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driver core: Add ability to delete device links of unregistered devices

PATCH Applied Adrian Hunter 5 participants 14 messages Jul 16, 2021 – Aug 17, 2021

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Adrian Hunter

author
#0 lore raw

v4 cover driver core: Add ability to delete device links of unregistered devices

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.

Since V2, these patches fix the issue by amending device link removal to accept removal of a link with an unregistered consumer device, as suggested by Rafael.

Changes in V4:
driver core: Prevent warning when removing a device link from unregistered consumer
Add stable tag and Rafael's Reviewed-by

driver core: Add ability to delete device links of unregistered devices
Amend comment "discover an error" -> "discovering an error" Merge with next patch

scsi: ufshcd: Fix device links when BOOT WLUN fails to probe
Merge with previous patch
Add Rafael's Reviewed-by

Changes in V3:

driver core: Prevent warning when removing a device link from unregistered consumer
New patch split from "driver core: Add ability to delete device links of unregistered devices" except first chunk from that patch dropped as unnecessary

driver core: Add ability to delete device links of unregistered devices
Move warning fix to separate patch.

Changes in V2:

Take approach suggested by Rafael

Adrian Hunter (2):
driver core: Prevent warning when removing a device link from unregistered consumer
scsi: ufshcd: Fix device links when BOOT WLUN fails to probe

 drivers/base/core.c       |  8 ++++++--
 drivers/scsi/ufs/ufshcd.c | 23 +++++++++++++++++++++--
 2 files changed, 27 insertions(+), 4 deletions(-)

Regards
Adrian

author
#1 lore raw

PATCH v4 1/2 driver core: Prevent warning when removing a device link from unregistered consumer

sysfs_remove_link() causes a warning if the parent directory does not exist. That can happen if the device link consumer has not been registered. So do not attempt sysfs_remove_link() in that case.

Fixes 287905e68dd29 ("driver core: Expose device link details in sysfs")
Signed-off-by Adrian Hunter <[email protected]>
Cc [email protected] # 5.9+
Reviewed-by Rafael J. Wysocki <[email protected]>
---
 drivers/base/core.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)
drivers/base/core.c +4 -2
index ea5b85354526..2de8f7d8cf54 100644
@@ -575,8 +575,10 @@ static void devlink_remove_symlinks(struct device *dev,
 		return;
 	}
 
-	snprintf(buf, len, "supplier:%s:%s", dev_bus_name(sup), dev_name(sup));
-	sysfs_remove_link(&con->kobj, buf);
+	if (device_is_registered(con)) {
+		snprintf(buf, len, "supplier:%s:%s", dev_bus_name(sup), dev_name(sup));
+		sysfs_remove_link(&con->kobj, buf);
+	}
 	snprintf(buf, len, "consumer:%s:%s", dev_bus_name(con), dev_name(con));
 	sysfs_remove_link(&sup->kobj, buf);
 	kfree(buf);
Signature · 1 line
2.17.1
maintainer Applied
#2 lore raw

Re: [PATCH V4 1/2] driver core: Prevent warning when removing a device link from unregistered consumer

Quoted 32 lines · Adrian Hunter

sysfs_remove_link() causes a warning if the parent directory does not exist. That can happen if the device link consumer has not been registered. So do not attempt sysfs_remove_link() in that case.

Fixes 287905e68dd29 ("driver core: Expose device link details in sysfs")
Signed-off-by Adrian Hunter <[email protected]>
Cc [email protected] # 5.9+
Reviewed-by Rafael J. Wysocki <[email protected]>
---
 drivers/base/core.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)
drivers/base/core.c +4 -2
index ea5b85354526..2de8f7d8cf54 100644
@@ -575,8 +575,10 @@ static void devlink_remove_symlinks(struct device *dev,
 		return;
 	}
 
