dax,ext2: replace ext2_clear_xip_target with dax_clear_blocks

This is practically generic code; other filesystems will want to call it
from other places, but there's nothing ext2-specific about it.

Make it a little more generic by allowing it to take a count of the number
of bytes to zero rather than fixing it to a single page.  Thanks to Dave
Hansen for suggesting that I need to call cond_resched() if zeroing more
than one page.

Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>
Cc: Andreas Dilger <andreas.dilger@intel.com>
Cc: Boaz Harrosh <boaz@plexistor.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/dax.c b/fs/dax.c
index 1a2bdbf..69c3126 100644 (file)
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -20,8 +20,45 @@
 #include <linux/fs.h>
 #include <linux/genhd.h>
 #include <linux/mutex.h>
+#include <linux/sched.h>
 #include <linux/uio.h>
 
+int dax_clear_blocks(struct inode *inode, sector_t block, long size)
+{
+       struct block_device *bdev = inode->i_sb->s_bdev;
+       sector_t sector = block << (inode->i_blkbits - 9);
+
+       might_sleep();
+       do {
+               void *addr;
+               unsigned long pfn;
+               long count;
+
+               count = bdev_direct_access(bdev, sector, &addr, &pfn, size);
+               if (count < 0)
+                       return count;
+               BUG_ON(size < count);
+               while (count > 0) {
+                       unsigned pgsz = PAGE_SIZE - offset_in_page(addr);
+                       if (pgsz > count)
+                               pgsz = count;
+                       if (pgsz < PAGE_SIZE)
+                               memset(addr, 0, pgsz);
+                       else
+                               clear_page(addr);
+                       addr += pgsz;
+                       size -= pgsz;
+                       count -= pgsz;
+                       BUG_ON(pgsz & 511);
+                       sector += pgsz / 512;
+                       cond_resched();
+               }
+       } while (size);
+
+       return 0;
+}
+EXPORT_SYMBOL_GPL(dax_clear_blocks);
+
 static long dax_get_addr(struct buffer_head *bh, void **addr, unsigned blkbits)
 {
        unsigned long pfn;

diff --cc fs/ext2/inode.c
Simple merge

diff --cc fs/ext2/xip.c
Simple merge

diff --cc fs/ext2/xip.h
Simple merge

diff --cc include/linux/fs.h
Simple merge