[PATCH v2 0/8] scsi: Make use of bus callbacks

[PATCH v2 0/8] scsi: Make use of bus callbacks

[Uwe Kleine-König]

Hello,

this is v2 of the series to make the scsi subsystem stop using the
callbacks .probe(), .remove() and .shutdown() of struct device_driver.
Instead use their designated alternatives in struct bus_type.

The eventual goal is to drop the callbacks from struct device_driver.

The 2nd patch introduces some legacy handling for drivers still using
the device_driver callbacks. This results in a runtime warning (in
driver_register()). The following patches convert all in-tree drivers
(and thus fix the warnings one after another).
Conceptually this legacy handling could be dropped at the end of the
series, but I think this is a bad idea because this silently breaks
out-of-tree drivers (which also covers drivers that are currently
prepared for mainline submission) and in-tree drivers I might have
missed (though I'm convinced I catched them all). That convinces me that
keeping the legacy handling for at least one development cycle is the
right choice. I'll care for that at the latest when I remove the
callbacks from struct device_driver.

Changes since (implicit) v1, available at
https://lore.kernel.org/linux-scsi/cover.1765312062.git.u.kleine-koenig@baylibre.com:

 - trivially rebase to v6.19-rc1
 - fix a kdoc warning uncovered by the intel kernel test robot
 - rename a few variables to align with the already existing naming in
   the individual drivers
 - slightly reword the commit logs
 - add the tags received in v1

Best regards
Uwe

Uwe Kleine-König (8):
  scsi: Pass a struct scsi_driver to scsi_{,un}register_driver()
  scsi: Make use of bus callbacks
  scsi: ch: Convert to scsi bus methods
  scsi: sd: Convert to scsi bus methods
  scsi: ses: Convert to scsi bus methods
  scsi: sr: Convert to scsi bus methods
  scsi: st: Convert to scsi bus methods
  scsi: ufs: Convert to scsi bus methods

 drivers/scsi/ch.c          | 18 ++++-----
 drivers/scsi/scsi_sysfs.c  | 77 ++++++++++++++++++++++++++++++++++++--
 drivers/scsi/sd.c          | 29 +++++++-------
 drivers/scsi/ses.c         | 15 ++------
 drivers/scsi/sr.c          | 21 +++++------
 drivers/scsi/st.c          | 22 +++++------
 drivers/ufs/core/ufshcd.c  | 22 +++++------
 include/scsi/scsi_driver.h |  7 +++-
 8 files changed, 139 insertions(+), 72 deletions(-)


base-commit: 8f0b4cce4481fb22653697cced8d0d04027cb1e8
-- 
2.47.3

[PATCH v2 1/8] scsi: Pass a struct scsi_driver to scsi_{,un}register_driver()

[Uwe Kleine-König]

This aligns with what other subsystems do, reduces boilerplate a bit for
device drivers and is less error prone.

Reviewed-by: Peter Wang <peter.wang@mediatek.com>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
---
 drivers/scsi/ch.c          | 4 ++--
 drivers/scsi/scsi_sysfs.c  | 4 +++-
 drivers/scsi/sd.c          | 4 ++--
 drivers/scsi/ses.c         | 4 ++--
 drivers/scsi/sr.c          | 4 ++--
 drivers/scsi/st.c          | 4 ++--
 drivers/ufs/core/ufshcd.c  | 4 ++--
 include/scsi/scsi_driver.h | 4 ++--
 8 files changed, 17 insertions(+), 15 deletions(-)

diff --git a/drivers/scsi/ch.c b/drivers/scsi/ch.c
index fa07a6f54003..f2b63e4b9b99 100644
--- a/drivers/scsi/ch.c
+++ b/drivers/scsi/ch.c
@@ -1014,7 +1014,7 @@ static int __init init_ch_module(void)
 		       SCSI_CHANGER_MAJOR);
 		goto fail1;
 	}
-	rc = scsi_register_driver(&ch_template.gendrv);
+	rc = scsi_register_driver(&ch_template);
 	if (rc < 0)
 		goto fail2;
 	return 0;
@@ -1028,7 +1028,7 @@ static int __init init_ch_module(void)
 