-	snprintf(buf, len, "supplier:%s:%s", dev_bus_name(sup), dev_name(sup));
-	sysfs_remove_link(&con->kobj, buf);
+	if (device_is_registered(con)) {
+		snprintf(buf, len, "supplier:%s:%s", dev_bus_name(sup), dev_name(sup));
+		sysfs_remove_link(&con->kobj, buf);
+	}
 	snprintf(buf, len, "consumer:%s:%s", dev_bus_name(con), dev_name(con));
 	sysfs_remove_link(&sup->kobj, buf);
 	kfree(buf);
Signature · 1 line
2.17.1

I've applied this patch to my tree now.

thanks,

greg k-h

author
#3 lore raw

PATCH v4 2/2 scsi: ufshcd: Fix device links when BOOT WLUN fails to probe

In reply to Adrian Hunter

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 discovering 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).

For UFSHCD, if a LUN fails to probe (e.g. absent BOOT WLUN), the device will not have been registered but can still have a device link holding a reference to the device. The unwanted device link will prevent runtime suspend indefinitely.

Amend device link removal to accept removal of a link with an unregistered consumer device (suggested by Rafael), and fix UFSHCD by explicitly deleting the device link when SCSI destroys the SCSI device.

Fixes b294ff3e34490 ("scsi: ufs: core: Enable power management for wlun")
Signed-off-by Adrian Hunter <[email protected]>
Reviewed-by Rafael J. Wysocki <[email protected]>
---
 drivers/base/core.c       |  2 ++
 drivers/scsi/ufs/ufshcd.c | 23 +++++++++++++++++++++--
 2 files changed, 23 insertions(+), 2 deletions(-)
drivers/base/core.c +2 -0
index 2de8f7d8cf54..983e895d4ced 100644
@@ -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");
 }
drivers/scsi/ufs/ufshcd.c +21 -2
index 708b3b62fc4d..9864a8ee0263 100644
@@ -5020,15 +5020,34 @@ static int ufshcd_slave_configure(struct scsi_device *sdev)
 static void ufshcd_slave_destroy(struct scsi_device *sdev)
 {
 	struct ufs_hba *hba;
+	unsigned long flags;
 
 	hba = shost_priv(sdev->host);
 	/* Drop the reference as it won't be needed anymore */
 	if (ufshcd_scsi_to_upiu_lun(sdev->lun) == UFS_UPIU_UFS_DEVICE_WLUN) {
-		unsigned long flags;
-
 		spin_lock_irqsave(hba->host->host_lock, flags);
 		hba->sdev_ufs_device = NULL;
 		spin_unlock_irqrestore(hba->host->host_lock, flags);
+	} else if (hba->sdev_ufs_device) {
+		struct device *supplier = NULL;
+
+		/* Ensure UFS Device WLUN exists and does not disappear */
+		spin_lock_irqsave(hba->host->host_lock, flags);
+		if (hba->sdev_ufs_device) {
+			supplier = &hba->sdev_ufs_device->sdev_gendev;
+			get_device(supplier);
+		}
+		spin_unlock_irqrestore(hba->host->host_lock, flags);
+
+		if (supplier) {
+			/*
+			 * If a LUN fails to probe (e.g. absent BOOT WLUN), the
+			 * device will not have been registered but can still
+			 * have a device link holding a reference to the device.
+			 */
+			device_link_remove(&sdev->sdev_gendev, supplier);
+			put_device(supplier);
+		}
 	}
 }
Signature · 1 line
2.17.1
#4 lore raw

