Commit 9ad9718b authored by Wei Yang's avatar Wei Yang Committed by Linus Torvalds

mm/mremap: calculate extent in one place

Page tables is moved on the base of PMD.  This requires both source and
destination range should meet the requirement.

Current code works well since move_huge_pmd() and move_normal_pmd() would
check old_addr and new_addr again.  And then return to move_ptes() if the
either of them is not aligned.

Instead of calculating the extent separately, it is better to calculate in
one place, so we know it is not necessary to try move pmd.  By doing so,
the logic seems a little clear.
Signed-off-by: default avatarWei Yang <richard.weiyang@linux.alibaba.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Tested-by: default avatarDmitry Osipenko <digetx@gmail.com>
Acked-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: Thomas Hellstrom <thellstrom@vmware.com>
Cc: Thomas Hellstrom (VMware) <thomas_os@shipmail.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yang Shi <yang.shi@linux.alibaba.com>
Link: http://lkml.kernel.org/r/20200708095028.41706-3-richard.weiyang@linux.alibaba.comSigned-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent b8aa9d9d
...@@ -277,6 +277,9 @@ unsigned long move_page_tables(struct vm_area_struct *vma, ...@@ -277,6 +277,9 @@ unsigned long move_page_tables(struct vm_area_struct *vma,
extent = next - old_addr; extent = next - old_addr;
if (extent > old_end - old_addr) if (extent > old_end - old_addr)
extent = old_end - old_addr; extent = old_end - old_addr;
next = (new_addr + PMD_SIZE) & PMD_MASK;
if (extent > next - new_addr)
extent = next - new_addr;
old_pmd = get_old_pmd(vma->vm_mm, old_addr); old_pmd = get_old_pmd(vma->vm_mm, old_addr);
if (!old_pmd) if (!old_pmd)
continue; continue;
...@@ -320,9 +323,6 @@ unsigned long move_page_tables(struct vm_area_struct *vma, ...@@ -320,9 +323,6 @@ unsigned long move_page_tables(struct vm_area_struct *vma,
if (pte_alloc(new_vma->vm_mm, new_pmd)) if (pte_alloc(new_vma->vm_mm, new_pmd))
break; break;
next = (new_addr + PMD_SIZE) & PMD_MASK;
if (extent > next - new_addr)
extent = next - new_addr;
move_ptes(vma, old_pmd, old_addr, old_addr + extent, new_vma, move_ptes(vma, old_pmd, old_addr, old_addr + extent, new_vma,
new_pmd, new_addr, need_rmap_locks); new_pmd, new_addr, need_rmap_locks);
} }
......
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