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[PATCH] revert blockdev direct io back to 2.6.19 version

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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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Andrew Morton 2007-02-03 01:14:01 -08:00 committed by Linus Torvalds
parent 8560a10e16
commit b2e895dbd8
1 changed files with 41 additions and 0 deletions
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41
fs/block_dev.c
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@ -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 @@ backout:
return PTR_ERR(page);
goto completion;
}
#endif
static int blkdev_writepage(struct page *page, struct writeback_control *wbc)
{