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Commit 70688e4d authored by Nick Piggin's avatar Nick Piggin Committed by Linus Torvalds
Browse files

xip: support non-struct page backed memory 



Convert XIP to support non-struct page backed memory, using VM_MIXEDMAP for
the user mappings.

This requires the get_xip_page API to be changed to an address based one.
Improve the API layering a little bit too, while we're here.

This is required in order to support XIP filesystems on memory that isn't
backed with struct page (but memory with struct page is still supported too).

Signed-off-by: default avatarNick Piggin <npiggin@suse.de>
Acked-by: default avatarCarsten Otte <cotte@de.ibm.com>
Cc: Jared Hulbert <jaredeh@gmail.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 30afcb4b

fs/ext2/inode.c

+1 −1
Original line number Diff line number Diff line
@@ -796,7 +796,7 @@ const struct address_space_operations ext2_aops = { 


const struct address_space_operations ext2_aops_xip = {

	.bmap			= ext2_bmap,

	.get_xip_page		= ext2_get_xip_page,

	.get_xip_mem		= ext2_get_xip_mem,

};



const struct address_space_operations ext2_nobh_aops = {

fs/ext2/xip.c

+15 −22
Original line number Diff line number Diff line
@@ -15,26 +15,28 @@ 
#include "xip.h"



static inline int

__inode_direct_access(struct inode *inode, sector_t sector,

__inode_direct_access(struct inode *inode, sector_t block,

		      void **kaddr, unsigned long *pfn)

{

	struct block_device *bdev = inode->i_sb->s_bdev;

	struct block_device_operations *ops = bdev->bd_disk->fops;

	sector_t sector;



	sector = block * (PAGE_SIZE / 512); /* ext2 block to bdev sector */



	BUG_ON(!ops->direct_access);

	return ops->direct_access(bdev, sector, kaddr, pfn);

}



static inline int

__ext2_get_sector(struct inode *inode, sector_t offset, int create,

__ext2_get_block(struct inode *inode, pgoff_t pgoff, int create,

		   sector_t *result)

{

	struct buffer_head tmp;

	int rc;



	memset(&tmp, 0, sizeof(struct buffer_head));

	rc = ext2_get_block(inode, offset/ (PAGE_SIZE/512), &tmp,

			    create);

	rc = ext2_get_block(inode, pgoff, &tmp, create);

	*result = tmp.b_blocknr;



	/* did we get a sparse block (hole in the file)? */
@@ -47,14 +49,13 @@ __ext2_get_sector(struct inode *inode, sector_t offset, int create, 
}



int

ext2_clear_xip_target(struct inode *inode, int block)

ext2_clear_xip_target(struct inode *inode, sector_t block)

{

	sector_t sector = block * (PAGE_SIZE/512);

	void *kaddr;

	unsigned long pfn;

	int rc;



	rc = __inode_direct_access(inode, sector, &kaddr, &pfn);

	rc = __inode_direct_access(inode, block, &kaddr, &pfn);

	if (!rc)

		clear_page(kaddr);

	return rc;
@@ -72,26 +73,18 @@ void ext2_xip_verify_sb(struct super_block *sb) 
	}

}



struct page *

ext2_get_xip_page(struct address_space *mapping, sector_t offset,

		   int create)

int ext2_get_xip_mem(struct address_space *mapping, pgoff_t pgoff, int create,

				void **kmem, unsigned long *pfn)

{

	int rc;

	void *kaddr;

	unsigned long pfn;

	sector_t sector;

	sector_t block;



	/* first, retrieve the sector number */

	rc = __ext2_get_sector(mapping->host, offset, create, &sector);

	rc = __ext2_get_block(mapping->host, pgoff, create, &block);

	if (rc)

		goto error;

		return rc;



	/* retrieve address of the target data */

	rc = __inode_direct_access

		(mapping->host, sector * (PAGE_SIZE/512), &kaddr, &pfn);

	if (!rc)

		return pfn_to_page(pfn);



 error:

	return ERR_PTR(rc);

	rc = __inode_direct_access(mapping->host, block, kmem, pfn);

	return rc;

}

fs/ext2/xip.h

+5 −4
Original line number Diff line number Diff line
@@ -7,19 +7,20 @@ 


#ifdef CONFIG_EXT2_FS_XIP

extern void ext2_xip_verify_sb (struct super_block *);

extern int ext2_clear_xip_target (struct inode *, int);

extern int ext2_clear_xip_target (struct inode *, sector_t);



static inline int ext2_use_xip (struct super_block *sb)

{

	struct ext2_sb_info *sbi = EXT2_SB(sb);

	return (sbi->s_mount_opt & EXT2_MOUNT_XIP);

}

struct page* ext2_get_xip_page (struct address_space *, sector_t, int);

#define mapping_is_xip(map) unlikely(map->a_ops->get_xip_page)

int ext2_get_xip_mem(struct address_space *, pgoff_t, int,

				void **, unsigned long *);

#define mapping_is_xip(map) unlikely(map->a_ops->get_xip_mem)

#else

#define mapping_is_xip(map)			0

#define ext2_xip_verify_sb(sb)			do { } while (0)

#define ext2_use_xip(sb)			0

#define ext2_clear_xip_target(inode, chain)	0

#define ext2_get_xip_page			NULL

#define ext2_get_xip_mem			NULL

#endif

fs/open.c

+1 −1
Original line number Diff line number Diff line
@@ -837,7 +837,7 @@ static struct file *__dentry_open(struct dentry *dentry, struct vfsmount *mnt, 
	if (f->f_flags & O_DIRECT) {

		if (!f->f_mapping->a_ops ||

		    ((!f->f_mapping->a_ops->direct_IO) &&

		    (!f->f_mapping->a_ops->get_xip_page))) {

		    (!f->f_mapping->a_ops->get_xip_mem))) {

			fput(f);

			f = ERR_PTR(-EINVAL);

		}

include/linux/fs.h

+2 −2
Original line number Diff line number Diff line
@@ -474,8 +474,8 @@ struct address_space_operations { 
	int (*releasepage) (struct page *, gfp_t);

	ssize_t (*direct_IO)(int, struct kiocb *, const struct iovec *iov,

			loff_t offset, unsigned long nr_segs);

	struct page* (*get_xip_page)(struct address_space *, sector_t,

			int);

	int (*get_xip_mem)(struct address_space *, pgoff_t, int,

						void **, unsigned long *);

	/* migrate the contents of a page to the specified target */

	int (*migratepage) (struct address_space *,

			struct page *, struct page *);