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From: Ferruh Yigit <ferruh.yigit@intel.com>
To: Dmitry Kozlyuk <dmitry.kozliuk@gmail.com>
Cc: dev@dpdk.org, Pallavi Kadam <pallavi.kadam@intel.com>,
	Dmitry Malloy <dmitrym@microsoft.com>,
	Narcisa Ana Maria Vasile <navasile@linux.microsoft.com>,
	Ray Kinsella <mdr@ashroe.eu>, Neil Horman <nhorman@tuxdriver.com>
Subject: Re: [dpdk-dev] [PATCH] doc: announce renaming of rte_ether_hdr fields
Date: Thu, 20 May 2021 17:04:06 +0100	[thread overview]
Message-ID: <f72bd5ba-4e7c-6e61-1c12-97ceb27cf90e@intel.com> (raw)
In-Reply-To: <20210520185055.7646d8fc@sovereign>

On 5/20/2021 4:50 PM, Dmitry Kozlyuk wrote:
> 2021-05-20 16:27 (UTC+0100), Ferruh Yigit:
>> On 5/20/2021 4:06 PM, Dmitry Kozlyuk wrote:
>>> 2021-05-20 15:24 (UTC+0100), Ferruh Yigit:  
>>>> On 3/3/2021 10:51 PM, Dmitry Kozlyuk wrote:  
>>> [...]  
>>>>>
>>>>> It is not mandatory to rename `d_addr`, this is for consistency only.
>>>>> Naming in `rte_ether_hdr` will also resemble `rte_ipv4/6_hdr`.
>>>>>
>>>>> Workaround is to define `struct rte_ether_hdr` in such a away that
>>>>> it can be used with or without `s_addr` macro (as defined on Windows)
>>>>> This can be done for Windows only or for all platforms to save space.
>>>>>
>>>>>     #pragma push_macro("s_addr")
>>>>>     #ifdef s_addr
>>>>>     #undef s_addr
>>>>>     #endif
>>>>>
>>>>>     struct rte_ether_hdr {
>>>>>         struct rte_ether_addr d_addr; /**< Destination address. */
>>>>>         RTE_STD_C11
>>>>>         union {
>>>>>             struct rte_ether_addr s_addr; /**< Source address. */
>>>>>             struct {
>>>>>                 struct rte_ether_addr S_un;
>>>>>                 /**< MUST NOT be used directly, only via s_addr */
>>>>>             } S_addr;
>>>>>             /*< MUST NOT be used directly, only via s_addr */
>>>>>         };
>>>>>         uint16_t ether_type; /**< Frame type. */
>>>>>     } __rte_aligned(2);
>>>>>
>>>>>     #pragma pop_macro("s_addr")
>>>>>     
>>>>
>>>> What is the problem with the workaround, why we can't live with it?
>>>>
>>>> It requires an order in include files, right?  
>>>
>>> There's no problem except a tricky structure definition with fields that
>>> violate DPDK coding rules. It works with any include order.
>>>
>>> Will fix typos in v3, thanks.
>>>   
>>
>> For following case, won't compiler take 's_addr' as macro?
>>
>>     #include <rte_ether.h>
>>     #include <winsock2.h>
>>     struct rte_ether_hdr eh;
>>     /* eh.s_addr.addr_bytes[0] = 0;
>>
> 
> Yes, it will. The macro will expand to `S_addr.S_un` and compile successfully.

will 'eh.S_addr.S_un.addr_bytes[0] = 0;' compile successfully?

> In theory, Microsoft can change the definition of `s_addr`, and while I doubt
> they will, it's a valid concern and a reason to remove workaround in 21.11.
> 


  reply	other threads:[~2021-05-20 16:04 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-03 22:51 Dmitry Kozlyuk
2021-03-03 23:54 ` Stephen Hemminger
2021-03-04  7:09   ` Dmitry Kozlyuk
2021-05-20 14:28     ` Ferruh Yigit
2021-03-10 23:54 ` [dpdk-dev] [PATCH v2] doc: announce API changes for Windows compatibility Dmitry Kozlyuk
2021-03-11 16:19   ` John Alexander
2021-03-11 17:01     ` Dmitry Kozlyuk
2021-03-11 17:08       ` Tyler Retzlaff
2021-03-16 10:37   ` Thomas Monjalon
2021-05-20 18:42   ` [dpdk-dev] [PATCH v3] " Dmitry Kozlyuk
2021-05-20 18:59     ` [dpdk-dev] [EXT] " Akhil Goyal
2021-05-20 19:31       ` Dmitry Kozlyuk
2021-05-20 20:17         ` Akhil Goyal
2021-06-09 15:52           ` Dmitry Kozlyuk
2021-06-23 15:14             ` Dmitry Kozlyuk
2021-06-17 14:27           ` Tyler Retzlaff
2021-07-21 19:55     ` [dpdk-dev] " Dmitry Kozlyuk
2021-07-21 19:55       ` [dpdk-dev] [PATCH v4] " Dmitry Kozlyuk
2021-08-02 12:13         ` Thomas Monjalon
2021-08-02 12:45           ` [dpdk-dev] [EXT] " Akhil Goyal
2021-08-02 13:00             ` Dmitry Kozlyuk
2021-08-02 13:48               ` Akhil Goyal
2021-08-02 14:57                 ` Tal Shnaiderman
2021-08-02 17:46                 ` Thomas Monjalon
2021-05-20 14:24 ` [dpdk-dev] [PATCH] doc: announce renaming of rte_ether_hdr fields Ferruh Yigit
2021-05-20 15:06   ` Dmitry Kozlyuk
2021-05-20 15:27     ` Ferruh Yigit
2021-05-20 15:50       ` Dmitry Kozlyuk
2021-05-20 16:04         ` Ferruh Yigit [this message]
2021-05-20 16:16           ` Dmitry Kozlyuk
2021-05-20 16:25             ` Ferruh Yigit

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