[PATCH -next] net/ipv4/tcp_metrics.c: remove superfluous header files from tcp_metrics.c

tcp_metrics.c hasn't use any macro or function declared in rcupdate.h
spinlock.h, module.h, cache.h, hash.h and vmalloc.h. Thus, these files
can be removed from tcp_metrics.c safely without affecting the compilation
of the net module.

Signed-off-by: Mianhan Liu <redacted>

---
 net/ipv4/tcp_metrics.c | 6 ------
 1 file changed, 6 deletions(-)

diff --git a/net/ipv4/tcp_metrics.c b/net/ipv4/tcp_metrics.c
index 0588b004d..7b819530d 100644
--- a/net/ipv4/tcp_metrics.c
+++ b/net/ipv4/tcp_metrics.c

@@ -1,15 +1,9 @@
 // SPDX-License-Identifier: GPL-2.0
-#include <linux/rcupdate.h>
-#include <linux/spinlock.h>
 #include <linux/jiffies.h>
-#include <linux/module.h>
-#include <linux/cache.h>
 #include <linux/slab.h>
 #include <linux/init.h>
 #include <linux/tcp.h>
-#include <linux/hash.h>
 #include <linux/tcp_metrics.h>
-#include <linux/vmalloc.h>
 
 #include <net/inet_connection_sock.h>
 #include <net/net_namespace.h>

-- 
2.25.1

On Sat, Sep 25, 2021 at 7:27 AM Mianhan Liu [off-list ref] wrote:

tcp_metrics.c hasn't use any macro or function declared in rcupdate.h
spinlock.h, module.h, cache.h, hash.h and vmalloc.h. Thus, these files
can be removed from tcp_metrics.c safely without affecting the compilation
of the net module.

This seems pretty much relying on other includes.
(eg #include <linux/tcp.h> brings many things already)

We do not generally do this.

We do use rcu stuff in this file.

-#include <linux/spinlock.h>

We do use spinlocks in tcp_metrics.c

 #include <linux/jiffies.h>
-#include <linux/module.h>
-#include <linux/cache.h>
 #include <linux/slab.h>
 #include <linux/init.h>
 #include <linux/tcp.h>
-#include <linux/hash.h>
 #include <linux/tcp_metrics.h>
-#include <linux/vmalloc.h>

Not sure why kvzalloc() is not in linux/vmalloc.h

Honestly I do not even know why we spend time trying to reduce list of includes.