[PATCH kernel 1/2] powerpc/iommu: Get rid of default group_release()
David Gibson
david at gibson.dropbear.id.au
Thu Apr 14 11:35:55 AEST 2016
On Fri, Apr 08, 2016 at 04:36:43PM +1000, Alexey Kardashevskiy wrote:
> IBM PPC IOMMU API users always set IOMMU data and IOMMU release callback
> to an IOMMU group. At the moment the callback clears one pointer in
> iommu_table_group and that's it.
>
> The platform code calls iommu_group_put() and counts on _put() being
> called last so they check for table_group->group being reset which
> is conceptually wrong as there may be another user holding a reference.
>
> This removes the default IOMMU group release() callback and adds it
> as a parameter to iommu_register_group(). As we are changing the prototype
> anyway, this also changes the function name to more distinctive
> iommu_register_table_group().
>
> This should cause no behavioral change as it leaves BUG_ON for IODA2
> (where it was reported) and removes BUG_ON for pseries/IODA1 as they
> do not support IOV anyway and this BUG_ON has never been reported for
> these platforms.
>
> Signed-off-by: Alexey Kardashevskiy <aik at ozlabs.ru>
Reviewed-by: David Gibson <david at gibson.dropbear.id.au>
> ---
> arch/powerpc/include/asm/iommu.h | 12 +++++++-----
> arch/powerpc/kernel/iommu.c | 14 ++++----------
> arch/powerpc/platforms/powernv/pci-ioda.c | 15 +++++++++++----
> arch/powerpc/platforms/pseries/iommu.c | 17 +++++++++--------
> 4 files changed, 31 insertions(+), 27 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/iommu.h b/arch/powerpc/include/asm/iommu.h
> index 7b87bab..d7ba3b4 100644
> --- a/arch/powerpc/include/asm/iommu.h
> +++ b/arch/powerpc/include/asm/iommu.h
> @@ -201,17 +201,19 @@ struct iommu_table_group {
>
> #ifdef CONFIG_IOMMU_API
>
> -extern void iommu_register_group(struct iommu_table_group *table_group,
> - int pci_domain_number, unsigned long pe_num);
> +extern void iommu_register_table_group(struct iommu_table_group *table_group,
> + int pci_domain_number, unsigned long pe_num,
> + void (*release)(void *iommu_data));
> extern int iommu_add_device(struct device *dev);
> extern void iommu_del_device(struct device *dev);
> extern int __init tce_iommu_bus_notifier_init(void);
> extern long iommu_tce_xchg(struct iommu_table *tbl, unsigned long entry,
> unsigned long *hpa, enum dma_data_direction *direction);
> #else
> -static inline void iommu_register_group(struct iommu_table_group *table_group,
> - int pci_domain_number,
> - unsigned long pe_num)
> +static inline void iommu_register_table_group(
> + struct iommu_table_group *table_group,
> + int pci_domain_number, unsigned long pe_num,
> + void (*release)(void *iommu_data))
> {
> }
>
> diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c
> index a8e3490..8eed2fa 100644
> --- a/arch/powerpc/kernel/iommu.c
> +++ b/arch/powerpc/kernel/iommu.c
> @@ -887,15 +887,9 @@ EXPORT_SYMBOL_GPL(iommu_direction_to_tce_perm);
> /*
> * SPAPR TCE API
> */
> -static void group_release(void *iommu_data)
> -{
> - struct iommu_table_group *table_group = iommu_data;
> -
> - table_group->group = NULL;
> -}
> -
> -void iommu_register_group(struct iommu_table_group *table_group,
> - int pci_domain_number, unsigned long pe_num)
> +void iommu_register_table_group(struct iommu_table_group *table_group,
> + int pci_domain_number, unsigned long pe_num,
> + void (*release)(void *iommu_data))
> {
> struct iommu_group *grp;
> char *name;
> @@ -907,7 +901,7 @@ void iommu_register_group(struct iommu_table_group *table_group,
> return;
> }
> table_group->group = grp;
> - iommu_group_set_iommudata(grp, table_group, group_release);
> + iommu_group_set_iommudata(grp, table_group, release);
> name = kasprintf(GFP_KERNEL, "domain%d-pe%lx",
> pci_domain_number, pe_num);
> if (!name)
> diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
> index c5baaf3..ce9f2bf 100644
> --- a/arch/powerpc/platforms/powernv/pci-ioda.c
