simplify gendisk lookup and remove struct block_device aliases v4

simplify gendisk lookup and remove struct block_device aliases v4

[Christoph Hellwig]

Hi all,

this series removes the annoying struct block_device aliases, which can
happen for a bunch of old floppy drivers (and z2ram).  In that case
multiple struct block device instances for different dev_t's can point
to the same gendisk, without being partitions.  The cause for that
is the probe/get callback registered through blk_register_regions.

This series removes blk_register_region entirely, splitting it it into
a simple xarray lookup of registered gendisks, and a probe callback
stored in the major_names array that can be used for modprobe overrides
or creating devices on demands when no gendisk is found.  The old
remapping is gone entirely, and instead the 4 remaining drivers just
register a gendisk for each operating mode.  In case of the two drivers
that have lots of aliases that is done on-demand using the new probe
callback, while for the other two I simply register all at probe time
to keep things simple.

Note that the m68k drivers are compile tested only.

Changes since v3:
 - keep kobj_map for char dev lookup for now, as the testbot found
   some very strange and unexplained regressions, so I'll get back to
   this later separately
 - fix a commit message typo

Changes since v2:
 - fix a wrong variable passed to ERR_PTR in the floppy driver
 - slightly adjust the del_gendisk cleanups to prepare for the next
   series touching this area

Changes since v1:
 - add back a missing kobject_put in the cdev code
 - improve the xarray delete loops

[PATCH 01/18] block: cleanup del_gendisk a bit

[Christoph Hellwig]

Merge three hidden gendisk checks into one.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
---
 block/genhd.c | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/block/genhd.c b/block/genhd.c
index 0a273211fec283..3ed591970ea640 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -892,6 +892,9 @@ void del_gendisk(struct gendisk *disk)
 
 	might_sleep();
 
+	if (WARN_ON_ONCE(!disk->queue))
+		return;
+
 	blk_integrity_del(disk);
 	disk_del_events(disk);
 
@@ -914,20 +917,18 @@ void del_gendisk(struct gendisk *disk)
 	disk->flags &= ~GENHD_FL_UP;
 	up_write(&disk->lookup_sem);
 
-	if (!(disk->flags & GENHD_FL_HIDDEN))
+	if (!(disk->flags & GENHD_FL_HIDDEN)) {
 		sysfs_remove_link(&disk_to_dev(disk)->kobj, "bdi");
-	if (disk->queue) {
+
 		/*
 		 * Unregister bdi before releasing device numbers (as they can
 		 * get reused and we'd get clashes in sysfs).
 		 */
-		if (!(disk->flags & GENHD_FL_HIDDEN))
-			bdi_unregister(disk->queue->backing_dev_info);
-		blk_unregister_queue(disk);
-	} else {
-		WARN_ON(1);
+		bdi_unregister(disk->queue->backing_dev_info);
 	}
 
+	blk_unregister_queue(disk);
+	
 	if (!(disk->flags & GENHD_FL_HIDDEN))
 		blk_unregister_region(disk_devt(disk), disk->minors);
 	/*
-- 
2.28.0

[PATCH 02/18] block: open code kobj_map into in block/genhd.c

[Christoph Hellwig]

Copy and paste the kobj_map functionality in the block code in preparation
for completely rewriting it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/genhd.c | 130 +++++++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 117 insertions(+), 13 deletions(-)

diff --git a/block/genhd.c b/block/genhd.c
index 3ed591970ea640..0e22ca64aca09e 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -17,7 +17,6 @@
 #include <linux/seq_file.h>
 #include <linux/slab.h>
 #include <linux/kmod.h>
-#include <linux/kobj_map.h>
 #include <linux/mutex.h>
 #include <linux/idr.h>
 #include <linux/log2.h>
@@ -29,6 +28,16 @@
 static DEFINE_MUTEX(block_class_lock);
 static struct kobject *block_depr;
 
+struct bdev_map {
+	struct bdev_map *next;
+	dev_t dev;
+	unsigned long range;
+	struct module *owner;
+	struct kobject *(*probe)(dev_t, int *, void *);
+	int (*lock)(dev_t, void *);
+	void *data;
+} *bdev_map[255];
+
 /* for extended dynamic devt allocation, currently only one major is used */
 #define NR_EXT_DEVT		(1 << MINORBITS)
 
@@ -517,8 +526,6 @@ void unregister_blkdev(unsigned int major, const char *name)
 
 EXPORT_SYMBOL(unregister_blkdev);
 
-static struct kobj_map *bdev_map;
-
 /**
  * blk_mangle_minor - scatter minor numbers apart
  * @minor: minor number to mangle
@@ -645,16 +652,60 @@ void blk_register_region(dev_t devt, unsigned long range, struct module *module,
 			 struct kobject *(*probe)(dev_t, int *, void *),
 			 int (*lock)(dev_t, void *), void *data)
 {
-	kobj_map(bdev_map, devt, range, module, probe, lock, data);
-}
+	unsigned n = MAJOR(devt + range - 1) - MAJOR(devt) + 1;
+	unsigned index = MAJOR(devt);
+	unsigned i;
+	struct bdev_map *p;
+
+	n = min(n, 255u);
+	p = kmalloc_array(n, sizeof(struct bdev_map), GFP_KERNEL);
+	if (p == NULL)
+		return;
 
+	for (i = 0; i < n; i++, p++) {
+		p->owner = module;
+		p->probe = probe;
+		p->lock = lock;
+		p->dev = devt;
+		p->range = range;
+		p->data = data;
+	}
+
+	mutex_lock(&block_class_lock);
+	for (i = 0, p -= n; i < n; i++, p++, index++) {
+		struct bdev_map **s = &bdev_map[index % 255];
+		while (*s && (*s)->range < range)
+			s = &(*s)->next;
+		p->next = *s;
+		*s = p;
+	}
+	mutex_unlock(&block_class_lock);
+}
 EXPORT_SYMBOL(blk_register_region);
 
 void blk_unregister_region(dev_t devt, unsigned long range)
 {
-	kobj_unmap(bdev_map, devt, range);
-}
+	unsigned n = MAJOR(devt + range - 1) - MAJOR(devt) + 1;
+	unsigned index = MAJOR(devt);
+	unsigned i;
+	struct bdev_map *found = NULL;
 
+	mutex_lock(&block_class_lock);
+	for (i = 0; i < min(n, 255u); i++, index++) {
+		struct bdev_map **s;
+		for (s = &bdev_map[index % 255]; *s; s = &(*s)->next) {
+			struct bdev_map *p = *s;
+			if (p->dev == devt && p->range == range) {
+				*s = p->next;
+				if (!found)
+					found = p;
+				break;
+			}
+		}
+	}
+	mutex_unlock(&block_class_lock);
+	kfree(found);
+}
 EXPORT_SYMBOL(blk_unregister_region);
 
 static struct kobject *exact_match(dev_t devt, int *partno, void *data)
@@ -976,6 +1027,47 @@ static ssize_t disk_badblocks_store(struct device *dev,
 	return badblocks_store(disk->bb, page, len, 0);
 }
 
+static struct gendisk *lookup_gendisk(dev_t dev, int *partno)
+{
+	struct kobject *kobj;
+	struct bdev_map *p;
+	unsigned long best = ~0UL;
+
+retry:
+	mutex_lock(&block_class_lock);
+	for (p = bdev_map[MAJOR(dev) % 255]; p; p = p->next) {
+		struct kobject *(*probe)(dev_t, int *, void *);
+		struct module *owner;
+		void *data;
+
+		if (p->dev > dev || p->dev + p->range - 1 < dev)
+			continue;
+		if (p->range - 1 >= best)
+			break;
+		if (!try_module_get(p->owner))
+			continue;
+		owner = p->owner;
+		data = p->data;
+		probe = p->probe;
+		best = p->range - 1;
+		*partno = dev - p->dev;
+		if (p->lock && p->lock(dev, data) < 0) {
+			module_put(owner);
+			continue;
+		}
+		mutex_unlock(&block_class_lock);
+		kobj = probe(dev, partno, data);
+		/* Currently ->owner protects _only_ ->probe() itself. */
+		module_put(owner);
+		if (kobj)
+			return dev_to_disk(kobj_to_dev(kobj));
+		goto retry;
+	}
+	mutex_unlock(&block_class_lock);
+	return NULL;
+}
+
+
 /**
  * get_gendisk - get partitioning information for a given device
  * @devt: device to get partitioning information for
@@ -993,11 +1085,7 @@ struct gendisk *get_gendisk(dev_t devt, int *partno)
 	might_sleep();
 
 	if (MAJOR(devt) != BLOCK_EXT_MAJOR) {
-		struct kobject *kobj;
-
-		kobj = kobj_lookup(bdev_map, devt, partno);
-		if (kobj)
-			disk = dev_to_disk(kobj_to_dev(kobj));
+		disk = lookup_gendisk(devt, partno);
 	} else {
 		struct hd_struct *part;
 
@@ -1210,6 +1298,22 @@ static struct kobject *base_probe(dev_t devt, int *partno, void *data)
 	return NULL;
 }
 
+static void bdev_map_init(void)
+{
+	struct bdev_map *base;
+	int i;
+
+	base = kzalloc(sizeof(*base), GFP_KERNEL);
+	if (!base)
+		panic("cannot allocate bdev_map");
+
+	base->dev = 1;
+	base->range = ~0 ;
+	base->probe = base_probe;
+	for (i = 0; i < 255; i++)
+		bdev_map[i] = base;
+}
+
 static int __init genhd_device_init(void)
 {
 	int error;
@@ -1218,7 +1322,7 @@ static int __init genhd_device_init(void)
 	error = class_register(&block_class);
 	if (unlikely(error))
 		return error;
-	bdev_map = kobj_map_init(base_probe, &block_class_lock);
+	bdev_map_init();
 	blk_dev_init();
 
 	register_blkdev(BLOCK_EXT_MAJOR, "blkext");
-- 
2.28.0

Re: [PATCH 02/18] block: open code kobj_map into in block/genhd.c

[Greg Kroah-Hartman]

On Thu, Oct 29, 2020 at 03:58:25PM +0100, Christoph Hellwig wrote:
> Copy and paste the kobj_map functionality in the block code in preparation
> for completely rewriting it.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Yes!

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

After this, you want me to get rid of kobj_map, right?  Or you don't
care as block doesn't use it anymore?  :)

thanks,

greg k-h

Re: [PATCH 02/18] block: open code kobj_map into in block/genhd.c

[Christoph Hellwig]

On Thu, Oct 29, 2020 at 08:22:36PM +0100, Greg Kroah-Hartman wrote:
> After this, you want me to get rid of kobj_map, right?  Or you don't
> care as block doesn't use it anymore?  :)

I have a patch to kill it, but it causes odd regressions with the
tpm driver according to the kernel test.  As I have grand plans that
build on the block ѕide of this series for 5.11, I plan to defer the
chardev side and address it for 5.12.

Re: [PATCH 02/18] block: open code kobj_map into in block/genhd.c

[Greg Kroah-Hartman]

On Thu, Oct 29, 2020 at 08:32:42PM +0100, Christoph Hellwig wrote:
> On Thu, Oct 29, 2020 at 08:22:36PM +0100, Greg Kroah-Hartman wrote:
> > After this, you want me to get rid of kobj_map, right?  Or you don't
> > care as block doesn't use it anymore?  :)
> 
> I have a patch to kill it, but it causes odd regressions with the
> tpm driver according to the kernel test.  As I have grand plans that
> build on the block ѕide of this series for 5.11, I plan to defer the
> chardev side and address it for 5.12.

Ok, sounds good.

Wow, I just looked at the tpm code, and it is, um, "interesting" in how
it thinks device lifespans work.  Nothing like having 4 different
structures with different lifespans embedded within a single structure.
Good thing that no one can dynamically remove a TPM device during
"normal" operation.

greg k-h

Re: [PATCH 02/18] block: open code kobj_map into in block/genhd.c

[Geert Uytterhoeven]

Hi Greg,

On Fri, Oct 30, 2020 at 11:40 AM Greg Kroah-Hartman
<gregkh@linuxfoundation.org> wrote:
> On Thu, Oct 29, 2020 at 08:32:42PM +0100, Christoph Hellwig wrote:
> > On Thu, Oct 29, 2020 at 08:22:36PM +0100, Greg Kroah-Hartman wrote:
> > > After this, you want me to get rid of kobj_map, right?  Or you don't
> > > care as block doesn't use it anymore?  :)
> >
> > I have a patch to kill it, but it causes odd regressions with the
> > tpm driver according to the kernel test.  As I have grand plans that
> > build on the block ѕide of this series for 5.11, I plan to defer the
> > chardev side and address it for 5.12.
>
> Ok, sounds good.
>
> Wow, I just looked at the tpm code, and it is, um, "interesting" in how
> it thinks device lifespans work.  Nothing like having 4 different
> structures with different lifespans embedded within a single structure.
> Good thing that no one can dynamically remove a TPM device during
> "normal" operation.

/sys/.../unbind?

