On 2021-09-29 10:47 p.m., Chaitanya Kulkarni wrote:
> Logan,
>
>> +/*
>> + * bit 2 is the third free bit in the page_link on 64bit systems which
>> + * is used by dma_unmap_sg() to determine if the dma_address is a PCI
>> + * bus address when doing P2PDMA.
>> + * Note: CONFIG_PCI_P2PDMA
Logan,
> +/*
> + * bit 2 is the third free bit in the page_link on 64bit systems which
> + * is used by dma_unmap_sg() to determine if the dma_address is a PCI
> + * bus address when doing P2PDMA.
> + * Note: CONFIG_PCI_P2PDMA depends on CONFIG_64BIT because of this.
> + */
> +
> +#ifdef
> +/**
> + * sg_unmark_pci_p2pdma - Unmark the scatterlist entry for PCI p2pdma
> + * @sg: SG entryScatterlist
> + *
> + * Description:
> + * Clears the PCI P2PDMA mark
> + **/
nit:- Probably want to add '.' above.
> +static inline void sg_dma_unmark_pci_p2pdma(struct scatterlist
On 2021-09-28 12:32 p.m., Jason Gunthorpe wrote:
> On Thu, Sep 16, 2021 at 05:40:41PM -0600, Logan Gunthorpe wrote:
>> config PCI_P2PDMA
>> bool "PCI peer-to-peer transfer support"
>> -depends on ZONE_DEVICE
>> +depends on ZONE_DEVICE && 64BIT
>
> Perhaps a comment to explain what
On Thu, Sep 16, 2021 at 05:40:41PM -0600, Logan Gunthorpe wrote:
> Make use of the third free LSB in scatterlist's page_link on 64bit systems.
>
> The extra bit will be used by dma_[un]map_sg_p2pdma() to determine when a
> given SGL segments dma_address points to a PCI bus address.
>
Make use of the third free LSB in scatterlist's page_link on 64bit systems.
The extra bit will be used by dma_[un]map_sg_p2pdma() to determine when a
given SGL segments dma_address points to a PCI bus address.
dma_unmap_sg_p2pdma() will need to perform different cleanup when a
segment is marked