 static void __exit exit_ch_module(void)
 {
-	scsi_unregister_driver(&ch_template.gendrv);
+	scsi_unregister_driver(&ch_template);
 	unregister_chrdev(SCSI_CHANGER_MAJOR, "ch");
 	class_unregister(&ch_sysfs_class);
 	idr_destroy(&ch_index_idr);
diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
index 99eb0a30df61..db0ba68f2e6e 100644
--- a/drivers/scsi/scsi_sysfs.c
+++ b/drivers/scsi/scsi_sysfs.c
@@ -1554,8 +1554,10 @@ void scsi_remove_target(struct device *dev)
 }
 EXPORT_SYMBOL(scsi_remove_target);
 
-int __scsi_register_driver(struct device_driver *drv, struct module *owner)
+int __scsi_register_driver(struct scsi_driver *sdrv, struct module *owner)
 {
+	struct device_driver *drv = &sdrv->gendrv;
+
 	drv->bus = &scsi_bus_type;
 	drv->owner = owner;
 
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index f50b92e63201..6ea6ee2830a4 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -4417,7 +4417,7 @@ static int __init init_sd(void)
 		goto err_out_class;
 	}
 
-	err = scsi_register_driver(&sd_template.gendrv);
+	err = scsi_register_driver(&sd_template);
 	if (err)
 		goto err_out_driver;
 
@@ -4444,7 +4444,7 @@ static void __exit exit_sd(void)
 
 	SCSI_LOG_HLQUEUE(3, printk("exit_sd: exiting sd driver\n"));
 
-	scsi_unregister_driver(&sd_template.gendrv);
+	scsi_unregister_driver(&sd_template);
 	mempool_destroy(sd_page_pool);
 
 	class_unregister(&sd_disk_class);
diff --git a/drivers/scsi/ses.c b/drivers/scsi/ses.c
index 2c61624cb4b0..f8f5164f3de2 100644
--- a/drivers/scsi/ses.c
+++ b/drivers/scsi/ses.c
@@ -921,7 +921,7 @@ static int __init ses_init(void)
 	if (err)
 		return err;
 
-	err = scsi_register_driver(&ses_template.gendrv);
+	err = scsi_register_driver(&ses_template);
 	if (err)
 		goto out_unreg;
 
@@ -934,7 +934,7 @@ static int __init ses_init(void)
 
 static void __exit ses_exit(void)
 {
-	scsi_unregister_driver(&ses_template.gendrv);
+	scsi_unregister_driver(&ses_template);
 	scsi_unregister_interface(&ses_interface);
 }
 
diff --git a/drivers/scsi/sr.c b/drivers/scsi/sr.c
index add13e306898..2f6bb6355186 100644
--- a/drivers/scsi/sr.c
+++ b/drivers/scsi/sr.c
@@ -1001,7 +1001,7 @@ static int __init init_sr(void)
 	rc = register_blkdev(SCSI_CDROM_MAJOR, "sr");
 	if (rc)
 		return rc;
-	rc = scsi_register_driver(&sr_template.gendrv);
+	rc = scsi_register_driver(&sr_template);
 	if (rc)
 		unregister_blkdev(SCSI_CDROM_MAJOR, "sr");
 
@@ -1010,7 +1010,7 @@ static int __init init_sr(void)
 
 static void __exit exit_sr(void)
 {
-	scsi_unregister_driver(&sr_template.gendrv);
+	scsi_unregister_driver(&sr_template);
 	unregister_blkdev(SCSI_CDROM_MAJOR, "sr");
 }
 
diff --git a/drivers/scsi/st.c b/drivers/scsi/st.c
index 168f25e4aaa3..45622cfce926 100644
--- a/drivers/scsi/st.c
+++ b/drivers/scsi/st.c
@@ -4576,7 +4576,7 @@ static int __init init_st(void)
 		goto err_class;
 	}
 
