[PATCH RFC 0/2] driver core: Add ability to delete device links of unregistered devices

From: Adrian Hunter <adrian.hunter@intel.com>
To: "Rafael J . Wysocki" <rafael@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Saravana Kannan <saravanak@google.com>,
	"Martin K . Petersen" <martin.petersen@oracle.com>,
	"James E . J . Bottomley" <jejb@linux.ibm.com>,
	linux-scsi@vger.kernel.org, Avri Altman <avri.altman@wdc.com>,
	Bean Huo <huobean@gmail.com>, Can Guo <cang@codeaurora.org>,
	Asutosh Das <asutoshd@codeaurora.org>,
	Bart Van Assche <bvanassche@acm.org>,
	linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH RFC 0/2] driver core: Add ability to delete device links of unregistered devices
Date: Wed,  7 Jul 2021 20:29:46 +0300	[thread overview]
Message-ID: <20210707172948.1025-1-adrian.hunter@intel.com> (raw)

Hi

There is an issue with the SCSI UFS driver when the optional
BOOT well-known LUN fails to probe, which is not a fatal error.
The issue is that the device and its "managed" device link do not
then get deleted.  The device because the device link has a
reference to it.  The device link because it can only be deleted
by device_del(), but device_add() was never called, so device_del()
never will be either.

It is not clear if there is a way to get rid of the device link in
this case, so here is a patch to add a function that does just that.

There is also a patch to use the new function to fix the issue with
the SCSI UFS driver.

Adrian Hunter (2):
      driver core: Add ability to delete device links of unregistered devices
      scsi: ufshcd: Fix device links when BOOT WLUN fails to probe

 Documentation/driver-api/device_link.rst |  7 +++++--
 drivers/base/core.c                      | 22 +++++++++++++++++++---
 drivers/scsi/ufs/ufshcd.c                |  7 +++++++
 include/linux/device.h                   |  1 +
 4 files changed, 32 insertions(+), 5 deletions(-)

Regards
Adrian