+ fsdax-output-address-in-dax_iomap_pfn-and-rename-it.patch added to mm-unstable branch

+ fsdax-output-address-in-dax_iomap_pfn-and-rename-it.patch added to mm-unstable branch

[Andrew Morton]

The patch titled
     Subject: fsdax: output address in dax_iomap_pfn() and rename it
has been added to the -mm mm-unstable branch.  Its filename is
     fsdax-output-address-in-dax_iomap_pfn-and-rename-it.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/fsdax-output-address-in-dax_iomap_pfn-and-rename-it.patch

This patch will later appear in the mm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Shiyang Ruan <ruansy.fnst@fujitsu.com>
Subject: fsdax: output address in dax_iomap_pfn() and rename it
Date: Fri, 3 Jun 2022 13:37:32 +0800

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().

Link: https://lkml.kernel.org/r/20220603053738.1218681-9-ruansy.fnst@fujitsu.com
Signed-off-by: Shiyang Ruan <ruansy.fnst@fujitsu.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ritesh Harjani <riteshh@linux.ibm.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Dan Williams <dan.j.wiliams@intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Goldwyn Rodrigues <rgoldwyn@suse.com>
Cc: Goldwyn Rodrigues <rgoldwyn@suse.de>
Cc: Jane Chu <jane.chu@oracle.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

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

--- a/fs/dax.c~fsdax-output-address-in-dax_iomap_pfn-and-rename-it
+++ a/fs/dax.c
@@ -1026,8 +1026,8 @@ int dax_writeback_mapping_range(struct a
 }
 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;
@@ -1035,11 +1035,13 @@ static int dax_iomap_pfn(const struct io
 
 	id = dax_read_lock();
 	length = dax_direct_access(iomap->dax_dev, pgoff, PHYS_PFN(size),
-				   DAX_ACCESS, NULL, pfnp);
+				   DAX_ACCESS, kaddr, pfnp);
 	if (length < 0) {
 		rc = length;
 		goto out;
 	}
+	if (!pfnp)
+		goto out_check_addr;
 	rc = -EINVAL;
 	if (PFN_PHYS(length) < size)
 		goto out;
@@ -1049,6 +1051,12 @@ static int dax_iomap_pfn(const struct io
 	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;
@@ -1456,7 +1464,7 @@ static vm_fault_t dax_fault_iter(struct
 		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);
 
_

Patches currently in -mm which might be from ruansy.fnst@fujitsu.com are

dax-introduce-holder-for-dax_device.patch
mm-factor-helpers-for-memory_failure_dev_pagemap.patch
pagemappmem-introduce-memory_failure.patch
fsdax-introduce-dax_lock_mapping_entry.patch
mm-introduce-mf_dax_kill_procs-for-fsdax-case.patch
xfs-implement-notify_failure-for-xfs.patch
fsdax-set-a-cow-flag-when-associate-reflink-mappings.patch
fsdax-output-address-in-dax_iomap_pfn-and-rename-it.patch
fsdax-introduce-dax_iomap_cow_copy.patch
fsdax-replace-mmap-entry-in-case-of-cow.patch
fsdax-add-dax_iomap_cow_copy-for-dax-zero.patch
fsdax-dedup-file-range-to-use-a-compare-function.patch
xfs-support-cow-in-fsdax-mode.patch
xfs-add-dax-dedupe-support.patch