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From: Alexey Kardashevskiy <aik@ozlabs.ru>
To: "Leonardo Brás" <leobras.c@gmail.com>,
	"Frederic Barrat" <fbarrat@linux.ibm.com>,
	"Michael Ellerman" <mpe@ellerman.id.au>,
	"Benjamin Herrenschmidt" <benh@kernel.crashing.org>,
	"Paul Mackerras" <paulus@samba.org>,
	"David Gibson" <david@gibson.dropbear.id.au>,
	"kernel test robot" <lkp@intel.com>,
	"Nicolin Chen" <nicoleotsuka@gmail.com>
Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v5 08/11] powerpc/pseries/iommu: Update remove_dma_window() to accept property name
Date: Tue, 24 Aug 2021 16:31:41 +1000	[thread overview]
Message-ID: <ec7a7443-9896-decd-9757-0cbe9740b237@ozlabs.ru> (raw)
In-Reply-To: <f9f7bcd75d534ebde7cc83c4138176da4680e30f.camel@gmail.com>



On 17/08/2021 16:12, Leonardo Brás wrote:
> On Tue, 2021-08-17 at 02:59 -0300, Leonardo Brás wrote:
>> Hello Fred, thanks for the feedback!
>>
>> On Tue, 2021-07-20 at 19:51 +0200, Frederic Barrat wrote:
>>>
>>>
>>> On 16/07/2021 10:27, Leonardo Bras wrote:
>>>> Update remove_dma_window() so it can be used to remove DDW with a
>>>> given
>>>> property name.
>>>>
>>>> This enables the creation of new property names for DDW, so we
>>>> can
>>>> have different usage for it, like indirect mapping.
>>>>
>>>> Signed-off-by: Leonardo Bras <leobras.c@gmail.com>
>>>> Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
>>>> ---
>>>>    arch/powerpc/platforms/pseries/iommu.c | 21 +++++++++++--------
>>>> --
>>>>    1 file changed, 11 insertions(+), 10 deletions(-)
>>>>
>>>> diff --git a/arch/powerpc/platforms/pseries/iommu.c
>>>> b/arch/powerpc/platforms/pseries/iommu.c
>>>> index 108c3dcca686..17c6f4706e76 100644
>>>> --- a/arch/powerpc/platforms/pseries/iommu.c
>>>> +++ b/arch/powerpc/platforms/pseries/iommu.c
>>>> @@ -830,31 +830,32 @@ static void remove_dma_window(struct
>>>> device_node *np, u32 *ddw_avail,
>>>>                          np, ret,
>>>> ddw_avail[DDW_REMOVE_PE_DMA_WIN],
>>>> liobn);
>>>>    }
>>>>    
>>>> -static void remove_ddw(struct device_node *np, bool remove_prop)
>>>> +static int remove_ddw(struct device_node *np, bool remove_prop,
>>>> const char *win_name)
>>>>    {
>>>
>>>
>>> Why switch to returning an int? None of the callers check it.
>>
>> IIRC, in a previous version it did make sense, which is not the case
>> anymore. I will revert this.
>>
>> Thanks!
> 
> Oh, sorry about that, it is in fact still needed:


Then you should have added it in 10/11.

> 
> It will make sense in patch v5 10/11:
> On iommu_reconfig_notifier(), if (action == OF_RECONFIG_DETACH_NODE),
> we need to remove a DDW if it exists.
> 
> As there may be different window names, it tests for DIRECT64_PROPNAME,
> and if it's not found, it tests for DMA64_PROPNAME.
> 
> This approach will skip scanning for DMA64_PROPNAME if
> DIRECT64_PROPNAME was found, as both may not exist in the same node.
> But for this approach to work we need remove_ddw() to return error if
> the property is not found.
> 
> Does it make sense? or should I just test for both?

Or you could just try removing both without checking the return code, it 
is one extra of_find_property in very rare code path. Not worth 
reposting though imho. (sorry I was off last week, catching up). Thanks,



-- 
Alexey

  reply	other threads:[~2021-08-24  6:32 UTC|newest]

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-16  8:27 [PATCH v5 00/11] DDW + Indirect Mapping Leonardo Bras
2021-07-16  8:27 ` [PATCH v5 01/11] powerpc/pseries/iommu: Replace hard-coded page shift Leonardo Bras
2021-07-19 13:48   ` Frederic Barrat
2021-07-19 18:43     ` Leonardo Brás
2021-07-16  8:27 ` [PATCH v5 02/11] powerpc/kernel/iommu: Add new iommu_table_in_use() helper Leonardo Bras
2021-07-19 13:53   ` Frederic Barrat
2021-07-20  5:38     ` Leonardo Brás
2021-07-20  9:41       ` Alexey Kardashevskiy
2021-07-16  8:27 ` [PATCH v5 03/11] powerpc/pseries/iommu: Add iommu_pseries_alloc_table() helper Leonardo Bras
2021-07-19 14:04   ` Frederic Barrat
2021-07-19 18:47     ` Leonardo Brás
2021-07-16  8:27 ` [PATCH v5 04/11] powerpc/pseries/iommu: Add ddw_list_new_entry() helper Leonardo Bras
2021-07-19 14:14   ` Frederic Barrat
2021-07-19 18:47     ` Leonardo Brás
2021-07-16  8:27 ` [PATCH v5 05/11] powerpc/pseries/iommu: Allow DDW windows starting at 0x00 Leonardo Bras
2021-07-20 17:44   ` Frederic Barrat
2021-07-16  8:27 ` [PATCH v5 06/11] powerpc/pseries/iommu: Add ddw_property_create() and refactor enable_ddw() Leonardo Bras
2021-07-20 17:49   ` Frederic Barrat
2021-08-17  5:59     ` Leonardo Brás
2021-07-16  8:27 ` [PATCH v5 07/11] powerpc/pseries/iommu: Reorganize iommu_table_setparms*() with new helper Leonardo Bras
2021-07-20 17:50   ` Frederic Barrat
2021-07-16  8:27 ` [PATCH v5 08/11] powerpc/pseries/iommu: Update remove_dma_window() to accept property name Leonardo Bras
2021-07-20 17:51   ` Frederic Barrat
2021-08-17  5:59     ` Leonardo Brás
2021-08-17  6:12       ` Leonardo Brás
2021-08-24  6:31         ` Alexey Kardashevskiy [this message]
2021-07-16  8:27 ` [PATCH v5 09/11] powerpc/pseries/iommu: Find existing DDW with given " Leonardo Bras
2021-07-20 17:52   ` Frederic Barrat
2021-07-16  8:27 ` [PATCH v5 10/11] powerpc/pseries/iommu: Make use of DDW for indirect mapping Leonardo Bras
2021-07-20 18:12   ` Frederic Barrat
2021-07-21  3:32     ` Alexey Kardashevskiy
2021-07-21 15:04       ` Frederic Barrat
2021-07-23  5:34         ` Alexey Kardashevskiy
2021-08-17  5:59           ` Leonardo Brás
2021-08-17  5:59       ` Leonardo Brás
2021-07-16  8:27 ` [PATCH v5 11/11] powerpc/pseries/iommu: Rename "direct window" to "dma window" Leonardo Bras
2021-07-20 18:12   ` Frederic Barrat

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