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dax: Use new dax zero page method for zeroing a page 

Use new dax native zero page method for zeroing page if I/O is page
aligned. Otherwise fall back to direct_access() + memcpy().

This gets rid of one of the depenendency on block device in dax path.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Link: https://lore.kernel.org/r/20200228163456.1587-6-vgoyal@redhat.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This commit is contained in:
Vivek Goyal 2020-02-28 11:34:55 -05:00 committed by Dan Williams
parent cdf6cdcd3b
commit 0a23f9ffa5
1 changed files with 23 additions and 30 deletions
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33
fs/dax.c
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@ -1038,47 +1038,40 @@ static vm_fault_t dax_load_hole(struct xa_state *xas,
return ret;
}
static bool dax_range_is_aligned(struct block_device *bdev,
unsigned int offset, unsigned int length)
{
unsigned short sector_size = bdev_logical_block_size(bdev);
if (!IS_ALIGNED(offset, sector_size))
return false;
if (!IS_ALIGNED(length, sector_size))
return false;
return true;
}
int __dax_zero_page_range(struct block_device *bdev,
struct dax_device *dax_dev, sector_t sector,
unsigned int offset, unsigned int size)
{
if (dax_range_is_aligned(bdev, offset, size)) {
sector_t start_sector = sector + (offset >> 9);
return blkdev_issue_zeroout(bdev, start_sector,
size >> 9, GFP_NOFS, 0);
} else {
pgoff_t pgoff;
long rc, id;
void *kaddr;
bool page_aligned = false;
if (IS_ALIGNED(sector << SECTOR_SHIFT, PAGE_SIZE) &&
IS_ALIGNED(size, PAGE_SIZE))
page_aligned = true;
rc = bdev_dax_pgoff(bdev, sector, PAGE_SIZE, &pgoff);
if (rc)
return rc;
id = dax_read_lock();
if (page_aligned)
rc = dax_zero_page_range(dax_dev, pgoff, size >> PAGE_SHIFT);
else
rc = dax_direct_access(dax_dev, pgoff, 1, &kaddr, NULL);
if (rc < 0) {
dax_read_unlock(id);
return rc;
}
if (!page_aligned) {
memset(kaddr + offset, 0, size);
dax_flush(dax_dev, kaddr + offset, size);
dax_read_unlock(id);
}
dax_read_unlock(id);
return 0;
}
EXPORT_SYMBOL_GPL(__dax_zero_page_range);