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-rw-r--r--kernel/locking/qrwlock.c12
1 files changed, 4 insertions, 8 deletions
diff --git a/kernel/locking/qrwlock.c b/kernel/locking/qrwlock.c
index d9c36c5f5711..6a7a3b8d5ac9 100644
--- a/kernel/locking/qrwlock.c
+++ b/kernel/locking/qrwlock.c
@@ -88,15 +88,11 @@ void queued_read_lock_slowpath(struct qrwlock *lock, u32 cnts)
arch_spin_lock(&lock->lock);
/*
- * At the head of the wait queue now, wait until the writer state
- * goes to 0 and then try to increment the reader count and get
- * the lock. It is possible that an incoming writer may steal the
- * lock in the interim, so it is necessary to check the writer byte
- * to make sure that the write lock isn't taken.
+ * At the head of the wait queue now, increment the reader count
+ * and wait until the writer, if it has the lock, has gone away.
+ * At ths stage, it is not possible for a writer to remain in the
+ * waiting state (_QW_WAITING). So there won't be any deadlock.
*/
- while (atomic_read(&lock->cnts) & _QW_WMASK)
- cpu_relax_lowlatency();
-
cnts = atomic_add_return(_QR_BIAS, &lock->cnts) - _QR_BIAS;
rspin_until_writer_unlock(lock, cnts);