From: Maximilian Luz <luzmaximilian@gmail.com>
To: Hans de Goede <hdegoede@redhat.com>
Cc: Mark Gross <mgross@linux.intel.com>,
Jonathan Corbet <corbet@lwn.net>,
platform-driver-x86@vger.kernel.org, linux-doc@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 4/7] platform/surface: aggregator_cdev: Add support for forwarding events to user-space
Date: Fri, 4 Jun 2021 14:47:15 +0200 [thread overview]
Message-ID: <778047e2-2b1d-ef8b-4fe3-aafba8fa2dba@gmail.com> (raw)
In-Reply-To: <a1a43f55-378f-d5e7-c439-d5397abdf838@redhat.com>
On 6/4/21 1:32 PM, Hans de Goede wrote:
> Hi,
>
> I've one review remark inline below.
>
> On 6/4/21 1:45 AM, Maximilian Luz wrote:
[...]
>> +static int ssam_cdev_device_open(struct inode *inode, struct file *filp)
>> +{
>> + struct miscdevice *mdev = filp->private_data;
>> + struct ssam_cdev_client *client;
>> + struct ssam_cdev *cdev = container_of(mdev, struct ssam_cdev, mdev);
>> +
>> + /* Initialize client */
>> + client = vzalloc(sizeof(*client));
>> + if (!client)
>> + return -ENOMEM;
>> +
>> + client->cdev = ssam_cdev_get(cdev);
>> +
>> + INIT_LIST_HEAD(&client->node);
>> +
>> + mutex_init(&client->notifier_lock);
>> +
>> + mutex_init(&client->read_lock);
>> + mutex_init(&client->write_lock);
>> + INIT_KFIFO(client->buffer);
>> + init_waitqueue_head(&client->waitq);
>> +
>> + filp->private_data = client;
>> +
>> + /* Attach client. */
>> + down_write(&cdev->client_lock);
>> +
>> + if (test_bit(SSAM_CDEV_DEVICE_SHUTDOWN_BIT, &cdev->flags)) {
>> + up_write(&cdev->client_lock);
>> + ssam_cdev_put(client->cdev);
>
> You are missing the mutex_destroy() calls here which you are
> doing in ssam_cdev_device_release().
Thank you for noticing this! This code is based on Surface DTX code
which has the same problem, I'll send in a fix for that shortly.
> Or maybe move the mutex_init calls below this check
> (before the up_write()) since I don't think the client can
> be accessed by any code until the up_write is done?
Yes, that would also be possible, but I'd prefer adding the
mutex_destroy() calls in the failure path. To me that seems a bit easier
to reason about.
Thanks,
Max
next prev parent reply other threads:[~2021-06-04 12:48 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-03 23:45 [PATCH 0/7] platform/surface: aggregator: Extend user-space interface for events Maximilian Luz
2021-06-03 23:45 ` [PATCH 1/7] platform/surface: aggregator: Allow registering notifiers without enabling events Maximilian Luz
2021-06-03 23:45 ` [PATCH 2/7] platform/surface: aggregator: Allow enabling of events without notifiers Maximilian Luz
2021-06-04 5:55 ` kernel test robot
2021-06-03 23:45 ` [PATCH 3/7] platform/surface: aggregator: Update copyright Maximilian Luz
2021-06-03 23:45 ` [PATCH 4/7] platform/surface: aggregator_cdev: Add support for forwarding events to user-space Maximilian Luz
2021-06-04 11:32 ` Hans de Goede
2021-06-04 12:47 ` Maximilian Luz [this message]
2021-06-03 23:45 ` [PATCH 5/7] platform/surface: aggregator_cdev: Allow enabling of events from user-space Maximilian Luz
2021-06-03 23:45 ` [PATCH 6/7] platform/surface: aggregator_cdev: Add lockdep support Maximilian Luz
2021-06-03 23:45 ` [PATCH 7/7] docs: driver-api: Update Surface Aggregator user-space interface documentation Maximilian Luz
2021-06-04 11:40 ` [PATCH 0/7] platform/surface: aggregator: Extend user-space interface for events Hans de Goede
2021-06-04 12:58 ` Maximilian Luz
Reply instructions:
You may reply publicly 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=778047e2-2b1d-ef8b-4fe3-aafba8fa2dba@gmail.com \
--to=luzmaximilian@gmail.com \
--cc=corbet@lwn.net \
--cc=hdegoede@redhat.com \
--cc=linux-doc@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mgross@linux.intel.com \
--cc=platform-driver-x86@vger.kernel.org \
/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
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).