On Thu, 08 Aug 2013 16:00:18 +0200, Tomasz Figa wrote:
> On Thursday 08 of August 2013 18:38:04 Cho KyongHo wrote:
> > Since kmalloc() does not guarantee that the allignment of 1KiB when it
> > allocates 1KiB, it is required to allocate lv2 page table from own
> > slab that guarantees alignment of 1KiB
> > 
> > Signed-off-by: Cho KyongHo <[email protected]>
> > ---
> >  drivers/iommu/exynos-iommu.c |   24 ++++++++++++++++++++----
> >  1 files changed, 20 insertions(+), 4 deletions(-)
> > 
> > diff --git a/drivers/iommu/exynos-iommu.c b/drivers/iommu/exynos-iommu.c
> > index d90e6fa..a318049 100644
> > --- a/drivers/iommu/exynos-iommu.c
> > +++ b/drivers/iommu/exynos-iommu.c
> > @@ -100,6 +100,8 @@
> >  #define REG_PB1_SADDR              0x054
> >  #define REG_PB1_EADDR              0x058
> > 
> > +static struct kmem_cache *lv2table_kmem_cache;
> > +
> >  static unsigned long *section_entry(unsigned long *pgtable, unsigned
> > long iova) {
> >     return pgtable + lv1ent_offset(iova);
> > @@ -765,7 +767,8 @@ static void exynos_iommu_domain_destroy(struct
> > iommu_domain *domain)
> > 
> >     for (i = 0; i < NUM_LV1ENTRIES; i++)
> >             if (lv1ent_page(priv->pgtable + i))
> > -                   kfree(__va(lv2table_base(priv->pgtable + i)));
> > +                   kmem_cache_free(lv2table_kmem_cache,
> > +                                   __va(lv2table_base(priv->pgtable + i)));
> > 
> >     free_pages((unsigned long)priv->pgtable, 2);
> >     free_pages((unsigned long)priv->lv2entcnt, 1);
> > @@ -861,7 +864,7 @@ static unsigned long *alloc_lv2entry(unsigned long
> > *sent, unsigned long iova, if (lv1ent_fault(sent)) {
> >             unsigned long *pent;
> > 
> > -           pent = kzalloc(LV2TABLE_SIZE, GFP_ATOMIC);
> > +           pent = kmem_cache_zalloc(lv2table_kmem_cache, GFP_ATOMIC);
> >             BUG_ON((unsigned long)pent & (LV2TABLE_SIZE - 1));
> >             if (!pent)
> >                     return ERR_PTR(-ENOMEM);
> > @@ -881,7 +884,7 @@ static int lv1set_section(unsigned long *sent,
> > phys_addr_t paddr, short *pgcnt)
> > 
> >     if (lv1ent_page(sent)) {
> >             BUG_ON(*pgcnt != NUM_LV2ENTRIES);
> > -           kfree(page_entry(sent, 0));
> > +           kmem_cache_free(lv2table_kmem_cache, page_entry(sent, 0));
> >             *pgcnt = 0;
> >     }
> > 
> > @@ -1082,10 +1085,23 @@ static int __init exynos_iommu_init(void)
> >  {
> >     int ret;
> > 
> > +   lv2table_kmem_cache = kmem_cache_create("exynos-iommu-lv2table",
> > +                           LV2TABLE_SIZE, LV2TABLE_SIZE, 0, NULL);
> > +   if (!lv2table_kmem_cache) {
> > +           pr_err("%s: Failed to create kmem cache\n", __func__);
> > +           return -ENOMEM;
> > +   }
> > +
> >     ret = platform_driver_register(&exynos_sysmmu_driver);
> > 
> >     if (ret == 0)
> > -           bus_set_iommu(&platform_bus_type, &exynos_iommu_ops);
> > +           ret = bus_set_iommu(&platform_bus_type, &exynos_iommu_ops);
> > +
> > +   if (ret) {
> > +           pr_err("%s: Failed to register exynos-iommu driver.\n",
> > +                                                           __func__);
> > +           kmem_cache_destroy(lv2table_kmem_cache);
> > +   }
> 
> What about making the return value handling here cleaner? For example:
> 
>       lv2table_kmem_cache = kmem_cache_create("exynos-iommu-lv2table",
>                               LV2TABLE_SIZE, LV2TABLE_SIZE, 0, NULL);
>       if (!lv2table_kmem_cache) {
>               ...
>               return -ENOMEM;
>       }
> 
>       ret = platform_driver_register(&exynos_sysmmu_driver);
>       if (ret) {
>               ...
>               goto err_destroy_kmem_cache;
>       }
> 
>       ret = bus_set_iommu(&platform_bus_type, &exynos_iommu_ops);
>       if (ret) {
>               ...
>               goto err_platform_unregister;
>       }
> 
>       return 0;
> 
> err_platform_unregister:
>       ...
> err_destroy_kmem_cache:
>       ...
>       return ret;
> }
> 

Thank you for suggestion.
I think you are worrying about missing the information who makes 'ret' non-zero.
Ok. I will process it separately.

thanks

KyongHo.
> Best regards,
> Tomasz
> 
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