+ fsdax-dax_unshare_iter-should-return-a-valid-length-fix.patch added to mm-hotfixes-unstable branch

+ fsdax-dax_unshare_iter-should-return-a-valid-length-fix.patch added to mm-hotfixes-unstable branch

[Andrew Morton]

The patch titled
     Subject: fsdax-dax_unshare_iter-should-return-a-valid-length-fix
has been added to the -mm mm-hotfixes-unstable branch.  Its filename is
     fsdax-dax_unshare_iter-should-return-a-valid-length-fix.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/fsdax-dax_unshare_iter-should-return-a-valid-length-fix.patch

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

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------------------------------------------------------
From: Andrew Morton <akpm@linux-foundation.org>
Subject: fsdax-dax_unshare_iter-should-return-a-valid-length-fix
Date: Thu Feb  2 04:15:00 PM PST 2023

don't mess up `ret', per Matthew

Cc: Alistair Popple <apopple@nvidia.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Darrick J. Wong <djwong@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Shiyang Ruan <ruansy.fnst@fujitsu.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---


--- a/fs/dax.c~fsdax-dax_unshare_iter-should-return-a-valid-length-fix
+++ a/fs/dax.c
@@ -1271,10 +1271,10 @@ static s64 dax_unshare_iter(struct iomap
 	if (ret < 0)
 		goto out_unlock;
 
-	ret = copy_mc_to_kernel(daddr, saddr, length);
-	if (ret)
+	if (copy_mc_to_kernel(daddr, saddr, length) == 0)
+		ret = length;
+	else
 		ret = -EIO;
-	ret = length;
 
 out_unlock:
 	dax_read_unlock(id);
_

Patches currently in -mm which might be from akpm@linux-foundation.org are

fsdax-dax_unshare_iter-should-return-a-valid-length-fix.patch
mm-add-folio_add_new_anon_rmap-fix.patch
mm-remove-page_evictable-fix.patch
mm-remove-the-swap_readpage-return-value-fix.patch
block-remove-rw_page-fix.patch
mm-add-memcpy_from_file_folio-fix.patch
mm-replace-vma-vm_flags-direct-modifications-with-modifier-calls-fix.patch
kasan-infer-allocation-size-by-scanning-metadata-fix.patch
error-injection-remove-ei_etype_none-fix.patch
hfsplus-remove-unnecessary-variable-initialization-fix.patch
scripts-gdb-add-mm-introspection-utils-fix.patch
lib-stackdepot-mm-rename-stack_depot_want_early_init-fix.patch
lib-stackdepot-annotate-racy-slab_index-accesses-fix.patch