Re: [PATCH 17/29] fsdax: factor out a dax_memzero helper
From: Dan Williams <hidden>
Date: 2021-11-23 21:22:28
Also in:
dm-devel, linux-ext4, linux-fsdevel, linux-s390, linux-xfs, nvdimm
On Tue, Nov 9, 2021 at 12:34 AM Christoph Hellwig [off-list ref] wrote:
Factor out a helper for the "manual" zeroing of a DAX range to clean up dax_iomap_zero a lot.
Small / optional fixup below: Reviewed-by: Dan Williams <redacted>
quoted hunk ↗ jump to hunk
Signed-off-by: Christoph Hellwig <hch@lst.de> --- fs/dax.c | 36 +++++++++++++++++++----------------- 1 file changed, 19 insertions(+), 17 deletions(-)diff --git a/fs/dax.c b/fs/dax.c index d7a923d152240..dc9ebeff850ab 100644 --- a/fs/dax.c +++ b/fs/dax.c@@ -1121,34 +1121,36 @@ static vm_fault_t dax_pmd_load_hole(struct xa_state *xas, struct vm_fault *vmf, } #endif /* CONFIG_FS_DAX_PMD */ +static int dax_memzero(struct dax_device *dax_dev, pgoff_t pgoff, + unsigned int offset, size_t size) +{ + void *kaddr; + long rc; + + rc = dax_direct_access(dax_dev, pgoff, 1, &kaddr, NULL); + if (rc >= 0) {
Technically this should be "> 0" because dax_direct_access() returns nr_available_pages @pgoff, but this isn't broken because dax_direct_access() converts the "zero pages available" case into -ERANGE.
+ memset(kaddr + offset, 0, size);
+ dax_flush(dax_dev, kaddr + offset, size);
+ }
+ return rc;
+}
+
s64 dax_iomap_zero(loff_t pos, u64 length, struct iomap *iomap)
{
pgoff_t pgoff = dax_iomap_pgoff(iomap, pos);
long rc, id;
- void *kaddr;
- bool page_aligned = false;
unsigned offset = offset_in_page(pos);
unsigned size = min_t(u64, PAGE_SIZE - offset, length);
- if (IS_ALIGNED(pos, PAGE_SIZE) && size == PAGE_SIZE)
- page_aligned = true;
-
id = dax_read_lock();
-
- if (page_aligned)
+ if (IS_ALIGNED(pos, PAGE_SIZE) && size == PAGE_SIZE)
rc = dax_zero_page_range(iomap->dax_dev, pgoff, 1);
else
- rc = dax_direct_access(iomap->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(iomap->dax_dev, kaddr + offset, size);
- }
+ rc = dax_memzero(iomap->dax_dev, pgoff, offset, size);
dax_read_unlock(id);
+
+ if (rc < 0)
+ return rc;
return size;
}
--
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