Re: [PATCH v2 6/8] scsi/ipr: Use sgl_alloc_order() and sgl_free_order()

[Brian King]

On 10/30/2017 03:37 PM, Bart Van Assche wrote:
> On Wed, 2017-10-18 at 15:57 -0500, Brian King wrote:
>> On 10/17/2017 01:19 AM, Hannes Reinecke wrote:
>>> On 10/17/2017 12:49 AM, Bart Van Assche wrote:
>>>> [ ... ]
>>>
>>> Not sure if this is a valid conversion.
>>> Originally the driver would allocate a single buffer; with this buffer
>>> we have two distinct buffers.
>>> Given that this is used to download the microcode I'm not sure if this
>>> isn't a hardware-dependent structure which requires a single buffer
>>> including the sglist.
>>> Brian, can you shed some light here?
>>
>> The struct ipr_sglist is not a hardware defined data structure, so on initial
>> glance, this should be OK. I'll load it up and give it a try to make sure
>> it doesn't break code download.
> 
> Hello Brian,
> 
> Have you already obtained any test results?

Bart,

Yes. I tried this out on an ipr adapter and it looks fine.

Acked-by: Brian King 

Thanks,

Brian

-- 
Brian King
Power Linux I/O
IBM Linux Technology Center

Re: [PATCH v2 6/8] scsi/ipr: Use sgl_alloc_order() and sgl_free_order()

[Brian King]

On 10/17/2017 01:19 AM, Hannes Reinecke wrote:
> On 10/17/2017 12:49 AM, Bart Van Assche wrote:
>> Use the sgl_alloc_order() and sgl_free_order() functions instead
>> of open coding these functions.
>>
>> Signed-off-by: Bart Van Assche 
>> Reviewed-by: Johannes Thumshirn 
>> Cc: linux-s...@vger.kernel.org
>> Cc: Martin K. Petersen 
>> Cc: Brian King 
>> ---
>>  drivers/scsi/Kconfig |  1 +
>>  drivers/scsi/ipr.c   | 49 -
>>  drivers/scsi/ipr.h   |  2 +-
>>  3 files changed, 10 insertions(+), 42 deletions(-)
>>
>> diff --git a/drivers/scsi/Kconfig b/drivers/scsi/Kconfig
>> index 41366339b950..d11e75e76195 100644
>> --- a/drivers/scsi/Kconfig
>> +++ b/drivers/scsi/Kconfig
>> @@ -1058,6 +1058,7 @@ config SCSI_IPR
>>  depends on PCI && SCSI && ATA
>>  select FW_LOADER
>>  select IRQ_POLL
>> +select SGL_ALLOC
>>  ---help---
>>This driver supports the IBM Power Linux family RAID adapters.
>>This includes IBM pSeries 5712, 5703, 5709, and 570A, as well
>> diff --git a/drivers/scsi/ipr.c b/drivers/scsi/ipr.c
>> index f838bd73befa..6fed5db6255e 100644
>> --- a/drivers/scsi/ipr.c
>> +++ b/drivers/scsi/ipr.c
>> @@ -3815,10 +3815,8 @@ static struct device_attribute ipr_iopoll_weight_attr 
>> = {
>>   **/
>>  static struct ipr_sglist *ipr_alloc_ucode_buffer(int buf_len)
>>  {
>> -int sg_size, order, bsize_elem, num_elem, i, j;
>> +int sg_size, order;
>>  struct ipr_sglist *sglist;
>> -struct scatterlist *scatterlist;
>> -struct page *page;
>>  
>>  /* Get the minimum size per scatter/gather element */
>>  sg_size = buf_len / (IPR_MAX_SGLIST - 1);
>> @@ -3826,45 +3824,18 @@ static struct ipr_sglist *ipr_alloc_ucode_buffer(int 
>> buf_len)
>>  /* Get the actual size per element */
>>  order = get_order(sg_size);
>>  
>> -/* Determine the actual number of bytes per element */
>> -bsize_elem = PAGE_SIZE * (1 << order);
>> -
>> -/* Determine the actual number of sg entries needed */
>> -if (buf_len % bsize_elem)
>> -num_elem = (buf_len / bsize_elem) + 1;
>> -else
>> -num_elem = buf_len / bsize_elem;
>> -
>>  /* Allocate a scatter/gather list for the DMA */
>> -sglist = kzalloc(sizeof(struct ipr_sglist) +
>> - (sizeof(struct scatterlist) * (num_elem - 1)),
>> - GFP_KERNEL);
>> -
>> +sglist = kzalloc(sizeof(struct ipr_sglist), GFP_KERNEL);
>>  if (sglist == NULL) {
>>  ipr_trace;
>>  return NULL;
>>  }
>> -
>> -scatterlist = sglist->scatterlist;
>> -sg_init_table(scatterlist, num_elem);
>> -
>>  sglist->order = order;
>> -sglist->num_sg = num_elem;
>> -
>> -/* Allocate a bunch of sg elements */
>> -for (i = 0; i < num_elem; i++) {
>> -page = alloc_pages(GFP_KERNEL, order);
>> -if (!page) {
>> -ipr_trace;
>> -
>> -/* Free up what we already allocated */
>> -for (j = i - 1; j >= 0; j--)
>> -__free_pages(sg_page(&scatterlist[j]), order);
>> -kfree(sglist);
>> -return NULL;
>> -}
>> -
>> -sg_set_page(&scatterlist[i], page, 0, 0);
>> +sglist->scatterlist = sgl_alloc_order(buf_len, order, false, GFP_KERNEL,
>> +  &sglist->num_sg);
>> +if (!sglist->scatterlist) {
>> +kfree(sglist);
>> +return NULL;
>>  }
>>  
>>  return sglist;
>> @@ -3882,11 +3853,7 @@ static struct ipr_sglist *ipr_alloc_ucode_buffer(int 
>> buf_len)
>>   **/
>>  static void ipr_free_ucode_buffer(struct ipr_sglist *sglist)
>>  {
>> -int i;
>> -
>> -for (i = 0; i < sglist->num_sg; i++)
>> -__free_pages(sg_page(&sglist->scatterlist[i]), sglist->order);
>> -
>> +sgl_free_order(sglist->scatterlist, sglist->order);
>>  kfree(sglist);
>>  }
>>  
>> diff --git a/drivers/scsi/ipr.h b/drivers/scsi/ipr.h
>> index c7f0e9e3cd7d..93570734cbfb 100644
>> --- a/drivers/scsi/ipr.h
>> +++ b/drivers/scsi/ipr.h
>> @@ -1454,7 +1454,7 @@ struct ipr_sglist {
>>  u32 num_sg;