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authorGreg Kroah-Hartman <gregkh@linuxfoundation.org>2023-07-31 09:31:38 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2023-07-31 09:31:38 +0200
commit1346e9331abe8d08c05148def1cb2cdf03085c40 (patch)
tree2cab2825e6292ec41354b5b3da7d4137f5e62941 /include/linux/mmap_lock.h
parent0995c95b0882ee0ed0ea1930c8918bb0899e924c (diff)
parent5d0c230f1de8c7515b6567d9afba1f196fb4e2f4 (diff)
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Merge 6.5-rc4 into char-misc-next
We need the char-misc fixes in here as well for testing. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include/linux/mmap_lock.h')
-rw-r--r--include/linux/mmap_lock.h10
1 files changed, 8 insertions, 2 deletions
diff --git a/include/linux/mmap_lock.h b/include/linux/mmap_lock.h
index aab8f1b28d26..e05e167dbd16 100644
--- a/include/linux/mmap_lock.h
+++ b/include/linux/mmap_lock.h
@@ -76,8 +76,14 @@ static inline void mmap_assert_write_locked(struct mm_struct *mm)
static inline void vma_end_write_all(struct mm_struct *mm)
{
mmap_assert_write_locked(mm);
- /* No races during update due to exclusive mmap_lock being held */
- WRITE_ONCE(mm->mm_lock_seq, mm->mm_lock_seq + 1);
+ /*
+ * Nobody can concurrently modify mm->mm_lock_seq due to exclusive
+ * mmap_lock being held.
+ * We need RELEASE semantics here to ensure that preceding stores into
+ * the VMA take effect before we unlock it with this store.
+ * Pairs with ACQUIRE semantics in vma_start_read().
+ */
+ smp_store_release(&mm->mm_lock_seq, mm->mm_lock_seq + 1);
}
#else
static inline void vma_end_write_all(struct mm_struct *mm) {}