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* [PATCH] ata: sata_rcar: Fix DMA boundary mask
@ 2020-05-13 11:04 Geert Uytterhoeven
  2020-05-13 11:08 ` Christoph Hellwig
                   ` (2 more replies)
  0 siblings, 3 replies; 4+ messages in thread
From: Geert Uytterhoeven @ 2020-05-13 11:04 UTC (permalink / raw)
  To: Jens Axboe, Ulf Hansson, Greg Kroah-Hartman, Christoph Hellwig
  Cc: Sergei Shtylyov, linux-ide, linux-renesas-soc, linux-scsi,
	linux-kernel, Geert Uytterhoeven

Before commit 9495b7e92f716ab2 ("driver core: platform: Initialize
dma_parms for platform devices"), the R-Car SATA device didn't have DMA
parameters.  Hence the DMA boundary mask supplied by its driver was
silently ignored, as __scsi_init_queue() doesn't check the return value
of dma_set_seg_boundary(), and the default value of 0xffffffff was used.

Now the device has gained DMA parameters, the driver-supplied value is
used, and the following warning is printed on Salvator-XS:

    DMA-API: sata_rcar ee300000.sata: mapping sg segment across boundary [start=0x00000000ffffe000] [end=0x00000000ffffefff] [boundary=0x000000001ffffffe]
    WARNING: CPU: 5 PID: 38 at kernel/dma/debug.c:1233 debug_dma_map_sg+0x298/0x300

(the range of start/end values depend on whether IOMMU support is
 enabled or not)

The issue here is that SATA_RCAR_DMA_BOUNDARY doesn't have bit 0 set, so
any typical end value, which is odd, will trigger the check.

Fix this by increasing the DMA boundary value by 1.

Fixes: 8bfbeed58665dbbf ("sata_rcar: correct 'sata_rcar_sht'")
Fixes: 9495b7e92f716ab2 ("driver core: platform: Initialize dma_parms for platform devices")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
As by default the DMA debug code prints the first error only, this issue
may be hidden on plain v5.7-rc5, where the FCP driver triggers a similar
warning.  Merging commit dd844fb8e50b12e6 ("media: platform: fcp: Set
appropriate DMA parameters") from the media tree fixes the FCP issue,
and exposes the SATA issue.

I added the second fixes tag because that commit is already being
backported to stable kernels, and this patch thus needs backporting,
too.
---
 drivers/ata/sata_rcar.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/ata/sata_rcar.c b/drivers/ata/sata_rcar.c
index 980aacdbcf3b42b9..752db75b611e8f8a 100644
--- a/drivers/ata/sata_rcar.c
+++ b/drivers/ata/sata_rcar.c
@@ -120,7 +120,7 @@
 /* Descriptor table word 0 bit (when DTA32M = 1) */
 #define SATA_RCAR_DTEND			BIT(0)
 
-#define SATA_RCAR_DMA_BOUNDARY		0x1FFFFFFEUL
+#define SATA_RCAR_DMA_BOUNDARY		0x1FFFFFFFUL
 
 /* Gen2 Physical Layer Control Registers */
 #define RCAR_GEN2_PHY_CTL1_REG		0x1704
-- 
2.17.1


^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH] ata: sata_rcar: Fix DMA boundary mask
  2020-05-13 11:04 [PATCH] ata: sata_rcar: Fix DMA boundary mask Geert Uytterhoeven
@ 2020-05-13 11:08 ` Christoph Hellwig
  2020-05-13 11:11 ` Greg Kroah-Hartman
  2020-05-13 12:43 ` Sergei Shtylyov
  2 siblings, 0 replies; 4+ messages in thread
From: Christoph Hellwig @ 2020-05-13 11:08 UTC (permalink / raw)
  To: Geert Uytterhoeven
  Cc: Jens Axboe, Ulf Hansson, Greg Kroah-Hartman, Christoph Hellwig,
	Sergei Shtylyov, linux-ide, linux-renesas-soc, linux-scsi,
	linux-kernel

Looks good,

Reviewed-by: Christoph Hellwig <hch@lst.de>

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH] ata: sata_rcar: Fix DMA boundary mask
  2020-05-13 11:04 [PATCH] ata: sata_rcar: Fix DMA boundary mask Geert Uytterhoeven
  2020-05-13 11:08 ` Christoph Hellwig
@ 2020-05-13 11:11 ` Greg Kroah-Hartman
  2020-05-13 12:43 ` Sergei Shtylyov
  2 siblings, 0 replies; 4+ messages in thread
From: Greg Kroah-Hartman @ 2020-05-13 11:11 UTC (permalink / raw)
  To: Geert Uytterhoeven
  Cc: Jens Axboe, Ulf Hansson, Christoph Hellwig, Sergei Shtylyov,
	linux-ide, linux-renesas-soc, linux-scsi, linux-kernel

