From: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
To: Geert Uytterhoeven <geert@linux-m68k.org>,
Christoph Hellwig <hch@lst.de>
Cc: Joerg Roedel <joro@8bytes.org>, Jens Axboe <axboe@kernel.dk>,
Ulf Hansson <ulf.hansson@linaro.org>,
Wolfram Sang <wsa+renesas@sang-engineering.com>,
Linux IOMMU <iommu@lists.linux-foundation.org>,
"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
Linux MMC List <linux-mmc@vger.kernel.org>,
Linux-Renesas <linux-renesas-soc@vger.kernel.org>
Subject: RE: [RFC PATCH v6 4/5] mmc: tmio: Use dma_max_mapping_size() instead of a workaround
Date: Mon, 17 Jun 2019 04:54:27 +0000 [thread overview]
Message-ID: <OSBPR01MB3590D4EF069F4554DA5D7ABBD8EB0@OSBPR01MB3590.jpnprd01.prod.outlook.com> (raw)
In-Reply-To: <CAMuHMdXm5RtDUL5Wkyd6aJihu9nykYOhRf7vN6hOtB-OO8CTQQ@mail.gmail.com>
Hi Geert, Christoph,
Thank you for your comments!
> From: Geert Uytterhoeven, Sent: Friday, June 14, 2019 4:27 PM
>
> Hi Christoph,
>
> On Fri, Jun 14, 2019 at 9:18 AM Christoph Hellwig wrote:
> > On Thu, Jun 13, 2019 at 10:35:44PM +0200, Geert Uytterhoeven wrote:
> > > I'm always triggered by the use of min_t() and other casts:
> > > mmc->max_blk_size and mmc->max_blk_count are both unsigned int.
> > > dma_max_mapping_size() returns size_t, which can be 64-bit.
> > >
> > > 1) Can the multiplication overflow?
> > > Probably not, as per commit 2a55c1eac7882232 ("mmc: renesas_sdhi:
> > > prevent overflow for max_req_size"), but I thought I'd better ask.
Geert-san:
I agree.
> > > 2) In theory, dma_max_mapping_size() can return a number that doesn't
> > > fit in 32-bit, and will be truncated (to e.g. 0), leading to max_req_size
> > > is zero?
Geert-san:
I agree. If dma_max_mapping_size() return 0x1_0000_0000, it will be truncated to 0
and then max_req_size is set to zero. It is a problem. Also, the second argument
"mmc->max_blk_size * mmc->max_blk_count" will not be overflow and then the value is
0xffff_ffff or less. So, I also think this should use size_t instead of unsigned int.
> > This really should use a min_t on size_t. Otherwise the patch looks
> > fine:
>
> Followed by another min() to make it fit in mmc->max_req_size, which is
> unsigned int.
Geert-san:
I'm afraid, but I cannot understand this means.
Is this patch is possible to be upstream? Or, do you have any concern?
Best regards,
Yoshihiro Shimoda
WARNING: multiple messages have this Message-ID (diff)
From: Yoshihiro Shimoda <yoshihiro.shimoda.uh-zM6kxYcvzFBBDgjK7y7TUQ@public.gmane.org>
To: Geert Uytterhoeven
<geert-Td1EMuHUCqxL1ZNQvxDV9g@public.gmane.org>,
Christoph Hellwig <hch-jcswGhMUV9g@public.gmane.org>
Cc: Jens Axboe <axboe-tSWWG44O7X1aa/9Udqfwiw@public.gmane.org>,
Linux-Renesas
<linux-renesas-soc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
Ulf Hansson <ulf.hansson-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>,
Linux MMC List
<linux-mmc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
"linux-block-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
<linux-block-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
Wolfram Sang
<wsa+renesas-jBu1N2QxHDJrcw3mvpCnnVaTQe2KTcn/@public.gmane.org>,
Linux IOMMU
<iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org>
Subject: RE: [RFC PATCH v6 4/5] mmc: tmio: Use dma_max_mapping_size() instead of a workaround
Date: Mon, 17 Jun 2019 04:54:27 +0000 [thread overview]
Message-ID: <OSBPR01MB3590D4EF069F4554DA5D7ABBD8EB0@OSBPR01MB3590.jpnprd01.prod.outlook.com> (raw)
In-Reply-To: <CAMuHMdXm5RtDUL5Wkyd6aJihu9nykYOhRf7vN6hOtB-OO8CTQQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
Hi Geert, Christoph,
Thank you for your comments!
