Message-ID: <54A41A64.9080909@mellanox.com>
Date: Wed, 31 Dec 2014 17:46:44 +0200
From: Haggai Eran <haggaie@mellanox.com>
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To: <j.glisse@gmail.com>, <akpm@linux-foundation.org>
CC: <linux-kernel@vger.kernel.org>, <linux-mm@kvack.org>,
        Linus Torvalds <torvalds@linux-foundation.org>, <joro@8bytes.org>,
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        Oded Gabbay <Oded.Gabbay@amd.com>,
        =?UTF-8?B?SsOpcsO0bWUgR2xpc3Nl?= <jglisse@redhat.com>,
        Jatin Kumar <jakumar@nvidia.com>
Subject: Re: [PATCH 3/7] HMM: introduce heterogeneous memory management.
References: <1419266940-5440-1-git-send-email-j.glisse@gmail.com>
 <1419266940-5440-4-git-send-email-j.glisse@gmail.com>
In-Reply-To: <1419266940-5440-4-git-send-email-j.glisse@gmail.com>
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Hi,

On 22/12/2014 18:48, j.glisse@gmail.com wrote:
> +/* hmm_device_register() - register a device with HMM.
> + *
> + * @device: The hmm_device struct.
> + * Returns: 0 on success or -EINVAL otherwise.
> + *
> + *
> + * Call when device driver want to register itself with HMM. Device driver can
> + * only register once. It will return a reference on the device thus to release
> + * a device the driver must unreference the device.

I see that the code doesn't actually have a reference count on the
hmm_device, but just registers and unregisters it through the
hmm_device_register/hmm_device_unregister functions. Perhaps you should
update the comment here to tell that.

> + */
> +int hmm_device_register(struct hmm_device *device)
> +{
> +	/* sanity check */
> +	BUG_ON(!device);
> +	BUG_ON(!device->name);
> +	BUG_ON(!device->ops);
> +	BUG_ON(!device->ops->release);
> +
> +	mutex_init(&device->mutex);
> +	INIT_LIST_HEAD(&device->mirrors);
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL(hmm_device_register);

Regards,
Haggai
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