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From: Al Viro <[email protected]>
To: Keith Busch <[email protected]>
Cc: Keith Busch <[email protected]>,
	[email protected], [email protected],
	[email protected], [email protected],
	[email protected], [email protected]
Subject: Re: [PATCH 4/5] io_uring: add support for dma pre-mapping
Date: Wed, 27 Jul 2022 15:04:56 +0100	[thread overview]
Message-ID: <YuFGCO7M29fr3bVB@ZenIV> (raw)
In-Reply-To: <[email protected]>

On Wed, Jul 27, 2022 at 07:58:29AM -0600, Keith Busch wrote:
> On Wed, Jul 27, 2022 at 12:12:53AM +0100, Al Viro wrote:
> > On Tue, Jul 26, 2022 at 10:38:13AM -0700, Keith Busch wrote:
> > 
> > > +	if (S_ISBLK(file_inode(file)->i_mode))
> > > +		bdev = I_BDEV(file->f_mapping->host);
> > > +	else if (S_ISREG(file_inode(file)->i_mode))
> > > +		bdev = file->f_inode->i_sb->s_bdev;
> > 
> > *blink*
> > 
> > Just what's the intended use of the second case here?
> 
> ??
> 
> The use case is same as the first's: dma map the user addresses to the backing
> storage. There's two cases here because getting the block_device for a regular
> filesystem file is different than a raw block device.

Excuse me, but "file on some filesystem + block number on underlying device"
makes no sense as an API...

  reply	other threads:[~2022-07-27 14:05 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-07-26 17:38 [PATCH 0/5] dma mapping optimisations Keith Busch
2022-07-26 17:38 ` [PATCH 1/5] blk-mq: add ops to dma map bvec Keith Busch
2022-07-26 17:38 ` [PATCH 2/5] iov_iter: introduce type for preregistered dma tags Keith Busch
2022-07-26 23:10   ` Al Viro
2022-07-27 13:52     ` Keith Busch
2022-07-26 17:38 ` [PATCH 3/5] block: add dma tag bio type Keith Busch
2022-07-26 17:38 ` [PATCH 4/5] io_uring: add support for dma pre-mapping Keith Busch
2022-07-26 23:12   ` Al Viro
2022-07-27 13:58     ` Keith Busch
2022-07-27 14:04       ` Al Viro [this message]
2022-07-27 15:04         ` Keith Busch
2022-07-27 22:32           ` Dave Chinner
2022-07-27 23:00             ` Keith Busch
2022-07-28  2:35               ` Dave Chinner
2022-07-28 13:25                 ` Keith Busch
2022-07-27 14:11   ` Al Viro
2022-07-27 14:48     ` Keith Busch
2022-07-27 15:26       ` Al Viro
2022-07-26 17:38 ` [PATCH 5/5] nvme-pci: implement dma_map support Keith Busch

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