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From: Yuanhan Liu <yliu@fridaylinux.org>
To: Qi Zhang <qi.z.zhang@intel.com>, thomas@monjalon.net,
anatoly.burakov@intel.com
Cc: konstantin.ananyev@intel.com, dev@dpdk.org, bruce.richardson@intel.com,
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References: <20180607123849.14439-1-qi.z.zhang@intel.com>
<20180702054450.29269-1-qi.z.zhang@intel.com>
<20180702054450.29269-5-qi.z.zhang@intel.com>
Date: Wed, 04 Jul 2018 10:19:51 +0800
In-Reply-To: <20180702054450.29269-5-qi.z.zhang@intel.com>
Subject: Re: [dpdk-dev] [PATCH v8 04/19] ethdev: introduce device lock
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On Mon, Jul 2, 2018, at 1:44 PM, Qi Zhang wrote:
> Introduce API rte_eth_dev_lock and rte_eth_dev_unlock to let
> application lock or unlock on specific ethdev, a locked device
> can't be detached, this help applicaiton to prevent unexpected
> device detaching, especially in multi-process envrionment.
I'm just wondering why the need of introducing such 2 (very specific)
APIs, judging that it looks like a ref count could solve this kind of issues
perfectly.
Also, the API name (_dev_lock/unlock) looks like an over killing, judging
that you just want to pin a device (if I understand this commit log correctly).
What firstly comes to my mind when I see "lock" was "no one can *access*
a device after another has grabbed the lock", which doesn't quite match
what you described here.
That said, if I were you, I would go with introducing few generic refcount
APIs.
--yliu
>
> Aslo introduce the new API rte_eth_dev_lock_with_callback and
> rte_eth_dev_unlock_with callback to let application to register
> a callback function which will be invoked before a device is going
> to be detached, the return value of the function will decide if
> device will continue be detached or not, this support application
> to do condition check at runtime.
>
> Signed-off-by: Qi Zhang <qi.z.zhang@intel.com>
> Reviewed-by: Anatoly Burakov <anatoly.burakov@intel.com>