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From: Arnd Bergmann <arnd@arndb.de>
To: Russell King - ARM Linux <linux@arm.linux.org.uk>
Cc: Felipe Balbi <balbi@kernel.org>,
	linux-arm-kernel@lists.infradead.org,
	Grygorii Strashko <grygorii.strashko@ti.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>,
	linux-usb@vger.kernel.org, Sekhar Nori <nsekhar@ti.com>,
	linux-kernel@vger.kernel.org,
	David Fisher <david.fisher1@synopsys.com>,
	"Thang Q. Nguyen" <tqnguyen@apm.com>,
	Alan Stern <stern@rowland.harvard.edu>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Subject: Re: [PATCH] usb: dwc3: host: inherit dma configuration from parent dev
Date: Thu, 28 Apr 2016 16:23:56 +0200	[thread overview]
Message-ID: <2806018.GHhm6tEuKR@wuerfel> (raw)
In-Reply-To: <20160428141611.GK19428@n2100.arm.linux.org.uk>

On Thursday 28 April 2016 15:16:12 Russell King - ARM Linux wrote:
> On Thu, Apr 28, 2016 at 09:37:08AM +0300, Felipe Balbi wrote:
> > 
> > Hi,
> > 
> > Arnd Bergmann <arnd@arndb.de> writes:
> > >    pointer and pass that in platform_data. This is really easy, it's
> > 
> > Sorry but passing a struct device pointer in platform_data is
> > ridiculous. Not to mention that, as I said before, we can't assume which
> > device to pass to xhci_plat in the first place. It might be dwc->dev and
> > it might be dwc->dev->parent.
> 
> +1.  Passing an unref-counted struct device through platform data is
> totally mad, Arnd you're off your rocker if you think that's a good
> idea.  What's more is that there's no way to properly refcount the
> thing.

It's the parent device (or NULL), there is no way it can ever go away as
it's already refcounted through the device subsystem by the creation
of the child device.

I do realize that it's a hack, but the idea is to get rid of that
as soon as possibly by fixing the way the xhci device is probe so
we no longer need to fake a platform_device as the child here and
can just use the device itself.

	Arnd

WARNING: multiple messages have this Message-ID (diff)
From: arnd@arndb.de (Arnd Bergmann)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] usb: dwc3: host: inherit dma configuration from parent dev
Date: Thu, 28 Apr 2016 16:23:56 +0200	[thread overview]
Message-ID: <2806018.GHhm6tEuKR@wuerfel> (raw)
In-Reply-To: <20160428141611.GK19428@n2100.arm.linux.org.uk>

On Thursday 28 April 2016 15:16:12 Russell King - ARM Linux wrote:
> On Thu, Apr 28, 2016 at 09:37:08AM +0300, Felipe Balbi wrote:
> > 
> > Hi,
> > 
> > Arnd Bergmann <arnd@arndb.de> writes:
> > >    pointer and pass that in platform_data. This is really easy, it's
> > 
> > Sorry but passing a struct device pointer in platform_data is
> > ridiculous. Not to mention that, as I said before, we can't assume which
> > device to pass to xhci_plat in the first place. It might be dwc->dev and
> > it might be dwc->dev->parent.
> 
> +1.  Passing an unref-counted struct device through platform data is
> totally mad, Arnd you're off your rocker if you think that's a good
> idea.  What's more is that there's no way to properly refcount the
> thing.

It's the parent device (or NULL), there is no way it can ever go away as
it's already refcounted through the device subsystem by the creation
of the child device.

I do realize that it's a hack, but the idea is to get rid of that
as soon as possibly by fixing the way the xhci device is probe so
we no longer need to fake a platform_device as the child here and
can just use the device itself.

	Arnd

  reply	other threads:[~2016-04-28 14:24 UTC|newest]

