[PATCH 2/2] arch/arm/mm: fix major fault accounting when retrying under per-VMA lock

[Suren Baghdasaryan <surenb@google.com>]

The change [1] missed ARM architecture when fixing major fault accounting
for page fault retry under per-VMA lock.

The user-visible effects is that it restores correct major fault
accounting that was broken after [2] was merged in 6.7 kernel. The
more detailed description is in [3] and this patch simply adds the
same fix to ARM architecture which I missed in [3].

Add missing code to fix ARM architecture fault accounting.

[1] 46e714c729c8 ("arch/mm/fault: fix major fault accounting when retrying under per-VMA lock")
[2] https://lore.kernel.org/all/20231006195318.4087158-6-willy@infradead.org/
[3] https://lore.kernel.org/all/20231226214610.109282-1-surenb@google.com/

Link: https://lkml.kernel.org/r/20240123064305.2829244-1-surenb@google.com
Fixes: 12214eba1992 ("mm: handle read faults under the VMA lock")
Reported-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
 arch/arm/mm/fault.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/arm/mm/fault.c b/arch/arm/mm/fault.c
index e96fb40b9cc3..07565b593ed6 100644
--- a/arch/arm/mm/fault.c
+++ b/arch/arm/mm/fault.c
@@ -298,6 +298,8 @@ do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
 		goto done;
 	}
 	count_vm_vma_lock_event(VMA_LOCK_RETRY);
+	if (fault & VM_FAULT_MAJOR)
+		flags |= FAULT_FLAG_TRIED;
 
 	/* Quick path to respond to signals */
 	if (fault_signal_pending(fault, regs)) {
-- 
2.44.0.rc0.258.g7320e95886-goog