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

Re: [PATCH 02/18] block: open code kobj_map into in block/genhd.c

[Greg Kroah-Hartman]

On Fri, Oct 30, 2020 at 11:49:11AM +0100, Geert Uytterhoeven wrote:
> Hi Greg,
> 
> On Fri, Oct 30, 2020 at 11:40 AM Greg Kroah-Hartman
> <gregkh@linuxfoundation.org> wrote:
> > On Thu, Oct 29, 2020 at 08:32:42PM +0100, Christoph Hellwig wrote:
> > > On Thu, Oct 29, 2020 at 08:22:36PM +0100, Greg Kroah-Hartman wrote:
> > > > After this, you want me to get rid of kobj_map, right?  Or you don't
> > > > care as block doesn't use it anymore?  :)
> > >
> > > I have a patch to kill it, but it causes odd regressions with the
> > > tpm driver according to the kernel test.  As I have grand plans that
> > > build on the block ѕide of this series for 5.11, I plan to defer the
> > > chardev side and address it for 5.12.
> >
> > Ok, sounds good.
> >
> > Wow, I just looked at the tpm code, and it is, um, "interesting" in how
> > it thinks device lifespans work.  Nothing like having 4 different
> > structures with different lifespans embedded within a single structure.
> > Good thing that no one can dynamically remove a TPM device during
> > "normal" operation.
> 
> /sys/.../unbind?

I said "normal" operations :)

Anyone who uses unbind and is suprised when things go "boom" is naive.

thanks,

greg k-h

Re: [PATCH 02/18] block: open code kobj_map into in block/genhd.c

[Christoph Hellwig]

On Fri, Oct 30, 2020 at 11:40:33AM +0100, Greg Kroah-Hartman wrote:
> On Thu, Oct 29, 2020 at 08:32:42PM +0100, Christoph Hellwig wrote:
> > On Thu, Oct 29, 2020 at 08:22:36PM +0100, Greg Kroah-Hartman wrote:
> > > After this, you want me to get rid of kobj_map, right?  Or you don't
> > > care as block doesn't use it anymore?  :)
> > 
> > I have a patch to kill it, but it causes odd regressions with the
> > tpm driver according to the kernel test.  As I have grand plans that
> > build on the block ѕide of this series for 5.11, I plan to defer the
> > chardev side and address it for 5.12.
> 
> Ok, sounds good.
> 
> Wow, I just looked at the tpm code, and it is, um, "interesting" in how
> it thinks device lifespans work.  Nothing like having 4 different
> structures with different lifespans embedded within a single structure.
> Good thing that no one can dynamically remove a TPM device during
> "normal" operation.

The regressions were during suspend then the tpm gets removed.  In
fact I'm pretty sure it is an existing problem that the change in the
lookup just surfaced in a way that the test bot notices, but I didn't
want to guard the block changes on it.

[PATCH 03/18] block: split block_class_lock

[Christoph Hellwig]

Split the block_class_lock mutex into one each to protect bdev_map
and major_names.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
---
 block/genhd.c | 29 +++++++++++++++--------------
 1 file changed, 15 insertions(+), 14 deletions(-)

diff --git a/block/genhd.c b/block/genhd.c
index 0e22ca64aca09e..8be38725aad4e5 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -25,7 +25,6 @@
 
 #include "blk.h"
 
-static DEFINE_MUTEX(block_class_lock);
 static struct kobject *block_depr;
 
 struct bdev_map {
@@ -37,6 +36,7 @@ struct bdev_map {
 	int (*lock)(dev_t, void *);
 	void *data;
 } *bdev_map[255];
+static DEFINE_MUTEX(bdev_map_lock);
 
 /* for extended dynamic devt allocation, currently only one major is used */
 #define NR_EXT_DEVT		(1 << MINORBITS)
@@ -400,6 +400,7 @@ static struct blk_major_name {
 	int major;
 	char name[16];
 } *major_names[BLKDEV_MAJOR_HASH_SIZE];
+static DEFINE_MUTEX(major_names_lock);
 
 /* index in the above - for now: assume no multimajor ranges */
 static inline int major_to_index(unsigned major)
@@ -412,11 +413,11 @@ void blkdev_show(struct seq_file *seqf, off_t offset)
 {
 	struct blk_major_name *dp;
 
-	mutex_lock(&block_class_lock);
+	mutex_lock(&major_names_lock);
 	for (dp = major_names[major_to_index(offset)]; dp; dp = dp->next)
 		if (dp->major == offset)
 			seq_printf(seqf, "%3d %s\n", dp->major, dp->name);
-	mutex_unlock(&block_class_lock);
+	mutex_unlock(&major_names_lock);
 }
 #endif /* CONFIG_PROC_FS */
 
@@ -445,7 +446,7 @@ int register_blkdev(unsigned int major, const char *name)
 	struct blk_major_name **n, *p;
 	int index, ret = 0;
 
-	mutex_lock(&block_class_lock);
+	mutex_lock(&major_names_lock);
 
 	/* temporary */
 	if (major == 0) {
@@ -498,7 +499,7 @@ int register_blkdev(unsigned int major, const char *name)
 		kfree(p);
 	}
 out:
-	mutex_unlock(&block_class_lock);
+	mutex_unlock(&major_names_lock);
 	return ret;
 }
 
@@ -510,7 +511,7 @@ void unregister_blkdev(unsigned int major, const char *name)
 	struct blk_major_name *p = NULL;
 	int index = major_to_index(major);
 
-	mutex_lock(&block_class_lock);
+	mutex_lock(&major_names_lock);
 	for (n = &major_names[index]; *n; n = &(*n)->next)
 		if ((*n)->major == major)
 			break;
@@ -520,7 +521,7 @@ void unregister_blkdev(unsigned int major, const char *name)
 		p = *n;
 		*n = p->next;
 	}
-	mutex_unlock(&block_class_lock);
+	mutex_unlock(&major_names_lock);
 	kfree(p);
 }
 
@@ -671,7 +672,7 @@ void blk_register_region(dev_t devt, unsigned long range, struct module *module,
 		p->data = data;
 	}
 
-	mutex_lock(&block_class_lock);
+	mutex_lock(&bdev_map_lock);
 	for (i = 0, p -= n; i < n; i++, p++, index++) {
 		struct bdev_map **s = &bdev_map[index % 255];
 		while (*s && (*s)->range < range)
@@ -679,7 +680,7 @@ void blk_register_region(dev_t devt, unsigned long range, struct module *module,
 		p->next = *s;
 		*s = p;
 	}
-	mutex_unlock(&block_class_lock);
+	mutex_unlock(&bdev_map_lock);
 }
 EXPORT_SYMBOL(blk_register_region);
 
@@ -690,7 +691,7 @@ void blk_unregister_region(dev_t devt, unsigned long range)
 	unsigned i;
 	struct bdev_map *found = NULL;
 
-	mutex_lock(&block_class_lock);
+	mutex_lock(&bdev_map_lock);
 	for (i = 0; i < min(n, 255u); i++, index++) {
 		struct bdev_map **s;
 		for (s = &bdev_map[index % 255]; *s; s = &(*s)->next) {
@@ -703,7 +704,7 @@ void blk_unregister_region(dev_t devt, unsigned long range)
 			}
 		}
 	}
-	mutex_unlock(&block_class_lock);
+	mutex_unlock(&bdev_map_lock);
 	kfree(found);
 }
 EXPORT_SYMBOL(blk_unregister_region);
@@ -1034,7 +1035,7 @@ static struct gendisk *lookup_gendisk(dev_t dev, int *partno)
 	unsigned long best = ~0UL;
 
 retry:
-	mutex_lock(&block_class_lock);
+	mutex_lock(&bdev_map_lock);
 	for (p = bdev_map[MAJOR(dev) % 255]; p; p = p->next) {
 		struct kobject *(*probe)(dev_t, int *, void *);
 		struct module *owner;
@@ -1055,7 +1056,7 @@ static struct gendisk *lookup_gendisk(dev_t dev, int *partno)
 			module_put(owner);
 			continue;
 		}
-		mutex_unlock(&block_class_lock);
+		mutex_unlock(&bdev_map_lock);
 		kobj = probe(dev, partno, data);
 		/* Currently ->owner protects _only_ ->probe() itself. */
 		module_put(owner);
@@ -1063,7 +1064,7 @@ static struct gendisk *lookup_gendisk(dev_t dev, int *partno)
 			return dev_to_disk(kobj_to_dev(kobj));
 		goto retry;
 	}
-	mutex_unlock(&block_class_lock);
+	mutex_unlock(&bdev_map_lock);
 	return NULL;
 }
 
-- 
2.28.0

[PATCH 04/18] block: rework requesting modules for unclaimed devices

[Christoph Hellwig]

Instead of reusing the ranges in bdev_map, add a new helper that is
called if no ranges was found.  This is a first step to unpeel and
eventually remove the complex ranges structure.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
---
 block/genhd.c | 25 +++++++++++++++----------
 1 file changed, 15 insertions(+), 10 deletions(-)

diff --git a/block/genhd.c b/block/genhd.c
index 8be38725aad4e5..0e9f67e79c53fd 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -1028,6 +1028,13 @@ static ssize_t disk_badblocks_store(struct device *dev,
 	return badblocks_store(disk->bb, page, len, 0);
 }
 
+static void request_gendisk_module(dev_t devt)
+{
+	if (request_module("block-major-%d-%d", MAJOR(devt), MINOR(devt)) > 0)
+		/* Make old-style 2.4 aliases work */
+		request_module("block-major-%d", MAJOR(devt));
+}
+
 static struct gendisk *lookup_gendisk(dev_t dev, int *partno)
 {
 	struct kobject *kobj;
@@ -1052,6 +1059,14 @@ static struct gendisk *lookup_gendisk(dev_t dev, int *partno)
 		probe = p->probe;
 		best = p->range - 1;
 		*partno = dev - p->dev;
+
+		if (!probe) {
+			mutex_unlock(&bdev_map_lock);
+			module_put(owner);
+			request_gendisk_module(dev);
+			goto retry;
+		}
+
 		if (p->lock && p->lock(dev, data) < 0) {
 			module_put(owner);
 			continue;
@@ -1290,15 +1305,6 @@ static const struct seq_operations partitions_op = {
 };
 #endif
 
-
-static struct kobject *base_probe(dev_t devt, int *partno, void *data)
-{
-	if (request_module("block-major-%d-%d", MAJOR(devt), MINOR(devt)) > 0)
-		/* Make old-style 2.4 aliases work */
-		request_module("block-major-%d", MAJOR(devt));
-	return NULL;
-}
-
 static void bdev_map_init(void)
 {
 	struct bdev_map *base;
@@ -1310,7 +1316,6 @@ static void bdev_map_init(void)
 
 	base->dev = 1;
 	base->range = ~0 ;
-	base->probe = base_probe;
 	for (i = 0; i < 255; i++)
 		bdev_map[i] = base;
 }
-- 
2.28.0

[PATCH 05/18] block: add an optional probe callback to major_names

[Christoph Hellwig]

Add a callback to the major_names array that allows a driver to override
how to probe for dev_t that doesn't currently have a gendisk registered.
This will help separating the lookup of the gendisk by dev_t vs probe
action for a not currently registered dev_t.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
---
 block/genhd.c         | 21 ++++++++++++++++++---
 include/linux/genhd.h |  5 ++++-
 2 files changed, 22 insertions(+), 4 deletions(-)

diff --git a/block/genhd.c b/block/genhd.c
index 0e9f67e79c53fd..e78c95cf3c00a9 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -399,6 +399,7 @@ static struct blk_major_name {
 	struct blk_major_name *next;
 	int major;
 	char name[16];
+	void (*probe)(dev_t devt);
 } *major_names[BLKDEV_MAJOR_HASH_SIZE];
 static DEFINE_MUTEX(major_names_lock);
 
@@ -441,7 +442,8 @@ void blkdev_show(struct seq_file *seqf, off_t offset)
  * See Documentation/admin-guide/devices.txt for the list of allocated
  * major numbers.
  */
-int register_blkdev(unsigned int major, const char *name)
+int __register_blkdev(unsigned int major, const char *name,
+		void (*probe)(dev_t devt))
 {
 	struct blk_major_name **n, *p;
 	int index, ret = 0;
@@ -480,6 +482,7 @@ int register_blkdev(unsigned int major, const char *name)
 	}
 
 	p->major = major;
+	p->probe = probe;
 	strlcpy(p->name, name, sizeof(p->name));
 	p->next = NULL;
 	index = major_to_index(major);
@@ -502,8 +505,7 @@ int register_blkdev(unsigned int major, const char *name)
 	mutex_unlock(&major_names_lock);
 	return ret;
 }
-
-EXPORT_SYMBOL(register_blkdev);
+EXPORT_SYMBOL(__register_blkdev);
 
 void unregister_blkdev(unsigned int major, const char *name)
 {
@@ -1030,6 +1032,19 @@ static ssize_t disk_badblocks_store(struct device *dev,
 
 static void request_gendisk_module(dev_t devt)
 {
+	unsigned int major = MAJOR(devt);
+	struct blk_major_name **n;
+
+	mutex_lock(&major_names_lock);
+	for (n = &major_names[major_to_index(major)]; *n; n = &(*n)->next) {
+		if ((*n)->major == major && (*n)->probe) {
+			(*n)->probe(devt);
+			mutex_unlock(&major_names_lock);
+			return;
+		}
+	}
+	mutex_unlock(&major_names_lock);
+
 	if (request_module("block-major-%d-%d", MAJOR(devt), MINOR(devt)) > 0)
 		/* Make old-style 2.4 aliases work */
 		request_module("block-major-%d", MAJOR(devt));
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index 38f23d75701379..14b1bc7dea21d8 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -368,7 +368,10 @@ extern void blk_unregister_region(dev_t devt, unsigned long range);
 
 #define alloc_disk(minors) alloc_disk_node(minors, NUMA_NO_NODE)
 