> From: Geert Uytterhoeven, Sent: Friday, June 14, 2019 4:27 PM
>
> Hi Christoph,
>
> On Fri, Jun 14, 2019 at 9:18 AM Christoph Hellwig wrote:
> > On Thu, Jun 13, 2019 at 10:35:44PM +0200, Geert Uytterhoeven wrote:
> > > I'm always triggered by the use of min_t() and other casts:
> > > mmc->max_blk_size and mmc->max_blk_count are both unsigned int.
> > > dma_max_mapping_size() returns size_t, which can be 64-bit.
> > >
> > > 1) Can the multiplication overflow?
> > > Probably not, as per commit 2a55c1eac7882232 ("mmc: renesas_sdhi:
> > > prevent overflow for max_req_size"), but I thought I'd better ask.
Geert-san:
I agree.
> > > 2) In theory, dma_max_mapping_size() can return a number that doesn't
> > > fit in 32-bit, and will be truncated (to e.g. 0), leading to max_req_size
> > > is zero?
Geert-san:
I agree. If dma_max_mapping_size() return 0x1_0000_0000, it will be truncated to 0
and then max_req_size is set to zero. It is a problem. Also, the second argument
"mmc->max_blk_size * mmc->max_blk_count" will not be overflow and then the value is
0xffff_ffff or less. So, I also think this should use size_t instead of unsigned int.
> > This really should use a min_t on size_t. Otherwise the patch looks
> > fine:
>
> Followed by another min() to make it fit in mmc->max_req_size, which is
> unsigned int.
Geert-san:
I'm afraid, but I cannot understand this means.
Is this patch is possible to be upstream? Or, do you have any concern?
Best regards,
Yoshihiro Shimoda
WARNING: multiple messages have this Message-ID (diff)
From: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
To: Geert Uytterhoeven <geert@linux-m68k.org>,
Christoph Hellwig <hch@lst.de>
Cc: Jens Axboe <axboe@kernel.dk>,
Linux-Renesas <linux-renesas-soc@vger.kernel.org>,
Ulf Hansson <ulf.hansson@linaro.org>,
Linux MMC List <linux-mmc@vger.kernel.org>,
"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
Wolfram Sang <wsa+renesas@sang-engineering.com>,
Linux IOMMU <iommu@lists.linux-foundation.org>
Subject: RE: [RFC PATCH v6 4/5] mmc: tmio: Use dma_max_mapping_size() instead of a workaround
Date: Mon, 17 Jun 2019 04:54:27 +0000 [thread overview]
Message-ID: <OSBPR01MB3590D4EF069F4554DA5D7ABBD8EB0@OSBPR01MB3590.jpnprd01.prod.outlook.com> (raw)
In-Reply-To: <CAMuHMdXm5RtDUL5Wkyd6aJihu9nykYOhRf7vN6hOtB-OO8CTQQ@mail.gmail.com>
Hi Geert, Christoph,
Thank you for your comments!
> From: Geert Uytterhoeven, Sent: Friday, June 14, 2019 4:27 PM
>
> Hi Christoph,
>
> On Fri, Jun 14, 2019 at 9:18 AM Christoph Hellwig wrote:
> > On Thu, Jun 13, 2019 at 10:35:44PM +0200, Geert Uytterhoeven wrote:
> > > I'm always triggered by the use of min_t() and other casts:
> > > mmc->max_blk_size and mmc->max_blk_count are both unsigned int.
