blk-mq: add file comments and update copyright notices

None of the blk-mq files have an explanatory comment at the top
for what that particular file does. Add that and add appropriate
copyright notices as well.

Signed-off-by: Jens Axboe <axboe@fb.com>

diff --git a/block/blk-mq-cpu.c b/block/blk-mq-cpu.c
index d2c253f71b8665cd333dd6c45dfe06f757dacb53..bb3ed488f7b5b26053e91dd3a5f02a0f2c472a70 100644 (file)
--- a/block/blk-mq-cpu.c
+++ b/block/blk-mq-cpu.c
@@ -1,3 +1,8 @@
+/*
+ * CPU notifier helper code for blk-mq
+ *
+ * Copyright (C) 2013-2014 Jens Axboe
+ */
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/init.h>

diff --git a/block/blk-mq-cpumap.c b/block/blk-mq-cpumap.c
index 0daacb927be1a32e5731c48f7fd6953ea291fc30..1065d7c65fa15b60b1104944322533033df69df7 100644 (file)
--- a/block/blk-mq-cpumap.c
+++ b/block/blk-mq-cpumap.c
@@ -1,3 +1,8 @@
+/*
+ * CPU <-> hardware queue mapping helpers
+ *
+ * Copyright (C) 2013-2014 Jens Axboe
+ */
 #include <linux/kernel.h>
 #include <linux/threads.h>
 #include <linux/module.h>

diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c
index 0d0640d38a06244bb12dbc53b555bd59df981326..d90c4aeb7dd38c02582d8f8e88f0e176dd9118be 100644 (file)
--- a/block/blk-mq-tag.c
+++ b/block/blk-mq-tag.c
@@ -1,3 +1,15 @@
+/*
+ * Fast and scalable bitmap tagging variant. Uses sparser bitmaps spread
+ * over multiple cachelines to avoid ping-pong between multiple submitters
+ * or submitter and completer. Uses rolling wakeups to avoid falling of
+ * the scaling cliff when we run out of tags and have to start putting
+ * submitters to sleep.
+ *
+ * Uses active queue tracking to support fairer distribution of tags
+ * between multiple submitters when a shared tag map is used.
+ *
+ * Copyright (C) 2013-2014 Jens Axboe
+ */
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/random.h>

diff --git a/block/blk-mq.c b/block/blk-mq.c
index ae14749b530cc08e181142c3570550af099e4a8f..5cc4b871cb1155690b03454f6d772858c12b68fd 100644 (file)
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1,3 +1,9 @@
+/*
+ * Block multiqueue core code
+ *
+ * Copyright (C) 2013-2014 Jens Axboe
+ * Copyright (C) 2013-2014 Christoph Hellwig
+ */
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/backing-dev.h>