Thread overview: 182+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-04-25 19:21 [PATCH] usb: dwc3: host: inherit dma configuration from parent dev Grygorii Strashko
2016-04-25 19:21 ` Grygorii Strashko
2016-04-26  6:17 ` Felipe Balbi
2016-04-26  6:17   ` Felipe Balbi
2016-04-26  8:14   ` Grygorii Strashko
2016-04-26  8:14     ` Grygorii Strashko
2016-04-27  5:41     ` Felipe Balbi
2016-04-27  5:41       ` Felipe Balbi
2016-04-27 11:55       ` Grygorii Strashko
2016-04-27 11:55         ` Grygorii Strashko
2016-04-27 13:59       ` Catalin Marinas
2016-04-27 13:59         ` Catalin Marinas
2016-04-27 14:11         ` Arnd Bergmann
2016-04-27 14:11           ` Arnd Bergmann
2016-04-27 15:50           ` Catalin Marinas
2016-04-27 15:50             ` Catalin Marinas
2016-04-27 16:04             ` Arnd Bergmann
2016-04-27 16:04               ` Arnd Bergmann
2016-04-27 16:53               ` Felipe Balbi
2016-04-27 16:53                 ` Felipe Balbi
2016-04-27 17:42                 ` Arnd Bergmann
2016-04-27 17:42                   ` Arnd Bergmann
2016-04-27 17:59                   ` Alan Stern
2016-04-27 17:59                     ` Alan Stern
2016-04-27 18:08                     ` Arnd Bergmann
2016-04-27 18:08                       ` Arnd Bergmann
2016-04-27 20:05                       ` Felipe Balbi
2016-04-27 20:05                         ` Felipe Balbi
2016-04-27 21:05                         ` Arnd Bergmann
2016-04-27 21:05                           ` Arnd Bergmann
2016-04-28  6:37                           ` Felipe Balbi
2016-04-28  6:37                             ` Felipe Balbi
2016-04-28 14:16                             ` Russell King - ARM Linux
2016-04-28 14:16                               ` Russell King - ARM Linux
2016-04-28 14:23                               ` Arnd Bergmann [this message]
2016-04-28 14:23                                 ` Arnd Bergmann
2016-04-28 14:27                                 ` Felipe Balbi
2016-04-28 14:27                                   ` Felipe Balbi
2016-09-01 22:14                                   ` Leo Li
2016-09-01 22:14                                     ` Leo Li
2016-09-02 10:43                                     ` Arnd Bergmann
2016-09-02 10:43                                       ` Arnd Bergmann
2016-09-02 10:47                                       ` Russell King - ARM Linux
2016-09-02 10:47                                         ` Russell King - ARM Linux
2016-09-02 11:08                                         ` Felipe Balbi
2016-09-02 11:08                                           ` Felipe Balbi
2016-09-02 14:11                                           ` Felipe Balbi
2016-09-02 14:11                                             ` Felipe Balbi
2016-09-02 14:21                                           ` Alan Stern
2016-09-02 14:21                                             ` Alan Stern
2016-09-02 15:51                                             ` Arnd Bergmann
2016-09-02 15:51                                               ` Arnd Bergmann
2016-09-07  7:17                                               ` Roger Quadros
2016-09-07  7:17                                                 ` Roger Quadros
2016-09-07  8:29                                                 ` Arnd Bergmann
2016-09-07  8:29                                                   ` Arnd Bergmann
2016-09-07 13:04                                                   ` Roger Quadros
2016-09-07 13:04                                                     ` Roger Quadros
2016-09-07 14:38                                                     ` Arnd Bergmann
2016-09-07 14:38                                                       ` Arnd Bergmann
2016-09-02 16:23                                           ` Grygorii Strashko
2016-09-02 16:23                                             ` Grygorii Strashko
2016-09-02 10:53                                       ` Felipe Balbi
2016-09-02 10:53                                         ` Felipe Balbi
2016-09-02 11:55                                         ` Robin Murphy
2016-09-02 11:55                                           ` Robin Murphy
2016-09-02 12:56                                           ` Felipe Balbi
2016-09-02 12:56                                             ` Felipe Balbi
2016-09-02 13:10                                           ` Arnd Bergmann
2016-09-02 13:10                                             ` Arnd Bergmann
2016-09-02 22:16                                       ` Leo Li
2016-09-02 22:16                                         ` Leo Li
2016-09-05 15:39                                         ` Arnd Bergmann
2016-09-05 15:39                                           ` Arnd Bergmann
2016-09-06  6:35                                           ` Peter Chen
2016-09-06  6:35                                             ` Peter Chen
2016-09-06  6:40                                             ` Felipe Balbi
2016-09-06  6:40                                               ` Felipe Balbi
2016-09-06 10:46                                               ` Arnd Bergmann
2016-09-06 10:46                                                 ` Arnd Bergmann
2016-09-06 10:50                                                 ` Felipe Balbi
2016-09-06 10:50                                                   ` Felipe Balbi
2016-09-06 13:27                                                   ` Arnd Bergmann
2016-09-06 13:27                                                     ` Arnd Bergmann
2016-09-07  6:51                                                     ` Felipe Balbi
2016-09-07  6:51                                                       ` Felipe Balbi
2016-09-07  7:44                                                     ` Peter Chen
2016-09-07  7:44                                                       ` Peter Chen
2016-09-07  8:52                                                       ` Arnd Bergmann
2016-09-07  8:52                                                         ` Arnd Bergmann
2016-09-07  9:29                                                         ` Peter Chen
2016-09-07  9:29                                                           ` Peter Chen
2016-09-07  9:35                                                           ` Russell King - ARM Linux
2016-09-07  9:35                                                             ` Russell King - ARM Linux
2016-09-07 10:18                                                             ` Felipe Balbi
2016-09-07 10:18                                                               ` Felipe Balbi
2016-09-06 10:38                                             ` Arnd Bergmann
2016-09-06 10:38                                               ` Arnd Bergmann
2016-09-07  6:33                                               ` Peter Chen
2016-09-07  6:33                                                 ` Peter Chen
2016-09-07  8:48                                                 ` Arnd Bergmann
2016-09-07  8:48                                                   ` Arnd Bergmann
2016-09-07  9:55                                                   ` Peter Chen
2016-09-07  9:55                                                     ` Peter Chen
