diff mbox series

[37/41] mm: introduce mod_vm_flags_nolock

Message ID	20230109205336.3665937-38-surenb@google.com (mailing list archive)
State	New, archived
Headers	show Return-Path: <linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org> Date: Mon, 9 Jan 2023 12:53:32 -0800 In-Reply-To: <20230109205336.3665937-1-surenb@google.com> Mime-Version: 1.0 References: <20230109205336.3665937-1-surenb@google.com> Message-ID: <20230109205336.3665937-38-surenb@google.com> Subject: [PATCH 37/41] mm: introduce mod_vm_flags_nolock From: Suren Baghdasaryan <surenb@google.com> To: akpm@linux-foundation.org Cc: michel@lespinasse.org, jglisse@google.com, mhocko@suse.com, vbabka@suse.cz, hannes@cmpxchg.org, mgorman@techsingularity.net, dave@stgolabs.net, willy@infradead.org, liam.howlett@oracle.com, peterz@infradead.org, ldufour@linux.ibm.com, laurent.dufour@fr.ibm.com, paulmck@kernel.org, luto@kernel.org, songliubraving@fb.com, peterx@redhat.com, david@redhat.com, dhowells@redhat.com, hughd@google.com, bigeasy@linutronix.de, kent.overstreet@linux.dev, punit.agrawal@bytedance.com, lstoakes@gmail.com, peterjung1337@gmail.com, rientjes@google.com, axelrasmussen@google.com, joelaf@google.com, minchan@google.com, jannh@google.com, shakeelb@google.com, tatashin@google.com, edumazet@google.com, gthelen@google.com, gurua@google.com, arjunroy@google.com, soheil@google.com, hughlynch@google.com, leewalsh@google.com, posk@google.com, linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, x86@kernel.org, linux-kernel@vger.kernel.org, kernel-team@android.com, surenb@google.com Precedence: list Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" <linux-arm-kernel-bounces@lists.infradead.org> Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org
Series	Per-VMA locks \| expand [00/41] Per-VMA locks [01/41] maple_tree: Be more cautious about dead nodes [02/41] maple_tree: Detect dead nodes in mas_start() [03/41] maple_tree: Fix freeing of nodes in rcu mode [04/41] maple_tree: remove extra smp_wmb() from mas_dead_leaves() [05/41] maple_tree: Fix write memory barrier of nodes once dead for RCU mode [06/41] maple_tree: Add smp_rmb() to dead node detection [07/41] mm: Enable maple tree RCU mode by default. [08/41] mm: introduce CONFIG_PER_VMA_LOCK [09/41] mm: rcu safe VMA freeing [10/41] mm: move mmap_lock assert function definitions [11/41] mm: export dump_mm() [12/41] mm: add per-VMA lock and helper functions to control it [13/41] mm: introduce vma->vm_flags modifier functions [14/41] mm: replace VM_LOCKED_CLEAR_MASK with VM_LOCKED_MASK [15/41] mm: replace vma->vm_flags direct modifications with modifier calls [16/41] mm: replace vma->vm_flags indirect modification in ksm_madvise [17/41] mm/mmap: move VMA locking before anon_vma_lock_write call [18/41] mm/khugepaged: write-lock VMA while collapsing a huge page [19/41] mm/mmap: write-lock VMAs before merging, splitting or expanding them [20/41] mm/mmap: write-lock VMAs in vma_adjust [21/41] mm/mmap: write-lock VMAs affected by VMA expansion [22/41] mm/mremap: write-lock VMA while remapping it to a new address range [23/41] mm: write-lock VMAs before removing them from VMA tree [24/41] mm: conditionally write-lock VMA in free_pgtables [25/41] mm/mmap: write-lock adjacent VMAs if they can grow into unmapped area [26/41] kernel/fork: assert no VMA readers during its destruction [27/41] mm/mmap: prevent pagefault handler from racing with mmu_notifier registration [28/41] mm: introduce lock_vma_under_rcu to be used from arch-specific code [29/41] mm: fall back to mmap_lock if vma->anon_vma is not yet set [30/41] mm: add FAULT_FLAG_VMA_LOCK flag [31/41] mm: prevent do_swap_page from handling page faults under VMA lock [32/41] mm: prevent userfaults to be handled under per-vma lock [33/41] mm: introduce per-VMA lock statistics [34/41] x86/mm: try VMA lock-based page fault handling first [35/41] arm64/mm: try VMA lock-based page fault handling first [36/41] powerc/mm: try VMA lock-based page fault handling first [37/41] mm: introduce mod_vm_flags_nolock [38/41] mm: avoid assertion in untrack_pfn [39/41] kernel/fork: throttle call_rcu() calls in vm_area_free [40/41] mm: separate vma->lock from vm_area_struct [41/41] mm: replace rw_semaphore with atomic_t in vma_lock

Commit Message

Suren Baghdasaryan Jan. 9, 2023, 8:53 p.m. UTC

In cases when VMA flags are modified after VMA was isolated and mmap_lock
was downgraded, flags modifications do not require per-VMA locking and
an attempt to lock the VMA would result in an assertion because mmap
write lock is not held.
Introduce mod_vm_flags_nolock to be used in such situation.

Signed-off-by: Suren Baghdasaryan <surenb@google.com>
---
 include/linux/mm.h | 8 ++++++++
 1 file changed, 8 insertions(+)

diff mbox series

Patch

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 2e3be1d45371..7d436a5027cc 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -743,6 +743,14 @@  void clear_vm_flags(struct vm_area_struct *vma, unsigned long flags)
 	vma->vm_flags &= ~flags;
 }
 
+static inline
+void mod_vm_flags_nolock(struct vm_area_struct *vma,
+		  unsigned long set, unsigned long clear)
+{
+	vma->vm_flags |= set;
+	vma->vm_flags &= ~clear;
+}
+
 static inline
 void mod_vm_flags(struct vm_area_struct *vma,
 		  unsigned long set, unsigned long clear)