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Date:   Mon, 22 May 2023 17:43:07 -0700
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Subject: [PATCH v4 0/3] mm: Fix bug affecting swapping in MTE tagged pages
From:   Peter Collingbourne <pcc@google.com>
To:     Catalin Marinas <catalin.marinas@arm.com>
Cc:     Peter Collingbourne <pcc@google.com>,
        "=?UTF-8?q?Qun-wei=20Lin=20=28=E6=9E=97=E7=BE=A4=E5=B4=B4=29?=" 
        <Qun-wei.Lin@mediatek.com>, linux-arm-kernel@lists.infradead.org,
        linux-mm@kvack.org, linux-kernel@vger.kernel.org,
        "surenb@google.com" <surenb@google.com>,
        "david@redhat.com" <david@redhat.com>,
        "=?UTF-8?q?Chinwen=20Chang=20=28=E5=BC=B5=E9=8C=A6=E6=96=87=29?=" 
        <chinwen.chang@mediatek.com>,
        "kasan-dev@googlegroups.com" <kasan-dev@googlegroups.com>,
        "=?UTF-8?q?Kuan-Ying=20Lee=20=28=E6=9D=8E=E5=86=A0=E7=A9=8E=29?=" 
        <Kuan-Ying.Lee@mediatek.com>,
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        <casper.li@mediatek.com>,
        "gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
        vincenzo.frascino@arm.com,
        Alexandru Elisei <alexandru.elisei@arm.com>, will@kernel.org,
        eugenis@google.com, Steven Price <steven.price@arm.com>
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This patch series reworks the logic that handles swapping in page
metadata to fix a reported bug [1] where metadata can sometimes not
be swapped in correctly after commit c145e0b47c77 ("mm: streamline COW
logic in do_swap_page()").

- Patch 1 fixes the bug itself, but still requires architectures
  to restore metadata in both arch_swap_restore() and set_pte_at().

- Patch 2 makes it so that architectures only need to restore metadata
  in arch_swap_restore().

- Patch 3 changes arm64 to remove support for restoring metadata
  in set_pte_at().

[1] https://lore.kernel.org/all/5050805753ac469e8d727c797c2218a9d780d434.camel@mediatek.com/

v4:
- Rebased onto v6.4-rc3
- Reverted change to arch/arm64/mm/mteswap.c; this change was not
  valid because swapcache pages can have arch_swap_restore() called
  on them multiple times

v3:
- Added patch to call arch_swap_restore() from unuse_pte()
- Rebased onto arm64/for-next/fixes

v2:
- Call arch_swap_restore() directly instead of via arch_do_swap_page()

Peter Collingbourne (3):
  mm: Call arch_swap_restore() from do_swap_page()
  mm: Call arch_swap_restore() from unuse_pte()
  arm64: mte: Simplify swap tag restoration logic

 arch/arm64/include/asm/mte.h     |  4 ++--
 arch/arm64/include/asm/pgtable.h | 14 ++----------
 arch/arm64/kernel/mte.c          | 37 ++++++--------------------------
 mm/memory.c                      |  7 ++++++
 mm/swapfile.c                    |  7 ++++++
 5 files changed, 25 insertions(+), 44 deletions(-)

-- 
2.40.1.698.g37aff9b760-goog