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From: "hch@infradead.org" <hch@infradead.org>
To: Qu Wenruo <quwenruo.btrfs@gmx.com>
Cc: "hch@infradead.org" <hch@infradead.org>,
	Johannes Thumshirn <Johannes.Thumshirn@wdc.com>,
	Linux FS Devel <linux-fsdevel@vger.kernel.org>,
	"dm-devel@redhat.com" <dm-devel@redhat.com>,
	"linux-btrfs@vger.kernel.org" <linux-btrfs@vger.kernel.org>
Subject: Re: Any bio_clone_slow() implementation which doesn't share bi_io_vec?
Date: Tue, 23 Nov 2021 22:09:35 -0800	[thread overview]
Message-ID: <YZ3XH2PWwrIl/XMy@infradead.org> (raw)
In-Reply-To: <133792e9-b89b-bc82-04fe-41202c3453a5@gmx.com>

On Wed, Nov 24, 2021 at 07:07:18AM +0800, Qu Wenruo wrote:
> In that case, the missing piece seems to be a way to convert a splitted
> plain bio into a REQ_OP_ZONE_APPEND bio.
> 
> Can this be done without slow bvec copying?

Yes.  I have a WIP stacking driver that converts writes to zone appends
and it does just that:

	sector_t orig_sector = bio->bi_iter.bi_sector;
	unsigned int bio_flags = bio->bi_opf & ~REQ_OP_MASK;

	...

	clone = bio_clone_fast(bio, GFP_NOIO, &bdev->write_bio_set);

	...

	clone->bi_opf = REQ_OP_ZONE_APPEND | REQ_NOMERGE | bio_flags;
	bio_set_dev(clone, dev->lower_bdev);
	clone->bi_iter.bi_sector = zone_sector;
	trace_block_bio_remap(clone, disk_devt(disk), orig_sector);

> 
> Thanks,
> Qu
---end quoted text---

WARNING: multiple messages have this Message-ID (diff)
From: "hch@infradead.org" <hch@infradead.org>
To: Qu Wenruo <quwenruo.btrfs@gmx.com>
Cc: "hch@infradead.org" <hch@infradead.org>,
	Johannes Thumshirn <Johannes.Thumshirn@wdc.com>,
	"dm-devel@redhat.com" <dm-devel@redhat.com>,
	Linux FS Devel <linux-fsdevel@vger.kernel.org>,
	"linux-btrfs@vger.kernel.org" <linux-btrfs@vger.kernel.org>
Subject: Re: [dm-devel] Any bio_clone_slow() implementation which doesn't share bi_io_vec?
Date: Tue, 23 Nov 2021 22:09:35 -0800	[thread overview]
Message-ID: <YZ3XH2PWwrIl/XMy@infradead.org> (raw)
In-Reply-To: <133792e9-b89b-bc82-04fe-41202c3453a5@gmx.com>

On Wed, Nov 24, 2021 at 07:07:18AM +0800, Qu Wenruo wrote:
> In that case, the missing piece seems to be a way to convert a splitted
> plain bio into a REQ_OP_ZONE_APPEND bio.
> 
> Can this be done without slow bvec copying?

Yes.  I have a WIP stacking driver that converts writes to zone appends
and it does just that:

	sector_t orig_sector = bio->bi_iter.bi_sector;
	unsigned int bio_flags = bio->bi_opf & ~REQ_OP_MASK;

	...

	clone = bio_clone_fast(bio, GFP_NOIO, &bdev->write_bio_set);

	...

	clone->bi_opf = REQ_OP_ZONE_APPEND | REQ_NOMERGE | bio_flags;
	bio_set_dev(clone, dev->lower_bdev);
	clone->bi_iter.bi_sector = zone_sector;
	trace_block_bio_remap(clone, disk_devt(disk), orig_sector);

> 
> Thanks,
> Qu
---end quoted text---

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  reply	other threads:[~2021-11-24  6:09 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-11-23  6:44 Any bio_clone_slow() implementation which doesn't share bi_io_vec? Qu Wenruo
2021-11-23  6:44 ` [dm-devel] " Qu Wenruo
2021-11-23  7:43 ` Christoph Hellwig
2021-11-23  7:43   ` [dm-devel] " Christoph Hellwig
2021-11-23  8:10   ` Qu Wenruo
2021-11-23  8:10     ` [dm-devel] " Qu Wenruo
2021-11-23  8:13     ` Christoph Hellwig
2021-11-23  8:13       ` [dm-devel] " Christoph Hellwig
2021-11-23 11:09       ` Qu Wenruo
2021-11-23 11:09         ` [dm-devel] " Qu Wenruo
2021-11-23 11:39         ` Johannes Thumshirn
2021-11-23 11:39           ` [dm-devel] " Johannes Thumshirn
2021-11-23 14:28           ` hch
2021-11-23 14:28             ` [dm-devel] " hch
2021-11-23 23:07             ` Qu Wenruo
2021-11-23 23:07               ` [dm-devel] " Qu Wenruo
2021-11-24  6:09               ` hch [this message]
2021-11-24  6:09                 ` hch
2021-11-24  6:18                 ` Qu Wenruo
2021-11-24  6:18                   ` [dm-devel] " Qu Wenruo
2021-11-24  7:02                   ` hch
2021-11-24  7:02                     ` [dm-devel] " hch
2021-11-24  7:22                     ` hch
2021-11-24  7:22                       ` [dm-devel] " hch
2021-11-24  7:25               ` Naohiro Aota
2021-11-24  7:25                 ` [dm-devel] " Naohiro Aota
2021-11-24  7:39                 ` Qu Wenruo
2021-11-24  7:39                   ` [dm-devel] " Qu Wenruo
2021-11-26 12:33       ` Qu Wenruo
2021-11-26 12:33         ` Qu Wenruo

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