-int register_blkdev(unsigned int major, const char *name);
+int __register_blkdev(unsigned int major, const char *name,
+		void (*probe)(dev_t devt));
+#define register_blkdev(major, name) \
+	__register_blkdev(major, name, NULL)
 void unregister_blkdev(unsigned int major, const char *name);
 
 void revalidate_disk_size(struct gendisk *disk, bool verbose);
-- 
2.28.0

[PATCH 06/18] ide: remove ide_{,un}register_region

[Christoph Hellwig]

There is no need to ever register the fake gendisk used for ide-tape.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
---
 drivers/ide/ide-probe.c | 32 --------------------------------
 drivers/ide/ide-tape.c  |  2 --
 include/linux/ide.h     |  3 ---
 3 files changed, 37 deletions(-)

diff --git a/drivers/ide/ide-probe.c b/drivers/ide/ide-probe.c
index 1ddc45a04418cd..076d34b381720f 100644
--- a/drivers/ide/ide-probe.c
+++ b/drivers/ide/ide-probe.c
@@ -929,38 +929,6 @@ static struct kobject *ata_probe(dev_t dev, int *part, void *data)
 	return NULL;
 }
 
-static struct kobject *exact_match(dev_t dev, int *part, void *data)
-{
-	struct gendisk *p = data;
-	*part &= (1 << PARTN_BITS) - 1;
-	return &disk_to_dev(p)->kobj;
-}
-
-static int exact_lock(dev_t dev, void *data)
-{
-	struct gendisk *p = data;
-
-	if (!get_disk_and_module(p))
-		return -1;
-	return 0;
-}
-
-void ide_register_region(struct gendisk *disk)
-{
-	blk_register_region(MKDEV(disk->major, disk->first_minor),
-			    disk->minors, NULL, exact_match, exact_lock, disk);
-}
-
-EXPORT_SYMBOL_GPL(ide_register_region);
-
-void ide_unregister_region(struct gendisk *disk)
-{
-	blk_unregister_region(MKDEV(disk->major, disk->first_minor),
-			      disk->minors);
-}
-
-EXPORT_SYMBOL_GPL(ide_unregister_region);
-
 void ide_init_disk(struct gendisk *disk, ide_drive_t *drive)
 {
 	ide_hwif_t *hwif = drive->hwif;
diff --git a/drivers/ide/ide-tape.c b/drivers/ide/ide-tape.c
index 6f26634b22bbec..88b96437b22e62 100644
--- a/drivers/ide/ide-tape.c
+++ b/drivers/ide/ide-tape.c
@@ -1822,7 +1822,6 @@ static void ide_tape_remove(ide_drive_t *drive)
 
 	ide_proc_unregister_driver(drive, tape->driver);
 	device_del(&tape->dev);
-	ide_unregister_region(tape->disk);
 
 	mutex_lock(&idetape_ref_mutex);
 	put_device(&tape->dev);
@@ -2026,7 +2025,6 @@ static int ide_tape_probe(ide_drive_t *drive)
 		      "n%s", tape->name);
 
 	g->fops = &idetape_block_ops;
-	ide_register_region(g);
 
 	return 0;
 
diff --git a/include/linux/ide.h b/include/linux/ide.h
index 62653769509f89..2c300689a51a5c 100644
--- a/include/linux/ide.h
+++ b/include/linux/ide.h
@@ -1493,9 +1493,6 @@ static inline void ide_acpi_port_init_devices(ide_hwif_t *hwif) { ; }
 static inline void ide_acpi_set_state(ide_hwif_t *hwif, int on) {}
 #endif
 
-void ide_register_region(struct gendisk *);
-void ide_unregister_region(struct gendisk *);
-
 void ide_check_nien_quirk_list(ide_drive_t *);
 void ide_undecoded_slave(ide_drive_t *);
 
-- 
2.28.0

[PATCH 07/18] swim: don't call blk_register_region

[Christoph Hellwig]

The swim driver (unlike various other floppy drivers) doesn't have
magic device nodes for certain modes, and already registers a gendisk
for each of the floppies supported by a device.  Thus the region
registered is a no-op and can be removed.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
---
 drivers/block/swim.c | 17 -----------------
 1 file changed, 17 deletions(-)

diff --git a/drivers/block/swim.c b/drivers/block/swim.c
index 52dd1efa00f9c5..cc6a0bc6c005a7 100644
--- a/drivers/block/swim.c
+++ b/drivers/block/swim.c
@@ -745,18 +745,6 @@ static const struct block_device_operations floppy_fops = {
 	.check_events	 = floppy_check_events,
 };
 
-static struct kobject *floppy_find(dev_t dev, int *part, void *data)
-{
-	struct swim_priv *swd = data;
-	int drive = (*part & 3);
-
-	if (drive >= swd->floppy_count)
-		return NULL;
-
-	*part = 0;
-	return get_disk_and_module(swd->unit[drive].disk);
-}
-
 static int swim_add_floppy(struct swim_priv *swd, enum drive_location location)
 {
 	struct floppy_state *fs = &swd->unit[swd->floppy_count];
@@ -846,9 +834,6 @@ static int swim_floppy_init(struct swim_priv *swd)
 		add_disk(swd->unit[drive].disk);
 	}
 
-	blk_register_region(MKDEV(FLOPPY_MAJOR, 0), 256, THIS_MODULE,
-			    floppy_find, NULL, swd);
-
 	return 0;
 
 exit_put_disks:
@@ -932,8 +917,6 @@ static int swim_remove(struct platform_device *dev)
 	int drive;
 	struct resource *res;
 
-	blk_unregister_region(MKDEV(FLOPPY_MAJOR, 0), 256);
-
 	for (drive = 0; drive < swd->floppy_count; drive++) {
 		del_gendisk(swd->unit[drive].disk);
 		blk_cleanup_queue(swd->unit[drive].disk->queue);
-- 
2.28.0

[PATCH 08/18] sd: use __register_blkdev to avoid a modprobe for an unregistered dev_t

[Christoph Hellwig]

Switch from using blk_register_region to the probe callback passed to
__register_blkdev to disable the request_module call for an unclaimed
dev_t in the SD majors.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
---
 drivers/scsi/sd.c | 19 +++++--------------
 1 file changed, 5 insertions(+), 14 deletions(-)

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 656bcf4940d6d1..106a9cda0eb7ed 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -630,13 +630,11 @@ static struct scsi_driver sd_template = {
 };
 
 /*
- * Dummy kobj_map->probe function.
- * The default ->probe function will call modprobe, which is
- * pointless as this module is already loaded.
+ * Don't request a new module, as that could deadlock in multipath
+ * environment.
  */
-static struct kobject *sd_default_probe(dev_t devt, int *partno, void *data)
+static void sd_default_probe(dev_t devt)
 {
-	return NULL;
 }
 
 /*
@@ -3528,9 +3526,6 @@ static int sd_remove(struct device *dev)
 
 	free_opal_dev(sdkp->opal_dev);
 
-	blk_register_region(devt, SD_MINORS, NULL,
-			    sd_default_probe, NULL, NULL);
-
 	mutex_lock(&sd_ref_mutex);
 	dev_set_drvdata(dev, NULL);
 	put_device(&sdkp->dev);
@@ -3720,11 +3715,9 @@ static int __init init_sd(void)
 	SCSI_LOG_HLQUEUE(3, printk("init_sd: sd driver entry point\n"));
 
 	for (i = 0; i < SD_MAJORS; i++) {
-		if (register_blkdev(sd_major(i), "sd") != 0)
+		if (__register_blkdev(sd_major(i), "sd", sd_default_probe))
 			continue;
 		majors++;
-		blk_register_region(sd_major(i), SD_MINORS, NULL,
-				    sd_default_probe, NULL, NULL);
 	}
 
 	if (!majors)
@@ -3797,10 +3790,8 @@ static void __exit exit_sd(void)
 
 	class_unregister(&sd_disk_class);
 
-	for (i = 0; i < SD_MAJORS; i++) {
-		blk_unregister_region(sd_major(i), SD_MINORS);
+	for (i = 0; i < SD_MAJORS; i++)
 		unregister_blkdev(sd_major(i), "sd");
-	}
 }
 
 module_init(init_sd);
-- 
2.28.0

Re: [PATCH 08/18] sd: use __register_blkdev to avoid a modprobe for an unregistered dev_t

[Martin K. Petersen]

Christoph,

> Switch from using blk_register_region to the probe callback passed to
> __register_blkdev to disable the request_module call for an unclaimed
> dev_t in the SD majors.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> Reviewed-by: Hannes Reinecke <hare@suse.de>

Acked-by: Martin K. Petersen <martin.petersen@oracle.com>

-- 
Martin K. Petersen	Oracle Linux Engineering

[PATCH 09/18] brd: use __register_blkdev to allocate devices on demand

[Christoph Hellwig]

Use the simpler mechanism attached to major_name to allocate a brd device
when a currently unregistered minor is accessed.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
---
 drivers/block/brd.c | 39 +++++++++++----------------------------
 1 file changed, 11 insertions(+), 28 deletions(-)

diff --git a/drivers/block/brd.c b/drivers/block/brd.c
index cc49a921339f77..c43a6ab4b1f39f 100644
--- a/drivers/block/brd.c
+++ b/drivers/block/brd.c
@@ -426,14 +426,15 @@ static void brd_free(struct brd_device *brd)
 	kfree(brd);
 }
 
-static struct brd_device *brd_init_one(int i, bool *new)
+static void brd_probe(dev_t dev)
 {
 	struct brd_device *brd;
+	int i = MINOR(dev) / max_part;
 
-	*new = false;
+	mutex_lock(&brd_devices_mutex);
 	list_for_each_entry(brd, &brd_devices, brd_list) {
 		if (brd->brd_number == i)
-			goto out;
+			goto out_unlock;
 	}
 
 	brd = brd_alloc(i);
@@ -442,9 +443,9 @@ static struct brd_device *brd_init_one(int i, bool *new)
 		add_disk(brd->brd_disk);
 		list_add_tail(&brd->brd_list, &brd_devices);
 	}
-	*new = true;
-out:
-	return brd;
+
+out_unlock:
+	mutex_unlock(&brd_devices_mutex);
 }
 
 static void brd_del_one(struct brd_device *brd)
@@ -454,23 +455,6 @@ static void brd_del_one(struct brd_device *brd)
 	brd_free(brd);
 }
 
-static struct kobject *brd_probe(dev_t dev, int *part, void *data)
-{
-	struct brd_device *brd;
-	struct kobject *kobj;
-	bool new;
-
-	mutex_lock(&brd_devices_mutex);
-	brd = brd_init_one(MINOR(dev) / max_part, &new);
-	kobj = brd ? get_disk_and_module(brd->brd_disk) : NULL;
-	mutex_unlock(&brd_devices_mutex);
-
-	if (new)
-		*part = 0;
-
-	return kobj;
-}
-
 static inline void brd_check_and_reset_par(void)
 {
 	if (unlikely(!max_part))
@@ -510,11 +494,12 @@ static int __init brd_init(void)
 	 *	dynamically.
 	 */
 
-	if (register_blkdev(RAMDISK_MAJOR, "ramdisk"))
+	if (__register_blkdev(RAMDISK_MAJOR, "ramdisk", brd_probe))
 		return -EIO;
 
 	brd_check_and_reset_par();
 
+	mutex_lock(&brd_devices_mutex);
 	for (i = 0; i < rd_nr; i++) {
 		brd = brd_alloc(i);
 		if (!brd)
@@ -532,9 +517,7 @@ static int __init brd_init(void)
 		brd->brd_disk->queue = brd->brd_queue;
 		add_disk(brd->brd_disk);
 	}
-
-	blk_register_region(MKDEV(RAMDISK_MAJOR, 0), 1UL << MINORBITS,
-				  THIS_MODULE, brd_probe, NULL, NULL);
+	mutex_unlock(&brd_devices_mutex);
 
 	pr_info("brd: module loaded\n");
 	return 0;
@@ -544,6 +527,7 @@ static int __init brd_init(void)
 		list_del(&brd->brd_list);
 		brd_free(brd);
 	}
+	mutex_unlock(&brd_devices_mutex);
 	unregister_blkdev(RAMDISK_MAJOR, "ramdisk");
 
 	pr_info("brd: module NOT loaded !!!\n");
@@ -557,7 +541,6 @@ static void __exit brd_exit(void)
 	list_for_each_entry_safe(brd, next, &brd_devices, brd_list)
 		brd_del_one(brd);
 
-	blk_unregister_region(MKDEV(RAMDISK_MAJOR, 0), 1UL << MINORBITS);
 	unregister_blkdev(RAMDISK_MAJOR, "ramdisk");
 
 	pr_info("brd: module unloaded\n");
-- 
2.28.0

[PATCH 10/18] loop: use __register_blkdev to allocate devices on demand

[Christoph Hellwig]

Use the simpler mechanism attached to major_name to allocate a brd device
when a currently unregistered minor is accessed.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
---
 drivers/block/loop.c | 30 ++++++++----------------------
 1 file changed, 8 insertions(+), 22 deletions(-)

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index cb1191d6e945f2..15b5a0ea7cc4a9 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -2234,24 +2234,18 @@ static int loop_lookup(struct loop_device **l, int i)
 	return ret;
 }
 
