This is a note to let you know that I've just added the patch titled
erofs: address D-cache aliasing
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-address-d-cache-aliasing.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 12:00:48 2025
From: Gao Xiang <[email protected]>
Date: Tue, 22 Jul 2025 18:00:29 +0800
Subject: erofs: address D-cache aliasing
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]>
Message-ID: <[email protected]>
From: Gao Xiang <[email protected]>
commit 27917e8194f91dffd8b4825350c63cb68e98ce58 upstream.
Flush the D-cache before unlocking folios for compressed inodes, as
they are dirtied during decompression.
Avoid calling flush_dcache_folio() on every CPU write, since it's more
like playing whack-a-mole without real benefit.
It has no impact on x86 and arm64/risc-v: on x86, flush_dcache_folio()
is a no-op, and on arm64/risc-v, PG_dcache_clean (PG_arch_1) is clear
for new page cache folios. However, certain ARM boards are affected,
as reported.
Fixes: 3883a79abd02 ("staging: erofs: introduce VLE decompression support")
Closes:
https://lore.kernel.org/r/[email protected]
Closes:
https://lore.kernel.org/r/[email protected]
Tested-by: Jan Kiszka <[email protected]>
Tested-by: Stefan Kerkmann <[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 | 6 ++----
fs/erofs/zdata.c | 32 +++++++++++++++++++-------------
2 files changed, 21 insertions(+), 17 deletions(-)
--- a/fs/erofs/decompressor.c
+++ b/fs/erofs/decompressor.c
@@ -342,14 +342,12 @@ static int z_erofs_transform_plain(struc
if (outpages > inpages) {
DBG_BUGON(!rq->out[outpages - 1]);
- if (rq->out[outpages - 1] != rq->in[inpages - 1]) {
+ if (rq->out[outpages - 1] != rq->in[inpages - 1])
memcpy_to_page(rq->out[outpages - 1], 0, src +
(interlaced_offset ? 0 : righthalf),
lefthalf);
- } else if (!interlaced_offset) {
+ else if (!interlaced_offset)
memmove(src, src + righthalf, lefthalf);
- flush_dcache_page(rq->in[inpages - 1]);
- }
}
kunmap_local(src);
return 0;
--- a/fs/erofs/zdata.c
+++ b/fs/erofs/zdata.c
@@ -123,9 +123,11 @@ static inline unsigned int z_erofs_pclus
/*
* bit 30: I/O error occurred on this page
+ * bit 29: CPU has dirty data in D-cache (needs aliasing handling);
* bit 0 - 29: remaining parts to complete this page
*/
-#define Z_EROFS_PAGE_EIO (1 << 30)
+#define Z_EROFS_ONLINEPAGE_EIO 30
+#define Z_EROFS_ONLINEPAGE_DIRTY 29
static inline void z_erofs_onlinepage_init(struct page *page)
{
@@ -144,7 +146,7 @@ static inline void z_erofs_onlinepage_sp
atomic_inc((atomic_t *)&page->private);
}
-static void z_erofs_onlinepage_endio(struct page *page, int err)
+static void z_erofs_onlinepage_end(struct page *page, int err, bool dirty)
{
int orig, v;
@@ -152,16 +154,20 @@ static void z_erofs_onlinepage_endio(str
do {
orig = atomic_read((atomic_t *)&page->private);
- v = (orig - 1) | (err ? Z_EROFS_PAGE_EIO : 0);
+ DBG_BUGON(orig <= 0);
+ v = dirty << Z_EROFS_ONLINEPAGE_DIRTY;
+ v |= (orig - 1) | (!!err << Z_EROFS_ONLINEPAGE_EIO);
} while (atomic_cmpxchg((atomic_t *)&page->private, orig, v) != orig);
- if (!(v & ~Z_EROFS_PAGE_EIO)) {
- set_page_private(page, 0);
- ClearPagePrivate(page);
- if (!(v & Z_EROFS_PAGE_EIO))
- SetPageUptodate(page);
- unlock_page(page);
- }
+ if (v & (BIT(Z_EROFS_ONLINEPAGE_DIRTY) - 1))
+ return;
+ set_page_private(page, 0);
+ ClearPagePrivate(page);
+ if (v & BIT(Z_EROFS_ONLINEPAGE_DIRTY))
+ flush_dcache_page(page);
+ if (!(v & BIT(Z_EROFS_ONLINEPAGE_EIO)))
+ SetPageUptodate(page);
+ unlock_page(page);
}
#define Z_EROFS_ONSTACK_PAGES 32
@@ -925,7 +931,7 @@ next_part:
goto repeat;
out:
- z_erofs_onlinepage_endio(page, err);
+ z_erofs_onlinepage_end(page, err, false);
return err;
}
@@ -1028,7 +1034,7 @@ static void z_erofs_fill_other_copies(st
cur += len;
}
kunmap_local(dst);
- z_erofs_onlinepage_endio(bvi->bvec.page, err);
+ z_erofs_onlinepage_end(bvi->bvec.page, err, true);
list_del(p);
kfree(bvi);
}
@@ -1196,7 +1202,7 @@ out:
/* recycle all individual short-lived pages */
if (z_erofs_put_shortlivedpage(be->pagepool, page))
continue;
- z_erofs_onlinepage_endio(page, err);
+ z_erofs_onlinepage_end(page, err, true);
}
if (be->decompressed_pages != be->onstack_pages)
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
