[Very RFC 17/46] powernv/eeh: add pnv_eeh_find_edev()

[Alexey Kardashevskiy]

On 20/11/2019 12:28, Oliver O'Halloran wrote:
> To get away from using pci_dn we need a way to find the edev for a given
> bdfn. The easiest way to do this is to find the ioda_pe for that BDFN in
> the PHB's reverse mapping table and scan the device list of the
> corresponding eeh_pe.
> 
> Is this slow? Yeah probably. Is it slower than the existing "traverse the
> pdn tree" method? Probably not.
> 
> Signed-off-by: Oliver O'Halloran <oohall at gmail.com>
> ---
>  arch/powerpc/platforms/powernv/eeh-powernv.c | 31 ++++++++++++++++++++
>  arch/powerpc/platforms/powernv/pci.h         |  2 ++
>  2 files changed, 33 insertions(+)
> 
> diff --git a/arch/powerpc/platforms/powernv/eeh-powernv.c b/arch/powerpc/platforms/powernv/eeh-powernv.c
> index f58fe6bda46e..a974822c5097 100644
> --- a/arch/powerpc/platforms/powernv/eeh-powernv.c
> +++ b/arch/powerpc/platforms/powernv/eeh-powernv.c
> @@ -278,6 +278,37 @@ int pnv_eeh_post_init(void)
>  	return ret;
>  }
>  
> +struct eeh_dev *pnv_eeh_find_edev(struct pnv_phb *phb, u16 bdfn)
> +{
> +	struct pnv_ioda_pe *ioda_pe;
> +	struct eeh_dev *tmp, *edev;
> +	struct eeh_pe *pe;
> +
> +	/* EEH not enabled ? */
> +	if (!(phb->flags & PNV_PHB_FLAG_EEH))
> +		return NULL;
> +
> +	/* Fish the EEH PE from the IODA PE */
> +	ioda_pe = __pnv_ioda_get_pe(phb, bdfn);
> +	if (!ioda_pe)
> +		return NULL;
> +
> +	/*
> +	 * FIXME: Doing a tree-traversal followed by a list traversal
> +	 * on every config access is dumb. Not much dumber than the pci_dn
> +	 * tree traversal we did before, but still quite dumb.


Reviewed-by: Alexey Kardashevskiy <aik at ozlabs.ru>


Although I would reduce the comment above to "FIXME: replace 3
traversals with something better".



> +	 */
> +	pe = eeh_pe_get(phb->hose, ioda_pe->pe_number, 0);
> +	if (!pe)
> +		return NULL;
> +
> +	eeh_pe_for_each_dev(pe, edev, tmp)
> +		if (edev->bdfn == bdfn)
> +			return edev;
> +
> +	return NULL;
> +}
> +
>  static inline bool pnv_eeh_cfg_blocked(struct eeh_dev *edev)
>  {
>  	if (!edev || !edev->pe)
> diff --git a/arch/powerpc/platforms/powernv/pci.h b/arch/powerpc/platforms/powernv/pci.h
> index 3c33a0c91a69..a343f3c8e65c 100644
> --- a/arch/powerpc/platforms/powernv/pci.h
> +++ b/arch/powerpc/platforms/powernv/pci.h
> @@ -196,6 +196,8 @@ extern void pnv_set_msi_irq_chip(struct pnv_phb *phb, unsigned int virq);
>  extern unsigned long pnv_pci_ioda2_get_table_size(__u32 page_shift,
>  		__u64 window_size, __u32 levels);
>  extern int pnv_eeh_post_init(void);
> +struct eeh_dev;
> +struct eeh_dev *pnv_eeh_find_edev(struct pnv_phb *phb, u16 bdfn);
>  
>  __printf(3, 4)
>  extern void pe_level_printk(const struct pnv_ioda_pe *pe, const char *level,
> 

-- 
Alexey