-static struct kobject *loop_probe(dev_t dev, int *part, void *data)
+static void loop_probe(dev_t dev)
 {
+	int idx = MINOR(dev) >> part_shift;
 	struct loop_device *lo;
-	struct kobject *kobj;
-	int err;
+
+	if (max_loop && idx >= max_loop)
+		return;
 
 	mutex_lock(&loop_ctl_mutex);
-	err = loop_lookup(&lo, MINOR(dev) >> part_shift);
-	if (err < 0)
-		err = loop_add(&lo, MINOR(dev) >> part_shift);
-	if (err < 0)
-		kobj = NULL;
-	else
-		kobj = get_disk_and_module(lo->lo_disk);
+	if (loop_lookup(&lo, idx) < 0)
+		loop_add(&lo, idx);
 	mutex_unlock(&loop_ctl_mutex);
-
-	*part = 0;
-	return kobj;
 }
 
 static long loop_control_ioctl(struct file *file, unsigned int cmd,
@@ -2371,14 +2365,11 @@ static int __init loop_init(void)
 		goto err_out;
 
 
-	if (register_blkdev(LOOP_MAJOR, "loop")) {
+	if (__register_blkdev(LOOP_MAJOR, "loop", loop_probe)) {
 		err = -EIO;
 		goto misc_out;
 	}
 
-	blk_register_region(MKDEV(LOOP_MAJOR, 0), range,
-				  THIS_MODULE, loop_probe, NULL, NULL);
-
 	/* pre-create number of devices given by config or max_loop */
 	mutex_lock(&loop_ctl_mutex);
 	for (i = 0; i < nr; i++)
@@ -2404,16 +2395,11 @@ static int loop_exit_cb(int id, void *ptr, void *data)
 
 static void __exit loop_exit(void)
 {
-	unsigned long range;
-
-	range = max_loop ? max_loop << part_shift : 1UL << MINORBITS;
-
 	mutex_lock(&loop_ctl_mutex);
 
 	idr_for_each(&loop_index_idr, &loop_exit_cb, NULL);
 	idr_destroy(&loop_index_idr);
 
-	blk_unregister_region(MKDEV(LOOP_MAJOR, 0), range);
 	unregister_blkdev(LOOP_MAJOR, "loop");
 
 	misc_deregister(&loop_misc);
-- 
2.28.0

[PATCH 11/18] md: use __register_blkdev to allocate devices on demand

[Christoph Hellwig]

Use the simpler mechanism attached to major_name to allocate a md device
when a currently unregistered minor is accessed.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Song Liu <song@kernel.org>
Reviewed-by: Hannes Reinecke <hare@suse.de>
---
 drivers/md/md.c | 21 ++++++++-------------
 1 file changed, 8 insertions(+), 13 deletions(-)

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 98bac4f304ae26..2268bd92a2267b 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -5765,11 +5765,12 @@ static int md_alloc(dev_t dev, char *name)
 	return error;
 }
 
-static struct kobject *md_probe(dev_t dev, int *part, void *data)
+static void md_probe(dev_t dev)
 {
+	if (MAJOR(dev) == MD_MAJOR && MINOR(dev) >= 512)
+		return;
 	if (create_on_open)
 		md_alloc(dev, NULL);
-	return NULL;
 }
 
 static int add_named_array(const char *val, const struct kernel_param *kp)
@@ -6535,7 +6536,7 @@ static void autorun_devices(int part)
 			break;
 		}
 
-		md_probe(dev, NULL, NULL);
+		md_probe(dev);
 		mddev = mddev_find(dev);
 		if (!mddev || !mddev->gendisk) {
 			if (mddev)
@@ -9567,18 +9568,15 @@ static int __init md_init(void)
 	if (!md_rdev_misc_wq)
 		goto err_rdev_misc_wq;
 
-	if ((ret = register_blkdev(MD_MAJOR, "md")) < 0)
+	ret = __register_blkdev(MD_MAJOR, "md", md_probe);
+	if (ret < 0)
 		goto err_md;
 
-	if ((ret = register_blkdev(0, "mdp")) < 0)
+	ret = __register_blkdev(0, "mdp", md_probe);
+	if (ret < 0)
 		goto err_mdp;
 	mdp_major = ret;
 
-	blk_register_region(MKDEV(MD_MAJOR, 0), 512, THIS_MODULE,
-			    md_probe, NULL, NULL);
-	blk_register_region(MKDEV(mdp_major, 0), 1UL<<MINORBITS, THIS_MODULE,
-			    md_probe, NULL, NULL);
-
 	register_reboot_notifier(&md_notifier);
 	raid_table_header = register_sysctl_table(raid_root_table);
 
@@ -9845,9 +9843,6 @@ static __exit void md_exit(void)
 	struct list_head *tmp;
 	int delay = 1;
 
-	blk_unregister_region(MKDEV(MD_MAJOR,0), 512);
-	blk_unregister_region(MKDEV(mdp_major,0), 1U << MINORBITS);
-
 	unregister_blkdev(MD_MAJOR,"md");
 	unregister_blkdev(mdp_major, "mdp");
 	unregister_reboot_notifier(&md_notifier);
-- 
2.28.0

[PATCH 12/18] ide: switch to __register_blkdev for command set probing

[Christoph Hellwig]

ide is the last user of the blk_register_region framework except for the
tracking of allocated gendisk.  Switch to __register_blkdev, even if that
doesn't allow us to trivially find out which command set to probe for.
That means we now always request all modules when a user tries to access
an unclaimed ide device node, but except for a few potentially loaded
modules for a fringe use case of a deprecated and soon to be removed
driver that doesn't make a difference.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
---
 drivers/ide/ide-probe.c | 34 ++++++----------------------------
 1 file changed, 6 insertions(+), 28 deletions(-)

diff --git a/drivers/ide/ide-probe.c b/drivers/ide/ide-probe.c
index 076d34b381720f..1c1567bb519429 100644
--- a/drivers/ide/ide-probe.c
+++ b/drivers/ide/ide-probe.c
@@ -902,31 +902,12 @@ static int init_irq (ide_hwif_t *hwif)
 	return 1;
 }
 
-static int ata_lock(dev_t dev, void *data)
+static void ata_probe(dev_t dev)
 {
-	/* FIXME: we want to pin hwif down */
-	return 0;
-}
-
-static struct kobject *ata_probe(dev_t dev, int *part, void *data)
-{
-	ide_hwif_t *hwif = data;
-	int unit = *part >> PARTN_BITS;
-	ide_drive_t *drive = hwif->devices[unit];
-
-	if ((drive->dev_flags & IDE_DFLAG_PRESENT) == 0)
-		return NULL;
-
-	if (drive->media == ide_disk)
-		request_module("ide-disk");
-	if (drive->media == ide_cdrom || drive->media == ide_optical)
-		request_module("ide-cd");
-	if (drive->media == ide_tape)
-		request_module("ide-tape");
-	if (drive->media == ide_floppy)
-		request_module("ide-floppy");
-
-	return NULL;
+	request_module("ide-disk");
+	request_module("ide-cd");
+	request_module("ide-tape");
+	request_module("ide-floppy");
 }
 
 void ide_init_disk(struct gendisk *disk, ide_drive_t *drive)
@@ -967,7 +948,7 @@ static int hwif_init(ide_hwif_t *hwif)
 		return 0;
 	}
 
-	if (register_blkdev(hwif->major, hwif->name))
+	if (__register_blkdev(hwif->major, hwif->name, ata_probe))
 		return 0;
 
 	if (!hwif->sg_max_nents)
@@ -989,8 +970,6 @@ static int hwif_init(ide_hwif_t *hwif)
 		goto out;
 	}
 
-	blk_register_region(MKDEV(hwif->major, 0), MAX_DRIVES << PARTN_BITS,
-			    THIS_MODULE, ata_probe, ata_lock, hwif);
 	return 1;
 
 out:
@@ -1582,7 +1561,6 @@ static void ide_unregister(ide_hwif_t *hwif)
 	/*
 	 * Remove us from the kernel's knowledge
 	 */
-	blk_unregister_region(MKDEV(hwif->major, 0), MAX_DRIVES<<PARTN_BITS);
 	kfree(hwif->sg_table);
 	unregister_blkdev(hwif->major, hwif->name);
 
-- 
2.28.0

[PATCH 13/18] floppy: use a separate gendisk for each media format

[Christoph Hellwig]

The floppy driver usually autodetects the media when used with the
normal /dev/fd? devices, which also are the only nodes created by udev.
But it also supports various aliases that force a given media format.
That is currently supported using the blk_register_region framework
which finds the floppy gendisk even for a 'mismatched' dev_t.  The
problem with this (besides the code complexity) is that it creates
multiple struct block_device instances for the whole device of a
single gendisk, which can lead to interesting issues in code not
aware of that fact.

To fix this just create a separate gendisk for each of the aliases
if they are accessed.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/block/floppy.c | 154 ++++++++++++++++++++++++++---------------
 1 file changed, 97 insertions(+), 57 deletions(-)

diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c
index 7df79ae6b0a1e1..dfe1dfc901ccc2 100644
--- a/drivers/block/floppy.c
+++ b/drivers/block/floppy.c
@@ -402,7 +402,6 @@ static struct floppy_drive_params drive_params[N_DRIVE];
 static struct floppy_drive_struct drive_state[N_DRIVE];
 static struct floppy_write_errors write_errors[N_DRIVE];
 static struct timer_list motor_off_timer[N_DRIVE];
-static struct gendisk *disks[N_DRIVE];
 static struct blk_mq_tag_set tag_sets[N_DRIVE];
 static struct block_device *opened_bdev[N_DRIVE];
 static DEFINE_MUTEX(open_lock);
@@ -477,6 +476,8 @@ static struct floppy_struct floppy_type[32] = {
 	{ 3200,20,2,80,0,0x1C,0x00,0xCF,0x2C,"H1600" }, /* 31 1.6MB 3.5"    */
 };
 
+static struct gendisk *disks[N_DRIVE][ARRAY_SIZE(floppy_type)];
+
 #define SECTSIZE (_FD_SECTSIZE(*floppy))
 
 /* Auto-detection: Disk type used until the next media change occurs. */
@@ -4111,7 +4112,7 @@ static int floppy_open(struct block_device *bdev, fmode_t mode)
 
 	new_dev = MINOR(bdev->bd_dev);
 	drive_state[drive].fd_device = new_dev;
-	set_capacity(disks[drive], floppy_sizes[new_dev]);
+	set_capacity(disks[drive][ITYPE(new_dev)], floppy_sizes[new_dev]);
 	if (old_dev != -1 && old_dev != new_dev) {
 		if (buffer_drive == drive)
 			buffer_track = -1;
@@ -4579,15 +4580,58 @@ static bool floppy_available(int drive)
 	return true;
 }
 
-static struct kobject *floppy_find(dev_t dev, int *part, void *data)
+static int floppy_alloc_disk(unsigned int drive, unsigned int type)
 {
-	int drive = (*part & 3) | ((*part & 0x80) >> 5);
-	if (drive >= N_DRIVE || !floppy_available(drive))
-		return NULL;
-	if (((*part >> 2) & 0x1f) >= ARRAY_SIZE(floppy_type))
-		return NULL;
-	*part = 0;
-	return get_disk_and_module(disks[drive]);
+	struct gendisk *disk;
+	int err;
+
+	disk = alloc_disk(1);
+	if (!disk)
+		return -ENOMEM;
+
+	disk->queue = blk_mq_init_queue(&tag_sets[drive]);
+	if (IS_ERR(disk->queue)) {
+		err = PTR_ERR(disk->queue);
+		disk->queue = NULL;
+		put_disk(disk);
+		return err;
+	}
+
+	blk_queue_bounce_limit(disk->queue, BLK_BOUNCE_HIGH);
+	blk_queue_max_hw_sectors(disk->queue, 64);
+	disk->major = FLOPPY_MAJOR;
+	disk->first_minor = TOMINOR(drive) | (type << 2);
+	disk->fops = &floppy_fops;
+	disk->events = DISK_EVENT_MEDIA_CHANGE;
+	if (type)
+		sprintf(disk->disk_name, "fd%d_type%d", drive, type);
+	else
+		sprintf(disk->disk_name, "fd%d", drive);
+	/* to be cleaned up... */
+	disk->private_data = (void *)(long)drive;
+	disk->flags |= GENHD_FL_REMOVABLE;
+
+	disks[drive][type] = disk;
+	return 0;
+}
+
+static DEFINE_MUTEX(floppy_probe_lock);
+
+static void floppy_probe(dev_t dev)
+{
+	unsigned int drive = (MINOR(dev) & 3) | ((MINOR(dev) & 0x80) >> 5);
+	unsigned int type = (MINOR(dev) >> 2) & 0x1f;
+
+	if (drive >= N_DRIVE || !floppy_available(drive) ||
+	    type >= ARRAY_SIZE(floppy_type))
+		return;
+
+	mutex_lock(&floppy_probe_lock);
+	if (!disks[drive][type]) {
+		if (floppy_alloc_disk(drive, type) == 0)
+			add_disk(disks[drive][type]);
+	}
+	mutex_unlock(&floppy_probe_lock);
 }
 
 static int __init do_floppy_init(void)
@@ -4609,33 +4653,25 @@ static int __init do_floppy_init(void)
 		return -ENOMEM;
 
 	for (drive = 0; drive < N_DRIVE; drive++) {
-		disks[drive] = alloc_disk(1);
-		if (!disks[drive]) {
-			err = -ENOMEM;
+		memset(&tag_sets[drive], 0, sizeof(tag_sets[drive]));
+		tag_sets[drive].ops = &floppy_mq_ops;
+		tag_sets[drive].nr_hw_queues = 1;
+		tag_sets[drive].nr_maps = 1;
+		tag_sets[drive].queue_depth = 2;
+		tag_sets[drive].numa_node = NUMA_NO_NODE;
+		tag_sets[drive].flags = BLK_MQ_F_SHOULD_MERGE;
+		err = blk_mq_alloc_tag_set(&tag_sets[drive]);
+		if (err)
 			goto out_put_disk;
-		}
 