> +++ b/arch/powerpc/platforms/powernv/pci-ioda.c
> @@ -1330,6 +1330,13 @@ static long pnv_pci_ioda2_unset_window(struct iommu_table_group *table_group,
> int num);
> static void pnv_pci_ioda2_set_bypass(struct pnv_ioda_pe *pe, bool enable);
>
> +static void pnv_pci_ioda2_group_release(void *iommu_data)
> +{
> + struct iommu_table_group *table_group = iommu_data;
> +
> + table_group->group = NULL;
> +}
> +
> static void pnv_pci_ioda2_release_dma_pe(struct pci_dev *dev, struct pnv_ioda_pe *pe)
> {
> struct iommu_table *tbl;
> @@ -1965,8 +1972,8 @@ static void pnv_pci_ioda_setup_dma_pe(struct pnv_phb *phb,
> return;
>
> tbl = pnv_pci_table_alloc(phb->hose->node);
> - iommu_register_group(&pe->table_group, phb->hose->global_number,
> - pe->pe_number);
> + iommu_register_table_group(&pe->table_group, phb->hose->global_number,
> + pe->pe_number, NULL);
> pnv_pci_link_table_and_group(phb->hose->node, 0, tbl, &pe->table_group);
>
> /* Grab a 32-bit TCE table */
> @@ -2450,8 +2457,8 @@ static void pnv_pci_ioda2_setup_dma_pe(struct pnv_phb *phb,
> /* TVE #1 is selected by PCI address bit 59 */
> pe->tce_bypass_base = 1ull << 59;
>
> - iommu_register_group(&pe->table_group, phb->hose->global_number,
> - pe->pe_number);
> + iommu_register_table_group(&pe->table_group, phb->hose->global_number,
> + pe->pe_number, pnv_pci_ioda2_group_release);
>
> /* The PE will reserve all possible 32-bits space */
> pe->tce32_seg = 0;
> diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c
> index bd98ce2..0f6f06c 100644
> --- a/arch/powerpc/platforms/pseries/iommu.c
> +++ b/arch/powerpc/platforms/pseries/iommu.c
> @@ -112,7 +112,7 @@ static void iommu_pseries_free_group(struct iommu_table_group *table_group,
> }
> if (table_group->group) {
> iommu_group_put(table_group->group);
> - BUG_ON(table_group->group);
> + table_group->group = NULL;
> }
> #endif
> iommu_free_table(tbl, node_name);
> @@ -692,7 +692,8 @@ static void pci_dma_bus_setup_pSeries(struct pci_bus *bus)
> iommu_table_setparms(pci->phb, dn, tbl);
> tbl->it_ops = &iommu_table_pseries_ops;
> iommu_init_table(tbl, pci->phb->node);
> - iommu_register_group(pci->table_group, pci_domain_nr(bus), 0);
> + iommu_register_table_group(pci->table_group, pci_domain_nr(bus), 0,
> + NULL);
>
> /* Divide the rest (1.75GB) among the children */
> pci->phb->dma_window_size = 0x80000000ul;
> @@ -743,8 +744,8 @@ static void pci_dma_bus_setup_pSeriesLP(struct pci_bus *bus)
> iommu_table_setparms_lpar(ppci->phb, pdn, tbl, dma_window);
> tbl->it_ops = &iommu_table_lpar_multi_ops;
> iommu_init_table(tbl, ppci->phb->node);
> - iommu_register_group(ppci->table_group,
> - pci_domain_nr(bus), 0);
> + iommu_register_table_group(ppci->table_group,
> + pci_domain_nr(bus), 0, NULL);
> pr_debug(" created table: %p\n", ppci->table_group);
> }
> }
> @@ -772,8 +773,8 @@ static void pci_dma_dev_setup_pSeries(struct pci_dev *dev)
> iommu_table_setparms(phb, dn, tbl);
> tbl->it_ops = &iommu_table_pseries_ops;
> iommu_init_table(tbl, phb->node);
> - iommu_register_group(PCI_DN(dn)->table_group,
> - pci_domain_nr(phb->bus), 0);
> + iommu_register_table_group(PCI_DN(dn)->table_group,
> + pci_domain_nr(phb->bus), 0, NULL);
> set_iommu_table_base(&dev->dev, tbl);
> iommu_add_device(&dev->dev);
> return;
> @@ -1197,8 +1198,8 @@ static void pci_dma_dev_setup_pSeriesLP(struct pci_dev *dev)
> iommu_table_setparms_lpar(pci->phb, pdn, tbl, dma_window);
> tbl->it_ops = &iommu_table_lpar_multi_ops;
> iommu_init_table(tbl, pci->phb->node);
> - iommu_register_group(pci->table_group,
> - pci_domain_nr(pci->phb->bus), 0);
> + iommu_register_table_group(pci->table_group,
> + pci_domain_nr(pci->phb->bus), 0, NULL);
> pr_debug(" created table: %p\n", pci->table_group);
> } else {
> pr_debug(" found DMA window, table: %p\n", pci->table_group);
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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