From: William Kucharski <william.kuchar...@oracle.com>

When we have the opportunity to use transparent huge pages to map a
file, we want to follow the same rules as DAX.

Signed-off-by: William Kucharski <william.kuchar...@oracle.com>
[Inline __thp_get_unmapped_area() into thp_get_unmapped_area()]
Signed-off-by: Matthew Wilcox (Oracle) <wi...@infradead.org>
---
 mm/huge_memory.c | 40 +++++++++++++---------------------------
 1 file changed, 13 insertions(+), 27 deletions(-)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 15a86b06befc..e78686b628ae 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -535,30 +535,30 @@ bool is_transparent_hugepage(struct page *page)
 }
 EXPORT_SYMBOL_GPL(is_transparent_hugepage);
 
-static unsigned long __thp_get_unmapped_area(struct file *filp,
-               unsigned long addr, unsigned long len,
-               loff_t off, unsigned long flags, unsigned long size)
+unsigned long thp_get_unmapped_area(struct file *filp, unsigned long addr,
+               unsigned long len, unsigned long pgoff, unsigned long flags)
 {
+       loff_t off = (loff_t)pgoff << PAGE_SHIFT;
        loff_t off_end = off + len;
-       loff_t off_align = round_up(off, size);
+       loff_t off_align = round_up(off, PMD_SIZE);
        unsigned long len_pad, ret;
 
-       if (off_end <= off_align || (off_end - off_align) < size)
-               return 0;
+       if (off_end <= off_align || (off_end - off_align) < PMD_SIZE)
+               goto regular;
 
-       len_pad = len + size;
+       len_pad = len + PMD_SIZE;
        if (len_pad < len || (off + len_pad) < off)
-               return 0;
+               goto regular;
 
        ret = current->mm->get_unmapped_area(filp, addr, len_pad,
                                              off >> PAGE_SHIFT, flags);
 
        /*
-        * The failure might be due to length padding. The caller will retry
-        * without the padding.
+        * The failure might be due to length padding.  Retry without
+        * the padding.
         */
        if (IS_ERR_VALUE(ret))
-               return 0;
+               goto regular;
 
        /*
         * Do not try to align to THP boundary if allocation at the address
@@ -567,23 +567,9 @@ static unsigned long __thp_get_unmapped_area(struct file 
*filp,
        if (ret == addr)
                return addr;
 
-       ret += (off - ret) & (size - 1);
+       ret += (off - ret) & (PMD_SIZE - 1);
        return ret;
-}
-
-unsigned long thp_get_unmapped_area(struct file *filp, unsigned long addr,
-               unsigned long len, unsigned long pgoff, unsigned long flags)
-{
-       unsigned long ret;
-       loff_t off = (loff_t)pgoff << PAGE_SHIFT;
-
-       if (!IS_DAX(filp->f_mapping->host) || !IS_ENABLED(CONFIG_FS_DAX_PMD))
-               goto out;
-
-       ret = __thp_get_unmapped_area(filp, addr, len, off, flags, PMD_SIZE);
-       if (ret)
-               return ret;
-out:
+regular:
        return current->mm->get_unmapped_area(filp, addr, len, pgoff, flags);
 }
 EXPORT_SYMBOL_GPL(thp_get_unmapped_area);
-- 
2.26.2

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