-		disks[drive]->queue = blk_mq_init_sq_queue(&tag_sets[drive],
-							   &floppy_mq_ops, 2,
-							   BLK_MQ_F_SHOULD_MERGE);
-		if (IS_ERR(disks[drive]->queue)) {
-			err = PTR_ERR(disks[drive]->queue);
-			disks[drive]->queue = NULL;
+		err = floppy_alloc_disk(drive, 0);
+		if (err)
 			goto out_put_disk;
-		}
-
-		blk_queue_bounce_limit(disks[drive]->queue, BLK_BOUNCE_HIGH);
-		blk_queue_max_hw_sectors(disks[drive]->queue, 64);
-		disks[drive]->major = FLOPPY_MAJOR;
-		disks[drive]->first_minor = TOMINOR(drive);
-		disks[drive]->fops = &floppy_fops;
-		disks[drive]->events = DISK_EVENT_MEDIA_CHANGE;
-		sprintf(disks[drive]->disk_name, "fd%d", drive);
 
 		timer_setup(&motor_off_timer[drive], motor_off_callback, 0);
 	}
 
-	err = register_blkdev(FLOPPY_MAJOR, "fd");
+	err = __register_blkdev(FLOPPY_MAJOR, "fd", floppy_probe);
 	if (err)
 		goto out_put_disk;
 
@@ -4643,9 +4679,6 @@ static int __init do_floppy_init(void)
 	if (err)
 		goto out_unreg_blkdev;
 
-	blk_register_region(MKDEV(FLOPPY_MAJOR, 0), 256, THIS_MODULE,
-			    floppy_find, NULL, NULL);
-
 	for (i = 0; i < 256; i++)
 		if (ITYPE(i))
 			floppy_sizes[i] = floppy_type[ITYPE(i)].size;
@@ -4673,7 +4706,7 @@ static int __init do_floppy_init(void)
 	if (fdc_state[0].address == -1) {
 		cancel_delayed_work(&fd_timeout);
 		err = -ENODEV;
-		goto out_unreg_region;
+		goto out_unreg_driver;
 	}
 #if N_FDC > 1
 	fdc_state[1].address = FDC2;
@@ -4684,7 +4717,7 @@ static int __init do_floppy_init(void)
 	if (err) {
 		cancel_delayed_work(&fd_timeout);
 		err = -EBUSY;
-		goto out_unreg_region;
+		goto out_unreg_driver;
 	}
 
 	/* initialise drive state */
@@ -4761,10 +4794,8 @@ static int __init do_floppy_init(void)
 		if (err)
 			goto out_remove_drives;
 
-		/* to be cleaned up... */
-		disks[drive]->private_data = (void *)(long)drive;
-		disks[drive]->flags |= GENHD_FL_REMOVABLE;
-		device_add_disk(&floppy_device[drive].dev, disks[drive], NULL);
+		device_add_disk(&floppy_device[drive].dev, disks[drive][0],
+				NULL);
 	}
 
 	return 0;
@@ -4772,30 +4803,27 @@ static int __init do_floppy_init(void)
 out_remove_drives:
 	while (drive--) {
 		if (floppy_available(drive)) {
-			del_gendisk(disks[drive]);
+			del_gendisk(disks[drive][0]);
 			platform_device_unregister(&floppy_device[drive]);
 		}
 	}
 out_release_dma:
 	if (atomic_read(&usage_count))
 		floppy_release_irq_and_dma();
-out_unreg_region:
-	blk_unregister_region(MKDEV(FLOPPY_MAJOR, 0), 256);
+out_unreg_driver:
 	platform_driver_unregister(&floppy_driver);
 out_unreg_blkdev:
 	unregister_blkdev(FLOPPY_MAJOR, "fd");
 out_put_disk:
 	destroy_workqueue(floppy_wq);
 	for (drive = 0; drive < N_DRIVE; drive++) {
-		if (!disks[drive])
+		if (!disks[drive][0])
 			break;
-		if (disks[drive]->queue) {
-			del_timer_sync(&motor_off_timer[drive]);
-			blk_cleanup_queue(disks[drive]->queue);
-			disks[drive]->queue = NULL;
-			blk_mq_free_tag_set(&tag_sets[drive]);
-		}
-		put_disk(disks[drive]);
+		del_timer_sync(&motor_off_timer[drive]);
+		blk_cleanup_queue(disks[drive][0]->queue);
+		disks[drive][0]->queue = NULL;
+		blk_mq_free_tag_set(&tag_sets[drive]);
+		put_disk(disks[drive][0]);
 	}
 	return err;
 }
@@ -5006,9 +5034,8 @@ module_init(floppy_module_init);
 
 static void __exit floppy_module_exit(void)
 {
-	int drive;
+	int drive, i;
 
-	blk_unregister_region(MKDEV(FLOPPY_MAJOR, 0), 256);
 	unregister_blkdev(FLOPPY_MAJOR, "fd");
 	platform_driver_unregister(&floppy_driver);
 
@@ -5018,10 +5045,16 @@ static void __exit floppy_module_exit(void)
 		del_timer_sync(&motor_off_timer[drive]);
 
 		if (floppy_available(drive)) {
-			del_gendisk(disks[drive]);
+			for (i = 0; i < ARRAY_SIZE(floppy_type); i++) {
+				if (disks[drive][i])
+					del_gendisk(disks[drive][i]);
+			}
 			platform_device_unregister(&floppy_device[drive]);
 		}
-		blk_cleanup_queue(disks[drive]->queue);
+		for (i = 0; i < ARRAY_SIZE(floppy_type); i++) {
+			if (disks[drive][i])
+				blk_cleanup_queue(disks[drive][i]->queue);
+		}
 		blk_mq_free_tag_set(&tag_sets[drive]);
 
 		/*
@@ -5029,10 +5062,17 @@ static void __exit floppy_module_exit(void)
 		 * queue reference in put_disk().
 		 */
 		if (!(allowed_drive_mask & (1 << drive)) ||
-		    fdc_state[FDC(drive)].version == FDC_NONE)
-			disks[drive]->queue = NULL;
+		    fdc_state[FDC(drive)].version == FDC_NONE) {
+			for (i = 0; i < ARRAY_SIZE(floppy_type); i++) {
+				if (disks[drive][i])
+					disks[drive][i]->queue = NULL;
+			}
+		}
 
-		put_disk(disks[drive]);
+		for (i = 0; i < ARRAY_SIZE(floppy_type); i++) {
+			if (disks[drive][i])
+				put_disk(disks[drive][i]);
+		}
 	}
 
 	cancel_delayed_work_sync(&fd_timeout);
-- 
2.28.0

[PATCH 14/18] amiflop: use separate gendisks for Amiga vs MS-DOS mode

[Christoph Hellwig]

Use separate gendisks (which share a tag_set) for the native Amgiga vs
the MS-DOS mode instead of redirecting the gendisk lookup using a probe
callback.  This avoids potential problems with aliased block_device
instances and will eventually allow for removing the blk_register_region
framework.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
---
 drivers/block/amiflop.c | 98 +++++++++++++++++++++++------------------
 1 file changed, 55 insertions(+), 43 deletions(-)

diff --git a/drivers/block/amiflop.c b/drivers/block/amiflop.c
index 71c2b156455860..9e2d0c6a387721 100644
--- a/drivers/block/amiflop.c
+++ b/drivers/block/amiflop.c
@@ -201,7 +201,7 @@ struct amiga_floppy_struct {
 	int busy;			/* true when drive is active */
 	int dirty;			/* true when trackbuf is not on disk */
 	int status;			/* current error code for unit */
-	struct gendisk *gendisk;
+	struct gendisk *gendisk[2];
 	struct blk_mq_tag_set tag_set;
 };
 
@@ -1669,6 +1669,11 @@ static int floppy_open(struct block_device *bdev, fmode_t mode)
 		return -EBUSY;
 	}
 
+	if (unit[drive].type->code == FD_NODRIVE) {
+		mutex_unlock(&amiflop_mutex);
+		return -ENXIO;
+	}
+
 	if (mode & (FMODE_READ|FMODE_WRITE)) {
 		bdev_check_media_change(bdev);
 		if (mode & FMODE_WRITE) {
@@ -1695,7 +1700,7 @@ static int floppy_open(struct block_device *bdev, fmode_t mode)
 	unit[drive].dtype=&data_types[system];
 	unit[drive].blocks=unit[drive].type->heads*unit[drive].type->tracks*
 		data_types[system].sects*unit[drive].type->sect_mult;
-	set_capacity(unit[drive].gendisk, unit[drive].blocks);
+	set_capacity(unit[drive].gendisk[system], unit[drive].blocks);
 
 	printk(KERN_INFO "fd%d: accessing %s-disk with %s-layout\n",drive,
 	       unit[drive].type->name, data_types[system].name);
@@ -1772,36 +1777,68 @@ static const struct blk_mq_ops amiflop_mq_ops = {
 	.queue_rq = amiflop_queue_rq,
 };
 
-static struct gendisk *fd_alloc_disk(int drive)
+static int fd_alloc_disk(int drive, int system)
 {
 	struct gendisk *disk;
 
 	disk = alloc_disk(1);
 	if (!disk)
 		goto out;
-
-	disk->queue = blk_mq_init_sq_queue(&unit[drive].tag_set, &amiflop_mq_ops,
-						2, BLK_MQ_F_SHOULD_MERGE);
-	if (IS_ERR(disk->queue)) {
-		disk->queue = NULL;
+	disk->queue = blk_mq_init_queue(&unit[drive].tag_set);
+	if (IS_ERR(disk->queue))
 		goto out_put_disk;
-	}
 
+	disk->major = FLOPPY_MAJOR;
+	disk->first_minor = drive + system;
+	disk->fops = &floppy_fops;
+	disk->events = DISK_EVENT_MEDIA_CHANGE;
+	if (system)
+		sprintf(disk->disk_name, "fd%d_msdos", drive);
+	else
+		sprintf(disk->disk_name, "fd%d", drive);
+	disk->private_data = &unit[drive];
+	set_capacity(disk, 880 * 2);
+
+	unit[drive].gendisk[system] = disk;
+	add_disk(disk);
+	return 0;
+
+out_put_disk:
+	disk->queue = NULL;
+	put_disk(disk);
+out:
+	return -ENOMEM;
+}
+
+static int fd_alloc_drive(int drive)
+{
 	unit[drive].trackbuf = kmalloc(FLOPPY_MAX_SECTORS * 512, GFP_KERNEL);
 	if (!unit[drive].trackbuf)
-		goto out_cleanup_queue;
+		goto out;
 
-	return disk;
+	memset(&unit[drive].tag_set, 0, sizeof(unit[drive].tag_set));
+	unit[drive].tag_set.ops = &amiflop_mq_ops;
+	unit[drive].tag_set.nr_hw_queues = 1;
+	unit[drive].tag_set.nr_maps = 1;
+	unit[drive].tag_set.queue_depth = 2;
+	unit[drive].tag_set.numa_node = NUMA_NO_NODE;
+	unit[drive].tag_set.flags = BLK_MQ_F_SHOULD_MERGE;
+	if (blk_mq_alloc_tag_set(&unit[drive].tag_set))
+		goto out_cleanup_trackbuf;
 
-out_cleanup_queue:
-	blk_cleanup_queue(disk->queue);
-	disk->queue = NULL;
+	pr_cont(" fd%d", drive);
+
+	if (fd_alloc_disk(drive, 0) || fd_alloc_disk(drive, 1))
+		goto out_cleanup_tagset;
+	return 0;
+
+out_cleanup_tagset:
 	blk_mq_free_tag_set(&unit[drive].tag_set);
-out_put_disk:
-	put_disk(disk);
+out_cleanup_trackbuf:
+	kfree(unit[drive].trackbuf);
 out:
 	unit[drive].type->code = FD_NODRIVE;
-	return NULL;
+	return -ENOMEM;
 }
 
 static int __init fd_probe_drives(void)
@@ -1812,29 +1849,16 @@ static int __init fd_probe_drives(void)
 	drives=0;
 	nomem=0;
 	for(drive=0;drive<FD_MAX_UNITS;drive++) {
-		struct gendisk *disk;
 		fd_probe(drive);
 		if (unit[drive].type->code == FD_NODRIVE)
 			continue;
 
-		disk = fd_alloc_disk(drive);
-		if (!disk) {
+		if (fd_alloc_drive(drive) < 0) {
 			pr_cont(" no mem for fd%d", drive);
 			nomem = 1;
 			continue;
 		}
-		unit[drive].gendisk = disk;
 		drives++;
-
-		pr_cont(" fd%d",drive);
-		disk->major = FLOPPY_MAJOR;
-		disk->first_minor = drive;
-		disk->fops = &floppy_fops;
-		disk->events = DISK_EVENT_MEDIA_CHANGE;
-		sprintf(disk->disk_name, "fd%d", drive);
-		disk->private_data = &unit[drive];
-		set_capacity(disk, 880*2);
-		add_disk(disk);
 	}
 	if ((drives > 0) || (nomem == 0)) {
 		if (drives == 0)
@@ -1846,15 +1870,6 @@ static int __init fd_probe_drives(void)
 	return -ENOMEM;
 }
  
-static struct kobject *floppy_find(dev_t dev, int *part, void *data)
-{
-	int drive = *part & 3;
-	if (unit[drive].type->code == FD_NODRIVE)
-		return NULL;
-	*part = 0;
-	return get_disk_and_module(unit[drive].gendisk);
-}
-
 static int __init amiga_floppy_probe(struct platform_device *pdev)
 {
 	int i, ret;
@@ -1884,9 +1899,6 @@ static int __init amiga_floppy_probe(struct platform_device *pdev)
 	if (fd_probe_drives() < 1) /* No usable drives */
 		goto out_probe;
 
-	blk_register_region(MKDEV(FLOPPY_MAJOR, 0), 256, THIS_MODULE,
-				floppy_find, NULL, NULL);
-
 	/* initialize variables */
 	timer_setup(&motor_on_timer, motor_on_callback, 0);
 	motor_on_timer.expires = 0;
-- 
2.28.0

[PATCH 15/18] ataflop: use a separate gendisk for each media format

[Christoph Hellwig]

The Atari floppy driver usually autodetects the media when used with the
ormal /dev/fd? devices, which also are the only nodes created by udev.
But it also supports various aliases that force a given media format.
That is currently supported using the blk_register_region framework
which finds the floppy gendisk even for a 'mismatched' dev_t.  The
problem with this (besides the code complexity) is that it creates
multiple struct block_device instances for the whole device of a
single gendisk, which can lead to interesting issues in code not
aware of that fact.

