[RFC PATCH 3/3] block_dump: remove comments in docs

["zhangyi (F)" <yi.zhang@huawei.com>]

Now block_dump feature is gone, remove all comments in docs.

Signed-off-by: zhangyi (F) <yi.zhang@huawei.com>
---
 Documentation/admin-guide/laptops/laptop-mode.rst | 11 -----------
 Documentation/admin-guide/sysctl/vm.rst           |  8 --------
 2 files changed, 19 deletions(-)

diff --git a/Documentation/admin-guide/laptops/laptop-mode.rst b/Documentation/admin-guide/laptops/laptop-mode.rst
index c984c4262f2e..b61cc601d298 100644
--- a/Documentation/admin-guide/laptops/laptop-mode.rst
+++ b/Documentation/admin-guide/laptops/laptop-mode.rst
@@ -101,17 +101,6 @@ this results in concentration of disk activity in a small time interval which
 occurs only once every 10 minutes, or whenever the disk is forced to spin up by
 a cache miss. The disk can then be spun down in the periods of inactivity.
 
-If you want to find out which process caused the disk to spin up, you can
-gather information by setting the flag /proc/sys/vm/block_dump. When this flag
-is set, Linux reports all disk read and write operations that take place, and
-all block dirtyings done to files. This makes it possible to debug why a disk
-needs to spin up, and to increase battery life even more. The output of
-block_dump is written to the kernel output, and it can be retrieved using
-"dmesg". When you use block_dump and your kernel logging level also includes
-kernel debugging messages, you probably want to turn off klogd, otherwise
-the output of block_dump will be logged, causing disk activity that is not
-normally there.
-
 
 Configuration
 -------------
diff --git a/Documentation/admin-guide/sysctl/vm.rst b/Documentation/admin-guide/sysctl/vm.rst
index 586cd4b86428..3ca6679f16ea 100644
--- a/Documentation/admin-guide/sysctl/vm.rst
+++ b/Documentation/admin-guide/sysctl/vm.rst
@@ -25,7 +25,6 @@ files can be found in mm/swap.c.
 Currently, these files are in /proc/sys/vm:
 
 - admin_reserve_kbytes
-- block_dump
 - compact_memory
 - compaction_proactiveness
 - compact_unevictable_allowed
@@ -106,13 +105,6 @@ On x86_64 this is about 128MB.
 Changing this takes effect whenever an application requests memory.
 
 
-block_dump
-==========
-
-block_dump enables block I/O debugging when set to a nonzero value. More
-information on block I/O debugging is in Documentation/admin-guide/laptops/laptop-mode.rst.
-
-
 compact_memory
 ==============
 
-- 
2.25.4