From: Stephen Hemminger <stephen@networkplumber.org>
To: Phil Yang <phil.yang@arm.com>
Cc: dev@dpdk.org, jerin.jacob@caviumnetworks.com, Gavin.Hu@arm.com,
Honnappa.Nagarahalli@arm.com, Ola.Liljedahl@arm.com,
ferruh.yigit@intel.com
Subject: Re: [dpdk-dev] [PATCH v3 2/4] kni: fix kni fifo synchronization
Date: Mon, 8 Oct 2018 14:53:08 -0700 [thread overview]
Message-ID: <20181008145308.0fbc64de@xeon-e3> (raw)
In-Reply-To: <1538989906-8349-2-git-send-email-phil.yang@arm.com>
On Mon, 8 Oct 2018 17:11:44 +0800
Phil Yang <phil.yang@arm.com> wrote:
> diff --git a/lib/librte_kni/rte_kni_fifo.h b/lib/librte_kni/rte_kni_fifo.h
> index ac26a8c..70ac14e 100644
> --- a/lib/librte_kni/rte_kni_fifo.h
> +++ b/lib/librte_kni/rte_kni_fifo.h
> @@ -28,8 +28,9 @@ kni_fifo_put(struct rte_kni_fifo *fifo, void **data, unsigned num)
> {
> unsigned i = 0;
> unsigned fifo_write = fifo->write;
> - unsigned fifo_read = fifo->read;
> unsigned new_write = fifo_write;
> + rte_smp_rmb();
> + unsigned fifo_read = fifo->read;
>
The patch makes sense, but this function should be changed to match kernel code style.
That means no declarations after initial block, and use 'unsigned int' rather than 'unsigned'
Also. why is i initialized? Best practice now is to not do gratitious initialization
since it defeats compiler checks for accidental use of uninitialized variables.
What makes sense is something like:
kni_fifo_put(struct rte_kni_fifo *fifo, void **data, unsigned num)
{
unsigned int i, fifo_read, fifo_write, new_write;
fifo_write = fifo->write;
new_write = fifo_write;
rte_smb_rmb();
fifo_read = fifo->read;
Sorry, blaming you for issues which are inherited from original KNI code.
Maybe someone should run kernel checkpatch (not DPDK checkpatch) on it and fix those.
next prev parent reply other threads:[~2018-10-08 21:53 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-19 13:30 [dpdk-dev] [PATCH 1/3] config: use one single config option for C11 memory model Phil Yang
2018-09-19 13:30 ` [dpdk-dev] [PATCH 2/3] kni: fix kni fifo synchronization Phil Yang
2018-09-19 13:30 ` [dpdk-dev] [PATCH 3/3] kni: fix kni kernel " Phil Yang
2018-09-19 13:42 ` [dpdk-dev] [PATCH v2 1/3] config: use one single config option for C11 memory model Phil Yang
2018-09-19 13:42 ` [dpdk-dev] [PATCH v2 2/3] kni: fix kni fifo synchronization Phil Yang
2018-09-20 8:28 ` Jerin Jacob
2018-09-20 15:20 ` Honnappa Nagarahalli
2018-09-20 15:37 ` Jerin Jacob
2018-09-21 5:48 ` Honnappa Nagarahalli
2018-09-21 5:55 ` Jerin Jacob
2018-09-21 6:37 ` Honnappa Nagarahalli
2018-09-21 9:00 ` Phil Yang (Arm Technology China)
2018-09-25 4:44 ` Honnappa Nagarahalli
2018-09-26 11:42 ` Ferruh Yigit
2018-09-27 9:06 ` Phil Yang (Arm Technology China)
2018-09-26 11:45 ` Ferruh Yigit
2018-10-01 4:52 ` Honnappa Nagarahalli
2018-09-19 13:42 ` [dpdk-dev] [PATCH v2 3/3] kni: fix kni kernel " Phil Yang
2018-09-20 8:21 ` [dpdk-dev] [PATCH v2 1/3] config: use one single config option for C11 memory model Jerin Jacob
2018-10-08 9:11 ` [dpdk-dev] [PATCH v3 1/4] " Phil Yang
2018-10-08 9:11 ` [dpdk-dev] [PATCH v3 2/4] kni: fix kni fifo synchronization Phil Yang
2018-10-08 21:53 ` Stephen Hemminger [this message]
2018-10-10 9:58 ` Phil Yang (Arm Technology China)
2018-10-10 10:06 ` Gavin Hu (Arm Technology China)
2018-10-10 14:42 ` Ferruh Yigit
2018-10-08 9:11 ` [dpdk-dev] [PATCH v3 3/4] kni: fix kni kernel " Phil Yang
2018-10-08 9:11 ` [dpdk-dev] [PATCH v3 4/4] kni: introduce c11 atomic into kni " Phil Yang
2018-10-10 14:48 ` [dpdk-dev] [PATCH v3 1/4] config: use one single config option for C11 memory model Ferruh Yigit
2018-10-12 9:17 ` Phil Yang (Arm Technology China)
2018-10-26 15:56 ` Thomas Monjalon
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