Linux-RDMA Archive on lore.kernel.org
 help / color / Atom feed
From: Jason Gunthorpe <jgg@ziepe.ca>
To: Greg KH <gregkh@linuxfoundation.org>
Cc: Jeff Kirsher <jeffrey.t.kirsher@intel.com>,
	davem@davemloft.net, Dave Ertman <david.m.ertman@intel.com>,
	netdev@vger.kernel.org, linux-rdma@vger.kernel.org,
	nhorman@redhat.com, sassmann@redhat.com, parav@mellanox.com,
	galpress@amazon.com, selvin.xavier@broadcom.com,
	sriharsha.basavapatna@broadcom.com, benve@cisco.com,
	bharat@chelsio.com, xavier.huwei@huawei.com,
	yishaih@mellanox.com, leonro@mellanox.com, mkalderon@marvell.com,
	aditr@vmware.com, Kiran Patil <kiran.patil@intel.com>,
	Andrew Bowers <andrewx.bowers@intel.com>
Subject: Re: [RFC PATCH v4 01/25] virtual-bus: Implementation of Virtual Bus
Date: Fri, 14 Feb 2020 16:34:55 -0400
Message-ID: <20200214203455.GX31668@ziepe.ca> (raw)
In-Reply-To: <20200214170240.GA4034785@kroah.com>

On Fri, Feb 14, 2020 at 09:02:40AM -0800, Greg KH wrote:
> > +/**
> > + * virtbus_dev_register - add a virtual bus device
> > + * @vdev: virtual bus device to add
> > + */
> > +int virtbus_dev_register(struct virtbus_device *vdev)
> > +{
> > +	int ret;
> > +
> > +	if (!vdev->release) {
> > +		dev_err(&vdev->dev, "virtbus_device .release callback NULL\n");
> 
> "virtbus_device MUST have a .release callback that does something!\n" 
> 
> > +		return -EINVAL;
> > +	}
> > +
> > +	device_initialize(&vdev->dev);
> > +
> > +	vdev->dev.bus = &virtual_bus_type;
> > +	vdev->dev.release = virtbus_dev_release;
> > +	/* All device IDs are automatically allocated */
> > +	ret = ida_simple_get(&virtbus_dev_ida, 0, 0, GFP_KERNEL);
> > +	if (ret < 0) {
> > +		dev_err(&vdev->dev, "get IDA idx for virtbus device failed!\n");
> > +		put_device(&vdev->dev);
> 
> If you allocate the number before device_initialize(), no need to call
> put_device().  Just a minor thing, no big deal.

If *_regster does put_device on error then it must always do
put_device on any error, for instance the above return -EINVAL with
no put_device leaks memory.

Generally I find the design and audit of drivers simpler if the
register doesn't do device_initialize or put_device - have them
distinct and require the caller to manage this.

For instance look at ice_init_peer_devices() and ask who frees
the alloc_ordered_workqueue() if virtbus_dev_register() fails..

It is not all easy to tell if this is right or not..

> > +	put_device(&vdev->dev);
> > +	ida_simple_remove(&virtbus_dev_ida, vdev->id);
> 
> You need to do this before put_device().

Shouldn't it be in the release function? The ida index should not be
re-used until the kref goes to zero..

> > +struct virtbus_device {
> > +	struct device dev;
> > +	const char *name;
> > +	void (*release)(struct virtbus_device *);
> > +	int id;
> > +	const struct virtbus_dev_id *matched_element;
> > +};
> 
> Any reason you need to make "struct virtbus_device" a public structure
> at all? 

The general point of this scheme is to do this in a public header:

+struct iidc_virtbus_object {
+	struct virtbus_device vdev;
+	struct iidc_peer_dev *peer_dev;
+};

And then this when the driver binds:

+int irdma_probe(struct virtbus_device *vdev)
+{
+       struct iidc_virtbus_object *vo =
+                       container_of(vdev, struct iidc_virtbus_object, vdev);
+       struct iidc_peer_dev *ldev = vo->peer_dev;

So the virtbus_device is in a public header to enable the container_of
construction.