RE: [PATCH V4 2/2] scsi: ufshcd: Fix device links when BOOT WLUN fails to probe

Quoted 15 lines
drivers/scsi/ufs/ufshcd.c +1 -1
index 708b3b62fc4d..9864a8ee0263 100644
@@ -5020,15 +5020,34 @@ static int ufshcd_slave_configure(struct scsi_device
 *sdev)
 static void ufshcd_slave_destroy(struct scsi_device *sdev)
 {
        struct ufs_hba *hba;
+       unsigned long flags;
 
        hba = shost_priv(sdev->host);
        /* Drop the reference as it won't be needed anymore */
        if (ufshcd_scsi_to_upiu_lun(sdev->lun) == UFS_UPIU_UFS_DEVICE_WLUN) {
-               unsigned long flags;

drivers/scsi/ufs/ufshcd.c static int ufshcd_slave_configure(struct scsi_device · line 5037

Quoted 10 lines
drivers/scsi/ufs/ufshcd.c +6 -1
-
                spin_lock_irqsave(hba->host->host_lock, flags);
                hba->sdev_ufs_device = NULL;
                spin_unlock_irqrestore(hba->host->host_lock, flags);
+       } else if (hba->sdev_ufs_device) {
+               struct device *supplier = NULL;
+
+               /* Ensure UFS Device WLUN exists and does not disappear */
+               spin_lock_irqsave(hba->host->host_lock, flags);
+               if (hba->sdev_ufs_device) {

Was just checked in the outer clause?

Thanks,
Avri

Quoted 19 lines
drivers/scsi/ufs/ufshcd.c +14 -1
+                       supplier = &hba->sdev_ufs_device->sdev_gendev;
+                       get_device(supplier);
+               }
+               spin_unlock_irqrestore(hba->host->host_lock, flags);
+
+               if (supplier) {
+                       /*
+                        * If a LUN fails to probe (e.g. absent BOOT WLUN), the
+                        * device will not have been registered but can still
+                        * have a device link holding a reference to the device.
+                        */
+                       device_link_remove(&sdev->sdev_gendev, supplier);
+                       put_device(supplier);
+               }
        }
 }
 
--

2.17.1

author
#5 lore raw

Re: [PATCH V4 2/2] scsi: ufshcd: Fix device links when BOOT WLUN fails to probe

Quoted 11 lines · Avri Altman
Quoted 11 lines
drivers/scsi/ufs/ufshcd.c +1 -0
index 708b3b62fc4d..9864a8ee0263 100644
@@ -5020,15 +5020,34 @@ static int ufshcd_slave_configure(struct scsi_device
 *sdev)
 static void ufshcd_slave_destroy(struct scsi_device *sdev)
 {
        struct ufs_hba *hba;
+       unsigned long flags;
Quoted 15 lines
Quoted 4 lines
drivers/scsi/ufs/ufshcd.c +0 -1
        hba = shost_priv(sdev->host);
        /* Drop the reference as it won't be needed anymore */
        if (ufshcd_scsi_to_upiu_lun(sdev->lun) == UFS_UPIU_UFS_DEVICE_WLUN) {
-               unsigned long flags;

drivers/scsi/ufs/ufshcd.c static int ufshcd_slave_configure(struct scsi_device *sdev) · line 5036

Quoted 10 lines
drivers/scsi/ufs/ufshcd.c +6 -1
-
                spin_lock_irqsave(hba->host->host_lock, flags);
                hba->sdev_ufs_device = NULL;
                spin_unlock_irqrestore(hba->host->host_lock, flags);
+       } else if (hba->sdev_ufs_device) {
+               struct device *supplier = NULL;
+
+               /* Ensure UFS Device WLUN exists and does not disappear */
+               spin_lock_irqsave(hba->host->host_lock, flags);
+               if (hba->sdev_ufs_device) {

Was just checked in the outer clause?

Yes, but need to re-check with the spinlock locked.

