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From: "tj@kernel.org" <tj@kernel.org>
To: Bart Van Assche <Bart.VanAssche@wdc.com>
Cc: "mingo@kernel.org" <mingo@kernel.org>,
	"jthumshirn@suse.de" <jthumshirn@suse.de>,
	"oleg@redhat.com" <oleg@redhat.com>,
	"martin.petersen@oracle.com" <martin.petersen@oracle.com>,
	"stable@vger.kernel.org" <stable@vger.kernel.org>,
	"ebiederm@xmission.com" <ebiederm@xmission.com>,
	"linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>,
	"hare@suse.com" <hare@suse.com>,
	"jejb@linux.vnet.ibm.com" <jejb@linux.vnet.ibm.com>
Subject: Re: [PATCH, RESEND] Avoid that SCSI device removal through sysfs triggers a deadlock
Date: Mon, 30 Jul 2018 07:13:45 -0700	[thread overview]
Message-ID: <20180730141345.GC1206094@devbig004.ftw2.facebook.com> (raw)
In-Reply-To: <c73204ebe4ebfbbaa652a4fda910d25c9d055ce4.camel@wdc.com>

Hello, Bart.

On Thu, Jul 26, 2018 at 09:57:40PM +0000, Bart Van Assche wrote:
...
> @@ -440,11 +445,21 @@ bool sysfs_remove_file_self(struct kobject *kobj, const struct attribute *attr)
>  		return false;
>  
>  	ret = kernfs_remove_self(kn);
> +	if (ret && cb) {
> +		kernfs_break_active_protection(kn);
> +		cb(kobj, attr, data);
> +		kernfs_break_active_protection(kn);

unbreak?

Also, wouldn't it be better to just expose sysfs_break/unbreak and
then do sth like the following from scsi?

        kobject_get();
	sysfs_break_active_protection();
	do normal sysfs removal;
	sysfs_unbreak..();
	kobject_put();

Thanks.

-- 
tejun

  reply	other threads:[~2018-07-30 15:48 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-07-25 17:38 [PATCH, RESEND] Avoid that SCSI device removal through sysfs triggers a deadlock Bart Van Assche
2018-07-26  1:47 ` Martin K. Petersen
2018-07-26 11:46 ` Johannes Thumshirn
2018-07-26 12:50 ` Jack Wang
2018-07-26 13:35 ` Tejun Heo
2018-07-26 14:09   ` Bart Van Assche
2018-07-26 14:14     ` tj
2018-07-26 21:57       ` Bart Van Assche
2018-07-30 14:13         ` tj [this message]
2018-07-30 17:28           ` Bart Van Assche
2018-07-30 17:31             ` tj
2018-07-30 17:50               ` Bart Van Assche
2018-07-30 17:57                 ` tj
2018-07-29  4:03   ` Bart Van Assche
2018-07-30 14:17     ` tj

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