From: Hongbo Li <lihongbo22@huawei.com>
To: "Ricardo B. Marliere" <ricardo@marliere.net>,
Kent Overstreet <kent.overstreet@linux.dev>,
Brian Foster <bfoster@redhat.com>
Cc: <linux-bcachefs@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Subject: Re: [PATCH v2] bcachefs: chardev: make bch_chardev_class constant
Date: Fri, 12 Apr 2024 10:31:17 +0800 [thread overview]
Message-ID: <fa1e422c-17bd-4dff-abbd-660e15d87256@huawei.com> (raw)
In-Reply-To: <4ddd2362-2383-434a-b4b0-2075072572d6@huawei.com>
On 2024/3/11 9:41, Hongbo Li wrote:
> It's fine for me.
>
> On 2024/3/8 20:12, Ricardo B. Marliere wrote:
>> Since commit 43a7206b0963 ("driver core: class: make class_register()
>> take
>> a const *"), the driver core allows for struct class to be in read-only
>> memory, so move the bch_chardev_class structure to be declared at build
>> time placing it into read-only memory, instead of having to be
>> dynamically
>> allocated at boot time. Also, correctly clean up after failing paths in
>> bch2_chardev_init().
>>
>> Cc: Hongbo Li <lihongbo22@huawei.com>
>> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
>> Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
>> Signed-off-by: Ricardo B. Marliere <ricardo@marliere.net>
>> ---
>> Changes in v2:
>> - Used "free the last thing" pattern in bch2_chardev_init().
>> - Link to v1:
>> https://lore.kernel.org/r/20240305-bcachefs-v1-1-436196e25729@marliere.net
>> ---
>> fs/bcachefs/chardev.c | 35 ++++++++++++++++++++++-------------
>> 1 file changed, 22 insertions(+), 13 deletions(-)
>>
>> diff --git a/fs/bcachefs/chardev.c b/fs/bcachefs/chardev.c
>> index 226b39c17667..dc09f547dae6 100644
>> --- a/fs/bcachefs/chardev.c
>> +++ b/fs/bcachefs/chardev.c
>> @@ -940,7 +940,9 @@ static const struct file_operations
>> bch_chardev_fops = {
>> };
>> static int bch_chardev_major;
>> -static struct class *bch_chardev_class;
>> +static const struct class bch_chardev_class = {
>> + .name = "bcachefs",
>> +};
>> static struct device *bch_chardev;
>> void bch2_fs_chardev_exit(struct bch_fs *c)
>> @@ -957,7 +959,7 @@ int bch2_fs_chardev_init(struct bch_fs *c)
>> if (c->minor < 0)
>> return c->minor;
>> - c->chardev = device_create(bch_chardev_class, NULL,
>> + c->chardev = device_create(&bch_chardev_class, NULL,
>> MKDEV(bch_chardev_major, c->minor), c,
>> "bcachefs%u-ctl", c->minor);
>> if (IS_ERR(c->chardev))
>> @@ -968,32 +970,39 @@ int bch2_fs_chardev_init(struct bch_fs *c)
>> void bch2_chardev_exit(void)
>> {
>> - if (!IS_ERR_OR_NULL(bch_chardev_class))
>> - device_destroy(bch_chardev_class,
>> - MKDEV(bch_chardev_major, U8_MAX));
>> - if (!IS_ERR_OR_NULL(bch_chardev_class))
>> - class_destroy(bch_chardev_class);
>> + device_destroy(&bch_chardev_class, MKDEV(bch_chardev_major,
>> U8_MAX));
>> + class_unregister(&bch_chardev_class);
>> if (bch_chardev_major > 0)
>> unregister_chrdev(bch_chardev_major, "bcachefs");
>> }
>> int __init bch2_chardev_init(void)
>> {
>> + int ret;
>> +
>> bch_chardev_major = register_chrdev(0, "bcachefs-ctl",
>> &bch_chardev_fops);
>> if (bch_chardev_major < 0)
>> return bch_chardev_major;
>> - bch_chardev_class = class_create("bcachefs");
>> - if (IS_ERR(bch_chardev_class))
>> - return PTR_ERR(bch_chardev_class);
>> + ret = class_register(&bch_chardev_class);
>> + if (ret)
>> + goto major_out;
>> - bch_chardev = device_create(bch_chardev_class, NULL,
>> + bch_chardev = device_create(&bch_chardev_class, NULL,
>> MKDEV(bch_chardev_major, U8_MAX),
>> NULL, "bcachefs-ctl");
>> - if (IS_ERR(bch_chardev))
>> - return PTR_ERR(bch_chardev);
>> + if (IS_ERR(bch_chardev)) {
>> + ret = PTR_ERR(bch_chardev);
>> + goto class_out;
>> + }
>> return 0;
>> +
>> +class_out:
>> + class_unregister(&bch_chardev_class);
>> +major_out:
>> + unregister_chrdev(bch_chardev_major, "bcachefs-ctl");
>> + return ret;
>> }
>> #endif /* NO_BCACHEFS_CHARDEV */
>>
>> ---
>> base-commit: 90d35da658da8cff0d4ecbb5113f5fac9d00eb72
>> change-id: 20240305-bcachefs-27a4bb8b9f4f
>>
>> Best regards,
>
This is a useful patch, and also works on latest code. Maybe we almost
forgot it.
Reviewed-by: Hongbo Li <lihongbo22@huawei.com>
next prev parent reply other threads:[~2024-04-12 2:31 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-08 12:12 [PATCH v2] bcachefs: chardev: make bch_chardev_class constant Ricardo B. Marliere
2024-03-11 1:41 ` Hongbo Li
2024-04-12 2:31 ` Hongbo Li [this message]
2024-04-12 2:44 ` Kent Overstreet
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