Quoted 24 lines

Thanks,
Avri

Quoted 19 lines
drivers/scsi/ufs/ufshcd.c +14 -1
+                       supplier = &hba->sdev_ufs_device->sdev_gendev;
+                       get_device(supplier);
+               }
+               spin_unlock_irqrestore(hba->host->host_lock, flags);
+
+               if (supplier) {
+                       /*
+                        * If a LUN fails to probe (e.g. absent BOOT WLUN), the
+                        * device will not have been registered but can still
+                        * have a device link holding a reference to the device.
+                        */
+                       device_link_remove(&sdev->sdev_gendev, supplier);
+                       put_device(supplier);
+               }
        }
 }
 
--

2.17.1

#6 lore raw

RE: [PATCH V4 2/2] scsi: ufshcd: Fix device links when BOOT WLUN fails to probe

Quoted 30 lines · Avri Altman
Quoted 11 lines
Quoted 11 lines
drivers/scsi/ufs/ufshcd.c +0 -0
index 708b3b62fc4d..9864a8ee0263 100644
@@ -5020,15 +5020,34 @@ static int ufshcd_slave_configure(struct

scsi_device
*sdev)

 static void ufshcd_slave_destroy(struct scsi_device *sdev)  {
        struct ufs_hba *hba;

+ unsigned long flags;

Quoted 3 lines
Quoted 3 lines
        hba = shost_priv(sdev->host);
        /* Drop the reference as it won't be needed anymore */
        if (ufshcd_scsi_to_upiu_lun(sdev->lun) ==

UFS_UPIU_UFS_DEVICE_WLUN) {

Quoted 4 lines
Quoted 4 lines
drivers/scsi/ufs/ufshcd.c +0 -2
-               unsigned long flags;
-
                spin_lock_irqsave(hba->host->host_lock, flags);
                hba->sdev_ufs_device = NULL;
Quoted 8 lines

drivers/scsi/ufs/ufshcd.c static int ufshcd_slave_configure(struct scsi_device *sdev) · line 5036

Quoted 7 lines
                spin_unlock_irqrestore(hba->host->host_lock, flags);
drivers/scsi/ufs/ufshcd.c +6 -0
+       } else if (hba->sdev_ufs_device) {
+               struct device *supplier = NULL;
+
+               /* Ensure UFS Device WLUN exists and does not disappear */
+               spin_lock_irqsave(hba->host->host_lock, flags);
+               if (hba->sdev_ufs_device) {

Was just checked in the outer clause?

Quoted 1 line

Yes, but need to re-check with the spinlock locked.

OK.
Looks good to me.
Thanks,
Avri

Quoted 25 lines
Quoted 25 lines

Thanks,
Avri

Quoted 19 lines
drivers/scsi/ufs/ufshcd.c +14 -1
+                       supplier = &hba->sdev_ufs_device->sdev_gendev;
+                       get_device(supplier);
+               }
+               spin_unlock_irqrestore(hba->host->host_lock, flags);
+
+               if (supplier) {
+                       /*
+                        * If a LUN fails to probe (e.g. absent BOOT WLUN), the
+                        * device will not have been registered but can still
+                        * have a device link holding a reference to the device.
+                        */
+                       device_link_remove(&sdev->sdev_gendev, supplier);
+                       put_device(supplier);
+               }
        }
 }
 
--

2.17.1

author
#7 lore raw

Re: [PATCH V4 2/2] scsi: ufshcd: Fix device links when BOOT WLUN fails to probe

In reply to Adrian Hunter

Martin, perhaps you could consider picking up this patch if no one objects?

Quoted 79 lines · Adrian Hunter

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 discovering 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).

For UFSHCD, if a LUN fails to probe (e.g. absent BOOT WLUN), the device will not have been registered but can still have a device link holding a reference to the device. The unwanted device link will prevent runtime suspend indefinitely.

Amend device link removal to accept removal of a link with an unregistered consumer device (suggested by Rafael), and fix UFSHCD by explicitly deleting the device link when SCSI destroys the SCSI device.