-	err = scsi_register_driver(&st_template.gendrv);
+	err = scsi_register_driver(&st_template);
 	if (err)
 		goto err_chrdev;
 
@@ -4592,7 +4592,7 @@ static int __init init_st(void)
 
 static void __exit exit_st(void)
 {
-	scsi_unregister_driver(&st_template.gendrv);
+	scsi_unregister_driver(&st_template);
 	unregister_chrdev_region(MKDEV(SCSI_TAPE_MAJOR, 0),
 				 ST_MAX_TAPE_ENTRIES);
 	class_unregister(&st_sysfs_class);
diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
index 80c0b49f30b0..da1e89e95d07 100644
--- a/drivers/ufs/core/ufshcd.c
+++ b/drivers/ufs/core/ufshcd.c
@@ -11240,7 +11240,7 @@ static int __init ufshcd_core_init(void)
 
 	ufs_debugfs_init();
 
-	ret = scsi_register_driver(&ufs_dev_wlun_template.gendrv);
+	ret = scsi_register_driver(&ufs_dev_wlun_template);
 	if (ret)
 		ufs_debugfs_exit();
 	return ret;
@@ -11249,7 +11249,7 @@ static int __init ufshcd_core_init(void)
 static void __exit ufshcd_core_exit(void)
 {
 	ufs_debugfs_exit();
-	scsi_unregister_driver(&ufs_dev_wlun_template.gendrv);
+	scsi_unregister_driver(&ufs_dev_wlun_template);
 }
 
 module_init(ufshcd_core_init);
diff --git a/include/scsi/scsi_driver.h b/include/scsi/scsi_driver.h
index c0e89996bdb3..40aba9a9349a 100644
--- a/include/scsi/scsi_driver.h
+++ b/include/scsi/scsi_driver.h
@@ -25,9 +25,9 @@ struct scsi_driver {
 
 #define scsi_register_driver(drv) \
 	__scsi_register_driver(drv, THIS_MODULE)
-int __scsi_register_driver(struct device_driver *, struct module *);
+int __scsi_register_driver(struct scsi_driver *, struct module *);
 #define scsi_unregister_driver(drv) \
-	driver_unregister(drv);
+	driver_unregister(&(drv)->gendrv);
 
 extern int scsi_register_interface(struct class_interface *);
 #define scsi_unregister_interface(intf) \
-- 
2.47.3

[PATCH v2 2/8] scsi: Make use of bus callbacks

[Uwe Kleine-König]

Introduce a bus specific probe, remove and shutdown function. For now
this only allows to get rid of a cast of the generic device to an scsi
device in the drivers and changes the remove prototype to return
void---a non-zero return value is ignored anyhow.

The objective is to get rid of users of struct device_driver callbacks
.probe(), .remove() and .shutdown() to eventually remove these. Until
all scsi drivers are converted this results in a runtime warning about
the drivers needing an update because there is a bus probe function and
a driver probe function. The in-tree drivers are fixed by the following
commits.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
---
 drivers/scsi/scsi_sysfs.c  | 73 ++++++++++++++++++++++++++++++++++++--
 include/scsi/scsi_driver.h |  3 ++
 2 files changed, 74 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
index db0ba68f2e6e..6b8c5c05f294 100644
--- a/drivers/scsi/scsi_sysfs.c
+++ b/drivers/scsi/scsi_sysfs.c
@@ -554,10 +554,48 @@ static int scsi_bus_uevent(const struct device *dev, struct kobj_uevent_env *env
 	return 0;
 }
 
