From: "Krzysztof Wilczyński" <kw@linux.com>
To: Rajat Jain <rajatja@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"Rafael J. Wysocki" <rafael@kernel.org>,
Bjorn Helgaas <bhelgaas@google.com>,
Alan Stern <stern@rowland.harvard.edu>,
linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org,
linux-usb@vger.kernel.org, helgaas@kernel.org,
rajatxjain@gmail.com, jsbarnes@google.com, dtor@google.com
Subject: Re: [PATCH v2 1/2] driver core: Move the "removable" attribute from USB to core
Date: Wed, 12 May 2021 03:00:49 +0200 [thread overview]
Message-ID: <20210512010049.GA89346@rocinante.localdomain> (raw)
In-Reply-To: <20210424021631.1972022-1-rajatja@google.com>
Hi Rajat,
I have few questions below, but to add in advance, I might be confusing
the role that "type->supports_removable" and "dev->removable" plays
here, and if so then I apologise.
[...]
> @@ -2504,8 +2523,16 @@ static int device_add_attrs(struct device *dev)
> goto err_remove_dev_online;
> }
>
> + if (type && type->supports_removable) {
> + error = device_create_file(dev, &dev_attr_removable);
> + if (error)
> + goto err_remove_dev_waiting_for_supplier;
> + }
> +
> return 0;
Would a check for "dev->removable == DEVICE_REMOVABLE" here be more
appropriate?
Unless you wanted to add sysfs objects when the device hints that it has
a notion of being removable even though it might be set to "unknown" or
"fixed" (if that state is at all possible then), and in which case using
the dev_is_removable() helper would also not be an option since it does
a more complex check internally.
Technically, you could always add this sysfs object (similarly to what
USB core did) as it would then show the correct state depending on
"dev->removable".
Also, I suppose, it's not possible for a device to have
"supports_removable" set to true, but "removable" would be different
than "DEVICE_REMOVABLE", correct?
[...]
> +enum device_removable {
> + DEVICE_REMOVABLE_UNKNOWN = 0,
> + DEVICE_REMOVABLE,
> + DEVICE_FIXED,
> +};
I know this was moved from the USB core, but I personally find it
a little bit awkward to read, would something like that be acceptable?
enum device_removable {
DEVICE_STATE_UNKNOWN = 0,
DEVICE_STATE_REMOVABLE,
DEVICE_STATE_FIXED,
};
The addition of state to the name follows the removable_show() function
where the local variable is called "state", and I think it makes sense
to call this as such. What do you think?
> +static inline bool dev_is_removable(struct device *dev)
> +{
> + return dev && dev->type && dev->type->supports_removable
> + && dev->removable == DEVICE_REMOVABLE;
> +}
Similarly to my question about - would a simple check to see if
"dev->removable" is set to "DEVICE_REMOVABLE" here be enough?
Krzysztof
next prev parent reply other threads:[~2021-05-12 1:00 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-24 2:16 [PATCH v2 1/2] driver core: Move the "removable" attribute from USB to core Rajat Jain
2021-04-24 2:16 ` [PATCH v2 2/2] pci: Support "removable" attribute for PCI devices Rajat Jain
2021-04-26 9:17 ` Oliver Neukum
2021-04-26 11:49 ` Rafael J. Wysocki
2021-04-26 13:01 ` David Laight
2021-04-26 19:47 ` Rajat Jain
2021-04-27 11:59 ` Oliver Neukum
2021-04-27 12:59 ` David Laight
2021-04-28 6:56 ` Oliver Neukum
2021-04-28 12:21 ` Rafael J. Wysocki
2021-04-29 9:03 ` Oliver Neukum
2021-04-29 9:57 ` Rafael J. Wysocki
2021-04-29 16:59 ` Rajat Jain
2021-05-11 21:30 ` Bjorn Helgaas
2021-05-11 22:15 ` Rajat Jain
2021-05-11 23:02 ` Bjorn Helgaas
2021-05-12 0:02 ` Rajat Jain
2021-05-12 22:28 ` Rajat Jain
2021-04-25 14:58 ` [PATCH v2 1/2] driver core: Move the "removable" attribute from USB to core Alan Stern
2021-05-11 19:22 ` Bjorn Helgaas
2021-05-11 21:36 ` Rajat Jain
2021-05-12 1:00 ` Krzysztof Wilczyński [this message]
2021-05-12 1:20 ` Rajat Jain
2021-05-12 22:27 ` Rajat Jain
2021-05-12 23:32 ` Krzysztof Wilczyński
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