On Wed, May 13, 2020 at 01:04:26PM +0200, Geert Uytterhoeven wrote:
> Before commit 9495b7e92f716ab2 ("driver core: platform: Initialize
> dma_parms for platform devices"), the R-Car SATA device didn't have DMA
> parameters.  Hence the DMA boundary mask supplied by its driver was
> silently ignored, as __scsi_init_queue() doesn't check the return value
> of dma_set_seg_boundary(), and the default value of 0xffffffff was used.
> 
> Now the device has gained DMA parameters, the driver-supplied value is
> used, and the following warning is printed on Salvator-XS:
> 
>     DMA-API: sata_rcar ee300000.sata: mapping sg segment across boundary [start=0x00000000ffffe000] [end=0x00000000ffffefff] [boundary=0x000000001ffffffe]
>     WARNING: CPU: 5 PID: 38 at kernel/dma/debug.c:1233 debug_dma_map_sg+0x298/0x300
> 
> (the range of start/end values depend on whether IOMMU support is
>  enabled or not)
> 
> The issue here is that SATA_RCAR_DMA_BOUNDARY doesn't have bit 0 set, so
> any typical end value, which is odd, will trigger the check.
> 
> Fix this by increasing the DMA boundary value by 1.
> 
> Fixes: 8bfbeed58665dbbf ("sata_rcar: correct 'sata_rcar_sht'")
> Fixes: 9495b7e92f716ab2 ("driver core: platform: Initialize dma_parms for platform devices")
> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

Cc: stable <stable@vger.kernel.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH] ata: sata_rcar: Fix DMA boundary mask
  2020-05-13 11:04 [PATCH] ata: sata_rcar: Fix DMA boundary mask Geert Uytterhoeven
  2020-05-13 11:08 ` Christoph Hellwig
  2020-05-13 11:11 ` Greg Kroah-Hartman
@ 2020-05-13 12:43 ` Sergei Shtylyov
  2 siblings, 0 replies; 4+ messages in thread
From: Sergei Shtylyov @ 2020-05-13 12:43 UTC (permalink / raw)
  To: Geert Uytterhoeven, Jens Axboe, Ulf Hansson, Greg Kroah-Hartman,
	Christoph Hellwig
  Cc: linux-ide, linux-renesas-soc, linux-scsi, linux-kernel

Hello!

On 13.05.2020 14:04, Geert Uytterhoeven wrote:

> Before commit 9495b7e92f716ab2 ("driver core: platform: Initialize
> dma_parms for platform devices"), the R-Car SATA device didn't have DMA
> parameters.  Hence the DMA boundary mask supplied by its driver was
> silently ignored, as __scsi_init_queue() doesn't check the return value
> of dma_set_seg_boundary(), and the default value of 0xffffffff was used.
> 
> Now the device has gained DMA parameters, the driver-supplied value is
> used, and the following warning is printed on Salvator-XS:
> 
>      DMA-API: sata_rcar ee300000.sata: mapping sg segment across boundary [start=0x00000000ffffe000] [end=0x00000000ffffefff] [boundary=0x000000001ffffffe]
>      WARNING: CPU: 5 PID: 38 at kernel/dma/debug.c:1233 debug_dma_map_sg+0x298/0x300
> 
> (the range of start/end values depend on whether IOMMU support is
>   enabled or not)
> 
> The issue here is that SATA_RCAR_DMA_BOUNDARY doesn't have bit 0 set, so
> any typical end value, which is odd, will trigger the check.
> 
> Fix this by increasing the DMA boundary value by 1.
> 
> Fixes: 8bfbeed58665dbbf ("sata_rcar: correct 'sata_rcar_sht'")
> Fixes: 9495b7e92f716ab2 ("driver core: platform: Initialize dma_parms for platform devices")
> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

Reviewed-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>

    Sorry, my mistake that went undetected for many years. :-)

MBR, Sergei

^ permalink raw reply	[flat|nested] 4+ messages in thread

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2020-05-13 11:04 [PATCH] ata: sata_rcar: Fix DMA boundary mask Geert Uytterhoeven
2020-05-13 11:08 ` Christoph Hellwig
2020-05-13 11:11 ` Greg Kroah-Hartman
2020-05-13 12:43 ` Sergei Shtylyov

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