Jason

  reply index

Thread overview: 52+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-12 19:13 [RFC PATCH v4 00/25] Intel Wired LAN/RDMA Driver Updates 2020-02-11 Jeff Kirsher
2020-02-12 19:14 ` [RFC PATCH v4 01/25] virtual-bus: Implementation of Virtual Bus Jeff Kirsher
2020-02-14 17:02   ` Greg KH
2020-02-14 20:34     ` Jason Gunthorpe [this message]
2020-02-14 20:43       ` Greg KH
2020-02-15  0:01         ` Jason Gunthorpe
2020-02-15  0:53           ` Greg KH
2020-02-14 20:45       ` Greg KH
2020-02-20 18:55         ` Ertman, David M
2020-02-20 19:27           ` Jason Gunthorpe
2020-02-14 21:22   ` Parav Pandit
2020-02-15  0:08   ` Jason Gunthorpe
2020-02-12 19:14 ` [RFC PATCH v4 02/25] ice: Create and register virtual bus for RDMA Jeff Kirsher
2020-02-14 20:39   ` Jason Gunthorpe
2020-02-20 18:48     ` Ertman, David M
2020-02-20 20:58       ` Jason Gunthorpe
2020-02-12 19:14 ` [RFC PATCH v4 03/25] ice: Complete RDMA peer registration Jeff Kirsher
2020-02-12 19:14 ` [RFC PATCH v4 04/25] ice: Support resource allocation requests Jeff Kirsher
2020-02-12 19:14 ` [RFC PATCH v4 05/25] ice: Enable event notifications Jeff Kirsher
2020-02-12 19:14 ` [RFC PATCH v4 06/25] ice: Allow reset operations Jeff Kirsher
2020-02-12 19:14 ` [RFC PATCH v4 07/25] ice: Pass through communications to VF Jeff Kirsher
2020-02-12 19:14 ` [RFC PATCH v4 08/25] i40e: Move client header location Jeff Kirsher
2020-02-12 19:14 ` [RFC PATCH v4 09/25] i40e: Register a virtbus device to provide RDMA Jeff Kirsher
2020-02-12 19:14 ` [RFC PATCH v4 10/25] RDMA/irdma: Add driver framework definitions Jeff Kirsher
2020-02-14 22:13   ` Parav Pandit
2020-02-18 20:42     ` Saleem, Shiraz
2020-02-20 22:24       ` Parav Pandit
2020-02-20 23:06         ` Jason Gunthorpe
2020-02-21 17:01         ` Saleem, Shiraz
2020-02-21 17:23           ` Parav Pandit
2020-02-21 18:04             ` Jason Gunthorpe
2020-02-12 19:14 ` [RFC PATCH v4 11/25] RDMA/irdma: Implement device initialization definitions Jeff Kirsher
2020-02-12 19:14 ` [RFC PATCH v4 12/25] RDMA/irdma: Implement HW Admin Queue OPs Jeff Kirsher
2020-02-12 19:14 ` [RFC PATCH v4 13/25] RDMA/irdma: Add HMC backing store setup functions Jeff Kirsher
2020-02-12 19:14 ` [RFC PATCH v4 14/25] RDMA/irdma: Add privileged UDA queue implementation Jeff Kirsher
2020-02-12 19:14 ` [RFC PATCH v4 15/25] RDMA/irdma: Add QoS definitions Jeff Kirsher
2020-02-12 19:14 ` [RFC PATCH v4 16/25] RDMA/irdma: Add connection manager Jeff Kirsher
2020-02-12 19:14 ` [RFC PATCH v4 17/25] RDMA/irdma: Add PBLE resource manager Jeff Kirsher
2020-02-12 19:14 ` [RFC PATCH v4 18/25] RDMA/irdma: Implement device supported verb APIs Jeff Kirsher
2020-02-14 14:54   ` Jason Gunthorpe
2020-02-14 15:49     ` Andrew Boyer
2020-02-14 16:45       ` Jason Gunthorpe
2020-02-18 20:43     ` Saleem, Shiraz
2020-02-12 19:14 ` [RFC PATCH v4 19/25] RDMA/irdma: Add RoCEv2 UD OP support Jeff Kirsher
2020-02-12 19:14 ` [RFC PATCH v4 20/25] RDMA/irdma: Add user/kernel shared libraries Jeff Kirsher
2020-02-12 19:14 ` [RFC PATCH v4 21/25] RDMA/irdma: Add miscellaneous utility definitions Jeff Kirsher
2020-02-12 19:14 ` [RFC PATCH v4 22/25] RDMA/irdma: Add dynamic tracing for CM Jeff Kirsher
2020-02-14 14:53   ` Jason Gunthorpe
2020-02-18 20:43     ` Saleem, Shiraz
2020-02-12 19:14 ` [RFC PATCH v4 23/25] RDMA/irdma: Add ABI definitions Jeff Kirsher
2020-02-12 19:14 ` [RFC PATCH v4 24/25] RDMA: Add irdma Kconfig/Makefile and remove i40iw Jeff Kirsher
2020-02-12 19:14 ` [RFC PATCH v4 25/25] RDMA/irdma: Update MAINTAINERS file Jeff Kirsher

Reply instructions:

You may reply publically 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=20200214203455.GX31668@ziepe.ca \
    --to=jgg@ziepe.ca \
    --cc=aditr@vmware.com \
    --cc=andrewx.bowers@intel.com \
    --cc=benve@cisco.com \
    --cc=bharat@chelsio.com \
    --cc=davem@davemloft.net \
    --cc=david.m.ertman@intel.com \
    --cc=galpress@amazon.com \
    --cc=gregkh@linuxfoundation.org \
    --cc=jeffrey.t.kirsher@intel.com \
    --cc=kiran.patil@intel.com \
    --cc=leonro@mellanox.com \
    --cc=linux-rdma@vger.kernel.org \
    --cc=mkalderon@marvell.com \
    --cc=netdev@vger.kernel.org \
    --cc=nhorman@redhat.com \
    --cc=parav@mellanox.com \
    --cc=sassmann@redhat.com \
    --cc=selvin.xavier@broadcom.com \
    --cc=sriharsha.basavapatna@broadcom.com \
    --cc=xavier.huwei@huawei.com \
    --cc=yishaih@mellanox.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

Linux-RDMA Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-rdma/0 linux-rdma/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-rdma linux-rdma/ https://lore.kernel.org/linux-rdma \
		linux-rdma@vger.kernel.org
	public-inbox-index linux-rdma

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-rdma


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git