To fix this just create a separate gendisk for each of the aliases
if they are accessed.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/block/ataflop.c | 135 +++++++++++++++++++++++++---------------
 1 file changed, 86 insertions(+), 49 deletions(-)

diff --git a/drivers/block/ataflop.c b/drivers/block/ataflop.c
index 3e881fdb06e0ad..104b713f4055af 100644
--- a/drivers/block/ataflop.c
+++ b/drivers/block/ataflop.c
@@ -297,7 +297,7 @@ static struct atari_floppy_struct {
 	unsigned int wpstat;	/* current state of WP signal (for
 				   disk change detection) */
 	int flags;		/* flags */
-	struct gendisk *disk;
+	struct gendisk *disk[NUM_DISK_MINORS];
 	int ref;
 	int type;
 	struct blk_mq_tag_set tag_set;
@@ -723,12 +723,16 @@ static void fd_error( void )
 
 static int do_format(int drive, int type, struct atari_format_descr *desc)
 {
-	struct request_queue *q = unit[drive].disk->queue;
+	struct request_queue *q;
 	unsigned char	*p;
 	int sect, nsect;
 	unsigned long	flags;
 	int ret;
 
+	if (type)
+		type--;
+
+	q = unit[drive].disk[type]->queue;
 	blk_mq_freeze_queue(q);
 	blk_mq_quiesce_queue(q);
 
@@ -738,7 +742,7 @@ static int do_format(int drive, int type, struct atari_format_descr *desc)
 	local_irq_restore(flags);
 
 	if (type) {
-		if (--type >= NUM_DISK_MINORS ||
+		if (type >= NUM_DISK_MINORS ||
 		    minor2disktype[type].drive_types > DriveType) {
 			ret = -EINVAL;
 			goto out;
@@ -1154,7 +1158,7 @@ static void fd_rwsec_done1(int status)
 			    if (SUDT[-1].blocks > ReqBlock) {
 				/* try another disk type */
 				SUDT--;
-				set_capacity(unit[SelectedDrive].disk,
+				set_capacity(unit[SelectedDrive].disk[0],
 							SUDT->blocks);
 			    } else
 				Probing = 0;
@@ -1169,7 +1173,7 @@ static void fd_rwsec_done1(int status)
 /* record not found, but not probing. Maybe stretch wrong ? Restart probing */
 			if (SUD.autoprobe) {
 				SUDT = atari_disk_type + StartDiskType[DriveType];
-				set_capacity(unit[SelectedDrive].disk,
+				set_capacity(unit[SelectedDrive].disk[0],
 							SUDT->blocks);
 				Probing = 1;
 			}
@@ -1515,7 +1519,7 @@ static blk_status_t ataflop_queue_rq(struct blk_mq_hw_ctx *hctx,
 		if (!UDT) {
 			Probing = 1;
 			UDT = atari_disk_type + StartDiskType[DriveType];
-			set_capacity(floppy->disk, UDT->blocks);
+			set_capacity(bd->rq->rq_disk, UDT->blocks);
 			UD.autoprobe = 1;
 		}
 	} 
@@ -1533,7 +1537,7 @@ static blk_status_t ataflop_queue_rq(struct blk_mq_hw_ctx *hctx,
 		}
 		type = minor2disktype[type].index;
 		UDT = &atari_disk_type[type];
-		set_capacity(floppy->disk, UDT->blocks);
+		set_capacity(bd->rq->rq_disk, UDT->blocks);
 		UD.autoprobe = 0;
 	}
 
@@ -1658,7 +1662,7 @@ static int fd_locked_ioctl(struct block_device *bdev, fmode_t mode,
 				    printk (KERN_INFO "floppy%d: setting %s %p!\n",
 				        drive, dtp->name, dtp);
 				UDT = dtp;
-				set_capacity(floppy->disk, UDT->blocks);
+				set_capacity(disk, UDT->blocks);
 
 				if (cmd == FDDEFPRM) {
 				  /* save settings as permanent default type */
@@ -1702,7 +1706,7 @@ static int fd_locked_ioctl(struct block_device *bdev, fmode_t mode,
 			return -EINVAL;
 
 		UDT = dtp;
-		set_capacity(floppy->disk, UDT->blocks);
+		set_capacity(disk, UDT->blocks);
 
 		return 0;
 	case FDMSGON:
@@ -1725,7 +1729,7 @@ static int fd_locked_ioctl(struct block_device *bdev, fmode_t mode,
 		UDT = NULL;
 		/* MSch: invalidate default_params */
 		default_params[drive].blocks  = 0;
-		set_capacity(floppy->disk, MAX_DISK_SIZE * 2);
+		set_capacity(disk, MAX_DISK_SIZE * 2);
 		fallthrough;
 	case FDFMTEND:
 	case FDFLUSH:
@@ -1962,14 +1966,50 @@ static const struct blk_mq_ops ataflop_mq_ops = {
 	.commit_rqs = ataflop_commit_rqs,
 };
 
-static struct kobject *floppy_find(dev_t dev, int *part, void *data)
+static int ataflop_alloc_disk(unsigned int drive, unsigned int type)
 {
-	int drive = *part & 3;
-	int type  = *part >> 2;
+	struct gendisk *disk;
+	int ret;
+
+	disk = alloc_disk(1);
+	if (!disk)
+		return -ENOMEM;
+
+	disk->queue = blk_mq_init_queue(&unit[drive].tag_set);
+	if (IS_ERR(disk->queue)) {
+		ret = PTR_ERR(disk->queue);
+		disk->queue = NULL;
+		put_disk(disk);
+		return ret;
+	}
+
+	disk->major = FLOPPY_MAJOR;
+	disk->first_minor = drive + (type << 2);
+	sprintf(disk->disk_name, "fd%d", drive);
+	disk->fops = &floppy_fops;
+	disk->events = DISK_EVENT_MEDIA_CHANGE;
+	disk->private_data = &unit[drive];
+	set_capacity(disk, MAX_DISK_SIZE * 2);
+
+	unit[drive].disk[type] = disk;
+	return 0;
+}
+
+static DEFINE_MUTEX(ataflop_probe_lock);
+
+static void ataflop_probe(dev_t dev)
+{
+	int drive = MINOR(dev) & 3;
+	int type  = MINOR(dev) >> 2;
+
 	if (drive >= FD_MAX_UNITS || type > NUM_DISK_MINORS)
-		return NULL;
-	*part = 0;
-	return get_disk_and_module(unit[drive].disk);
+		return;
+	mutex_lock(&ataflop_probe_lock);
+	if (!unit[drive].disk[type]) {
+		if (ataflop_alloc_disk(drive, type) == 0)
+			add_disk(unit[drive].disk[type]);
+	}
+	mutex_unlock(&ataflop_probe_lock);
 }
 
 static int __init atari_floppy_init (void)
@@ -1981,23 +2021,26 @@ static int __init atari_floppy_init (void)
 		/* Amiga, Mac, ... don't have Atari-compatible floppy :-) */
 		return -ENODEV;
 
-	if (register_blkdev(FLOPPY_MAJOR,"fd"))
-		return -EBUSY;
+	mutex_lock(&ataflop_probe_lock);
+	ret = __register_blkdev(FLOPPY_MAJOR, "fd", ataflop_probe);
+	if (ret)
+		goto out_unlock;
 
 	for (i = 0; i < FD_MAX_UNITS; i++) {
-		unit[i].disk = alloc_disk(1);
-		if (!unit[i].disk) {
-			ret = -ENOMEM;
+		memset(&unit[i].tag_set, 0, sizeof(unit[i].tag_set));
+		unit[i].tag_set.ops = &ataflop_mq_ops;
+		unit[i].tag_set.nr_hw_queues = 1;
+		unit[i].tag_set.nr_maps = 1;
+		unit[i].tag_set.queue_depth = 2;
+		unit[i].tag_set.numa_node = NUMA_NO_NODE;
+		unit[i].tag_set.flags = BLK_MQ_F_SHOULD_MERGE;
+		ret = blk_mq_alloc_tag_set(&unit[i].tag_set);
+		if (ret)
 			goto err;
-		}
 
-		unit[i].disk->queue = blk_mq_init_sq_queue(&unit[i].tag_set,
-							   &ataflop_mq_ops, 2,
-							   BLK_MQ_F_SHOULD_MERGE);
-		if (IS_ERR(unit[i].disk->queue)) {
-			put_disk(unit[i].disk);
-			ret = PTR_ERR(unit[i].disk->queue);
-			unit[i].disk->queue = NULL;
+		ret = ataflop_alloc_disk(i, 0);
+		if (ret) {
+			blk_mq_free_tag_set(&unit[i].tag_set);
 			goto err;
 		}
 	}
@@ -2027,19 +2070,9 @@ static int __init atari_floppy_init (void)
 	for (i = 0; i < FD_MAX_UNITS; i++) {
 		unit[i].track = -1;
 		unit[i].flags = 0;
-		unit[i].disk->major = FLOPPY_MAJOR;
-		unit[i].disk->first_minor = i;
-		sprintf(unit[i].disk->disk_name, "fd%d", i);
-		unit[i].disk->fops = &floppy_fops;
-		unit[i].disk->events = DISK_EVENT_MEDIA_CHANGE;
-		unit[i].disk->private_data = &unit[i];
-		set_capacity(unit[i].disk, MAX_DISK_SIZE * 2);
-		add_disk(unit[i].disk);
+		add_disk(unit[i].disk[0]);
 	}
 
-	blk_register_region(MKDEV(FLOPPY_MAJOR, 0), 256, THIS_MODULE,
-				floppy_find, NULL, NULL);
-
 	printk(KERN_INFO "Atari floppy driver: max. %cD, %strack buffering\n",
 	       DriveType == 0 ? 'D' : DriveType == 1 ? 'H' : 'E',
 	       UseTrackbuffer ? "" : "no ");
@@ -2049,14 +2082,14 @@ static int __init atari_floppy_init (void)
 
 err:
 	while (--i >= 0) {
-		struct gendisk *disk = unit[i].disk;
-
-		blk_cleanup_queue(disk->queue);
+		blk_cleanup_queue(unit[i].disk[0]->queue);
+		put_disk(unit[i].disk[0]);
 		blk_mq_free_tag_set(&unit[i].tag_set);
-		put_disk(unit[i].disk);
 	}
 
 	unregister_blkdev(FLOPPY_MAJOR, "fd");
+out_unlock:
+	mutex_unlock(&ataflop_probe_lock);
 	return ret;
 }
 
@@ -2101,13 +2134,17 @@ __setup("floppy=", atari_floppy_setup);
 
 static void __exit atari_floppy_exit(void)
 {
-	int i;
-	blk_unregister_region(MKDEV(FLOPPY_MAJOR, 0), 256);
+	int i, type;
+
 	for (i = 0; i < FD_MAX_UNITS; i++) {
-		del_gendisk(unit[i].disk);
-		blk_cleanup_queue(unit[i].disk->queue);
+		for (type = 0; type < NUM_DISK_MINORS; type++) {
+			if (!unit[i].disk[type])
+				continue;
+			del_gendisk(unit[i].disk[type]);
+			blk_cleanup_queue(unit[i].disk[type]->queue);
+			put_disk(unit[i].disk[type]);
+		}
 		blk_mq_free_tag_set(&unit[i].tag_set);
-		put_disk(unit[i].disk);
 	}
 	unregister_blkdev(FLOPPY_MAJOR, "fd");
 
-- 
2.28.0

[PATCH 16/18] z2ram: reindent

[Christoph Hellwig]

reindent the driver using Lident as the code style was far away from
normal Linux code.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
---
 drivers/block/z2ram.c | 493 ++++++++++++++++++++----------------------
 1 file changed, 236 insertions(+), 257 deletions(-)

diff --git a/drivers/block/z2ram.c b/drivers/block/z2ram.c
index 0e734802ee7cc6..eafecc9a72b38d 100644
--- a/drivers/block/z2ram.c
+++ b/drivers/block/z2ram.c
@@ -42,7 +42,6 @@
 
 #include <linux/zorro.h>
 
-
 #define Z2MINOR_COMBINED      (0)
 #define Z2MINOR_Z2ONLY        (1)
 #define Z2MINOR_CHIPONLY      (2)
@@ -50,17 +49,17 @@
 #define Z2MINOR_MEMLIST2      (5)
 #define Z2MINOR_MEMLIST3      (6)
 #define Z2MINOR_MEMLIST4      (7)
-#define Z2MINOR_COUNT         (8) /* Move this down when adding a new minor */
+#define Z2MINOR_COUNT         (8)	/* Move this down when adding a new minor */
 
