Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1351370

Re: [PATCH v4 net-next 8/9] net: add a hardware buffer management helper API

Show all headers | View raw

Hi Marcin,
 
 On dim., mars 06 2016, Marcin Wojtas <mw@semihalf.com> wrote:

> Hi Gregory,
>
>
>> +int hwbm_pool_add(struct hwbm_pool *bm_pool, unsigned int buf_num, gfp_t gfp)
>> +{
>> +       int err, i;
>> +       unsigned long flags;
>> +
>> +       spin_lock_irqsave(&bm_pool->lock, flags);
>> +       if (bm_pool->buf_num == bm_pool->size) {
>
> 'size' field is used as a 'frag_size' but here it means pool capacity.
> I think it's better to keep 'size' for pool capacity and add
> 'buf_size' field to struct hwbm_pool.


I thought I already added this field, but it seems that I didn't so. So
I will add it.

>
>> +               pr_warn("pool already filled\n");
>> +               return bm_pool->buf_num;
>> +       }
>> +
>> +       if (buf_num + bm_pool->buf_num > bm_pool->size) {
>> +               pr_warn("cannot allocate %d buffers for pool\n",
>> +                       buf_num);
>> +               return 0;
>> +       }
>> +
>> +       if ((buf_num + bm_pool->buf_num) < bm_pool->buf_num) {
>
> What is a point of this condition? How possibly after checking if
> capacity of pool is not exceeded, this one would ever be true?

see http://thread.gmane.org/gmane.linux.kernel/2125152/focus=2137421

this test is here to ensure that (buf_num + bm_pool->buf_nu doesn't
wrap.

Thanks,

Gregory

-- 
Gregory Clement, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

[PATCH v4 net-next 0/9] API set for HW Buffer management Gregory CLEMENT <gregory.clement@free-electrons.com> - 2016-03-05 23:40 +0100
  [PATCH v4 net-next 9/9] net: mvneta: Use the new hwbm framework Gregory CLEMENT <gregory.clement@free-electrons.com> - 2016-03-05 23:40 +0100
  [PATCH v4 net-next 4/9] ARM: dts: armada-xp: enable buffer manager support on Armada XP boards Gregory CLEMENT <gregory.clement@free-electrons.com> - 2016-03-05 23:40 +0100
  [PATCH v4 net-next 3/9] ARM: dts: armada-xp: add buffer manager nodes Gregory CLEMENT <gregory.clement@free-electrons.com> - 2016-03-05 23:40 +0100
  [PATCH v4 net-next 2/9] ARM: dts: armada-38x: enable buffer manager support on Armada 38x boards Gregory CLEMENT <gregory.clement@free-electrons.com> - 2016-03-05 23:40 +0100
    Re: [PATCH v4 net-next 2/9] ARM: dts: armada-38x: enable buffer  manager support on Armada 38x boards Russell King - ARM Linux <linux@arm.linux.org.uk> - 2016-03-06 21:40 +0100
  [PATCH v4 net-next 8/9] net: add a hardware buffer management helper API Gregory CLEMENT <gregory.clement@free-electrons.com> - 2016-03-05 23:40 +0100
    Re: [PATCH v4 net-next 8/9] net: add a hardware buffer management  helper API Marcin Wojtas <mw@semihalf.com> - 2016-03-06 20:30 +0100
      Re: [PATCH v4 net-next 8/9] net: add a hardware buffer management helper API Gregory CLEMENT <gregory.clement@free-electrons.com> - 2016-03-07 09:20 +0100
  [PATCH v4 net-next 5/9] ARM: dts: armada-xp-openblocks-ax3-4: Add BM support Gregory CLEMENT <gregory.clement@free-electrons.com> - 2016-03-05 23:50 +0100
  [PATCH v4 net-next 1/9] ARM: dts: armada-38x: add buffer manager nodes Gregory CLEMENT <gregory.clement@free-electrons.com> - 2016-03-05 23:50 +0100
  [PATCH v4 net-next 6/9] bus: mvebu-mbus: provide api for obtaining IO and DRAM window information Gregory CLEMENT <gregory.clement@free-electrons.com> - 2016-03-05 23:50 +0100

csiph-web