linux-kernel - Re: [PATCH 3/3] Btrfs: add basic DIO read support

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20100506211400.GE2997@infradead.org>
Date:	Thu, 6 May 2010 17:14:01 -0400
From:	Christoph Hellwig <hch@...radead.org>
To:	Josef Bacik <josef@...hat.com>
Cc:	linux-btrfs@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-fsdevel@...r.kernel.org, linux-mm@...ck.org
Subject: Re: [PATCH 3/3] Btrfs: add basic DIO read support

> +struct btrfs_dio_private {
> +	struct inode *inode;
> +	u64 logical_offset;
> +	u32 *csums;
> +	void *private;
> +};
> +
> +static void btrfs_endio_direct(struct bio *bio, int err)
> +{
> +	struct bio_vec *bvec_end = bio->bi_io_vec + bio->bi_vcnt - 1;
> +	struct bio_vec *bvec = bio->bi_io_vec;
> +	struct btrfs_dio_private *dip = bio->bi_private;
> +	struct inode *inode = dip->inode;
> +	struct btrfs_root *root = BTRFS_I(inode)->root;
> +	u64 start;
> +	u32 *private = dip->csums;
> +
> +	start = dip->logical_offset;
> +	do {
> +		if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)) {
> +			struct page *page = bvec->bv_page;
> +			char *kaddr;
> +			u32 csum = ~(u32)0;
> +
> +			kaddr = kmap_atomic(page, KM_USER0);

KM_USER0 seems wrong given that the bio completion callback can and
usually will be called from some kind of IRQ context.

> +	ret = blockdev_direct_IO_own_submit(rw, iocb, inode, NULL, iov,
> +					    offset, nr_segs,
> +					    btrfs_get_blocks_direct,
> +					    btrfs_submit_direct);

Don't you need to do some alignment checks of your own given that you
don't pass in a block device?

Btw, passing in the bdev here is a really horrible API, I'd much rather
move this to the callers..

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/