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From: Chaitanya Kulkarni <Chaitanya.Kulkarni@wdc.com>
To: "hch@infradead.org" <hch@infradead.org>,
	Bart Van Assche <bvanassche@acm.org>
Cc: Jack Wang <jinpu.wang@cloud.ionos.com>,
	"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
	"linux-rdma@vger.kernel.org" <linux-rdma@vger.kernel.org>,
	"axboe@kernel.dk" <axboe@kernel.dk>,
	"sagi@grimberg.me" <sagi@grimberg.me>,
	"leon@kernel.org" <leon@kernel.org>,
	"dledford@redhat.com" <dledford@redhat.com>,
	"jgg@ziepe.ca" <jgg@ziepe.ca>,
	"danil.kipnis@cloud.ionos.com" <danil.kipnis@cloud.ionos.com>,
	"rpenyaev@suse.de" <rpenyaev@suse.de>,
	"pankaj.gupta@cloud.ionos.com" <pankaj.gupta@cloud.ionos.com>
Subject: Re: [PATCH v11 15/26] block: reexport bio_map_kern
Date: Sun, 29 Mar 2020 18:08:31 +0000	[thread overview]
Message-ID: <BYAPR04MB4965BA89446761D2C3D414D386CA0@BYAPR04MB4965.namprd04.prod.outlook.com> (raw)
In-Reply-To: 20200329150524.GA13909@infradead.org

On 03/29/2020 08:05 AM, Christoph Hellwig 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.
>

Since rw are most common operations, it'd be nice to have a helper
function for REQ_OP_[READ|WRITE] to map and submit bio from data buffer
with chaining to avoid code duplication in each driver which based on 
the bio_add_page().

I'd be happy to send a patch for that if that is acceptable.

  reply	other threads:[~2020-03-29 18:08 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 [this message]
2020-03-30  6:28             ` hch
2020-03-30 10:44           ` Jinpu Wang
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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