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Commit b2e895db authored by Andrew Morton's avatar Andrew Morton Committed by Linus Torvalds
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[PATCH] revert blockdev direct io back to 2.6.19 version 



Andrew Vasquez is reporting as-iosched oopses and a 65% throughput
slowdown due to the recent special-casing of direct-io against
blockdevs.  We don't know why either of these things are occurring.

The patch minimally reverts us back to the 2.6.19 code for a 2.6.20
release.

Cc: Andrew Vasquez <andrew.vasquez@qlogic.com>
Cc: Ken Chen <kenchen@google.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 8560a10e

fs/block_dev.c

+41 −0
Original line number Diff line number Diff line
@@ -129,6 +129,46 @@ blkdev_get_block(struct inode *inode, sector_t iblock, 
	return 0;

}



static int

blkdev_get_blocks(struct inode *inode, sector_t iblock,

		struct buffer_head *bh, int create)

{

	sector_t end_block = max_block(I_BDEV(inode));

	unsigned long max_blocks = bh->b_size >> inode->i_blkbits;



	if ((iblock + max_blocks) > end_block) {

		max_blocks = end_block - iblock;

		if ((long)max_blocks <= 0) {

			if (create)

				return -EIO;	/* write fully beyond EOF */

			/*

			 * It is a read which is fully beyond EOF.  We return

			 * a !buffer_mapped buffer

			 */

			max_blocks = 0;

		}

	}



	bh->b_bdev = I_BDEV(inode);

	bh->b_blocknr = iblock;

	bh->b_size = max_blocks << inode->i_blkbits;

	if (max_blocks)

		set_buffer_mapped(bh);

	return 0;

}



static ssize_t

blkdev_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,

			loff_t offset, unsigned long nr_segs)

{

	struct file *file = iocb->ki_filp;

	struct inode *inode = file->f_mapping->host;



	return blockdev_direct_IO_no_locking(rw, iocb, inode, I_BDEV(inode),

				iov, offset, nr_segs, blkdev_get_blocks, NULL);

}



#if 0

static int blk_end_aio(struct bio *bio, unsigned int bytes_done, int error)

{

	struct kiocb *iocb = bio->bi_private;
@@ -323,6 +363,7 @@ blkdev_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov, 
		return PTR_ERR(page);

	goto completion;

}

#endif



static int blkdev_writepage(struct page *page, struct writeback_control *wbc)

{