RE: block: remove unused header includes.

[Ma, Jianpeng]

> -----Original Message-----
> From: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
> Sent: Monday, April 27, 2020 11:06 AM
> To: Ma, Jianpeng <jianpeng.ma@xxxxxxxxx>; Christoph Hellwig
> <hch@xxxxxxxxxxxxx>
> Cc: axboe@xxxxxxxxx; Williams, Dan J <dan.j.williams@xxxxxxxxx>; linux-
> kernel@xxxxxxxxxxxxxxx
> Subject: Re: block: remove unused header includes.
> 
> Hi,
> 
> On 4/26/20 7:56 PM, Ma, Jianpeng wrote:
> > This used deheader(git@xxxxxxxxxx:esr/deheader.git) to produce.
> >
> > Signed-off-by: Jianpeng Ma <jianpeng.ma@xxxxxxxxx>
> > ---
> >  block/badblocks.c        |  6 ------
> >  block/bfq-cgroup.c       | 10 ----------
> >  block/bfq-iosched.c      | 13 -------------
> >  block/bio-integrity.c    |  6 ------
> >  block/bio.c              | 14 --------------
> >  block/blk-cgroup.c       | 10 ----------
> >  block/blk-core.c         | 24 ------------------------
> >  block/blk-exec.c         |  5 -----
> >  block/blk-flush.c        | 10 ----------
> >  block/blk-integrity.c    |  6 ------
> >  block/blk-ioc.c          |  7 -------
> >  block/blk-lib.c          |  5 -----
> >  block/blk-map.c          |  4 ----
> >  block/blk-merge.c        |  5 -----
> >  block/blk-mq-cpumap.c    |  8 --------
> >  block/blk-mq-debugfs.c   |  6 ------
> >  block/blk-mq-pci.c       |  4 ----
> >  block/blk-mq-rdma.c      |  1 -
> >  block/blk-mq-sched.c     |  7 -------
> >  block/blk-mq-sysfs.c     | 15 +--------------
> >  block/blk-mq-tag.c       |  5 -----
> >  block/blk-mq-virtio.c    |  4 ----
> >  block/blk-mq.c           | 22 ----------------------
> >  block/blk-pm.c           |  4 ----
> >  block/blk-settings.c     |  8 --------
> >  block/blk-softirq.c      |  6 ------
> >  block/blk-stat.c         |  5 -----
> >  block/blk-sysfs.c        |  9 ---------
> >  block/blk-throttle.c     |  5 -----
> >  block/blk-timeout.c      |  5 -----
> >  block/blk-wbt.c          |  6 ------
> >  block/blk-zoned.c        |  7 -------
> >  block/bounce.c           | 15 ---------------
> >  block/bsg-lib.c          |  5 -----
> >  block/bsg.c              | 11 -----------
> >  block/cmdline-parser.c   |  1 -
> >  block/elevator.c         | 15 ---------------
> >  block/genhd.c            | 14 --------------
> >  block/ioctl.c            |  8 --------
> >  block/ioprio.c           | 11 -----------
> >  block/kyber-iosched.c    |  9 ---------
> >  block/mq-deadline.c      | 14 --------------
> >  block/partitions/amiga.c |  1 -
> >  block/partitions/core.c  |  4 ----
> >  block/partitions/efi.c   |  3 ---
> >  block/partitions/karma.c |  1 -
> >  block/partitions/ldm.c   |  4 ----
> >  block/partitions/mac.c   |  1 -
> >  block/scsi_ioctl.c       | 14 --------------
> >  block/sed-opal.c         |  9 ---------
> >  block/t10-pi.c           |  1 -
> >  fs/block_dev.c           | 16 ----------------
> >  52 files changed, 1 insertion(+), 408 deletions(-)
> >
> > diff --git a/block/badblocks.c b/block/badblocks.c index
> > 2e5f5697db35..4e4eb0fc9eb9 100644
> > --- a/block/badblocks.c
> > +++ b/block/badblocks.c
> > @@ -8,12 +8,6 @@
> >   */
> >
> >  #include <linux/badblocks.h>
> > -#include <linux/seqlock.h>
> 
> above is used by:
> 	seq = read_seqbegin(&bb->lock);
> 
> > -#include <linux/device.h>
> 
> 	struct device is used in this source file.
> 
> > -#include <linux/kernel.h>
> > -#include <linux/module.h>
> > -#include <linux/stddef.h>
> 
> 	NULL is used in this source file.
> 
> > -#include <linux/types.h>
> 
> 	sector_t is used in this source file.
> 
> >  #include <linux/slab.h>
> >
> >  /**
> 
> 
> 
> Can you explain the criteria that 'deheader' use to decide that a header file can
> be removed?
> 
Deheader iterator remove the #include and do make. If no fail mean this #include can remove. 

> And are you aware of rule #1 in Documentation/process/submit-checklist.rst:
> 
> 1) If you use a facility then #include the file that defines/declares
>    that facility.  Don't depend on other header files pulling in ones
>    that you use.
> 
Is this rule mean for #ifdef case?

Jianpeng.
> 
> 
> --
> ~Randy