Linux-Block Archive on lore.kernel.org
 help / color / Atom feed
From: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
To: Christoph Hellwig <hch@lst.de>, Alan Stern <stern@rowland.harvard.edu>
Cc: 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 11:13:07 +0000
Message-ID: <OSAPR01MB3089BCA7CF78D6E4D9C83E1BD8130@OSAPR01MB3089.jpnprd01.prod.outlook.com> (raw)
In-Reply-To: <OSAPR01MB3089D50DBDAA6C7D427E72EED8100@OSAPR01MB3089.jpnprd01.prod.outlook.com>

Hi Christoph, Alan,
(add linux-usb ML on CC.)

> From: Yoshihiro Shimoda, Sent: Friday, June 7, 2019 9:00 PM
> 
> Hi Christoph,
> 
> I think we should continue to discuss on this email thread instead of the fixed DMA-API.txt patch [1]
> 
> [1]
> https://marc.info/?t=155989412200001&r=1&w=2
> 
> > From: Yoshihiro Shimoda, Sent: Monday, June 3, 2019 3:42 PM
> >
> > Hi linux-block and iommu mailing lists,
> >
> > I have an issue that a USB SSD with xHCI on R-Car H3 causes "swiotlb is full" like below.
> >
> >     [   36.745286] xhci-hcd ee000000.usb: swiotlb buffer is full (sz: 524288 bytes), total 32768 (slots), used 1338
> (slots)
> >
> > I have investigated this issue by using git bisect, and then I found the following commit:
> >
> > ---
> > commit 09324d32d2a0843e66652a087da6f77924358e62
> > Author: Christoph Hellwig <hch@lst.de>
> > Date:   Tue May 21 09:01:41 2019 +0200
> >
> >     block: force an unlimited segment size on queues with a virt boundary
> > ---
> 
> Thank you for your comment on other email thread [2] like below:
> ---
> Turns out it isn't as simple as I thought, as there doesn't seem to
> be an easy way to get to the struct device used for DMA mapping
> from USB drivers.  I'll need to think a bit more how to handle that
> best.
> ---
> 
> [2]
> https://marc.info/?l=linux-doc&m=155989651620473&w=2

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].

---
[3]
commit 747668dbc061b3e62bc1982767a3a1f9815fcf0e
Author: Alan Stern <stern@rowland.harvard.edu>
Date:   Mon Apr 15 13:19:25 2019 -0400

    usb-storage: Set virt_boundary_mask to avoid SG overflows
---
[4]
diff --git a/drivers/usb/storage/scsiglue.c b/drivers/usb/storage/scsiglue.c
index 59190d8..277c6f7e 100644
--- a/drivers/usb/storage/scsiglue.c
+++ b/drivers/usb/storage/scsiglue.c
@@ -30,6 +30,8 @@
 
 #include <linux/module.h>
 #include <linux/mutex.h>
+#include <linux/usb.h>
+#include <linux/usb/hcd.h>
 
 #include <scsi/scsi.h>
 #include <scsi/scsi_cmnd.h>
@@ -65,6 +67,7 @@ static const char* host_info(struct Scsi_Host *host)
 static int slave_alloc (struct scsi_device *sdev)
 {
 	struct us_data *us = host_to_us(sdev->host);
+	struct usb_hcd *hcd = bus_to_hcd(us->pusb_dev->bus);
 	int maxp;
 
 	/*
@@ -80,8 +83,10 @@ static int slave_alloc (struct scsi_device *sdev)
 	 * Bulk maxpacket value.  Fortunately this value is always a
 	 * power of 2.  Inform the block layer about this requirement.
 	 */
-	maxp = usb_maxpacket(us->pusb_dev, us->recv_bulk_pipe, 0);
-	blk_queue_virt_boundary(sdev->request_queue, maxp - 1);
+	if (!strcmp(hcd->driver->description, "vhci_hcd")) {
+		maxp = usb_maxpacket(us->pusb_dev, us->recv_bulk_pipe, 0);
+		blk_queue_virt_boundary(sdev->request_queue, maxp - 1);
+	}
 
 	/*
 	 * Some host controllers may have alignment requirements.
---
Best regards,
Yoshihiro Shimoda


  parent reply index

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-03  6:42 Yoshihiro Shimoda
2019-06-07 12:00 ` Yoshihiro Shimoda
2019-06-10  7:31   ` Biju Das
2019-06-10 11:13   ` Yoshihiro Shimoda [this message]
2019-06-10 12:32     ` Christoph Hellwig
2019-06-10 18:46       ` Alan Stern
2019-06-11  6:41         ` Christoph Hellwig
2019-06-11 14:51           ` Alan Stern
2019-06-12  7:30             ` Christoph Hellwig
2019-06-12  8:52               ` Yoshihiro Shimoda
2019-06-12 11:31                 ` Christoph Hellwig
2019-06-13  4:52                   ` Yoshihiro Shimoda
2019-06-12 11:46               ` Oliver Neukum
2019-06-12 12:06                 ` Christoph Hellwig
2019-06-12 14:43                   ` Alan Stern
2019-06-13  7:39                     ` Christoph Hellwig
2019-06-13 16:57                       ` Martin K. Petersen
2019-06-13 17:16                       ` Alan Stern
2019-06-13 18:18                         ` Greg KH
2019-06-13 23:01                         ` shuah
2019-06-14 14:44                           ` Alan Stern
2019-06-18 15:28                             ` shuah
2019-06-19 20:23                               ` shuah
2019-06-19 21:05                                 ` Alan Stern
2019-06-21 17:43                                   ` Suwan Kim
2019-06-11  6:49         ` Yoshihiro Shimoda

Reply instructions:

You may reply publically to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=OSAPR01MB3089BCA7CF78D6E4D9C83E1BD8130@OSAPR01MB3089.jpnprd01.prod.outlook.com \
    --to=yoshihiro.shimoda.uh@renesas.com \
    --cc=hch@lst.de \
    --cc=iommu@lists.linux-foundation.org \
    --cc=linux-block@vger.kernel.org \
    --cc=linux-renesas-soc@vger.kernel.org \
    --cc=linux-usb@vger.kernel.org \
    --cc=stern@rowland.harvard.edu \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Linux-Block Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-block/0 linux-block/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-block linux-block/ https://lore.kernel.org/linux-block \
		linux-block@vger.kernel.org linux-block@archiver.kernel.org
	public-inbox-index linux-block


Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-block


AGPL code for this site: git clone https://public-inbox.org/ public-inbox