[tip: locking/core] locking/qspinlock: Fix inaccessible URL of MCS lock paper

[tip-bot2 for Waiman Long]

The following commit has been merged into the locking/core branch of tip:

Commit-ID:     57097124cbbd310cc2b5884189e22e60a3c20514
Gitweb:        https://git.kernel.org/tip/57097124cbbd310cc2b5884189e22e60a3c20514
Author:        Waiman Long <longman@xxxxxxxxxx>
AuthorDate:    Tue, 07 Jan 2020 12:49:14 -05:00
Committer:     Peter Zijlstra <peterz@xxxxxxxxxxxxx>
CommitterDate: Fri, 17 Jan 2020 10:19:30 +01:00

locking/qspinlock: Fix inaccessible URL of MCS lock paper

It turns out that the URL of the MCS lock paper listed in the source
code is no longer accessible. I did got question about where the paper
was. This patch updates the URL to BZ 206115 which contains a copy of
the paper from

  https://www.cs.rochester.edu/u/scott/papers/1991_TOCS_synch.pdf

Signed-off-by: Waiman Long <longman@xxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Acked-by: Will Deacon <will@xxxxxxxxxx>
Link: https://lkml.kernel.org/r/20200107174914.4187-1-longman@xxxxxxxxxx
---
 kernel/locking/qspinlock.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/kernel/locking/qspinlock.c b/kernel/locking/qspinlock.c
index 2473f10..b9515fc 100644
--- a/kernel/locking/qspinlock.c
+++ b/kernel/locking/qspinlock.c
@@ -31,14 +31,15 @@
 /*
  * The basic principle of a queue-based spinlock can best be understood
  * by studying a classic queue-based spinlock implementation called the
- * MCS lock. The paper below provides a good description for this kind
- * of lock.
+ * MCS lock. A copy of the original MCS lock paper ("Algorithms for Scalable
+ * Synchronization on Shared-Memory Multiprocessors by Mellor-Crummey and
+ * Scott") is available at
  *
- * http://www.cise.ufl.edu/tr/DOC/REP-1992-71.pdf
+ * https://bugzilla.kernel.org/show_bug.cgi?id=206115
  *
- * This queued spinlock implementation is based on the MCS lock, however to make
- * it fit the 4 bytes we assume spinlock_t to be, and preserve its existing
- * API, we must modify it somehow.
+ * This queued spinlock implementation is based on the MCS lock, however to
+ * make it fit the 4 bytes we assume spinlock_t to be, and preserve its
+ * existing API, we must modify it somehow.
  *
  * In particular; where the traditional MCS lock consists of a tail pointer
  * (8 bytes) and needs the next pointer (another 8 bytes) of its own node to