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From:   Kashyap Desai <kashyap.desai@broadcom.com>
References: <20190605190836.32354-1-hch@lst.de> <20190605190836.32354-11-hch@lst.de>
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Date:   Thu, 6 Jun 2019 21:07:27 +0530
Message-ID: <cd713506efb9579d1f69a719d831c28d@mail.gmail.com>
Subject: RE: [PATCH 10/13] megaraid_sas: set virt_boundary_mask in the scsi host
To:     Christoph Hellwig <hch@lst.de>, Jens Axboe <axboe@kernel.dk>
Cc:     Sebastian Ott <sebott@linux.ibm.com>,
        Sagi Grimberg <sagi@grimberg.me>,
        Max Gurtovoy <maxg@mellanox.com>,
        Bart Van Assche <bvanassche@acm.org>,
        Ulf Hansson <ulf.hansson@linaro.org>,
        Alan Stern <stern@rowland.harvard.edu>,
        Oliver Neukum <oneukum@suse.com>, linux-block@vger.kernel.org,
        linux-rdma@vger.kernel.org, linux-mmc@vger.kernel.org,
        linux-nvme@lists.infradead.org, linux-scsi@vger.kernel.org,
        "PDL,MEGARAIDLINUX" <megaraidlinux.pdl@broadcom.com>,
        PDL-MPT-FUSIONLINUX <mpt-fusionlinux.pdl@broadcom.com>,
        linux-hyperv@vger.kernel.org, linux-usb@vger.kernel.org,
        usb-storage@lists.one-eyed-alien.net, linux-kernel@vger.kernel.org
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>
> This ensures all proper DMA layer handling is taken care of by the SCSI
> midlayer.  Note that the effect is global, as the IOMMU merging is based
> off a
> paramters in struct device.  We could still turn if off if no PCIe devices
> are
> present, but I don't know how to find that out.
>
> Also remove the bogus nomerges flag, merges do take the virt_boundary into
> account.

Hi Christoph, Changes for <megaraid_sas> and <mpt3sas> looks good. We want
to confirm few sanity before ACK. BTW, what benefit we will see moving
virt_boundry setting to SCSI mid layer ? Is it just modular approach OR any
functional fix ?

Kashyap