[RFC PATCH v6 4/5] mmc: tmio: Use dma_max_mapping_size() instead of a workaround
Since the commit 133d624b1cee ("dma: Introduce dma_max_mapping_size()")
provides a helper function to get the max mapping size, we can use
the function instead of the workaround code for swiotlb.
Signed-off-by: Yoshihiro Shimoda
---
drivers/mmc/host/tmio_mmc_core.c | 17 -
1 file changed, 4 insertions(+), 13 deletions(-)
diff --git a/drivers/mmc/host/tmio_mmc_core.c b/drivers/mmc/host/tmio_mmc_core.c
index 130b91c..85bd6aa6 100644
--- a/drivers/mmc/host/tmio_mmc_core.c
+++ b/drivers/mmc/host/tmio_mmc_core.c
@@ -26,6 +26,7 @@
#include
#include
+#include
#include
#include
#include
@@ -1189,19 +1190,9 @@ int tmio_mmc_host_probe(struct tmio_mmc_host *_host)
mmc->max_blk_size = TMIO_MAX_BLK_SIZE;
mmc->max_blk_count = pdata->max_blk_count ? :
(PAGE_SIZE / mmc->max_blk_size) * mmc->max_segs;
- mmc->max_req_size = mmc->max_blk_size * mmc->max_blk_count;
- /*
-* Since swiotlb has memory size limitation, this will calculate
-* the maximum size locally (because we don't have any APIs for it now)
-* and check the current max_req_size. And then, this will update
-* the max_req_size if needed as a workaround.
-*/
- if (swiotlb_max_segment()) {
- unsigned int max_size = (1 << IO_TLB_SHIFT) * IO_TLB_SEGSIZE;
-
- if (mmc->max_req_size > max_size)
- mmc->max_req_size = max_size;
- }
+ mmc->max_req_size = min_t(unsigned int,
+ mmc->max_blk_size * mmc->max_blk_count,
+ dma_max_mapping_size(&pdev->dev));
mmc->max_seg_size = mmc->max_req_size;
if (mmc_can_gpio_ro(mmc))
--
2.7.4
___
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu
Re: [RFC PATCH v6 4/5] mmc: tmio: Use dma_max_mapping_size() instead of a workaround
On Thu, Jun 13, 2019 at 07:20:14PM +0900, Yoshihiro Shimoda wrote:
> Since the commit 133d624b1cee ("dma: Introduce dma_max_mapping_size()")
> provides a helper function to get the max mapping size, we can use
> the function instead of the workaround code for swiotlb.
>
> Signed-off-by: Yoshihiro Shimoda
I love it! I'd really like to see this code go away. Do I get this right
that this patch is kinda independent of the reset of the series? Anyway:
Acked-by: Wolfram Sang
signature.asc
Description: PGP signature
Re: [RFC PATCH v6 4/5] mmc: tmio: Use dma_max_mapping_size() instead of a workaround
Hi Shimoda-san,
On Thu, Jun 13, 2019 at 5:37 PM Yoshihiro Shimoda
wrote:
> Since the commit 133d624b1cee ("dma: Introduce dma_max_mapping_size()")
> provides a helper function to get the max mapping size, we can use
> the function instead of the workaround code for swiotlb.
>
> Signed-off-by: Yoshihiro Shimoda
Thanks for your patch!
> --- a/drivers/mmc/host/tmio_mmc_core.c
> +++ b/drivers/mmc/host/tmio_mmc_core.c
> @@ -1189,19 +1190,9 @@ int tmio_mmc_host_probe(struct tmio_mmc_host *_host)
> mmc->max_blk_size = TMIO_MAX_BLK_SIZE;
> mmc->max_blk_count = pdata->max_blk_count ? :
> (PAGE_SIZE / mmc->max_blk_size) * mmc->max_segs;
> - mmc->max_req_size = mmc->max_blk_size * mmc->max_blk_count;
> - /*
> -* Since swiotlb has memory size limitation, this will calculate
> -* the maximum size locally (because we don't have any APIs for it
> now)
> -* and check the current max_req_size. And then, this will update
> -* the max_req_size if needed as a workaround.