+static int scsi_bus_probe(struct device *dev)
+{
+	struct scsi_device *sdp = to_scsi_device(dev);
+	struct scsi_driver *drv = to_scsi_driver(dev->driver);
+
+	if (drv->probe)
+		return drv->probe(sdp);
+	else
+		return 0;
+}
+
+static void scsi_bus_remove(struct device *dev)
+{
+	struct scsi_device *sdp = to_scsi_device(dev);
+	struct scsi_driver *drv = to_scsi_driver(dev->driver);
+
+	if (drv->remove)
+		drv->remove(sdp);
+}
+
+static void scsi_bus_shutdown(struct device *dev)
+{
+	struct scsi_device *sdp = to_scsi_device(dev);
+	struct scsi_driver *drv;
+
+	if (!dev->driver)
+		return;
+
+	drv = to_scsi_driver(dev->driver);
+
+	if (drv->shutdown)
+		drv->shutdown(sdp);
+}
+
+
 const struct bus_type scsi_bus_type = {
-        .name		= "scsi",
-        .match		= scsi_bus_match,
+	.name		= "scsi",
+	.match		= scsi_bus_match,
 	.uevent		= scsi_bus_uevent,
+	.probe		= scsi_bus_probe,
+	.remove		= scsi_bus_remove,
+	.shutdown	= scsi_bus_shutdown,
 #ifdef CONFIG_PM
 	.pm		= &scsi_bus_pm_ops,
 #endif
@@ -1554,6 +1592,30 @@ void scsi_remove_target(struct device *dev)
 }
 EXPORT_SYMBOL(scsi_remove_target);
 
+static int scsi_legacy_probe(struct scsi_device *sdp)
+{
+	struct device *dev = &sdp->sdev_gendev;
+	struct device_driver *driver = dev->driver;
+
+	return driver->probe(dev);
+}
+
+static void scsi_legacy_remove(struct scsi_device *sdp)
+{
+	struct device *dev = &sdp->sdev_gendev;
+	struct device_driver *driver = dev->driver;
+
+	driver->remove(dev);
+}
+
+static void scsi_legacy_shutdown(struct scsi_device *sdp)
+{
+	struct device *dev = &sdp->sdev_gendev;
+	struct device_driver *driver = dev->driver;
+
+	driver->shutdown(dev);
+}
+
 int __scsi_register_driver(struct scsi_driver *sdrv, struct module *owner)
 {
 	struct device_driver *drv = &sdrv->gendrv;
@@ -1561,6 +1623,13 @@ int __scsi_register_driver(struct scsi_driver *sdrv, struct module *owner)
 	drv->bus = &scsi_bus_type;
 	drv->owner = owner;
 
+	if (!sdrv->probe && drv->probe)
+		sdrv->probe = scsi_legacy_probe;
+	if (!sdrv->remove && drv->remove)
+		sdrv->remove = scsi_legacy_remove;
+	if (!sdrv->shutdown && drv->shutdown)
+		sdrv->shutdown = scsi_legacy_shutdown;
+
 	return driver_register(drv);
 }
 EXPORT_SYMBOL(__scsi_register_driver);
diff --git a/include/scsi/scsi_driver.h b/include/scsi/scsi_driver.h
index 40aba9a9349a..249cea724abd 100644
--- a/include/scsi/scsi_driver.h
+++ b/include/scsi/scsi_driver.h
@@ -12,6 +12,9 @@ struct request;
 struct scsi_driver {
 	struct device_driver	gendrv;
 
+	int (*probe)(struct scsi_device *);
+	void (*remove)(struct scsi_device *);
+	void (*shutdown)(struct scsi_device *);
 	int (*resume)(struct device *);
 	void (*rescan)(struct device *);
 	blk_status_t (*init_command)(struct scsi_cmnd *);
-- 
2.47.3

Re: [PATCH v2 2/8] scsi: Make use of bus callbacks

[Bart Van Assche]

On 12/19/25 1:25 AM, Uwe Kleine-König wrote:
> +static int scsi_bus_probe(struct device *dev)
> +{
> +	struct scsi_device *sdp = to_scsi_device(dev);
> +	struct scsi_driver *drv = to_scsi_driver(dev->driver);
> +
> +	if (drv->probe)
> +		return drv->probe(sdp);
> +	else
> +		return 0;
> +}

If this series has to be reposted, please leave out the "else" statement
from the above function. It is uncommon in Linux kernel code to have an
"else" statement after a "return" statement.

