Date:   Wed,  8 Dec 2021 13:22:10 -0800
In-Reply-To: <20211208212211.2860249-1-surenb@google.com>
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References: <20211208212211.2860249-1-surenb@google.com>
Subject: [PATCH v4 2/3] mm: document locking restrictions for vm_operations_struct::close
From:   Suren Baghdasaryan <surenb@google.com>
To:     akpm@linux-foundation.org
Cc:     mhocko@kernel.org, mhocko@suse.com, rientjes@google.com,
        willy@infradead.org, hannes@cmpxchg.org, guro@fb.com,
        riel@surriel.com, minchan@kernel.org, kirill@shutemov.name,
        aarcange@redhat.com, christian@brauner.io, hch@infradead.org,
        oleg@redhat.com, david@redhat.com, jannh@google.com,
        shakeelb@google.com, luto@kernel.org, christian.brauner@ubuntu.com,
        fweimer@redhat.com, jengelh@inai.de, timmurray@google.com,
        linux-mm@kvack.org, linux-kernel@vger.kernel.org,
        kernel-team@android.com, surenb@google.com
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Precedence: bulk

Add comments for vm_operations_struct::close documenting locking
requirements for this callback and its callers.

Signed-off-by: Suren Baghdasaryan <surenb@google.com>
---
 include/linux/mm.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index a7e4a9e7d807..b9b88ba7564b 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -577,6 +577,10 @@ enum page_entry_size {
  */
 struct vm_operations_struct {
 	void (*open)(struct vm_area_struct * area);
+	/**
+	 * @close: Called when the VMA is being removed from the MM.
+	 * Context: User context.  May sleep.  Caller holds mmap_lock.
+	 */
 	void (*close)(struct vm_area_struct * area);
 	/* Called any time before splitting to check if it's allowed */
 	int (*may_split)(struct vm_area_struct *area, unsigned long addr);
-- 
2.34.1.400.ga245620fadb-goog