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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 V3 2/3] driver core: Add ability to delete device links of unregistered devices
Date: Sat, 10 Jul 2021 13:38:18 +0300	[thread overview]
Message-ID: <20210710103819.12532-3-adrian.hunter@intel.com> (raw)
In-Reply-To: <20210710103819.12532-1-adrian.hunter@intel.com>

Managed device links are deleted by device_del(). However it is possible to
add a device link to a consumer before device_add(), and then discover an
error prevents the device from being used. In that case normally references
to the device would be dropped and the device would be deleted. However the
device link holds a reference to the device, so the device link and device
remain indefinitely (unless the supplier is deleted).

Amend device link removal to accept removal of a link with an
unregistered consumer device.

Suggested-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Fixes: b294ff3e34490 ("scsi: ufs: core: Enable power management for wlun")
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
 drivers/base/core.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/base/core.c b/drivers/base/core.c
index 2de8f7d8cf54..983e895d4ced 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -887,6 +887,8 @@ static void device_link_put_kref(struct device_link *link)
 {
 	if (link->flags & DL_FLAG_STATELESS)
 		kref_put(&link->kref, __device_link_del);
+	else if (!device_is_registered(link->consumer))
+		__device_link_del(&link->kref);
 	else
 		WARN(1, "Unable to drop a managed device link reference\n");
 }
-- 
2.17.1


  parent reply	other threads:[~2021-07-10 10:38 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-10 10:38 [PATCH V3 0/3] " Adrian Hunter
2021-07-10 10:38 ` [PATCH V3 1/3] driver core: Prevent warning when removing a device link from unregistered consumer Adrian Hunter
2021-07-10 15:19   ` Greg Kroah-Hartman
2021-07-14 18:21     ` Rafael J. Wysocki
2021-07-14 18:22   ` Rafael J. Wysocki
2021-07-10 10:38 ` Adrian Hunter [this message]
2021-07-14 18:26   ` [PATCH V3 2/3] driver core: Add ability to delete device links of unregistered devices Rafael J. Wysocki
2021-07-10 10:38 ` [PATCH V3 3/3] scsi: ufshcd: Fix device links when BOOT WLUN fails to probe Adrian Hunter

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