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From:   "Matthew Wilcox (Oracle)" <willy@infradead.org>
To:     Andrew Morton <akpm@linux-foundation.org>, linux-mm@kvack.org
Cc:     "Matthew Wilcox (Oracle)" <willy@infradead.org>,
        linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-bcache@vger.kernel.org, linux-nvdimm@lists.01.org,
        linux-scsi@vger.kernel.org
Subject: [PATCH v2] include: Remove pagemap.h from blkdev.h
Date:   Tue,  9 Mar 2021 19:57:47 +0000
Message-Id: <20210309195747.283796-1-willy@infradead.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

My UEK-derived config has 1030 files depending on pagemap.h before
this change.  Afterwards, just 326 files need to be rebuilt when I
touch pagemap.h.  I think blkdev.h is probably included too widely,
but untangling that dependency is harder and this solves my problem.
x86 allmodconfig builds, but there may be implicit include problems
on other architectures.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
v2: Fix CONFIG_SWAP=n implicit use of pagemap.h by swap.h.  Increases
    the number of files from 240, but that's still a big win -- 68%
    reduction instead of 77%.

 block/blk-settings.c      | 1 +
 drivers/block/brd.c       | 1 +
 drivers/block/loop.c      | 1 +
 drivers/md/bcache/super.c | 1 +
 drivers/nvdimm/btt.c      | 1 +
 drivers/nvdimm/pmem.c     | 1 +
 drivers/scsi/scsicam.c    | 1 +
 include/linux/blkdev.h    | 1 -
 include/linux/swap.h      | 1 +
 9 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/block/blk-settings.c b/block/blk-settings.c
index b4aa2f37fab6..976085a44fb8 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -7,6 +7,7 @@
 #include <linux/init.h>
 #include <linux/bio.h>
 #include <linux/blkdev.h>
+#include <linux/pagemap.h>
 #include <linux/memblock.h>	/* for max_pfn/max_low_pfn */
 #include <linux/gcd.h>
 #include <linux/lcm.h>
diff --git a/drivers/block/brd.c b/drivers/block/brd.c
index 18bf99906662..2a5a1933826b 100644
--- a/drivers/block/brd.c
+++ b/drivers/block/brd.c
@@ -18,6 +18,7 @@
 #include <linux/bio.h>
 #include <linux/highmem.h>
 #include <linux/mutex.h>
+#include <linux/pagemap.h>
 #include <linux/radix-tree.h>
 #include <linux/fs.h>
 #include <linux/slab.h>
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index a370cde3ddd4..d58d68f3c7cd 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -53,6 +53,7 @@
 #include <linux/moduleparam.h>
 #include <linux/sched.h>
 #include <linux/fs.h>
+#include <linux/pagemap.h>
 #include <linux/file.h>
 #include <linux/stat.h>
 #include <linux/errno.h>
diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index 71691f32959b..f154c89d1326 100644
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -16,6 +16,7 @@
 #include "features.h"
 
 #include <linux/blkdev.h>
+#include <linux/pagemap.h>
 #include <linux/debugfs.h>
 #include <linux/genhd.h>
 #include <linux/idr.h>
diff --git a/drivers/nvdimm/btt.c b/drivers/nvdimm/btt.c
index 41aa1f01fc07..18a267d5073f 100644
--- a/drivers/nvdimm/btt.c
+++ b/drivers/nvdimm/btt.c
@@ -6,6 +6,7 @@
 #include <linux/highmem.h>
 #include <linux/debugfs.h>
 #include <linux/blkdev.h>
+#include <linux/pagemap.h>
 #include <linux/module.h>
 #include <linux/device.h>
 #include <linux/mutex.h>
diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index b8a85bfb2e95..16760b237229 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -8,6 +8,7 @@
  */
 
 #include <linux/blkdev.h>
+#include <linux/pagemap.h>
 #include <linux/hdreg.h>
 #include <linux/init.h>
 #include <linux/platform_device.h>
diff --git a/drivers/scsi/scsicam.c b/drivers/scsi/scsicam.c
index f1553a453616..0ffdb8f2995f 100644
--- a/drivers/scsi/scsicam.c
+++ b/drivers/scsi/scsicam.c
@@ -17,6 +17,7 @@
 #include <linux/genhd.h>
 #include <linux/kernel.h>
 #include <linux/blkdev.h>
+#include <linux/pagemap.h>
 #include <linux/msdos_partition.h>
 #include <asm/unaligned.h>
 
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index c032cfe133c7..1e2a95599390 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -11,7 +11,6 @@
 #include <linux/minmax.h>
 #include <linux/timer.h>
 #include <linux/workqueue.h>
-#include <linux/pagemap.h>
 #include <linux/backing-dev-defs.h>
 #include <linux/wait.h>
 #include <linux/mempool.h>
diff --git a/include/linux/swap.h b/include/linux/swap.h
index 4cc6ec3bf0ab..ae194bb7ddb4 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -10,6 +10,7 @@
 #include <linux/sched.h>
 #include <linux/node.h>
 #include <linux/fs.h>
+#include <linux/pagemap.h>
 #include <linux/atomic.h>
 #include <linux/page-flags.h>
 #include <asm/page.h>
-- 
2.30.0