| Message ID | 20200513110426.22472-1-geert+renesas@glider.be |
|---|---|
| State | Not Applicable |
| Delegated to: | David Miller |
| Headers | show |
| Series | ata: sata_rcar: Fix DMA boundary mask | expand |
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>
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
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
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(-)