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From: Vivek Goyal <vgoyal@redhat.com>
To: Kent Overstreet <koverstreet@google.com>
Cc: linux-bcache@vger.kernel.org, linux-kernel@vger.kernel.org,
	dm-devel@redhat.com, axboe@kernel.dk,
	"Martin K. Petersen" <martin.petersen@oracle.com>,
	tj@kernel.org
Subject: Re: [dm-devel] [PATCH v3 02/26] block: Convert integrity to bvec_alloc_bs()
Date: Tue, 2 Oct 2012 11:12:02 -0400	[thread overview]
Message-ID: <20121002151202.GE758@redhat.com> (raw)
In-Reply-To: <1348526106-17074-3-git-send-email-koverstreet@google.com>

On Mon, Sep 24, 2012 at 03:34:42PM -0700, Kent Overstreet wrote:
> This adds a pointer to the bvec array to struct bio_integrity_payload,
> instead of the bvecs always being inline; then the bvecs are allocated
> with bvec_alloc_bs().

Ok, you are introducing bio_vec pointer in this patch. May be we can
do it earlier so that we take care of bio pair related issue.

> 
> Changed bvec_alloc_bs() and bvec_free_bs() to take a pointer to a
> mempool instead of the bioset, so that bio integrity can use a different
> mempool for its bvecs, and thus avoid a potential deadlock.

If you are taking mempool as input, then bvec_alloc_bs() name does not
make sense, as I think the very fact "bs" in the name their suggests
that you are taking a pointer to bio set (and not mempool).

Given the fact that bio_vec pool for integrity inside bio set, why not
take additional boolean/enum argument to function bvec_alloc_bs() and
that argument can tell whehter to allocate bvec from which bvec pool.

> 
> This is eventually for immutable bio vecs - immutable bvecs aren't
> useful if we still have to copy them, hence the need for the pointer.
> Less code is always nice too, though.

Can you explain a bit more about immutable bio vecs. I know there was
some discussion and I missed it. So either point me to right mail thread
or just explain a bit more what are immutable bio vecs, how we are
planning to use these.

Is it about during split we don't want to copy bio vecs and that's why we
need a pointer so that newly created bio/bip can point to parent's bio_vec?

Thanks
Vivek

  reply	other threads:[~2012-10-02 15:12 UTC|newest]

