linux-kernel - [PATCH 17/71] usb: get rid of PAGE_CACHE_* and page_cache

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Message-Id: <1458499278-1516-18-git-send-email-kirill.shutemov@linux.intel.com>
Date:	Sun, 20 Mar 2016 21:40:24 +0300
From:	"Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
To:	Andrew Morton <akpm@...ux-foundation.org>,
	Alexander Viro <viro@...iv.linux.org.uk>,
	Linus Torvalds <torvalds@...ux-foundation.org>
Cc:	Christoph Lameter <cl@...ux.com>,
	Matthew Wilcox <willy@...ux.intel.com>,
	linux-kernel@...r.kernel.org, linux-mm@...ck.org,
	linux-fsdevel@...r.kernel.org,
	"Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
	Felipe Balbi <balbi@...nel.org>,
	Matthew Dharm <mdharm-usb@...-eyed-alien.net>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Subject: [PATCH 17/71] usb: get rid of PAGE_CACHE_* and page_cache_{get,release} macros

PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago
with promise that one day it will be possible to implement page cache with
bigger chunks than PAGE_SIZE.

This promise never materialized. And unlikely will.

We have many places where PAGE_CACHE_SIZE assumed to be equal to
PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_*
or PAGE_* constant should be used in a particular case, especially on the
border between fs and mm.

Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much
breakage to be doable.

Let's stop pretending that pages in page cache are special. They are not.

The changes are pretty straight-forward:

 - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>;

 - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN};

 - page_cache_get() -> get_page();

 - page_cache_release() -> put_page();

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@...ux.intel.com>
Cc: Felipe Balbi <balbi@...nel.org>
Cc: Matthew Dharm <mdharm-usb@...-eyed-alien.net>
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 drivers/usb/gadget/function/f_fs.c | 4 ++--
 drivers/usb/gadget/legacy/inode.c  | 4 ++--
 drivers/usb/storage/scsiglue.c     | 2 +-
 3 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c
index 8cfce105c7ee..e21ca2bd6839 100644
--- a/drivers/usb/gadget/function/f_fs.c
+++ b/drivers/usb/gadget/function/f_fs.c
@@ -1147,8 +1147,8 @@ static int ffs_sb_fill(struct super_block *sb, void *_data, int silent)
 	ffs->sb              = sb;
 	data->ffs_data       = NULL;
 	sb->s_fs_info        = ffs;
-	sb->s_blocksize      = PAGE_CACHE_SIZE;
-	sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
+	sb->s_blocksize      = PAGE_SIZE;
+	sb->s_blocksize_bits = PAGE_SHIFT;
 	sb->s_magic          = FUNCTIONFS_MAGIC;
 	sb->s_op             = &ffs_sb_operations;
 	sb->s_time_gran      = 1;
diff --git a/drivers/usb/gadget/legacy/inode.c b/drivers/usb/gadget/legacy/inode.c
index 5cdaf0150a4e..e64479f882a5 100644
--- a/drivers/usb/gadget/legacy/inode.c
+++ b/drivers/usb/gadget/legacy/inode.c
@@ -1954,8 +1954,8 @@ gadgetfs_fill_super (struct super_block *sb, void *opts, int silent)
 		return -ENODEV;
 
 	/* superblock */
-	sb->s_blocksize = PAGE_CACHE_SIZE;
-	sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
+	sb->s_blocksize = PAGE_SIZE;
+	sb->s_blocksize_bits = PAGE_SHIFT;
 	sb->s_magic = GADGETFS_MAGIC;
 	sb->s_op = &gadget_fs_operations;
 	sb->s_time_gran = 1;
diff --git a/drivers/usb/storage/scsiglue.c b/drivers/usb/storage/scsiglue.c
index dba51362d2e2..90901861bfc0 100644
--- a/drivers/usb/storage/scsiglue.c
+++ b/drivers/usb/storage/scsiglue.c
@@ -123,7 +123,7 @@ static int slave_configure(struct scsi_device *sdev)
 		unsigned int max_sectors = 64;
 
 		if (us->fflags & US_FL_MAX_SECTORS_MIN)
-			max_sectors = PAGE_CACHE_SIZE >> 9;
+			max_sectors = PAGE_SIZE >> 9;
 		if (queue_max_hw_sectors(sdev->request_queue) > max_sectors)
 			blk_queue_max_hw_sectors(sdev->request_queue,
 					      max_sectors);
-- 
2.7.0