From: Jinpu Wang <jinpu.wang@cloud.ionos.com>
To: Christoph Hellwig <hch@infradead.org>,
Bart Van Assche <bvanassche@acm.org>,
Chaitanya.Kulkarni@wdc.com
Cc: linux-block@vger.kernel.org, linux-rdma@vger.kernel.org,
Jens Axboe <axboe@kernel.dk>, Sagi Grimberg <sagi@grimberg.me>,
Leon Romanovsky <leon@kernel.org>,
Doug Ledford <dledford@redhat.com>,
Jason Gunthorpe <jgg@ziepe.ca>,
Danil Kipnis <danil.kipnis@cloud.ionos.com>,
Roman Penyaev <rpenyaev@suse.de>,
Pankaj Gupta <pankaj.gupta@cloud.ionos.com>
Subject: Re: [PATCH v11 15/26] block: reexport bio_map_kern
Date: Mon, 30 Mar 2020 12:44:28 +0200 [thread overview]
Message-ID: <CAMGffE=Oz+x8PCG3NK4Oo+Y1oDV70XbhSF9oVy8q=Z5+ZwnCGQ@mail.gmail.com> (raw)
In-Reply-To: <20200329150524.GA13909@infradead.org>
On Sun, Mar 29, 2020 at 5:05 PM Christoph Hellwig <hch@infradead.org> wrote:
>
> On Sat, Mar 28, 2020 at 09:16:55AM -0700, Bart Van Assche wrote:
> > There are more users in the Linux kernel of bio_add_pc_page() than only
> > bio_map_kern(), e.g. the SCSI target pass-through code
> > (drivers/target/target_core_pscsi.c). The code that uses bio_map_kern()
> > is in patch 22/26: "block/rnbd: server: functionality for IO submission
> > to file or block dev". Isn't that use case similar to the SCSI
> > pass-through code? I think the RNBD server code also implements storage
> > target functionality.
>
> No, it is not at all. The RNBD case submits normal read/write bios, for
> which bio_map_kerl is the wrong interfac given that it
> uses bio_add_pc_page. Read, write and other non-passthrough requests
> must use bio_add_page instead.
Thanks for comments, Christoph.
If I understood you correctly, so the right way is to construct bio
similar to bio_map_kern, but we have to use bio_add_page instead of
bio_add_pc_page?
As mentioned by Bart also Chaitanya, looks it's reasonable to add a
helper for normal READ|WRITE operation to map and submit bio from the
data buffer,
but sure can be done later.
Thanks!
next prev parent reply other threads:[~2020-03-30 10:44 UTC|newest]
Thread overview: 71+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-20 12:16 [PATCH v11 00/26] RTRS (former IBTRS) RDMA Transport Library and RNBD (former IBNBD) RDMA Network Block Device Jack Wang
2020-03-20 12:16 ` [PATCH v11 01/26] sysfs: export sysfs_remove_file_self() Jack Wang
2020-03-20 12:16 ` [PATCH v11 02/26] RDMA/rtrs: public interface header to establish RDMA connections Jack Wang
2020-03-20 12:16 ` [PATCH v11 03/26] RDMA/rtrs: private headers with rtrs protocol structs and helpers Jack Wang
2020-03-20 12:16 ` [PATCH v11 04/26] RDMA/rtrs: core: lib functions shared between client and server modules Jack Wang
2020-03-28 4:26 ` Bart Van Assche
2020-03-30 10:34 ` Jinpu Wang
2020-03-30 22:25 ` Bart Van Assche
2020-03-31 7:11 ` Jinpu Wang
2020-03-20 12:16 ` [PATCH v11 05/26] RDMA/rtrs: client: private header with client structs and functions Jack Wang
2020-03-20 12:16 ` [PATCH v11 06/26] RDMA/rtrs: client: main functionality Jack Wang
2020-03-20 12:16 ` [PATCH v11 07/26] RDMA/rtrs: client: statistics functions Jack Wang
2020-03-20 12:16 ` [PATCH v11 08/26] RDMA/rtrs: client: sysfs interface functions Jack Wang
2020-03-30 22:28 ` Bart Van Assche