> -*/
> - if (swiotlb_max_segment()) {
> - unsigned int max_size = (1 << IO_TLB_SHIFT) * IO_TLB_SEGSIZE;
> -
> - if (mmc->max_req_size > max_size)
> - mmc->max_req_size = max_size;
> - }
> + mmc->max_req_size = min_t(unsigned int,
> + mmc->max_blk_size * mmc->max_blk_count,
> + dma_max_mapping_size(&pdev->dev));
> mmc->max_seg_size = mmc->max_req_size;
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.
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?
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- ge...@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
___
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu
Re: [RFC PATCH v6 4/5] mmc: tmio: Use dma_max_mapping_size() instead of a workaround
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.
> 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?
This really should use a min_t on size_t. Otherwise the patch looks
fine:
Reviewed-by: Christoph Hellwig
___
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu
Re: [RFC PATCH v6 4/5] mmc: tmio: Use dma_max_mapping_size() instead of a workaround
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.
> > 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?
>
> 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.
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- ge...@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
___
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu
RE: [RFC PATCH v6 4/5] mmc: tmio: Use dma_max_mapping_size() instead of a workaround
Hi Wolfram-san,
> From: Wolfram Sang, Sent: Friday, June 14, 2019 4:46 AM
>
> On Thu, Jun 13, 2019 at 07:20:14PM +0900, Yoshihiro Shimoda wrote:
> > Since the commit 133d624b1cee ("dma: Introduce dma_max_mapping_size()")
> > provides a helper function to get the max mapping size, we can use
> > the function instead of the workaround code for swiotlb.
> >
> > Signed-off-by: Yoshihiro Shimoda
>
> I love it! I'd really like to see this code go away. Do I get this right
> that this patch is kinda independent of the reset of the series? Anyway:
Thank you for your suggestion! I think so (because IOMMU and block patches seem
to need update). I'll submit 3/5 and 4/5 patches as independent later.
> Acked-by: Wolfram Sang
Thank you for your Acked-by!
Best regards,
Yoshihiro Shimoda
RE: [RFC PATCH v6 4/5] mmc: tmio: Use dma_max_mapping_size() instead of a workaround
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__, 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
0x_ 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
Re: [RFC PATCH v6 4/5] mmc: tmio: Use dma_max_mapping_size() instead of a workaround
Hi Shimoda-san,
On Mon, Jun 17, 2019 at 6:54 AM Yoshihiro Shimoda
wrote:
> > From: Geert Uytterhoeven, Sent: Friday, June 14, 2019 4:27 PM
> > 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__, 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
> 0x_ 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?
Please disregard my last comment: as the value of "mmc->max_blk_size *
mmc->max_blk_count" is always 0x_ or less, "min_t(size_t,
mmc->max_blk_size * mmc->max_blk_count, dma_max_mapping_size(&pdev->dev))"
will always be 0x_ or less, too, so there is no extra step needed
to make it fit in mmc->max_req_size.
Sorry for the confusion.
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- ge...@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
___
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu
RE: [RFC PATCH v6 4/5] mmc: tmio: Use dma_max_mapping_size() instead of a workaround
Hi Geert-san, > From: Geert Uytterhoeven, Sent: Monday, June 17, 2019 3:23 PM > > Hi Shimoda-san, > > On Mon, Jun 17, 2019 at 6:54 AM Yoshihiro Shimoda > wrote: > > > From: Geert Uytterhoeven, Sent: Friday, June 14, 2019 4:27 PM > > > 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: > > > > 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? > > Please disregard my last comment: as the value of "mmc->max_blk_size * > mmc->max_blk_count" is always 0x_ or less, "min_t(size_t, > mmc->max_blk_size * mmc->max_blk_count, dma_max_mapping_size(&pdev->dev))" > will always be 0x_ or less, too, so there is no extra step needed > to make it fit in mmc->max_req_size. Thank you for your prompt reply! I understood it. > Sorry for the confusion. No worries. Best regards, Yoshihiro Shimoda ___ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
