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From: Christoph Hellwig <hch@lst.de>
To: Max Gurtovoy <maxg@mellanox.com>
Cc: axboe@kernel.dk, jsmart2021@gmail.com, sagi@grimberg.me,
	martin.petersen@oracle.com, shlomin@mellanox.com,
	israelr@mellanox.com, vladimirk@mellanox.com,
	linux-nvme@lists.infradead.org, idanb@mellanox.com,
	oren@mellanox.com, kbusch@kernel.org, nitzanc@mellanox.com,
	Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH 15/15] nvmet-rdma: add metadata/T10-PI support
Date: Mon, 4 May 2020 16:08:00 +0200
Message-ID: <20200504140800.GA22747@lst.de> (raw)
In-Reply-To: <5cbfde4a-871e-51d4-bace-b7b0fbd675ba@mellanox.com>

On Sun, May 03, 2020 at 07:29:12PM +0300, Max Gurtovoy wrote:
>> Can we have a helper for metadata len that also uses
>> IS_ENABLED(CONFIG_BLK_DEV_INTEGRITY) to let the compiler garbage collect
>> the whole code if it is compiled out?
>
> We have it in:
>
> static inline u32 nvmet_rw_metadata_len(struct nvmet_req *req)
> {
>         if (!IS_ENABLED(CONFIG_BLK_DEV_INTEGRITY))
>                 return 0;
>         return ((u32)le16_to_cpu(req->cmd->rw.length) + 1) *
>                         req->ns->metadata_size;
> }
>
>
> and
>
> req->metadata_len = nvmet_rw_metadata_len(req);
>
> is it good enough for the compiler ?

Well, this is the calculated metadata len, not the field in the
request, and the compiler can't really know it always is 0 in that
case.  At some point these optimizations might become a little
too ugly, though.

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Thread overview: 43+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-28 13:11 [PATCH 00/15 V6] nvme-rdma/nvmet-rdma: Add " Max Gurtovoy
2020-04-28 13:11 ` [PATCH 01/15] nvme: introduce namespace features flag Max Gurtovoy
2020-05-01 13:20   ` Christoph Hellwig
2020-05-01 14:24   ` Christoph Hellwig
2020-05-01 14:33     ` Max Gurtovoy
2020-04-28 13:11 ` [PATCH 02/15] nvme: introduce NVME_NS_METADATA_SUPPORTED flag Max Gurtovoy
2020-05-01 13:20   ` Christoph Hellwig
2020-04-28 13:11 ` [PATCH 03/15] nvme: make nvme_ns_has_pi accessible to transports Max Gurtovoy
2020-05-01 13:20   ` Christoph Hellwig
2020-04-28 13:11 ` [PATCH 04/15] nvme: enforce extended LBA format for fabrics metadata Max Gurtovoy
2020-05-01 13:21   ` Christoph Hellwig
2020-05-01 13:41   ` Christoph Hellwig
2020-04-28 13:11 ` [PATCH 05/15] nvme: introduce max_integrity_segments ctrl attribute Max Gurtovoy
2020-04-28 13:11 ` [PATCH 06/15] nvme: introduce NVME_INLINE_MD_SG_CNT Max Gurtovoy
2020-04-28 13:11 ` [PATCH 07/15] nvme-rdma: introduce nvme_rdma_sgl structure Max Gurtovoy
2020-04-28 13:11 ` [PATCH 08/15] nvme-rdma: add metadata/T10-PI support Max Gurtovoy
2020-05-01 14:26   ` Christoph Hellwig
2020-05-01 15:00     ` Max Gurtovoy
2020-04-28 13:11 ` [PATCH 09/15] nvmet: add metadata characteristics for a namespace Max Gurtovoy
2020-05-01 15:50   ` Christoph Hellwig
2020-04-28 13:11 ` [PATCH 10/15] nvmet: rename nvmet_rw_len to nvmet_rw_data_len Max Gurtovoy
2020-04-28 13:11 ` [PATCH 11/15] nvmet: rename nvmet_check_data_len to nvmet_check_transfer_len Max Gurtovoy
2020-04-28 13:11 ` [PATCH 12/15] nvme: add Metadata Capabilities enumerations Max Gurtovoy
2020-05-01 15:53   ` Christoph Hellwig
2020-05-03 12:43     ` Max Gurtovoy
2020-04-28 13:11 ` [PATCH 13/15] nvmet: add metadata/T10-PI support Max Gurtovoy
2020-05-01 15:58   ` Christoph Hellwig
2020-05-01 16:19   ` Christoph Hellwig
2020-04-28 13:11 ` [PATCH 14/15] nvmet: add metadata support for block devices Max Gurtovoy
2020-05-01 16:25   ` Christoph Hellwig
2020-04-28 13:11 ` [PATCH 15/15] nvmet-rdma: add metadata/T10-PI support Max Gurtovoy
2020-05-01 16:48   ` Christoph Hellwig
2020-05-03 16:29     ` Max Gurtovoy
2020-05-04 14:08       ` Christoph Hellwig [this message]
2020-05-04 14:19         ` Max Gurtovoy
  -- strict thread matches above, loose matches on Subject: below --
2020-01-06 13:37 [PATCH 00/15 V3] nvme-rdma/nvmet-rdma: Add " Max Gurtovoy
2020-01-06 13:37 ` [PATCH 15/15] nvmet-rdma: " Max Gurtovoy
2020-01-09  3:29   ` Martin K. Petersen
2019-11-05 16:20 [PATCH 00/15] nvme-rdma/nvmet-rdma: " Max Gurtovoy
2019-11-05 16:20 ` [PATCH 15/15] nvmet-rdma: " Max Gurtovoy
2019-11-05 18:02   ` Christoph Hellwig
2019-11-07 13:43     ` Max Gurtovoy
2019-11-12 18:34   ` Sagi Grimberg
2019-11-13 13:56     ` Max Gurtovoy
2019-11-14 23:45       ` Sagi Grimberg

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