2020-03-31 7:20 ` Jinpu Wang
2020-03-20 12:16 ` [PATCH v11 09/26] RDMA/rtrs: server: private header with server structs and functions Jack Wang
2020-03-20 12:16 ` [PATCH v11 10/26] RDMA/rtrs: server: main functionality Jack Wang
2020-03-20 12:16 ` [PATCH v11 11/26] RDMA/rtrs: server: statistics functions Jack Wang
2020-03-20 12:16 ` [PATCH v11 12/26] RDMA/rtrs: server: sysfs interface functions Jack Wang
2020-03-30 22:29 ` Bart Van Assche
2020-03-31 7:13 ` Jinpu Wang
2020-03-20 12:16 ` [PATCH v11 13/26] RDMA/rtrs: include client and server modules into kernel compilation Jack Wang
2020-03-20 12:16 ` [PATCH v11 14/26] RDMA/rtrs: a bit of documentation Jack Wang
2020-03-20 12:16 ` [PATCH v11 15/26] block: reexport bio_map_kern Jack Wang
2020-03-28 3:58 ` Bart Van Assche
2020-03-28 8:29 ` Christoph Hellwig
2020-03-28 16:16 ` Bart Van Assche
2020-03-29 15:05 ` Christoph Hellwig
2020-03-29 18:08 ` Chaitanya Kulkarni
2020-03-30 6:28 ` hch
2020-03-30 10:44 ` Jinpu Wang [this message]
2020-03-30 18:57 ` Chaitanya Kulkarni
2020-03-20 12:16 ` [PATCH v11 16/26] block/rnbd: private headers with rnbd protocol structs and helpers Jack Wang
2020-03-28 4:58 ` Bart Van Assche
2020-03-31 7:32 ` Jinpu Wang
2020-03-20 12:16 ` [PATCH v11 17/26] block/rnbd: client: private header with client structs and functions Jack Wang
2020-03-28 4:26 ` Bart Van Assche
2020-03-31 9:08 ` Jinpu Wang
2020-03-20 12:16 ` [PATCH v11 18/26] block/rnbd: client: main functionality Jack Wang
2020-03-28 4:45 ` Bart Van Assche
2020-03-31 9:23 ` Jinpu Wang
2020-04-02 16:27 ` Jinpu Wang
2020-03-28 4:59 ` Bart Van Assche
2020-03-31 9:25 ` Jinpu Wang
2020-03-31 14:12 ` Bart Van Assche
2020-03-31 14:20 ` Jinpu Wang
2020-03-20 12:16 ` [PATCH v11 19/26] block/rnbd: client: sysfs interface functions Jack Wang
2020-03-28 4:59 ` Bart Van Assche
2020-03-31 9:26 ` Jinpu Wang
2020-03-20 12:16 ` [PATCH v11 20/26] block/rnbd: server: private header with server structs and functions Jack Wang
2020-03-20 12:16 ` [PATCH v11 21/26] block/rnbd: server: main functionality Jack Wang
2020-03-28 17:40 ` Bart Van Assche
2020-03-31 9:29 ` Jinpu Wang
2020-03-31 15:32 ` Jinpu Wang
2020-03-20 12:16 ` [PATCH v11 22/26] block/rnbd: server: functionality for IO submission to file or block dev Jack Wang
2020-03-28 18:39 ` Bart Van Assche
2020-03-31 10:06 ` Jinpu Wang
2020-03-20 12:16 ` [PATCH v11 23/26] block/rnbd: server: sysfs interface functions Jack Wang
2020-03-28 19:31 ` Bart Van Assche
2020-03-28 23:06 ` Jason Gunthorpe
2020-03-30 13:14 ` Danil Kipnis
2020-03-20 12:16 ` [PATCH v11 24/26] block/rnbd: include client and server modules into kernel compilation Jack Wang
2020-03-28 19:34 ` Bart Van Assche
2020-03-31 7:23 ` Jinpu Wang
2020-03-20 12:16 ` [PATCH v11 25/26] block/rnbd: a bit of documentation Jack Wang
2020-03-28 19:40 ` Bart Van Assche
2020-03-30 10:17 ` Danil Kipnis
2020-03-20 12:16 ` [PATCH v11 26/26] MAINTAINERS: Add maintainers for RNBD/RTRS modules Jack Wang
2020-03-28 19:40 ` Bart Van Assche
2020-03-30 10:12 ` Danil Kipnis
2020-03-26 17:38 ` [PATCH v11 00/26] RTRS (former IBTRS) RDMA Transport Library and RNBD (former IBNBD) RDMA Network Block Device Jinpu Wang
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