Hi Marc,
On 05/02/2017 11:16 AM, Marc Zyngier wrote:
> On Sun, Apr 30 2017 at 3:36:15 pm BST, Shanker Donthineni
> <shank...@codeaurora.org> wrote:
>> We are always allocating extra 255Bytes of memory to handle ITE
>> physical address alignment requirement. The kmalloc() satisfies
>> the ITE alignment since the ITS driver is requesting a minimum
>> size of ITS_ITT_ALIGN bytes.
>>
>> Let's try to allocate the exact amount of memory that is required
>> for ITEs to avoid wastage.
>>
>> Signed-off-by: Shanker Donthineni <shank...@codeaurora.org>
>> ---
>> Changes:
>> v2: removed 'Change-Id: Ia8084189833f2081ff13c392deb5070c46a64038' from
>> commit.
>> v3: changed from IITE to ITE.
>> v3: removed fallback since kmalloc() guarantees the right alignment.
>>
>> drivers/irqchip/irq-gic-v3-its.c | 6 +++---
>> 1 file changed, 3 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/irqchip/irq-gic-v3-its.c
>> b/drivers/irqchip/irq-gic-v3-its.c
>> index 45ea1933..72e56f03 100644
>> --- a/drivers/irqchip/irq-gic-v3-its.c
>> +++ b/drivers/irqchip/irq-gic-v3-its.c
>> @@ -261,7 +261,6 @@ static struct its_collection *its_build_mapd_cmd(struct
>> its_cmd_block *cmd,
>> u8 size = ilog2(desc->its_mapd_cmd.dev->nr_ites);
>>
>> itt_addr = virt_to_phys(desc->its_mapd_cmd.dev->itt);
>> - itt_addr = ALIGN(itt_addr, ITS_ITT_ALIGN);
>>
>> its_encode_cmd(cmd, GITS_CMD_MAPD);
>> its_encode_devid(cmd, desc->its_mapd_cmd.dev->device_id);
>> @@ -1329,13 +1328,14 @@ static struct its_device *its_create_device(struct
>> its_node *its, u32 dev_id,
>> */
>> nr_ites = max(2UL, roundup_pow_of_two(nvecs));
>> sz = nr_ites * its->ite_size;
>> - sz = max(sz, ITS_ITT_ALIGN) + ITS_ITT_ALIGN - 1;
>> + sz = max(sz, ITS_ITT_ALIGN);
>> itt = kzalloc(sz, GFP_KERNEL);
>> lpi_map = its_lpi_alloc_chunks(nvecs, &lpi_base, &nr_lpis);
>> if (lpi_map)
>> col_map = kzalloc(sizeof(*col_map) * nr_lpis, GFP_KERNEL);
>>
>> - if (!dev || !itt || !lpi_map || !col_map) {
>> + if (!dev || !itt || !lpi_map || !col_map ||
>> + !IS_ALIGNED(virt_to_phys(itt), ITS_ITT_ALIGN)) {
>> kfree(dev);
>> kfree(itt);
>> kfree(lpi_map);
> I'm confused. Either the alignment is guaranteed (and you should
> document why it is so), or it is not, and we need to handle the
> non-alignment (instead of failing).
Sorry for confusion, alignment is guaranteed by kmalloc(), added a check for
readability purpose only can be removed.
> Thanks,
>
> M.
--
Shanker Donthineni
Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm
Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux
Foundation Collaborative Project.
