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From: Christoph Hellwig <hch@lst.de>
To: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Cc: Christoph Hellwig <hch@lst.de>,
	Alan Stern <stern@rowland.harvard.edu>,
	Linux-Renesas <linux-renesas-soc@vger.kernel.org>,
	"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
	"iommu@lists.linux-foundation.org"
	<iommu@lists.linux-foundation.org>,
	"linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>
Subject: Re: How to resolve an issue in swiotlb environment?
Date: Mon, 10 Jun 2019 14:32:22 +0200	[thread overview]
Message-ID: <20190610123222.GA20985@lst.de> (raw)
In-Reply-To: <OSAPR01MB3089BCA7CF78D6E4D9C83E1BD8130@OSAPR01MB3089.jpnprd01.prod.outlook.com>

Hi Yoshihiro,

sorry for not taking care of this earlier, today is a public holiday
here and thus I'm not working much over the long weekend.

On Mon, Jun 10, 2019 at 11:13:07AM +0000, Yoshihiro Shimoda wrote:
> I have another way to avoid the issue. But it doesn't seem that a good way though...
> According to the commit that adding blk_queue_virt_boundary() [3],
> this is needed for vhci_hcd as a workaround so that if we avoid to call it
> on xhci-hcd driver, the issue disappeared. What do you think?
> JFYI, I pasted a tentative patch in the end of email [4].

Oh, I hadn't even look at why USB uses blk_queue_virt_boundary, and it
seems like the usage is wrong, as it doesn't follow the same rules as
all the others.  I think your patch goes in the right direction,
but instead of comparing a hcd name it needs to be keyed of a flag
set by the driver (I suspect there is one indicating native SG support,
but I can't quickly find it), and we need an alternative solution
for drivers that don't see like vhci.  I suspect just limiting the
entire transfer size to something that works for a single packet
for them would be fine.

WARNING: multiple messages have this Message-ID (diff)
From: Christoph Hellwig <hch@lst.de>
To: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Cc: "linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
	"linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>,
	Linux-Renesas <linux-renesas-soc@vger.kernel.org>,
	"iommu@lists.linux-foundation.org"
	<iommu@lists.linux-foundation.org>,
	Alan Stern <stern@rowland.harvard.edu>,
	Christoph Hellwig <hch@lst.de>
Subject: Re: How to resolve an issue in swiotlb environment?
Date: Mon, 10 Jun 2019 14:32:22 +0200	[thread overview]
Message-ID: <20190610123222.GA20985@lst.de> (raw)
In-Reply-To: <OSAPR01MB3089BCA7CF78D6E4D9C83E1BD8130@OSAPR01MB3089.jpnprd01.prod.outlook.com>

Hi Yoshihiro,

sorry for not taking care of this earlier, today is a public holiday
here and thus I'm not working much over the long weekend.

On Mon, Jun 10, 2019 at 11:13:07AM +0000, Yoshihiro Shimoda wrote:
> I have another way to avoid the issue. But it doesn't seem that a good way though...
> According to the commit that adding blk_queue_virt_boundary() [3],
> this is needed for vhci_hcd as a workaround so that if we avoid to call it
> on xhci-hcd driver, the issue disappeared. What do you think?
> JFYI, I pasted a tentative patch in the end of email [4].

Oh, I hadn't even look at why USB uses blk_queue_virt_boundary, and it
seems like the usage is wrong, as it doesn't follow the same rules as
all the others.  I think your patch goes in the right direction,
but instead of comparing a hcd name it needs to be keyed of a flag
set by the driver (I suspect there is one indicating native SG support,
but I can't quickly find it), and we need an alternative solution
for drivers that don't see like vhci.  I suspect just limiting the
entire transfer size to something that works for a single packet
for them would be fine.
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

  reply	other threads:[~2019-06-10 12:32 UTC|newest]

Thread overview: 52+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-03  6:42 How to resolve an issue in swiotlb environment? Yoshihiro Shimoda
2019-06-03  6:42 ` Yoshihiro Shimoda
2019-06-07 12:00 ` Yoshihiro Shimoda
2019-06-07 12:00   ` Yoshihiro Shimoda
2019-06-10  7:31   ` Biju Das
2019-06-10  7:31     ` Biju Das
2019-06-10 11:13   ` Yoshihiro Shimoda
2019-06-10 11:13     ` Yoshihiro Shimoda
2019-06-10 12:32     ` Christoph Hellwig [this message]
2019-06-10 12:32       ` Christoph Hellwig
2019-06-10 18:46       ` Alan Stern
2019-06-10 18:46         ` Alan Stern
2019-06-11  6:41         ` Christoph Hellwig
2019-06-11  6:41           ` Christoph Hellwig
2019-06-11 14:51           ` Alan Stern
2019-06-11 14:51             ` Alan Stern
2019-06-12  7:30             ` Christoph Hellwig
2019-06-12  7:30               ` Christoph Hellwig
2019-06-12  8:52               ` Yoshihiro Shimoda
2019-06-12  8:52                 ` Yoshihiro Shimoda
2019-06-12 11:31                 ` Christoph Hellwig
2019-06-12 11:31                   ` Christoph Hellwig
2019-06-13  4:52                   ` Yoshihiro Shimoda
2019-06-13  4:52                     ` Yoshihiro Shimoda
2019-06-12 11:46               ` Oliver Neukum
2019-06-12 11:46                 ` Oliver Neukum
2019-06-12 12:06                 ` Christoph Hellwig
2019-06-12 12:06                   ` Christoph Hellwig
2019-06-12 14:43                   ` Alan Stern
2019-06-12 14:43                     ` Alan Stern
2019-06-13  7:39                     ` Christoph Hellwig
2019-06-13  7:39                       ` Christoph Hellwig
2019-06-13 16:57                       ` Martin K. Petersen
2019-06-13 16:57                         ` Martin K. Petersen
2019-06-13 17:16                       ` Alan Stern
2019-06-13 17:16                         ` Alan Stern
2019-06-13 18:18                         ` Greg KH
2019-06-13 18:18                           ` Greg KH
2019-06-13 23:01                         ` shuah
2019-06-13 23:01                           ` shuah
2019-06-14 14:44                           ` Alan Stern
2019-06-14 14:44                             ` Alan Stern
2019-06-18 15:28                             ` shuah
2019-06-18 15:28                               ` shuah
2019-06-19 20:23                               ` shuah
2019-06-19 20:23                                 ` shuah
2019-06-19 21:05                                 ` Alan Stern
2019-06-19 21:05                                   ` Alan Stern
2019-06-21 17:43                                   ` Suwan Kim
2019-06-21 17:43                                     ` Suwan Kim
2019-06-11  6:49         ` Yoshihiro Shimoda
2019-06-11  6:49           ` Yoshihiro Shimoda

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