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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org,
	"Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>,
	Yang Shi <shy828301@gmail.com>,
	David Hildenbrand <david@redhat.com>,
	Peter Xu <peterx@redhat.com>,
	Christophe Leroy <christophe.leroy@csgroup.eu>,
	Hugh Dickins <hughd@google.com>, Jason Gunthorpe <jgg@nvidia.com>,
	John Hubbard <jhubbard@nvidia.com>,
	"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Nicholas Piggin <npiggin@gmail.com>,
	Andrew Morton <akpm@linux-foundation.org>
Subject: [PATCH 5.15 05/37] powerpc/64s/radix: dont need to broadcast IPI for radix pmd collapse flush
Date: Mon, 10 Oct 2022 09:05:24 +0200	[thread overview]
Message-ID: <20221010070331.409815434@linuxfoundation.org> (raw)
In-Reply-To: <20221010070331.211113813@linuxfoundation.org>

From: Yang Shi <shy828301@gmail.com>

commit bedf03416913d88c796288f9dca109a53608c745 upstream.

The IPI broadcast is used to serialize against fast-GUP, but fast-GUP will
move to use RCU instead of disabling local interrupts in fast-GUP.  Using
an IPI is the old-styled way of serializing against fast-GUP although it
still works as expected now.

And fast-GUP now fixed the potential race with THP collapse by checking
whether PMD is changed or not.  So IPI broadcast in radix pmd collapse
flush is not necessary anymore.  But it is still needed for hash TLB.

Link: https://lkml.kernel.org/r/20220907180144.555485-2-shy828301@gmail.com
Suggested-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Yang Shi <shy828301@gmail.com>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: Peter Xu <peterx@redhat.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 arch/powerpc/mm/book3s64/radix_pgtable.c |    9 ---------
 1 file changed, 9 deletions(-)

--- a/arch/powerpc/mm/book3s64/radix_pgtable.c
+++ b/arch/powerpc/mm/book3s64/radix_pgtable.c
@@ -954,15 +954,6 @@ pmd_t radix__pmdp_collapse_flush(struct
 	pmd = *pmdp;
 	pmd_clear(pmdp);
 
-	/*
-	 * pmdp collapse_flush need to ensure that there are no parallel gup
-	 * walk after this call. This is needed so that we can have stable
-	 * page ref count when collapsing a page. We don't allow a collapse page
-	 * if we have gup taken on the page. We can ensure that by sending IPI
-	 * because gup walk happens with IRQ disabled.
-	 */
-	serialize_against_pte_lookup(vma->vm_mm);
-
 	radix__flush_tlb_collapsed_pmd(vma->vm_mm, address);
 
 	return pmd;



  parent reply	other threads:[~2022-10-10  7:15 UTC|newest]