Thanks,

Bart.

Re: [PATCH v2 2/8] scsi: Make use of bus callbacks

[Peter Wang (王信友)]

On Fri, 2025-12-19 at 10:25 +0100, Uwe Kleine-König wrote:
> Introduce a bus specific probe, remove and shutdown function. For now
> this only allows to get rid of a cast of the generic device to an
> scsi
> device in the drivers and changes the remove prototype to return
> void---a non-zero return value is ignored anyhow.
> 
> The objective is to get rid of users of struct device_driver
> callbacks
> .probe(), .remove() and .shutdown() to eventually remove these. Until
> all scsi drivers are converted this results in a runtime warning
> about
> the drivers needing an update because there is a bus probe function
> and
> a driver probe function. The in-tree drivers are fixed by the
> following
> commits.
> 
> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>

Reviewed-by: Peter Wang <peter.wang@mediatek.com>

[PATCH v2 8/8] scsi: ufs: Convert to scsi bus methods

[Uwe Kleine-König]

The scsi subsystem has implemented dedicated callbacks for probe, remove
and shutdown. Make use of them. This fixes a runtime warning about the
driver needing to be converted to the bus probe method.

Reviewed-by: Peter Wang <peter.wang@mediatek.com>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
---
 drivers/ufs/core/ufshcd.c | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
index da1e89e95d07..78669c205568 100644
--- a/drivers/ufs/core/ufshcd.c
+++ b/drivers/ufs/core/ufshcd.c
@@ -10525,9 +10525,8 @@ int ufshcd_runtime_resume(struct device *dev)
 EXPORT_SYMBOL(ufshcd_runtime_resume);
 #endif /* CONFIG_PM */
 
-static void ufshcd_wl_shutdown(struct device *dev)
+static void ufshcd_wl_shutdown(struct scsi_device *sdev)
 {
-	struct scsi_device *sdev = to_scsi_device(dev);
 	struct ufs_hba *hba = shost_priv(sdev->host);
 
 	down(&hba->host_sem);
@@ -11133,9 +11132,9 @@ static int ufshcd_wl_poweroff(struct device *dev)
 }
 #endif
 
-static int ufshcd_wl_probe(struct device *dev)
+static int ufshcd_wl_probe(struct scsi_device *sdev)
 {
-	struct scsi_device *sdev = to_scsi_device(dev);
+	struct device *dev = &sdev->sdev_gendev;
 
 	if (!is_device_wlun(sdev))
 		return -ENODEV;
@@ -11147,10 +11146,11 @@ static int ufshcd_wl_probe(struct device *dev)
 	return  0;
 }
 
-static int ufshcd_wl_remove(struct device *dev)
+static void ufshcd_wl_remove(struct scsi_device *sdev)
 {
+	struct device *dev = &sdev->sdev_gendev;
+
 	pm_runtime_forbid(dev);
-	return 0;
 }
 
 static const struct dev_pm_ops ufshcd_wl_pm_ops = {
@@ -11223,12 +11223,12 @@ static void ufshcd_check_header_layout(void)
  * Hence register a scsi driver for ufs wluns only.
  */
 static struct scsi_driver ufs_dev_wlun_template = {
+	.probe = ufshcd_wl_probe,
+	.remove = ufshcd_wl_remove,
+	.shutdown = ufshcd_wl_shutdown,
 	.gendrv = {
 		.name = "ufs_device_wlun",
-		.probe = ufshcd_wl_probe,
-		.remove = ufshcd_wl_remove,
 		.pm = &ufshcd_wl_pm_ops,
-		.shutdown = ufshcd_wl_shutdown,
 	},
 };
 