> > > dma_max_mapping_size() returns size_t, which can be 64-bit.
> > >
> > > 1) Can the multiplication overflow?
> > > Probably not, as per commit 2a55c1eac7882232 ("mmc: renesas_sdhi:
> > > prevent overflow for max_req_size"), but I thought I'd better ask.
Geert-san:
I agree.
> > > 2) In theory, dma_max_mapping_size() can return a number that doesn't
> > > fit in 32-bit, and will be truncated (to e.g. 0), leading to max_req_size
> > > is zero?
Geert-san:
I agree. If dma_max_mapping_size() return 0x1_0000_0000, it will be truncated to 0
and then max_req_size is set to zero. It is a problem. Also, the second argument
"mmc->max_blk_size * mmc->max_blk_count" will not be overflow and then the value is
0xffff_ffff or less. So, I also think this should use size_t instead of unsigned int.
> > This really should use a min_t on size_t. Otherwise the patch looks
> > fine:
>
> Followed by another min() to make it fit in mmc->max_req_size, which is
> unsigned int.
Geert-san:
I'm afraid, but I cannot understand this means.
Is this patch is possible to be upstream? Or, do you have any concern?
Best regards,
Yoshihiro Shimoda
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu
next prev parent reply other threads:[~2019-06-17 4:54 UTC|newest]
Thread overview: 93+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-13 10:20 [RFC PATCH v6 0/5] treewide: improve R-Car SDHI performance Yoshihiro Shimoda
2019-06-13 10:20 ` Yoshihiro Shimoda
2019-06-13 10:20 ` Yoshihiro Shimoda
2019-06-13 10:20 ` [RFC PATCH v6 1/5] iommu: add an exported function to get minimum page size for a domain Yoshihiro Shimoda
2019-06-13 10:20 ` Yoshihiro Shimoda
2019-06-13 10:20 ` Yoshihiro Shimoda
2019-06-13 19:37 ` Wolfram Sang
2019-06-13 19:37 ` Wolfram Sang
2019-06-13 19:37 ` Wolfram Sang
2019-06-14 7:16 ` Christoph Hellwig
2019-06-14 7:16 ` Christoph Hellwig
2019-06-14 7:16 ` Christoph Hellwig
2019-06-17 5:08 ` Yoshihiro Shimoda
2019-06-17 5:08 ` Yoshihiro Shimoda
2019-06-17 5:08 ` Yoshihiro Shimoda
2019-06-14 9:41 ` Robin Murphy
2019-06-14 9:41 ` Robin Murphy
2019-06-14 9:41 ` Robin Murphy
2019-06-17 5:23 ` Yoshihiro Shimoda
2019-06-17 5:23 ` Yoshihiro Shimoda
2019-06-17 5:23 ` Yoshihiro Shimoda
2019-06-13 10:20 ` [RFC PATCH v6 2/5] block: sort headers on blk-setting.c Yoshihiro Shimoda
2019-06-13 10:20 ` Yoshihiro Shimoda
2019-06-13 10:20 ` Yoshihiro Shimoda
2019-06-13 19:40 ` Wolfram Sang
2019-06-13 19:40 ` Wolfram Sang
2019-06-13 19:40 ` Wolfram Sang
2019-06-13 10:20 ` [RFC PATCH v6 3/5] block: add a helper function to merge the segments by an IOMMU Yoshihiro Shimoda
