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 at 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 at dpdk.org] On Behalf Of Ferruh Yigit >>>> Sent: Thursday, March 03, 2016 5:08 PM >>>> To: dev at 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 at 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