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-10-10  7:05 [PATCH 5.15 00/37] 5.15.73-rc1 review Greg Kroah-Hartman
2022-10-10  7:05 ` [PATCH 5.15 01/37] Makefile.extrawarn: Move -Wcast-function-type-strict to W=1 Greg Kroah-Hartman
2022-10-10  7:05 ` [PATCH 5.15 02/37] docs: update mediator information in CoC docs Greg Kroah-Hartman
2022-10-10  7:05 ` [PATCH 5.15 03/37] xsk: Inherit need_wakeup flag for shared sockets Greg Kroah-Hartman
2022-10-10  7:05 ` [PATCH 5.15 04/37] mm: gup: fix the fast GUP race against THP collapse Greg Kroah-Hartman
2022-10-10  7:05 ` Greg Kroah-Hartman [this message]
2022-10-10  7:05 ` [PATCH 5.15 06/37] wait_on_bit: add an acquire memory barrier Greg Kroah-Hartman
2022-10-10  7:05 ` [PATCH 5.15 07/37] provide arch_test_bit_acquire for architectures that define test_bit Greg Kroah-Hartman
2022-10-10  7:05 ` [PATCH 5.15 08/37] fs: fix UAF/GPF bug in nilfs_mdt_destroy Greg Kroah-Hartman
2022-10-10  7:05 ` [PATCH 5.15 09/37] firmware: arm_scmi: Improve checks in the info_get operations Greg Kroah-Hartman
2022-10-10  7:05 ` [PATCH 5.15 10/37] firmware: arm_scmi: Harden accesses to the sensor domains Greg Kroah-Hartman
2022-10-10  7:05 ` [PATCH 5.15 11/37] firmware: arm_scmi: Add SCMI PM driver remove routine Greg Kroah-Hartman
2022-10-10  7:05 ` [PATCH 5.15 12/37] dmaengine: xilinx_dma: Fix devm_platform_ioremap_resource error handling Greg Kroah-Hartman
2022-10-10  7:05 ` [PATCH 5.15 13/37] dmaengine: xilinx_dma: cleanup for fetching xlnx,num-fstores property Greg Kroah-Hartman
2022-10-10  7:05 ` [PATCH 5.15 14/37] dmaengine: xilinx_dma: Report error in case of dma_set_mask_and_coherent API failure Greg Kroah-Hartman
2022-10-10  7:05 ` [PATCH 5.15 15/37] ARM: dts: fix Moxa SDIO compatible, remove sdhci misnomer Greg Kroah-Hartman
2022-10-10  7:05 ` [PATCH 5.15 16/37] scsi: qedf: Fix a UAF bug in __qedf_probe() Greg Kroah-Hartman
2022-10-10  7:05 ` [PATCH 5.15 17/37] net/ieee802154: fix uninit value bug in dgram_sendmsg Greg Kroah-Hartman
2022-10-10  7:05 ` [PATCH 5.15 18/37] net: marvell: prestera: add support for for Aldrin2 Greg Kroah-Hartman
2022-10-10  7:05 ` [PATCH 5.15 19/37] ALSA: hda/hdmi: Fix the converter reuse for the silent stream Greg Kroah-Hartman
2022-10-10  7:05 ` [PATCH 5.15 20/37] um: Cleanup syscall_handler_t cast in syscalls_32.h Greg Kroah-Hartman
2022-10-10  7:05 ` [PATCH 5.15 21/37] um: Cleanup compiler warning in arch/x86/um/tls_32.c Greg Kroah-Hartman
2022-10-10  7:05 ` [PATCH 5.15 22/37] arch: um: Mark the stack non-executable to fix a binutils warning Greg Kroah-Hartman
2022-10-10  7:05 ` [PATCH 5.15 23/37] net: atlantic: fix potential memory leak in aq_ndev_close() Greg Kroah-Hartman
2022-10-10  7:05 ` [PATCH 5.15 24/37] drm/amd/display: Fix double cursor on non-video RGB MPO Greg Kroah-Hartman
2022-10-10  7:05 ` [PATCH 5.15 25/37] drm/amd/display: Assume an LTTPR is always present on fixed_vs links Greg Kroah-Hartman
2022-10-10  7:05 ` [PATCH 5.15 26/37] drm/amd/display: update gamut remap if plane has changed Greg Kroah-Hartman
2022-10-10  7:05 ` [PATCH 5.15 27/37] drm/amd/display: skip audio setup when audio stream is enabled Greg Kroah-Hartman
2022-10-10  7:05 ` [PATCH 5.15 28/37] mmc: core: Replace with already defined values for readability Greg Kroah-Hartman
2022-10-10  7:05 ` [PATCH 5.15 29/37] mmc: core: Terminate infinite loop in SD-UHS voltage switch Greg Kroah-Hartman
2022-10-10  7:05 ` [PATCH 5.15 30/37] perf parse-events: Identify broken modifiers Greg Kroah-Hartman
2022-10-10  7:05 ` [PATCH 5.15 31/37] mm/huge_memory: minor cleanup for split_huge_pages_all Greg Kroah-Hartman
2022-10-10  7:05 ` [PATCH 5.15 32/37] mm/huge_memory: use pfn_to_online_page() in split_huge_pages_all() Greg Kroah-Hartman
2022-10-10  7:05 ` [PATCH 5.15 33/37] wifi: cfg80211: fix MCS divisor value Greg Kroah-Hartman
2022-10-10  7:05 ` [PATCH 5.15 34/37] net/mlx5: Disable irq when locking lag_lock Greg Kroah-Hartman
2022-10-10  7:05 ` [PATCH 5.15 35/37] usb: mon: make mmapped memory read only Greg Kroah-Hartman
2022-10-10  7:05 ` [PATCH 5.15 36/37] USB: serial: ftdi_sio: fix 300 bps rate for SIO Greg Kroah-Hartman
2022-10-10  7:05 ` [PATCH 5.15 37/37] rpmsg: qcom: glink: replace strncpy() with strscpy_pad() Greg Kroah-Hartman
2022-10-10 16:05 ` [PATCH 5.15 00/37] 5.15.73-rc1 review Naresh Kamboju
2022-10-10 17:49 ` Guenter Roeck
2022-10-10 19:07   ` Greg Kroah-Hartman
2022-10-10 18:26 ` Florian Fainelli
2022-10-10 18:59 ` Ron Economos
2022-10-10 21:28 ` Shuah Khan
2022-10-11  4:23 ` Bagas Sanjaya
2022-10-12  2:24   ` Bagas Sanjaya

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