 #define Z2RAM_CHUNK1024       ( Z2RAM_CHUNKSIZE >> 10 )
 
 static DEFINE_MUTEX(z2ram_mutex);
-static u_long *z2ram_map    = NULL;
-static u_long z2ram_size    = 0;
-static int z2_count         = 0;
-static int chip_count       = 0;
-static int list_count       = 0;
-static int current_device   = -1;
+static u_long *z2ram_map = NULL;
+static u_long z2ram_size = 0;
+static int z2_count = 0;
+static int chip_count = 0;
+static int list_count = 0;
+static int current_device = -1;
 
 static DEFINE_SPINLOCK(z2ram_lock);
 
@@ -71,7 +70,7 @@ static blk_status_t z2_queue_rq(struct blk_mq_hw_ctx *hctx,
 {
 	struct request *req = bd->rq;
 	unsigned long start = blk_rq_pos(req) << 9;
-	unsigned long len  = blk_rq_cur_bytes(req);
+	unsigned long len = blk_rq_cur_bytes(req);
 
 	blk_mq_start_request(req);
 
@@ -92,7 +91,7 @@ static blk_status_t z2_queue_rq(struct blk_mq_hw_ctx *hctx,
 
 		if (len < size)
 			size = len;
-		addr += z2ram_map[ start >> Z2RAM_CHUNKSHIFT ];
+		addr += z2ram_map[start >> Z2RAM_CHUNKSHIFT];
 		if (rq_data_dir(req) == READ)
 			memcpy(buffer, (char *)addr, size);
 		else
@@ -106,228 +105,214 @@ static blk_status_t z2_queue_rq(struct blk_mq_hw_ctx *hctx,
 	return BLK_STS_OK;
 }
 
-static void
-get_z2ram( void )
+static void get_z2ram(void)
 {
-    int i;
-
-    for ( i = 0; i < Z2RAM_SIZE / Z2RAM_CHUNKSIZE; i++ )
-    {
-	if ( test_bit( i, zorro_unused_z2ram ) )
-	{
-	    z2_count++;
-	    z2ram_map[z2ram_size++] = (unsigned long)ZTWO_VADDR(Z2RAM_START) +
-				      (i << Z2RAM_CHUNKSHIFT);
-	    clear_bit( i, zorro_unused_z2ram );
+	int i;
+
+	for (i = 0; i < Z2RAM_SIZE / Z2RAM_CHUNKSIZE; i++) {
+		if (test_bit(i, zorro_unused_z2ram)) {
+			z2_count++;
+			z2ram_map[z2ram_size++] =
+			    (unsigned long)ZTWO_VADDR(Z2RAM_START) +
+			    (i << Z2RAM_CHUNKSHIFT);
+			clear_bit(i, zorro_unused_z2ram);
+		}
 	}
-    }
 
-    return;
+	return;
 }
 
-static void
-get_chipram( void )
+static void get_chipram(void)
 {
 
-    while ( amiga_chip_avail() > ( Z2RAM_CHUNKSIZE * 4 ) )
-    {
-	chip_count++;
-	z2ram_map[ z2ram_size ] =
-	    (u_long)amiga_chip_alloc( Z2RAM_CHUNKSIZE, "z2ram" );
+	while (amiga_chip_avail() > (Z2RAM_CHUNKSIZE * 4)) {
+		chip_count++;
+		z2ram_map[z2ram_size] =
+		    (u_long) amiga_chip_alloc(Z2RAM_CHUNKSIZE, "z2ram");
 
-	if ( z2ram_map[ z2ram_size ] == 0 )
-	{
-	    break;
+		if (z2ram_map[z2ram_size] == 0) {
+			break;
+		}
+
+		z2ram_size++;
 	}
 
-	z2ram_size++;
-    }
-	
-    return;
+	return;
 }
 
 static int z2_open(struct block_device *bdev, fmode_t mode)
 {
-    int device;
-    int max_z2_map = ( Z2RAM_SIZE / Z2RAM_CHUNKSIZE ) *
-	sizeof( z2ram_map[0] );
-    int max_chip_map = ( amiga_chip_size / Z2RAM_CHUNKSIZE ) *
-	sizeof( z2ram_map[0] );
-    int rc = -ENOMEM;
-
-    device = MINOR(bdev->bd_dev);
-
-    mutex_lock(&z2ram_mutex);
-    if ( current_device != -1 && current_device != device )
-    {
-	rc = -EBUSY;
-	goto err_out;
-    }
-
-    if ( current_device == -1 )
-    {
-	z2_count   = 0;
-	chip_count = 0;
-	list_count = 0;
-	z2ram_size = 0;
-
-	/* Use a specific list entry. */
-	if (device >= Z2MINOR_MEMLIST1 && device <= Z2MINOR_MEMLIST4) {
-		int index = device - Z2MINOR_MEMLIST1 + 1;
-		unsigned long size, paddr, vaddr;
-
-		if (index >= m68k_realnum_memory) {
-			printk( KERN_ERR DEVICE_NAME
-				": no such entry in z2ram_map\n" );
-		        goto err_out;
-		}
-
-		paddr = m68k_memory[index].addr;
-		size = m68k_memory[index].size & ~(Z2RAM_CHUNKSIZE-1);
-
-#ifdef __powerpc__
-		/* FIXME: ioremap doesn't build correct memory tables. */
-		{
-			vfree(vmalloc (size));
-		}
+	int device;
+	int max_z2_map = (Z2RAM_SIZE / Z2RAM_CHUNKSIZE) * sizeof(z2ram_map[0]);
+	int max_chip_map = (amiga_chip_size / Z2RAM_CHUNKSIZE) *
+	    sizeof(z2ram_map[0]);
+	int rc = -ENOMEM;
 
-		vaddr = (unsigned long)ioremap_wt(paddr, size);
+	device = MINOR(bdev->bd_dev);
 
-#else
-		vaddr = (unsigned long)z_remap_nocache_nonser(paddr, size);
-#endif
-		z2ram_map = 
-			kmalloc_array(size / Z2RAM_CHUNKSIZE,
-                                      sizeof(z2ram_map[0]),
-                                      GFP_KERNEL);
-		if ( z2ram_map == NULL )
-		{
-		    printk( KERN_ERR DEVICE_NAME
-			": cannot get mem for z2ram_map\n" );
-		    goto err_out;
-		}
+	mutex_lock(&z2ram_mutex);
+	if (current_device != -1 && current_device != device) {
+		rc = -EBUSY;
+		goto err_out;
+	}
 
-		while (size) {
-			z2ram_map[ z2ram_size++ ] = vaddr;
-			size -= Z2RAM_CHUNKSIZE;
-			vaddr += Z2RAM_CHUNKSIZE;
-			list_count++;
-		}
+	if (current_device == -1) {
+		z2_count = 0;
+		chip_count = 0;
+		list_count = 0;
+		z2ram_size = 0;
 
-		if ( z2ram_size != 0 )
-		    printk( KERN_INFO DEVICE_NAME
-			": using %iK List Entry %d Memory\n",
-			list_count * Z2RAM_CHUNK1024, index );
-	} else
-
-	switch ( device )
-	{
-	    case Z2MINOR_COMBINED:
-
-		z2ram_map = kmalloc( max_z2_map + max_chip_map, GFP_KERNEL );
-		if ( z2ram_map == NULL )
-		{
-		    printk( KERN_ERR DEVICE_NAME
-			": cannot get mem for z2ram_map\n" );
-		    goto err_out;
-		}
+		/* Use a specific list entry. */
+		if (device >= Z2MINOR_MEMLIST1 && device <= Z2MINOR_MEMLIST4) {
+			int index = device - Z2MINOR_MEMLIST1 + 1;
+			unsigned long size, paddr, vaddr;
 
-		get_z2ram();
-		get_chipram();
-
-		if ( z2ram_size != 0 )
-		    printk( KERN_INFO DEVICE_NAME 
-			": using %iK Zorro II RAM and %iK Chip RAM (Total %dK)\n",
-			z2_count * Z2RAM_CHUNK1024,
-			chip_count * Z2RAM_CHUNK1024,
-			( z2_count + chip_count ) * Z2RAM_CHUNK1024 );
-
-	    break;
-
-    	    case Z2MINOR_Z2ONLY:
-		z2ram_map = kmalloc( max_z2_map, GFP_KERNEL );
-		if ( z2ram_map == NULL )
-		{
-		    printk( KERN_ERR DEVICE_NAME
-			": cannot get mem for z2ram_map\n" );
-		    goto err_out;
-		}
+			if (index >= m68k_realnum_memory) {
+				printk(KERN_ERR DEVICE_NAME
+				       ": no such entry in z2ram_map\n");
+				goto err_out;
+			}
 
-		get_z2ram();
+			paddr = m68k_memory[index].addr;
+			size = m68k_memory[index].size & ~(Z2RAM_CHUNKSIZE - 1);
 
-		if ( z2ram_size != 0 )
-		    printk( KERN_INFO DEVICE_NAME 
-			": using %iK of Zorro II RAM\n",
-			z2_count * Z2RAM_CHUNK1024 );
+#ifdef __powerpc__
+			/* FIXME: ioremap doesn't build correct memory tables. */
+			{
+				vfree(vmalloc(size));
+			}
 
-	    break;
+			vaddr = (unsigned long)ioremap_wt(paddr, size);
 
-	    case Z2MINOR_CHIPONLY:
-		z2ram_map = kmalloc( max_chip_map, GFP_KERNEL );
-		if ( z2ram_map == NULL )
-		{
-		    printk( KERN_ERR DEVICE_NAME
-			": cannot get mem for z2ram_map\n" );
-		    goto err_out;
+#else
+			vaddr =
+			    (unsigned long)z_remap_nocache_nonser(paddr, size);
+#endif
+			z2ram_map =
+			    kmalloc_array(size / Z2RAM_CHUNKSIZE,
+					  sizeof(z2ram_map[0]), GFP_KERNEL);
+			if (z2ram_map == NULL) {
+				printk(KERN_ERR DEVICE_NAME
+				       ": cannot get mem for z2ram_map\n");
+				goto err_out;
+			}
+
+			while (size) {
+				z2ram_map[z2ram_size++] = vaddr;
+				size -= Z2RAM_CHUNKSIZE;
+				vaddr += Z2RAM_CHUNKSIZE;
+				list_count++;
+			}
+
+			if (z2ram_size != 0)
+				printk(KERN_INFO DEVICE_NAME
+				       ": using %iK List Entry %d Memory\n",
+				       list_count * Z2RAM_CHUNK1024, index);
+		} else
+			switch (device) {
+			case Z2MINOR_COMBINED:
+
+				z2ram_map =
+				    kmalloc(max_z2_map + max_chip_map,
+					    GFP_KERNEL);
+				if (z2ram_map == NULL) {
+					printk(KERN_ERR DEVICE_NAME
+					       ": cannot get mem for z2ram_map\n");
+					goto err_out;
+				}
+
+				get_z2ram();
+				get_chipram();
+
+				if (z2ram_size != 0)
+					printk(KERN_INFO DEVICE_NAME
+					       ": using %iK Zorro II RAM and %iK Chip RAM (Total %dK)\n",
+					       z2_count * Z2RAM_CHUNK1024,
+					       chip_count * Z2RAM_CHUNK1024,
+					       (z2_count +
+						chip_count) * Z2RAM_CHUNK1024);
+
+				break;
+
+			case Z2MINOR_Z2ONLY:
+				z2ram_map = kmalloc(max_z2_map, GFP_KERNEL);
+				if (z2ram_map == NULL) {
+					printk(KERN_ERR DEVICE_NAME
+					       ": cannot get mem for z2ram_map\n");
+					goto err_out;
+				}
+
+				get_z2ram();
+
+				if (z2ram_size != 0)
+					printk(KERN_INFO DEVICE_NAME
+					       ": using %iK of Zorro II RAM\n",
+					       z2_count * Z2RAM_CHUNK1024);
+
+				break;
+
+			case Z2MINOR_CHIPONLY:
+				z2ram_map = kmalloc(max_chip_map, GFP_KERNEL);
+				if (z2ram_map == NULL) {
+					printk(KERN_ERR DEVICE_NAME
+					       ": cannot get mem for z2ram_map\n");
+					goto err_out;
+				}
+
+				get_chipram();
+
+				if (z2ram_size != 0)
+					printk(KERN_INFO DEVICE_NAME
+					       ": using %iK Chip RAM\n",
+					       chip_count * Z2RAM_CHUNK1024);
+
+				break;
+
+			default:
+				rc = -ENODEV;
+				goto err_out;
+
+				break;
+			}
+
+		if (z2ram_size == 0) {
+			printk(KERN_NOTICE DEVICE_NAME
+			       ": no unused ZII/Chip RAM found\n");
+			goto err_out_kfree;
 		}
 
-		get_chipram();
-
-		if ( z2ram_size != 0 )
-		    printk( KERN_INFO DEVICE_NAME 
-			": using %iK Chip RAM\n",
-			chip_count * Z2RAM_CHUNK1024 );
-		    
-	    break;
-
-	    default:
-		rc = -ENODEV;
-		goto err_out;
-	
-	    break;
+		current_device = device;
+		z2ram_size <<= Z2RAM_CHUNKSHIFT;
+		set_capacity(z2ram_gendisk, z2ram_size >> 9);
 	}
 
