On Fri, 09 Aug 2013 09:55:30 +0200, Tomasz Figa wrote: > Hi KyongHo, > > On Friday 09 of August 2013 14:58:49 Cho KyongHo wrote: > > 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. > > Oh, this is a valid point, but it was more a nitpick about the coding > style. Single path error handling (with goto) is widely used in the kernel > in cases when more than one thing has to be undone and so I suggested this > method of error handling here as well. > > > Ok. I will process it separately. > > Since this patch adds most of the error handling to this function, I think > it should be fine to do it as a part of this patch. >
I meant 'separately' that checking all return values each. I think it can be simpler without goto. There are just 2 cases to rollback previous changes in that function. > Best regards, > Tomasz > -- To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
