This is a note to let you know that I've just added the patch titled

    erofs: simplify z_erofs_transform_plain()

to the 6.1-stable tree which can be found at:
    
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     erofs-simplify-z_erofs_transform_plain.patch
and it can be found in the queue-6.1 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.


>From [email protected] Tue Jul 22 12:04:46 
>2025
From: Gao Xiang <[email protected]>
Date: Tue, 22 Jul 2025 18:00:28 +0800
Subject: erofs: simplify z_erofs_transform_plain()
To: [email protected], Greg Kroah-Hartman <[email protected]>, 
Jan Kiszka <[email protected]>, Stefan Kerkmann <[email protected]>
Cc: [email protected], LKML <[email protected]>, Gao 
Xiang <[email protected]>, Yue Hu <[email protected]>, Chao Yu 
<[email protected]>
Message-ID: <[email protected]>

From: Gao Xiang <[email protected]>

commit c5539762f32e97c5e16215fa1336e32095b8b0fd upstream.

Use memcpy_to_page() instead of open-coding them.

In addition, add a missing flush_dcache_page() even though almost all
modern architectures clear `PG_dcache_clean` flag for new file cache
pages so that it doesn't change anything in practice.

Signed-off-by: Gao Xiang <[email protected]>
Reviewed-by: Yue Hu <[email protected]>
Reviewed-by: Chao Yu <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Gao Xiang <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
 fs/erofs/decompressor.c |   19 ++++++++-----------
 1 file changed, 8 insertions(+), 11 deletions(-)

--- a/fs/erofs/decompressor.c
+++ b/fs/erofs/decompressor.c
@@ -323,7 +323,7 @@ static int z_erofs_transform_plain(struc
        const unsigned int lefthalf = rq->outputsize - righthalf;
        const unsigned int interlaced_offset =
                rq->alg == Z_EROFS_COMPRESSION_SHIFTED ? 0 : rq->pageofs_out;
-       unsigned char *src, *dst;
+       u8 *src;
 
        if (outpages > 2 && rq->alg == Z_EROFS_COMPRESSION_SHIFTED) {
                DBG_BUGON(1);
@@ -336,22 +336,19 @@ static int z_erofs_transform_plain(struc
        }
 
        src = kmap_local_page(rq->in[inpages - 1]) + rq->pageofs_in;
-       if (rq->out[0]) {
-               dst = kmap_local_page(rq->out[0]);
-               memcpy(dst + rq->pageofs_out, src + interlaced_offset,
-                      righthalf);
-               kunmap_local(dst);
-       }
+       if (rq->out[0])
+               memcpy_to_page(rq->out[0], rq->pageofs_out,
+                              src + interlaced_offset, righthalf);
 
        if (outpages > inpages) {
                DBG_BUGON(!rq->out[outpages - 1]);
                if (rq->out[outpages - 1] != rq->in[inpages - 1]) {
-                       dst = kmap_local_page(rq->out[outpages - 1]);
-                       memcpy(dst, interlaced_offset ? src :
-                                       (src + righthalf), lefthalf);
-                       kunmap_local(dst);
+                       memcpy_to_page(rq->out[outpages - 1], 0, src +
+                                       (interlaced_offset ? 0 : righthalf),
+                                      lefthalf);
                } else if (!interlaced_offset) {
                        memmove(src, src + righthalf, lefthalf);
+                       flush_dcache_page(rq->in[inpages - 1]);
                }
        }
        kunmap_local(src);


Patches currently in stable-queue which might be from 
[email protected] are

queue-6.1/erofs-sunset-erofs_dbg.patch
queue-6.1/erofs-simplify-z_erofs_transform_plain.patch
queue-6.1/erofs-get-rid-of-debug_one_dentry.patch
queue-6.1/erofs-drop-z_erofs_page_mark_eio.patch
queue-6.1/erofs-address-d-cache-aliasing.patch

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