From: pengdonglin Since commit a8bb74acd8efe ("rcu: Consolidate RCU-sched update-side function definitions") there is no difference between rcu_read_lock(), rcu_read_lock_bh() and rcu_read_lock_sched() in terms of RCU read section and the relevant grace period. That means that spin_lock(), which implies rcu_read_lock_sched(), also implies rcu_read_lock(). There is no need no explicitly start a RCU read section if one has already been started implicitly by spin_lock(). Simplify the code and remove the inner rcu_read_lock() invocation. Cc: Benjamin LaHaise Signed-off-by: pengdonglin Signed-off-by: pengdonglin --- fs/aio.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/fs/aio.c b/fs/aio.c index 7fc7b6221312..e3f9a5a391b5 100644 --- a/fs/aio.c +++ b/fs/aio.c @@ -359,15 +359,14 @@ static int aio_ring_mremap(struct vm_area_struct *vma) int i, res = -EINVAL; spin_lock(&mm->ioctx_lock); - rcu_read_lock(); - table = rcu_dereference(mm->ioctx_table); + table = rcu_dereference_check(mm->ioctx_table, lockdep_is_held(&mm->ioctx_lock)); if (!table) goto out_unlock; for (i = 0; i < table->nr; i++) { struct kioctx *ctx; - ctx = rcu_dereference(table->table[i]); + ctx = rcu_dereference_check(table->table[i], lockdep_is_held(&mm->ioctx_lock)); if (ctx && ctx->aio_ring_file == file) { if (!atomic_read(&ctx->dead)) { ctx->user_id = ctx->mmap_base = vma->vm_start; @@ -378,7 +377,6 @@ static int aio_ring_mremap(struct vm_area_struct *vma) } out_unlock: - rcu_read_unlock(); spin_unlock(&mm->ioctx_lock); return res; } -- 2.34.1