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Commit 30afcb4b authored by Jared Hulbert's avatar Jared Hulbert Committed by Linus Torvalds
Browse files

return pfn from direct_access, for XIP 



Alter the block device ->direct_access() API to work with the new
get_xip_mem() API (that requires both kaddr and pfn are returned).

Some architectures will not do the right thing in their virt_to_page() for use
by XIP (to translate from the kernel virtual address returned by
direct_access(), to a user mappable pfn in XIP's page fault handler.

However, we can't switch it to just return the pfn and not the kaddr, because
we have no good way to get a kva from a pfn, and XIP requires the kva for its
read(2) and write(2) handlers.  So we have to return both.

Signed-off-by: default avatarJared Hulbert <jaredeh@gmail.com>
Signed-off-by: default avatarNick Piggin <npiggin@suse.de>
Cc: Carsten Otte <cotte@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: linux-mm@kvack.org
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 423bad60

arch/powerpc/sysdev/axonram.c

+3 −2
Original line number Diff line number Diff line
@@ -143,7 +143,7 @@ axon_ram_make_request(struct request_queue *queue, struct bio *bio) 
 */

static int

axon_ram_direct_access(struct block_device *device, sector_t sector,

		       unsigned long *data)

		       void **kaddr, unsigned long *pfn)

{

	struct axon_ram_bank *bank = device->bd_disk->private_data;

	loff_t offset;
@@ -154,7 +154,8 @@ axon_ram_direct_access(struct block_device *device, sector_t sector, 
		return -ERANGE;

	}



	*data = bank->ph_addr + offset;

	*kaddr = (void *)(bank->ph_addr + offset);

	*pfn = virt_to_phys(kaddr) >> PAGE_SHIFT;



	return 0;

}

drivers/block/brd.c

+3 −2
Original line number Diff line number Diff line
@@ -319,7 +319,7 @@ out: 


#ifdef CONFIG_BLK_DEV_XIP

static int brd_direct_access (struct block_device *bdev, sector_t sector,

			unsigned long *data)

			void **kaddr, unsigned long *pfn)

{

	struct brd_device *brd = bdev->bd_disk->private_data;

	struct page *page;
@@ -333,7 +333,8 @@ static int brd_direct_access (struct block_device *bdev, sector_t sector, 
	page = brd_insert_page(brd, sector);

	if (!page)

		return -ENOMEM;

	*data = (unsigned long)page_address(page);

	*kaddr = page_address(page);

	*pfn = page_to_pfn(page);



	return 0;

}

drivers/s390/block/dcssblk.c

+5 −3
Original line number Diff line number Diff line
@@ -36,7 +36,7 @@ static int dcssblk_open(struct inode *inode, struct file *filp); 
static int dcssblk_release(struct inode *inode, struct file *filp);

static int dcssblk_make_request(struct request_queue *q, struct bio *bio);

static int dcssblk_direct_access(struct block_device *bdev, sector_t secnum,

				 unsigned long *data);

				 void **kaddr, unsigned long *pfn);



static char dcssblk_segments[DCSSBLK_PARM_LEN] = "\0";
@@ -636,7 +636,7 @@ fail: 


static int

dcssblk_direct_access (struct block_device *bdev, sector_t secnum,

			unsigned long *data)

			void **kaddr, unsigned long *pfn)

{

	struct dcssblk_dev_info *dev_info;

	unsigned long pgoff;
@@ -649,7 +649,9 @@ dcssblk_direct_access (struct block_device *bdev, sector_t secnum, 
	pgoff = secnum / (PAGE_SIZE / 512);

	if ((pgoff+1)*PAGE_SIZE-1 > dev_info->end - dev_info->start)

		return -ERANGE;

	*data = (unsigned long) (dev_info->start+pgoff*PAGE_SIZE);

	*kaddr = (void *) (dev_info->start+pgoff*PAGE_SIZE);

	*pfn = virt_to_phys(*kaddr) >> PAGE_SHIFT;



	return 0;

}

fs/ext2/xip.c

+14 −10
Original line number Diff line number Diff line
@@ -16,11 +16,13 @@ 


static inline int

__inode_direct_access(struct inode *inode, sector_t sector,

		      unsigned long *data)

		      void **kaddr, unsigned long *pfn)

{

	BUG_ON(!inode->i_sb->s_bdev->bd_disk->fops->direct_access);

	return inode->i_sb->s_bdev->bd_disk->fops

		->direct_access(inode->i_sb->s_bdev,sector,data);

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

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



	BUG_ON(!ops->direct_access);

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

}



static inline int
@@ -48,12 +50,13 @@ int 
ext2_clear_xip_target(struct inode *inode, int block)

{

	sector_t sector = block * (PAGE_SIZE/512);

	unsigned long data;

	void *kaddr;

	unsigned long pfn;

	int rc;



	rc = __inode_direct_access(inode, sector, &data);

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

	if (!rc)

		clear_page((void*)data);

		clear_page(kaddr);

	return rc;

}
@@ -74,7 +77,8 @@ ext2_get_xip_page(struct address_space *mapping, sector_t offset, 
		   int create)

{

	int rc;

	unsigned long data;

	void *kaddr;

	unsigned long pfn;

	sector_t sector;



	/* first, retrieve the sector number */
@@ -84,9 +88,9 @@ ext2_get_xip_page(struct address_space *mapping, sector_t offset, 


	/* retrieve address of the target data */

	rc = __inode_direct_access

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

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

	if (!rc)

		return virt_to_page(data);

		return pfn_to_page(pfn);



 error:

	return ERR_PTR(rc);

include/linux/fs.h

+2 −1
Original line number Diff line number Diff line
@@ -1178,7 +1178,8 @@ struct block_device_operations { 
	int (*ioctl) (struct inode *, struct file *, unsigned, unsigned long);

	long (*unlocked_ioctl) (struct file *, unsigned, unsigned long);

	long (*compat_ioctl) (struct file *, unsigned, unsigned long);

	int (*direct_access) (struct block_device *, sector_t, unsigned long *);

	int (*direct_access) (struct block_device *, sector_t,

						void **, unsigned long *);

	int (*media_changed) (struct gendisk *);

	int (*revalidate_disk) (struct gendisk *);

	int (*getgeo)(struct block_device *, struct hd_geometry *);