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SubjectRe: [PATCH kernel v8 21/31] powerpc/iommu: Split iommu_free_table into 2 helpers
On Fri, Apr 10, 2015 at 04:31:03PM +1000, Alexey Kardashevskiy wrote:
> The iommu_free_table helper release memory it is using (the TCE table and
> @it_map) and release the iommu_table struct as well. We might not want
> the very last step as we store iommu_table in parent structures.

Yeah, as I commented on the earlier patch, freeing the surrounding
group from a function taking just the individual table is wrong.

>
> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
> ---
> arch/powerpc/include/asm/iommu.h | 1 +
> arch/powerpc/kernel/iommu.c | 57 ++++++++++++++++++++++++----------------
> 2 files changed, 35 insertions(+), 23 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/iommu.h b/arch/powerpc/include/asm/iommu.h
> index bde7ee7..8ed4648 100644
> --- a/arch/powerpc/include/asm/iommu.h
> +++ b/arch/powerpc/include/asm/iommu.h
> @@ -127,6 +127,7 @@ static inline void *get_iommu_table_base(struct device *dev)
>
> extern struct iommu_table *iommu_table_alloc(int node);
> /* Frees table for an individual device node */
> +extern void iommu_reset_table(struct iommu_table *tbl, const char *node_name);
> extern void iommu_free_table(struct iommu_table *tbl, const char *node_name);
>
> /* Initializes an iommu_table based in values set in the passed-in
> diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c
> index 501e8ee..0bcd988 100644
> --- a/arch/powerpc/kernel/iommu.c
> +++ b/arch/powerpc/kernel/iommu.c
> @@ -721,24 +721,46 @@ struct iommu_table *iommu_table_alloc(int node)
> return &table_group->tables[0];
> }
>
> +void iommu_reset_table(struct iommu_table *tbl, const char *node_name)
> +{
> + if (!tbl)
> + return;
> +
> + if (tbl->it_map) {
> + unsigned long bitmap_sz;
> + unsigned int order;
> +
> + /*
> + * In case we have reserved the first bit, we should not emit
> + * the warning below.
> + */
> + if (tbl->it_offset == 0)
> + clear_bit(0, tbl->it_map);
> +
> + /* verify that table contains no entries */
> + if (!bitmap_empty(tbl->it_map, tbl->it_size))
> + pr_warn("%s: Unexpected TCEs for %s\n", __func__,
> + node_name);
> +
> + /* calculate bitmap size in bytes */
> + bitmap_sz = BITS_TO_LONGS(tbl->it_size) * sizeof(unsigned long);
> +
> + /* free bitmap */
> + order = get_order(bitmap_sz);
> + free_pages((unsigned long) tbl->it_map, order);
> + }
> +
> + memset(tbl, 0, sizeof(*tbl));
> +}
> +
> void iommu_free_table(struct iommu_table *tbl, const char *node_name)
> {
> - unsigned long bitmap_sz;
> - unsigned int order;
> struct iommu_table_group *table_group = tbl->it_group;
>
> - if (!tbl || !tbl->it_map) {
> - printk(KERN_ERR "%s: expected TCE map for %s\n", __func__,
> - node_name);
> + if (!tbl)
> return;
> - }
>
> - /*
> - * In case we have reserved the first bit, we should not emit
> - * the warning below.
> - */
> - if (tbl->it_offset == 0)
> - clear_bit(0, tbl->it_map);
> + iommu_reset_table(tbl, node_name);
>
> #ifdef CONFIG_IOMMU_API
> if (table_group->group) {
> @@ -747,17 +769,6 @@ void iommu_free_table(struct iommu_table *tbl, const char *node_name)
> }
> #endif
>
> - /* verify that table contains no entries */
> - if (!bitmap_empty(tbl->it_map, tbl->it_size))
> - pr_warn("%s: Unexpected TCEs for %s\n", __func__, node_name);
> -
> - /* calculate bitmap size in bytes */
> - bitmap_sz = BITS_TO_LONGS(tbl->it_size) * sizeof(unsigned long);
> -
> - /* free bitmap */
> - order = get_order(bitmap_sz);
> - free_pages((unsigned long) tbl->it_map, order);
> -
> /* free table */
> kfree(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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