Fixes b294ff3e34490 ("scsi: ufs: core: Enable power management for wlun")
Signed-off-by Adrian Hunter <[email protected]>
Reviewed-by Rafael J. Wysocki <[email protected]>
---
 drivers/base/core.c       |  2 ++
 drivers/scsi/ufs/ufshcd.c | 23 +++++++++++++++++++++--
 2 files changed, 23 insertions(+), 2 deletions(-)
drivers/base/core.c +2 -0
index 2de8f7d8cf54..983e895d4ced 100644
@@ -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");
 }
drivers/scsi/ufs/ufshcd.c +21 -2
index 708b3b62fc4d..9864a8ee0263 100644
@@ -5020,15 +5020,34 @@ static int ufshcd_slave_configure(struct scsi_device *sdev)
 static void ufshcd_slave_destroy(struct scsi_device *sdev)
 {
 	struct ufs_hba *hba;
+	unsigned long flags;
 
 	hba = shost_priv(sdev->host);
 	/* Drop the reference as it won't be needed anymore */
 	if (ufshcd_scsi_to_upiu_lun(sdev->lun) == UFS_UPIU_UFS_DEVICE_WLUN) {
-		unsigned long flags;
-
 		spin_lock_irqsave(hba->host->host_lock, flags);
 		hba->sdev_ufs_device = NULL;
 		spin_unlock_irqrestore(hba->host->host_lock, flags);
+	} else if (hba->sdev_ufs_device) {
+		struct device *supplier = NULL;
+
+		/* Ensure UFS Device WLUN exists and does not disappear */
+		spin_lock_irqsave(hba->host->host_lock, flags);
+		if (hba->sdev_ufs_device) {
+			supplier = &hba->sdev_ufs_device->sdev_gendev;
+			get_device(supplier);
+		}
+		spin_unlock_irqrestore(hba->host->host_lock, flags);
+
+		if (supplier) {
+			/*
+			 * If a LUN fails to probe (e.g. absent BOOT WLUN), the
+			 * device will not have been registered but can still
+			 * have a device link holding a reference to the device.
+			 */
+			device_link_remove(&sdev->sdev_gendev, supplier);
+			put_device(supplier);
+		}
 	}
 }
#8 lore raw

Re: [PATCH V4 2/2] scsi: ufshcd: Fix device links when BOOT WLUN fails to probe

Quoted 1 line · Adrian Hunter

Martin, perhaps you could consider picking up this patch if no one objects?

Since patch 1/2 went in through Greg's tree, if patch 2/2 goes upstream via Martin's tree, will the resulting kernel be bisectable if Linus pulls Martin's tree before he pulls Greg's tree?

Thanks,

Bart.

#9 lore raw

Re: [PATCH V4 2/2] scsi: ufshcd: Fix device links when BOOT WLUN fails to probe

Quoted 4 lines

Since patch 1/2 went in through Greg's tree, if patch 2/2 goes upstream via Martin's tree, will the resulting kernel be bisectable if Linus pulls Martin's tree before he pulls Greg's tree?

Also, this patch will need to be rebased on top of 5.15/scsi-staging due to all the UFS churn in this release.

Signature · 1 line
Martin K. Petersen	Oracle Linux Engineering
author
#10 lore raw

Re: [PATCH V4 2/2] scsi: ufshcd: Fix device links when BOOT WLUN fails to probe

Quoted 8 lines · Martin K. Petersen
Quoted 4 lines

Since patch 1/2 went in through Greg's tree, if patch 2/2 goes upstream via Martin's tree, will the resulting kernel be bisectable if Linus pulls Martin's tree before he pulls Greg's tree?

Also, this patch will need to be rebased on top of 5.15/scsi-staging due to all the UFS churn in this release.

Patch "driver core: Prevent warning when removing a device link from unregistered consumer" is already in Linus' tree:

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=e64daad660a0c9ace3acdc57099fffe5ed83f977

I will rebase on 5.15/scsi-staging

author
#11 lore raw

PATCH v5 1/1 scsi: ufshcd: Fix device links when BOOT WLUN fails to probe

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 discovering 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).

