentation.patch
hugetlb-move-all-the-in-use-pages-to-active-list.patch
hugetlb-cgroup-assign-the-page-hugetlb-cgroup-when-we-move-the-page-to-active-list.patch
hugetlb-cgroup-remove-exclude-and-wakeup-rmdir-calls-from-migrate.patch
memcg-rename-config-variables.patch
memcg-rename-config-variables-fix.patch
memcg-rename-config-variables-fix-fix.patch
linux-next.patch

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