-- 
2.47.3

Re: [PATCH v2 0/8] scsi: Make use of bus callbacks

[Bart Van Assche]

On 12/19/25 1:25 AM, Uwe Kleine-König wrote:
> this is v2 of the series to make the scsi subsystem stop using the
> callbacks .probe(), .remove() and .shutdown() of struct device_driver.
> Instead use their designated alternatives in struct bus_type.
> 
> The eventual goal is to drop the callbacks from struct device_driver.
> 
> The 2nd patch introduces some legacy handling for drivers still using
> the device_driver callbacks. This results in a runtime warning (in
> driver_register()). The following patches convert all in-tree drivers
> (and thus fix the warnings one after another).
> Conceptually this legacy handling could be dropped at the end of the
> series, but I think this is a bad idea because this silently breaks
> out-of-tree drivers (which also covers drivers that are currently
> prepared for mainline submission) and in-tree drivers I might have
> missed (though I'm convinced I catched them all). That convinces me that
> keeping the legacy handling for at least one development cycle is the
> right choice. I'll care for that at the latest when I remove the
> callbacks from struct device_driver.

For the entire series:

Reviewed-by: Bart Van Assche <bvanassche@acm.org>

Re: [PATCH v2 0/8] scsi: Make use of bus callbacks

[Martin K. Petersen]

Uwe,

> this is v2 of the series to make the scsi subsystem stop using the
> callbacks .probe(), .remove() and .shutdown() of struct device_driver.
> Instead use their designated alternatives in struct bus_type.

Applied to 6.20/scsi-staging, thanks!

-- 
Martin K. Petersen

Re: [PATCH v2 0/8] scsi: Make use of bus callbacks

[Martin K. Petersen]

On Fri, 19 Dec 2025 10:25:29 +0100, Uwe Kleine-König wrote:

> this is v2 of the series to make the scsi subsystem stop using the
> callbacks .probe(), .remove() and .shutdown() of struct device_driver.
> Instead use their designated alternatives in struct bus_type.
> 
> The eventual goal is to drop the callbacks from struct device_driver.
> 
> The 2nd patch introduces some legacy handling for drivers still using
> the device_driver callbacks. This results in a runtime warning (in
> driver_register()). The following patches convert all in-tree drivers
> (and thus fix the warnings one after another).
> Conceptually this legacy handling could be dropped at the end of the
> series, but I think this is a bad idea because this silently breaks
> out-of-tree drivers (which also covers drivers that are currently
> prepared for mainline submission) and in-tree drivers I might have
> missed (though I'm convinced I catched them all). That convinces me that
> keeping the legacy handling for at least one development cycle is the
> right choice. I'll care for that at the latest when I remove the
> callbacks from struct device_driver.
> 
> [...]

Applied to 6.20/scsi-queue, thanks!

[1/8] scsi: Pass a struct scsi_driver to scsi_{,un}register_driver()
      https://git.kernel.org/mkp/scsi/c/7d42bcea57ae
[2/8] scsi: Make use of bus callbacks
      https://git.kernel.org/mkp/scsi/c/f7d4f1bf5724
[3/8] scsi: ch: Convert to scsi bus methods
      https://git.kernel.org/mkp/scsi/c/fba333569c8a
[4/8] scsi: sd: Convert to scsi bus methods
      https://git.kernel.org/mkp/scsi/c/63b541f054e7
[5/8] scsi: ses: Convert to scsi bus methods
      https://git.kernel.org/mkp/scsi/c/a71d5deea6e9
[6/8] scsi: sr: Convert to scsi bus methods
      https://git.kernel.org/mkp/scsi/c/9ccda35df7d5
[7/8] scsi: st: Convert to scsi bus methods
      https://git.kernel.org/mkp/scsi/c/4bc2205be460
[8/8] scsi: ufs: Convert to scsi bus methods
      https://git.kernel.org/mkp/scsi/c/44859905375f

-- 
Martin K. Petersen