From: Ferruh Yigit <ferruh.yigit@intel.com>
To: "Ananyev, Konstantin" <konstantin.ananyev@intel.com>,
"dev@dpdk.org" <dev@dpdk.org>
Subject: Re: [dpdk-dev] [PATCH] igb_uio: use macros for array size calculation
Date: Thu, 3 Mar 2016 18:16:43 +0000 [thread overview]
Message-ID: <56D87F8B.7000103@intel.com> (raw)
In-Reply-To: <2601191342CEEE43887BDE71AB97725836B16008@irsmsx105.ger.corp.intel.com>
On 3/3/2016 5:45 PM, Ananyev, Konstantin wrote:
>
>
>> -----Original Message-----
>> From: Yigit, Ferruh
>> Sent: Thursday, March 03, 2016 5:35 PM
>> To: Ananyev, Konstantin; dev@dpdk.org
>> Subject: Re: [dpdk-dev] [PATCH] igb_uio: use macros for array size calculation
>>
>> On 3/3/2016 5:25 PM, Ananyev, Konstantin wrote:
>>>
>>>
>>>> -----Original Message-----
>>>> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Ferruh Yigit
>>>> Sent: Thursday, March 03, 2016 5:08 PM
>>>> To: dev@dpdk.org
>>>> Subject: [dpdk-dev] [PATCH] igb_uio: use macros for array size calculation
>>>>
>>>> Minor code cleanup.
>>>> Remove array size calculations and remove unnecessary assignment.
>>>>
>>>> Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com>
>>>> ---
>>>> lib/librte_eal/linuxapp/igb_uio/igb_uio.c | 8 ++++----
>>>> 1 file changed, 4 insertions(+), 4 deletions(-)
>>>>
>>>> diff --git a/lib/librte_eal/linuxapp/igb_uio/igb_uio.c b/lib/librte_eal/linuxapp/igb_uio/igb_uio.c
>>>> index 3374e44..563c57b 100644
>>>> --- a/lib/librte_eal/linuxapp/igb_uio/igb_uio.c
>>>> +++ b/lib/librte_eal/linuxapp/igb_uio/igb_uio.c
>>>> @@ -58,7 +58,7 @@ struct rte_uio_pci_dev {
>>>> enum rte_intr_mode mode;
>>>> };
>>>>
>>>> -static char *intr_mode = NULL;
>>>> +static char *intr_mode;
>>>> static enum rte_intr_mode igbuio_intr_mode_preferred = RTE_INTR_MODE_MSIX;
>>>>
>>>> /* sriov sysfs */
>>>> @@ -332,7 +332,7 @@ igbuio_pci_setup_iomem(struct pci_dev *dev, struct uio_info *info,
>>>> unsigned long addr, len;
>>>> void *internal_addr;
>>>>
>>>> - if (sizeof(info->mem) / sizeof(info->mem[0]) <= n)
>>>> + if (n >= MAX_UIO_MAPS)
>>>
>>> Why using hardcoded value is better than sizeof()?
>>> As I can see below there is a macro ARRAY_SIZE, why not to use it here then?
>>
>> Both are valid, but in uio (uio_driver.h) "mem" array defined as:
>> struct uio_mem mem[MAX_UIO_MAPS];
>
> Yep, so if both are valid, why to change it a the first place? :)
>
>>
>> So we already know the size of the array, and it is exposed to us, why
>> need to calculate. Is there any benefit of calculating it?
>
> if in future definition of the mem[] would change to let say:
> struct uio_mem mem[X]
> your code would still be valid, and no need to update it.
Since it is the part of uio API, I expect this will remain same,
otherwise igb_uio.c will already have problems because there is other
piece of code that already rely on this information.
But I don't have a strong opinion on one or other, I will update this to
use ARRAY_SIZE()
Thanks,
ferruh
next prev parent reply other threads:[~2016-03-03 18:16 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-03 17:08 [dpdk-dev] [PATCH] igb_uio: cast private data to correct struct type Ferruh Yigit
2016-03-03 17:08 ` [dpdk-dev] [PATCH] igb_uio: use macros for array size calculation Ferruh Yigit
2016-03-03 17:25 ` Ananyev, Konstantin
2016-03-03 17:34 ` Ferruh Yigit
2016-03-03 17:45 ` Ananyev, Konstantin
2016-03-03 18:16 ` Ferruh Yigit [this message]
2016-03-04 11:21 ` [dpdk-dev] [PATCH v2] " Ferruh Yigit
2016-03-04 11:43 ` Ananyev, Konstantin
2016-03-07 22:30 ` Thomas Monjalon
2016-03-04 13:17 ` [dpdk-dev] [PATCH] igb_uio: cast private data to correct struct type Ananyev, Konstantin
2016-03-07 22:29 ` Thomas Monjalon
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=56D87F8B.7000103@intel.com \
--to=ferruh.yigit@intel.com \
--cc=dev@dpdk.org \
--cc=konstantin.ananyev@intel.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).