2016-09-07 10:33                                                     ` Robin Murphy
2016-09-07 10:33                                                       ` Robin Murphy
2016-09-07 10:47                                                       ` Felipe Balbi
2016-09-07 10:47                                                         ` Felipe Balbi
2016-09-14 16:31                                                         ` Lorenzo Pieralisi
2016-09-14 16:31                                                           ` Lorenzo Pieralisi
2016-09-14 21:50                                                           ` Arnd Bergmann
2016-09-14 21:50                                                             ` Arnd Bergmann
2016-09-07 10:24                                                   ` Felipe Balbi
2016-09-07 10:24                                                     ` Felipe Balbi
2016-09-07 15:24                                                     ` Arnd Bergmann
2016-09-07 15:24                                                       ` Arnd Bergmann
2016-09-07 16:08                                                       ` Alan Stern
2016-09-07 16:08                                                         ` Alan Stern
2016-09-07 19:45                                                         ` Arnd Bergmann
2016-09-07 19:45                                                           ` Arnd Bergmann
2016-09-08  1:15                                                       ` Peter Chen
2016-09-08  1:15                                                         ` Peter Chen
2016-09-08  8:02                                                         ` Arnd Bergmann
2016-09-08  8:02                                                           ` Arnd Bergmann
2016-09-08  8:03                                                       ` Felipe Balbi
2016-09-08  8:03                                                         ` Felipe Balbi
2016-09-08  8:26                                                         ` Arnd Bergmann
2016-09-08  8:26                                                           ` Arnd Bergmann
2016-09-08  8:29                                                           ` Felipe Balbi
2016-09-08  8:29                                                             ` Felipe Balbi
2016-09-08  8:45                                                             ` Arnd Bergmann
2016-09-08  8:45                                                               ` Arnd Bergmann
2016-09-08  9:43                                                               ` Felipe Balbi
2016-09-08  9:43                                                                 ` Felipe Balbi
2016-09-08 10:17                                                                 ` Arnd Bergmann
2016-09-08 10:17                                                                   ` Arnd Bergmann
2016-09-08 11:00                                                                   ` Felipe Balbi
2016-09-08 11:00                                                                     ` Felipe Balbi
2016-09-08 11:11                                                                     ` Arnd Bergmann
2016-09-08 11:11                                                                       ` Arnd Bergmann
2016-09-08 11:20                                                                       ` Felipe Balbi
2016-09-08 11:20                                                                         ` Felipe Balbi
2016-09-08 11:39                                                                         ` Arnd Bergmann
2016-09-08 11:39                                                                           ` Arnd Bergmann
2016-09-08 11:52                                                                           ` Felipe Balbi
2016-09-08 11:52                                                                             ` Felipe Balbi
2016-09-08 12:46                                                                             ` Arnd Bergmann
2016-09-08 12:46                                                                               ` Arnd Bergmann
2016-09-08 12:02                                                                     ` Grygorii Strashko
2016-09-08 12:02                                                                       ` Grygorii Strashko
2016-09-08 12:14                                                                       ` Arnd Bergmann
2016-09-08 12:14                                                                         ` Arnd Bergmann
2016-09-08 12:28                                                                   ` Peter Chen
2016-09-08 12:28                                                                     ` Peter Chen
2016-09-08 12:52                                                                     ` Arnd Bergmann
2016-09-08 12:52                                                                       ` Arnd Bergmann
2016-09-09  1:37                                                                       ` Peter Chen
2016-09-09  1:37                                                                         ` Peter Chen
2016-09-08 12:59                                                                     ` Grygorii Strashko
2016-09-08 12:59                                                                       ` Grygorii Strashko
2016-09-09  1:52                                                                       ` Peter Chen
2016-09-09  1:52                                                                         ` Peter Chen
2016-09-21 11:06                                                       ` Sriram Dash
2016-09-21 11:06                                                         ` Sriram Dash
2016-09-21 11:31                                                         ` Arnd Bergmann
2016-09-21 11:31                                                           ` Arnd Bergmann
2016-09-21 11:43                                                           ` Sriram Dash
2016-09-21 11:43                                                             ` Sriram Dash
2016-09-21 12:48                                                             ` Arnd Bergmann
2016-09-21 12:48                                                               ` Arnd Bergmann
2016-09-22  5:02                                                               ` Sriram Dash
2016-09-22  5:02                                                                 ` Sriram Dash
2016-10-07 22:46                                                                 ` Leo Li
2016-10-07 22:46                                                                   ` Leo Li
2016-09-21 17:14                                                             ` [PATCH] usb: xhci: Fix the patch inherit dma configuration from kbuild test robot
2016-09-21 17:14                                                               ` kbuild test robot
2016-04-27 20:57                   ` [PATCH] usb: dwc3: host: inherit dma configuration from parent dev Felipe Balbi
2016-04-27 20:57                     ` Felipe Balbi
2016-04-27 14:14         ` Grygorii Strashko
2016-04-27 14:14           ` Grygorii Strashko
2016-05-05 17:07 ` Brian Norris
2016-05-05 17:07   ` Brian Norris

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