For UFSHCD, if a LUN fails to probe (e.g. absent BOOT WLUN), the device will not have been registered but can still have a device link holding a reference to the device. The unwanted device link will prevent runtime suspend indefinitely.

Amend device link removal to accept removal of a link with an unregistered consumer device (suggested by Rafael), and fix UFSHCD by explicitly deleting the device link when SCSI destroys the SCSI device.

Fixes b294ff3e34490 ("scsi: ufs: core: Enable power management for wlun")
Signed-off-by Adrian Hunter <[email protected]>
Reviewed-by Rafael J. Wysocki <[email protected]>

---

Patch "driver core: Prevent warning when removing a device link from unregistered consumer" is already in Linus' tree:

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=e64daad660a0c9ace3acdc57099fffe5ed83f977

Changes in V5:

Rebase on 5.15/scsi-staging

 drivers/base/core.c       |  2 ++
 drivers/scsi/ufs/ufshcd.c | 23 +++++++++++++++++++++--
 2 files changed, 23 insertions(+), 2 deletions(-)
drivers/base/core.c +2 -0
index cadcade65825..9badd7f7fe62 100644
@@ -884,6 +884,8 @@ 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");
 }
drivers/scsi/ufs/ufshcd.c +21 -2
index 6c263e94144b..9f72698ff597 100644
@@ -5028,6 +5028,7 @@ static int ufshcd_slave_configure(struct scsi_device *sdev)
 static void ufshcd_slave_destroy(struct scsi_device *sdev)
 {
 	struct ufs_hba *hba;
+	unsigned long flags;
 
 	hba = shost_priv(sdev->host);
 

@@ -5035,11 +5036,29 @@ static void ufshcd_slave_destroy(struct scsi_device *sdev)
 
 	/* Drop the reference as it won't be needed anymore */
 	if (ufshcd_scsi_to_upiu_lun(sdev->lun) == UFS_UPIU_UFS_DEVICE_WLUN) {
-		unsigned long flags;
-
 		spin_lock_irqsave(hba->host->host_lock, flags);
 		hba->sdev_ufs_device = NULL;
 		spin_unlock_irqrestore(hba->host->host_lock, flags);
+	} else if (hba->sdev_ufs_device) {
+		struct device *supplier = NULL;
+
+		/* Ensure UFS Device WLUN exists and does not disappear */
+		spin_lock_irqsave(hba->host->host_lock, flags);
+		if (hba->sdev_ufs_device) {
+			supplier = &hba->sdev_ufs_device->sdev_gendev;
+			get_device(supplier);
+		}
+		spin_unlock_irqrestore(hba->host->host_lock, flags);
+
+		if (supplier) {
+			/*
+			 * If a LUN fails to probe (e.g. absent BOOT WLUN), the
+			 * device will not have been registered but can still
+			 * have a device link holding a reference to the device.
+			 */
+			device_link_remove(&sdev->sdev_gendev, supplier);
+			put_device(supplier);
+		}
 	}
 }
Signature · 1 line
2.17.1
Applied
#12 lore raw

Re: [PATCH V5] scsi: ufshcd: Fix device links when BOOT WLUN fails to probe

Adrian,

Quoted 7 lines

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 discovering 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).

Applied to 5.15/scsi-staging, thanks!

Signature · 1 line
Martin K. Petersen	Oracle Linux Engineering
Applied
#13 lore raw

Re: [PATCH V5] scsi: ufshcd: Fix device links when BOOT WLUN fails to probe

In reply to Adrian Hunter
Quoted 8 lines · Adrian Hunter

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 discovering 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).

[...]

Applied to 5.15/scsi-queue, thanks!

[1/1] scsi: ufshcd: Fix device links when BOOT WLUN fails to probe

      https://git.kernel.org/mkp/scsi/c/bf25967ac541
Signature · 1 line
Martin K. Petersen	Oracle Linux Engineering