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SubjectRe: [PATCH kernel v8 21/31] powerpc/iommu: Split iommu_free_table into 2 helpers
On 04/16/2015 04:46 PM, David Gibson wrote:
> 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.


This is iommu tables created by the old code which stores these iommu_table
struct pointers in device nodes. I believe there is a plan to get rid of
iommu tables there and when this is done, this workaround will be gone.


>
>>
>> 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);
>> }
>


--
Alexey


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