mm: add unmap_mapping_pages()
Several users of unmap_mapping_range() would prefer to express their
range in pages rather than bytes. Unfortuately, on a 32-bit kernel, you
have to remember to cast your page number to a 64-bit type before
shifting it, and four places in the current tree didn't remember to do
that. That's a sign of a bad interface.
Conveniently, unmap_mapping_range() actually converts from bytes into
pages, so hoist the guts of unmap_mapping_range() into a new function
unmap_mapping_pages() and convert the callers which want to use pages.
Link: http://lkml.kernel.org/r/20171206142627.GD32044@bombadil.infradead.org
Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
Reported-by: "zhangyi (F)" <yi.zhang@huawei.com>
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/dax.c b/fs/dax.c
index c2ebf10..6ee6f7e 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -44,6 +44,7 @@
/* The 'colour' (ie low bits) within a PMD of a page offset. */
#define PG_PMD_COLOUR ((PMD_SIZE >> PAGE_SHIFT) - 1)
+#define PG_PMD_NR (PMD_SIZE >> PAGE_SHIFT)
static wait_queue_head_t wait_table[DAX_WAIT_TABLE_ENTRIES];
@@ -375,8 +376,8 @@
* unmapped.
*/
if (pmd_downgrade && dax_is_zero_entry(entry))
- unmap_mapping_range(mapping,
- (index << PAGE_SHIFT) & PMD_MASK, PMD_SIZE, 0);
+ unmap_mapping_pages(mapping, index & ~PG_PMD_COLOUR,
+ PG_PMD_NR, false);
err = radix_tree_preload(
mapping_gfp_mask(mapping) & ~__GFP_HIGHMEM);
@@ -538,12 +539,10 @@
if (dax_is_zero_entry(entry) && !(flags & RADIX_DAX_ZERO_PAGE)) {
/* we are replacing a zero page with block mapping */
if (dax_is_pmd_entry(entry))
- unmap_mapping_range(mapping,
- (vmf->pgoff << PAGE_SHIFT) & PMD_MASK,
- PMD_SIZE, 0);
+ unmap_mapping_pages(mapping, index & ~PG_PMD_COLOUR,
+ PG_PMD_NR, false);
else /* pte entry */
- unmap_mapping_range(mapping, vmf->pgoff << PAGE_SHIFT,
- PAGE_SIZE, 0);
+ unmap_mapping_pages(mapping, vmf->pgoff, 1, false);
}
spin_lock_irq(&mapping->tree_lock);
@@ -1269,12 +1268,6 @@
}
#ifdef CONFIG_FS_DAX_PMD
-/*
- * The 'colour' (ie low bits) within a PMD of a page offset. This comes up
- * more often than one might expect in the below functions.
- */
-#define PG_PMD_COLOUR ((PMD_SIZE >> PAGE_SHIFT) - 1)
-
static int dax_pmd_load_hole(struct vm_fault *vmf, struct iomap *iomap,
void *entry)
{