mm: uninline the main body of vma_start_write()

vma_start_write() is used in many places and will grow in size very soon.
It is not used in performance critical paths and uninlining it should
limit the future code size growth.  No functional changes.

Link: https://lkml.kernel.org/r/20250213224655.1680278-10-surenb@google.com
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Tested-by: Shivank Garg <shivankg@amd.com>
Link: https://lkml.kernel.org/r/5e19ec93-8307-47c2-bb13-3ddf7150624e@amd.com
Cc: Christian Brauner <brauner@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jann Horn <jannh@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Klara Modin <klarasmodin@gmail.com>
Cc: Liam R. Howlett <Liam.Howlett@Oracle.com>
Cc: Lokesh Gidra <lokeshgidra@google.com>
Cc: Mateusz Guzik <mjguzik@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Minchan Kim <minchan@google.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: "Paul E . McKenney" <paulmck@kernel.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Sourav Panda <souravpanda@google.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Will Deacon <will@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 9725ac900d96a52a14320153920282a03aa25416..d952c6459251f7d75a52713d2db8497eef0565b2 100644 (file)
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -787,6 +787,8 @@ static bool __is_vma_write_locked(struct vm_area_struct *vma, unsigned int *mm_l
        return (vma->vm_lock_seq == *mm_lock_seq);
 }
 
+void __vma_start_write(struct vm_area_struct *vma, unsigned int mm_lock_seq);
+
 /*
  * Begin writing to a VMA.
  * Exclude concurrent readers under the per-VMA lock until the currently
@@ -799,15 +801,7 @@ static inline void vma_start_write(struct vm_area_struct *vma)
        if (__is_vma_write_locked(vma, &mm_lock_seq))
                return;
 
-       down_write(&vma->vm_lock.lock);
-       /*
-        * We should use WRITE_ONCE() here because we can have concurrent reads
-        * from the early lockless pessimistic check in vma_start_read().
-        * We don't really care about the correctness of that early check, but
-        * we should use WRITE_ONCE() for cleanliness and to keep KCSAN happy.
-        */
-       WRITE_ONCE(vma->vm_lock_seq, mm_lock_seq);
-       up_write(&vma->vm_lock.lock);
+       __vma_start_write(vma, mm_lock_seq);
 }
 
 static inline void vma_assert_write_locked(struct vm_area_struct *vma)

diff --git a/mm/memory.c b/mm/memory.c
index c810c1808cfcf583260b4959be8a217e5f6837fe..6f33533a07716b412b474f691a5ed8062c16368d 100644 (file)
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -6355,6 +6355,20 @@ fail:
 #endif
 
 #ifdef CONFIG_PER_VMA_LOCK
+void __vma_start_write(struct vm_area_struct *vma, unsigned int mm_lock_seq)
+{
+       down_write(&vma->vm_lock.lock);
+       /*
+        * We should use WRITE_ONCE() here because we can have concurrent reads
+        * from the early lockless pessimistic check in vma_start_read().
+        * We don't really care about the correctness of that early check, but
+        * we should use WRITE_ONCE() for cleanliness and to keep KCSAN happy.
+        */
+       WRITE_ONCE(vma->vm_lock_seq, mm_lock_seq);
+       up_write(&vma->vm_lock.lock);
+}
+EXPORT_SYMBOL_GPL(__vma_start_write);
+
 /*
  * Lookup and lock a VMA under RCU protection. Returned VMA is guaranteed to be
  * stable and not isolated. If the VMA is not found or is being modified the