Add address output in dax_iomap_pfn() in order to perform a memcpy() in
CoW case. Since this function both output address and pfn, rename it to
dax_iomap_direct_access().
Signed-off-by: Shiyang Ruan <ruansy.fnst@xxxxxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Reviewed-by: Ritesh Harjani <riteshh@xxxxxxxxxxxxx>
Reviewed-by: Dan Williams <dan.j.williams@xxxxxxxxx>
Reviewed-by: Darrick J. Wong <djwong@xxxxxxxxxx>
---
fs/dax.c | 16 ++++++++++++----
1 file changed, 12 insertions(+), 4 deletions(-)
diff --git a/fs/dax.c b/fs/dax.c
index 4d3dfc8bee33..d4f195aeaa12 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -1025,8 +1025,8 @@ int dax_writeback_mapping_range(struct address_space *mapping,
}
EXPORT_SYMBOL_GPL(dax_writeback_mapping_range);
-static int dax_iomap_pfn(const struct iomap *iomap, loff_t pos, size_t size,
- pfn_t *pfnp)
+static int dax_iomap_direct_access(const struct iomap *iomap, loff_t pos,
+ size_t size, void **kaddr, pfn_t *pfnp)
{
pgoff_t pgoff = dax_iomap_pgoff(iomap, pos);
int id, rc;
@@ -1034,11 +1034,13 @@ static int dax_iomap_pfn(const struct iomap *iomap, loff_t pos, size_t size,
id = dax_read_lock();
length = dax_direct_access(iomap->dax_dev, pgoff, PHYS_PFN(size),
- NULL, pfnp);
+ kaddr, pfnp);
if (length < 0) {
rc = length;
goto out;
}
+ if (!pfnp)
+ goto out_check_addr;
rc = -EINVAL;
if (PFN_PHYS(length) < size)
goto out;
@@ -1048,6 +1050,12 @@ static int dax_iomap_pfn(const struct iomap *iomap, loff_t pos, size_t size,
if (length > 1 && !pfn_t_devmap(*pfnp))
goto out;
rc = 0;
+
+out_check_addr:
+ if (!kaddr)
+ goto out;
+ if (!*kaddr)
+ rc = -EFAULT;
out:
dax_read_unlock(id);
return rc;
@@ -1444,7 +1452,7 @@ static vm_fault_t dax_fault_iter(struct vm_fault *vmf,
return pmd ? VM_FAULT_FALLBACK : VM_FAULT_SIGBUS;
}
- err = dax_iomap_pfn(&iter->iomap, pos, size, &pfn);
+ err = dax_iomap_direct_access(&iter->iomap, pos, size, NULL, &pfn);
if (err)
return pmd ? VM_FAULT_FALLBACK : dax_fault_return(err);
--
2.35.1
