[3/3] fsdax: Output address in dax_iomap_pfn() and rename it

Commit Message

Shiyang Ruan April 7, 2021, 6:32 a.m. UTC

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 <[e-mail]>
Reviewed-by: Christoph Hellwig <[e-mail]>
Reviewed-by: Ritesh Harjani <[e-mail]>
---
 fs/dax.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

Comments

Ritesh Harjani April 7, 2021, 10:16 a.m. UTC | #1

On 21/04/07 02:32PM, Shiyang Ruan wrote:
> 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 <[e-mail]>
> Reviewed-by: Christoph Hellwig <[e-mail]>
> Reviewed-by: Ritesh Harjani <[e-mail]>

Same here. It should be either of below.

Reviewed-by: Ritesh Harjani <[e-mail]>
OR
Reviewed-by: Ritesh Harjani <[e-mail]>

> ---
>  fs/dax.c | 16 ++++++++++++----
>  1 file changed, 12 insertions(+), 4 deletions(-)

Patch

diff --git a/fs/dax.c b/fs/dax.c
index 19fa22ab50fa..ec66207a3199 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -998,8 +998,8 @@  static sector_t dax_iomap_sector(struct iomap *iomap, loff_t pos)
 	return (iomap->addr + (pos & PAGE_MASK) - iomap->offset) >> 9;
 }
 
-static int dax_iomap_pfn(struct iomap *iomap, loff_t pos, size_t size,
-			 pfn_t *pfnp)
+static int dax_iomap_direct_access(struct iomap *iomap, loff_t pos, size_t size,
+		void **kaddr, pfn_t *pfnp)
 {
 	const sector_t sector = dax_iomap_sector(iomap, pos);
 	pgoff_t pgoff;
@@ -1011,11 +1011,13 @@  static int dax_iomap_pfn(struct iomap *iomap, loff_t pos, size_t size,
 		return rc;
 	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;
@@ -1025,6 +1027,12 @@  static int dax_iomap_pfn(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;
@@ -1388,7 +1396,7 @@  static vm_fault_t dax_fault_actor(struct vm_fault *vmf, pfn_t *pfnp,
 		return pmd ? VM_FAULT_FALLBACK : VM_FAULT_SIGBUS;
 	}
 
-	err = dax_iomap_pfn(iomap, pos, size, &pfn);
+	err = dax_iomap_direct_access(iomap, pos, size, NULL, &pfn);
 	if (err)
 		return pmd ? VM_FAULT_FALLBACK : dax_fault_return(err);