2019-06-13 10:20 ` Yoshihiro Shimoda
2019-06-13 10:20 ` Yoshihiro Shimoda
2019-06-14 7:22 ` Christoph Hellwig
2019-06-14 7:22 ` Christoph Hellwig
2019-06-14 7:22 ` Christoph Hellwig
2019-06-14 9:54 ` Robin Murphy
2019-06-14 9:54 ` Robin Murphy
2019-06-14 9:54 ` Robin Murphy
2019-06-17 6:29 ` Yoshihiro Shimoda
2019-06-17 6:29 ` Yoshihiro Shimoda
2019-06-17 6:29 ` Yoshihiro Shimoda
2019-06-13 10:20 ` [RFC PATCH v6 4/5] mmc: tmio: Use dma_max_mapping_size() instead of a workaround Yoshihiro Shimoda
2019-06-13 10:20 ` Yoshihiro Shimoda
2019-06-13 10:20 ` Yoshihiro Shimoda
2019-06-13 19:45 ` Wolfram Sang
2019-06-13 19:45 ` Wolfram Sang
2019-06-13 19:45 ` Wolfram Sang
2019-06-17 4:25 ` Yoshihiro Shimoda
2019-06-17 4:25 ` Yoshihiro Shimoda
2019-06-17 4:25 ` Yoshihiro Shimoda
2019-06-13 20:35 ` Geert Uytterhoeven
2019-06-13 20:35 ` Geert Uytterhoeven
2019-06-13 20:35 ` Geert Uytterhoeven
2019-06-14 7:18 ` Christoph Hellwig
2019-06-14 7:18 ` Christoph Hellwig
2019-06-14 7:18 ` Christoph Hellwig
2019-06-14 7:27 ` Geert Uytterhoeven
2019-06-14 7:27 ` Geert Uytterhoeven
2019-06-14 7:27 ` Geert Uytterhoeven
2019-06-17 4:54 ` Yoshihiro Shimoda [this message]
2019-06-17 4:54 ` Yoshihiro Shimoda
2019-06-17 4:54 ` Yoshihiro Shimoda
2019-06-17 6:23 ` Geert Uytterhoeven
2019-06-17 6:23 ` Geert Uytterhoeven
2019-06-17 6:23 ` Geert Uytterhoeven
2019-06-17 6:54 ` Yoshihiro Shimoda
2019-06-17 6:54 ` Yoshihiro Shimoda
2019-06-17 6:54 ` Yoshihiro Shimoda
2019-06-13 10:20 ` [RFC PATCH v6 5/5] mmc: queue: Use bigger segments if IOMMU can merge the segments Yoshihiro Shimoda
2019-06-13 10:20 ` Yoshihiro Shimoda
2019-06-13 10:20 ` Yoshihiro Shimoda
2019-06-13 19:58 ` Wolfram Sang
2019-06-13 19:58 ` Wolfram Sang
2019-06-13 19:58 ` Wolfram Sang
2019-06-17 6:38 ` Yoshihiro Shimoda
2019-06-17 6:38 ` Yoshihiro Shimoda
2019-06-17 6:38 ` Yoshihiro Shimoda
2019-06-14 7:24 ` Christoph Hellwig
2019-06-14 7:24 ` Christoph Hellwig
2019-06-14 7:24 ` Christoph Hellwig
2019-06-14 10:42 ` Wolfram Sang
2019-06-14 10:42 ` Wolfram Sang
2019-06-14 10:42 ` Wolfram Sang
2019-06-17 6:46 ` Yoshihiro Shimoda
2019-06-17 6:46 ` Yoshihiro Shimoda
2019-06-17 6:46 ` Yoshihiro Shimoda
2019-06-17 6:53 ` Christoph Hellwig
2019-06-17 6:53 ` Christoph Hellwig
2019-06-17 6:53 ` Christoph Hellwig
2019-06-17 7:02 ` Yoshihiro Shimoda
2019-06-17 7:02 ` Yoshihiro Shimoda
2019-06-17 7:02 ` Yoshihiro Shimoda
2019-06-13 19:36 ` [RFC PATCH v6 0/5] treewide: improve R-Car SDHI performance Wolfram Sang
2019-06-13 19:36 ` Wolfram Sang
2019-06-13 19:36 ` Wolfram Sang
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