Thread overview: 69+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-09-24 22:34 [PATCH v3 00/26] Prep work for immutable bio vecs Kent Overstreet
2012-09-24 22:34 ` [PATCH v3 01/26] block: Fix a buffer overrun in bio_integrity_split() Kent Overstreet
2012-10-01 21:23   ` [dm-devel] " Vivek Goyal
2012-10-01 21:36     ` Kent Overstreet
2012-10-01 21:42     ` Kent Overstreet
2012-10-02 14:08       ` Vivek Goyal
2012-10-02 20:26         ` Kent Overstreet
2012-10-02 20:32           ` Vivek Goyal
2012-10-02 21:01             ` Kent Overstreet
2012-10-02 21:58               ` Vivek Goyal
2012-10-02 22:07                 ` Kent Overstreet
2012-10-02 22:30           ` Martin K. Petersen
2012-09-24 22:34 ` [PATCH v3 02/26] block: Convert integrity to bvec_alloc_bs() Kent Overstreet
2012-10-02 15:12   ` Vivek Goyal [this message]
2012-10-02 20:52     ` [dm-devel] " Kent Overstreet
2012-10-02 22:05       ` Vivek Goyal
2012-10-02 22:17         ` Kent Overstreet
2012-10-02 15:37   ` Vivek Goyal
2012-10-02 21:00     ` Kent Overstreet
2012-10-02 22:02       ` Vivek Goyal
2012-09-24 22:34 ` [PATCH v3 03/26] block: Add bio_advance() Kent Overstreet
2012-09-24 22:34 ` [PATCH v3 04/26] block: Refactor blk_update_request() Kent Overstreet
2012-10-02 18:43   ` [dm-devel] " Vivek Goyal
2012-10-02 20:10     ` Kent Overstreet
2012-10-02 20:14       ` Vivek Goyal
2012-10-02 20:25         ` Kent Overstreet
2012-10-02 18:59   ` Vivek Goyal
2012-10-02 20:09     ` Kent Overstreet
2012-09-24 22:34 ` [PATCH v3 05/26] md: Convert md_trim_bio() to use bio_advance() Kent Overstreet
2012-09-26  0:38   ` NeilBrown
2012-09-27  4:41     ` Kent Overstreet
2012-09-24 22:34 ` [PATCH v3 06/26] block: Add bio_end_sector() Kent Overstreet
2012-09-25 11:54   ` [Drbd-dev] " Lars Ellenberg
2012-09-25 22:06     ` Kent Overstreet
2012-09-26 15:16       ` Lars Ellenberg
2012-10-02 18:10   ` [dm-devel] " Vivek Goyal
2012-10-02 20:20     ` Kent Overstreet
2012-09-24 22:34 ` [PATCH v3 07/26] block: Use bio_sectors() more consistently Kent Overstreet
2012-09-24 23:04   ` Jim Paris
2012-09-24 23:09     ` Kent Overstreet
2012-09-25  0:54   ` Ed Cashin
2012-09-24 22:34 ` [PATCH v3 08/26] block: Change bio_split() to respect the current value of bi_idx Kent Overstreet
2012-09-24 22:34 ` [PATCH v3 09/26] block: Remove bi_idx references Kent Overstreet
2012-10-02 19:24   ` [dm-devel] " Vivek Goyal
2012-10-02 20:16     ` Kent Overstreet
2012-09-24 22:34 ` [PATCH v3 10/26] block: Remove some unnecessary bi_vcnt usage Kent Overstreet
2012-09-24 22:34 ` [PATCH v3 11/26] block: Add submit_bio_wait(), remove from md Kent Overstreet
2012-09-25  5:51   ` [dm-devel] " Hannes Reinecke
2012-09-25 22:15     ` Kent Overstreet
2012-10-02 19:41   ` Vivek Goyal
2012-10-02 20:11     ` Kent Overstreet
2012-10-02 20:16       ` Vivek Goyal
2012-10-02 20:22         ` Kent Overstreet
2012-10-04  6:07       ` Hannes Reinecke
2012-09-24 22:34 ` [PATCH v3 12/26] raid10: Use bio_reset() Kent Overstreet
2012-09-24 22:34 ` [PATCH v3 13/26] raid1: use bio_reset() Kent Overstreet
2012-09-24 22:34 ` [PATCH v3 14/26] raid5: " Kent Overstreet
2012-09-24 22:34 ` [PATCH v3 15/26] raid1: Refactor narrow_write_error() to not use bi_idx Kent Overstreet
2012-09-24 22:34 ` [PATCH v3 16/26] block: Add bio_copy_data() Kent Overstreet
2012-09-24 22:34 ` [PATCH v3 17/26] pktcdvd: use bio_copy_data() Kent Overstreet
2012-09-24 22:34 ` [PATCH v3 18/26] pktcdvd: Use bio_reset() in disabled code to kill bi_idx usage Kent Overstreet
2012-09-24 22:34 ` [PATCH v3 19/26] raid1: use bio_copy_data() Kent Overstreet
2012-09-24 22:35 ` [PATCH v3 20/26] bounce: Refactor __blk_queue_bounce to not use bi_io_vec Kent Overstreet
2012-09-24 22:35 ` [PATCH v3 21/26] block: Add bio_for_each_segment_all() Kent Overstreet
2012-09-24 22:35 ` [PATCH v3 22/26] block: Convert some code to bio_for_each_segment_all() Kent Overstreet
2012-09-24 22:35 ` [PATCH v3 23/26] block: Add bio_alloc_pages() Kent Overstreet
2012-09-24 22:35 ` [PATCH v3 24/26] block: Add an explicit bio flag for bios that own their bvec Kent Overstreet
2012-09-24 22:35 ` [PATCH v3 25/26] bio-integrity: Add explicit field for owner of bip_buf Kent Overstreet
2012-09-24 22:35 ` [PATCH v3 26/26] block: Add BIO_SUBMITTED flag, kill BIO_CLONED Kent Overstreet

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