-	if ( z2ram_size == 0 )
-	{
-	    printk( KERN_NOTICE DEVICE_NAME
-		": no unused ZII/Chip RAM found\n" );
-	    goto err_out_kfree;
-	}
-
-	current_device = device;
-	z2ram_size <<= Z2RAM_CHUNKSHIFT;
-	set_capacity(z2ram_gendisk, z2ram_size >> 9);
-    }
-
-    mutex_unlock(&z2ram_mutex);
-    return 0;
+	mutex_unlock(&z2ram_mutex);
+	return 0;
 
 err_out_kfree:
-    kfree(z2ram_map);
+	kfree(z2ram_map);
 err_out:
-    mutex_unlock(&z2ram_mutex);
-    return rc;
+	mutex_unlock(&z2ram_mutex);
+	return rc;
 }
 
-static void
-z2_release(struct gendisk *disk, fmode_t mode)
+static void z2_release(struct gendisk *disk, fmode_t mode)
 {
-    mutex_lock(&z2ram_mutex);
-    if ( current_device == -1 ) {
-    	mutex_unlock(&z2ram_mutex);
-    	return;
-    }
-    mutex_unlock(&z2ram_mutex);
-    /*
-     * FIXME: unmap memory
-     */
+	mutex_lock(&z2ram_mutex);
+	if (current_device == -1) {
+		mutex_unlock(&z2ram_mutex);
+		return;
+	}
+	mutex_unlock(&z2ram_mutex);
+	/*
+	 * FIXME: unmap memory
+	 */
 }
 
-static const struct block_device_operations z2_fops =
-{
-	.owner		= THIS_MODULE,
-	.open		= z2_open,
-	.release	= z2_release,
+static const struct block_device_operations z2_fops = {
+	.owner = THIS_MODULE,
+	.open = z2_open,
+	.release = z2_release,
 };
 
 static struct kobject *z2_find(dev_t dev, int *part, void *data)
@@ -340,89 +325,83 @@ static struct request_queue *z2_queue;
 static struct blk_mq_tag_set tag_set;
 
 static const struct blk_mq_ops z2_mq_ops = {
-	.queue_rq	= z2_queue_rq,
+	.queue_rq = z2_queue_rq,
 };
 
-static int __init 
-z2_init(void)
+static int __init z2_init(void)
 {
-    int ret;
+	int ret;
 
-    if (!MACH_IS_AMIGA)
-	return -ENODEV;
+	if (!MACH_IS_AMIGA)
+		return -ENODEV;
 
-    ret = -EBUSY;
-    if (register_blkdev(Z2RAM_MAJOR, DEVICE_NAME))
-	goto err;
+	ret = -EBUSY;
+	if (register_blkdev(Z2RAM_MAJOR, DEVICE_NAME))
+		goto err;
 
-    ret = -ENOMEM;
-    z2ram_gendisk = alloc_disk(1);
-    if (!z2ram_gendisk)
-	goto out_disk;
+	ret = -ENOMEM;
+	z2ram_gendisk = alloc_disk(1);
+	if (!z2ram_gendisk)
+		goto out_disk;
 
-    z2_queue = blk_mq_init_sq_queue(&tag_set, &z2_mq_ops, 16,
+	z2_queue = blk_mq_init_sq_queue(&tag_set, &z2_mq_ops, 16,
 					BLK_MQ_F_SHOULD_MERGE);
-    if (IS_ERR(z2_queue)) {
-	ret = PTR_ERR(z2_queue);
-	z2_queue = NULL;
-	goto out_queue;
-    }
+	if (IS_ERR(z2_queue)) {
+		ret = PTR_ERR(z2_queue);
+		z2_queue = NULL;
+		goto out_queue;
+	}
 
-    z2ram_gendisk->major = Z2RAM_MAJOR;
-    z2ram_gendisk->first_minor = 0;
-    z2ram_gendisk->fops = &z2_fops;
-    sprintf(z2ram_gendisk->disk_name, "z2ram");
+	z2ram_gendisk->major = Z2RAM_MAJOR;
+	z2ram_gendisk->first_minor = 0;
+	z2ram_gendisk->fops = &z2_fops;
+	sprintf(z2ram_gendisk->disk_name, "z2ram");
 
-    z2ram_gendisk->queue = z2_queue;
-    add_disk(z2ram_gendisk);
-    blk_register_region(MKDEV(Z2RAM_MAJOR, 0), Z2MINOR_COUNT, THIS_MODULE,
-				z2_find, NULL, NULL);
+	z2ram_gendisk->queue = z2_queue;
+	add_disk(z2ram_gendisk);
+	blk_register_region(MKDEV(Z2RAM_MAJOR, 0), Z2MINOR_COUNT, THIS_MODULE,
+			    z2_find, NULL, NULL);
 
-    return 0;
+	return 0;
 
 out_queue:
-    put_disk(z2ram_gendisk);
+	put_disk(z2ram_gendisk);
 out_disk:
-    unregister_blkdev(Z2RAM_MAJOR, DEVICE_NAME);
+	unregister_blkdev(Z2RAM_MAJOR, DEVICE_NAME);
 err:
-    return ret;
+	return ret;
 }
 
 static void __exit z2_exit(void)
 {
-    int i, j;
-    blk_unregister_region(MKDEV(Z2RAM_MAJOR, 0), Z2MINOR_COUNT);
-    unregister_blkdev(Z2RAM_MAJOR, DEVICE_NAME);
-    del_gendisk(z2ram_gendisk);
-    put_disk(z2ram_gendisk);
-    blk_cleanup_queue(z2_queue);
-    blk_mq_free_tag_set(&tag_set);
-
-    if ( current_device != -1 )
-    {
-	i = 0;
-
-	for ( j = 0 ; j < z2_count; j++ )
-	{
-	    set_bit( i++, zorro_unused_z2ram ); 
-	}
+	int i, j;
+	blk_unregister_region(MKDEV(Z2RAM_MAJOR, 0), Z2MINOR_COUNT);
+	unregister_blkdev(Z2RAM_MAJOR, DEVICE_NAME);
+	del_gendisk(z2ram_gendisk);
+	put_disk(z2ram_gendisk);
+	blk_cleanup_queue(z2_queue);
+	blk_mq_free_tag_set(&tag_set);
+
+	if (current_device != -1) {
+		i = 0;
+
+		for (j = 0; j < z2_count; j++) {
+			set_bit(i++, zorro_unused_z2ram);
+		}
 
-	for ( j = 0 ; j < chip_count; j++ )
-	{
-	    if ( z2ram_map[ i ] )
-	    {
-		amiga_chip_free( (void *) z2ram_map[ i++ ] );
-	    }
-	}
+		for (j = 0; j < chip_count; j++) {
+			if (z2ram_map[i]) {
+				amiga_chip_free((void *)z2ram_map[i++]);
+			}
+		}
 
-	if ( z2ram_map != NULL )
-	{
-	    kfree( z2ram_map );
+		if (z2ram_map != NULL) {
+			kfree(z2ram_map);
+		}
 	}
-    }
 
-    return;
-} 
+	return;
+}
 
 module_init(z2_init);
 module_exit(z2_exit);
-- 
2.28.0

[PATCH 17/18] z2ram: use separate gendisk for the different modes

[Christoph Hellwig]

Use separate gendisks (which share a tag_set) for the different operating
modes instead of redirecting the gendisk lookup using a probe callback.
This avoids potential problems with aliased block_device instances and
will eventually allow for removing the blk_register_region framework.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
---
 drivers/block/z2ram.c | 100 ++++++++++++++++++++++++------------------
 1 file changed, 58 insertions(+), 42 deletions(-)

diff --git a/drivers/block/z2ram.c b/drivers/block/z2ram.c
index eafecc9a72b38d..c1d20818e64920 100644
--- a/drivers/block/z2ram.c
+++ b/drivers/block/z2ram.c
@@ -63,7 +63,7 @@ static int current_device = -1;
 
 static DEFINE_SPINLOCK(z2ram_lock);
 
-static struct gendisk *z2ram_gendisk;
+static struct gendisk *z2ram_gendisk[Z2MINOR_COUNT];
 
 static blk_status_t z2_queue_rq(struct blk_mq_hw_ctx *hctx,
 				const struct blk_mq_queue_data *bd)
@@ -283,7 +283,7 @@ static int z2_open(struct block_device *bdev, fmode_t mode)
 
 		current_device = device;
 		z2ram_size <<= Z2RAM_CHUNKSHIFT;
-		set_capacity(z2ram_gendisk, z2ram_size >> 9);
+		set_capacity(z2ram_gendisk[device], z2ram_size >> 9);
 	}
 
 	mutex_unlock(&z2ram_mutex);
@@ -315,71 +315,87 @@ static const struct block_device_operations z2_fops = {
 	.release = z2_release,
 };
 
-static struct kobject *z2_find(dev_t dev, int *part, void *data)
-{
-	*part = 0;
-	return get_disk_and_module(z2ram_gendisk);
-}
-
-static struct request_queue *z2_queue;
 static struct blk_mq_tag_set tag_set;
 
 static const struct blk_mq_ops z2_mq_ops = {
 	.queue_rq = z2_queue_rq,
 };
 
+static int z2ram_register_disk(int minor)
+{
+	struct request_queue *q;
+	struct gendisk *disk;
+
+	disk = alloc_disk(1);
+	if (!disk)
+		return -ENOMEM;
+
+	q = blk_mq_init_queue(&tag_set);
+	if (IS_ERR(q)) {
+		put_disk(disk);
+		return PTR_ERR(q);
+	}
+
+	disk->major = Z2RAM_MAJOR;
+	disk->first_minor = minor;
+	disk->fops = &z2_fops;
+	if (minor)
+		sprintf(disk->disk_name, "z2ram%d", minor);
+	else
+		sprintf(disk->disk_name, "z2ram");
+	disk->queue = q;
+
+	z2ram_gendisk[minor] = disk;
+	add_disk(disk);
+	return 0;
+}
+
 static int __init z2_init(void)
 {
-	int ret;
+	int ret, i;
 
 	if (!MACH_IS_AMIGA)
 		return -ENODEV;
 
-	ret = -EBUSY;
 	if (register_blkdev(Z2RAM_MAJOR, DEVICE_NAME))
-		goto err;
-
-	ret = -ENOMEM;
-	z2ram_gendisk = alloc_disk(1);
-	if (!z2ram_gendisk)
-		goto out_disk;
-
-	z2_queue = blk_mq_init_sq_queue(&tag_set, &z2_mq_ops, 16,
-					BLK_MQ_F_SHOULD_MERGE);
-	if (IS_ERR(z2_queue)) {
-		ret = PTR_ERR(z2_queue);
-		z2_queue = NULL;
-		goto out_queue;
+		return -EBUSY;
+
+	tag_set.ops = &z2_mq_ops;
+	tag_set.nr_hw_queues = 1;
+	tag_set.nr_maps = 1;
+	tag_set.queue_depth = 16;
+	tag_set.numa_node = NUMA_NO_NODE;
+	tag_set.flags = BLK_MQ_F_SHOULD_MERGE;
+	ret = blk_mq_alloc_tag_set(&tag_set);
+	if (ret)
+		goto out_unregister_blkdev;
+
+	for (i = 0; i < Z2MINOR_COUNT; i++) {
+		ret = z2ram_register_disk(i);
+		if (ret && i == 0)
+			goto out_free_tagset;
 	}
 
-	z2ram_gendisk->major = Z2RAM_MAJOR;
-	z2ram_gendisk->first_minor = 0;
-	z2ram_gendisk->fops = &z2_fops;
-	sprintf(z2ram_gendisk->disk_name, "z2ram");
-
-	z2ram_gendisk->queue = z2_queue;
-	add_disk(z2ram_gendisk);
-	blk_register_region(MKDEV(Z2RAM_MAJOR, 0), Z2MINOR_COUNT, THIS_MODULE,
-			    z2_find, NULL, NULL);
-
 	return 0;
 
-out_queue:
-	put_disk(z2ram_gendisk);
-out_disk:
+out_free_tagset:
+	blk_mq_free_tag_set(&tag_set);
+out_unregister_blkdev:
 	unregister_blkdev(Z2RAM_MAJOR, DEVICE_NAME);
-err:
 	return ret;
 }
 
 static void __exit z2_exit(void)
 {
 	int i, j;
-	blk_unregister_region(MKDEV(Z2RAM_MAJOR, 0), Z2MINOR_COUNT);
+
 	unregister_blkdev(Z2RAM_MAJOR, DEVICE_NAME);
-	del_gendisk(z2ram_gendisk);
-	put_disk(z2ram_gendisk);
-	blk_cleanup_queue(z2_queue);
+
+	for (i = 0; i < Z2MINOR_COUNT; i++) {
+		del_gendisk(z2ram_gendisk[i]);
+		blk_cleanup_queue(z2ram_gendisk[i]->queue);
+		put_disk(z2ram_gendisk[i]);
+	}
 	blk_mq_free_tag_set(&tag_set);
 
 	if (current_device != -1) {
-- 
2.28.0

[PATCH] z2ram: MODULE_LICENSE update and neatening

[Joe Perches]

Additional style neatenings.

Miscellanea:

o Make MODULE_LICENSE match the actual license text
o Comment neatening
o alloc failure message removals as there is already a dump_stack()
o Add pr_fmt() and convert printks to pr_<level>
o Unindent code blocks by using continue
o Return early z2open when current_device != 1 and unindent code block
o Add and remove braces where appropriate

Signed-off-by: Joe Perches <joe@perches.com>
---

Uncompiled/untested.

On top of Christoph's changes.
This file still does not have an SPDX line.  What should it be?
Is this still used by anyone?

 drivers/block/z2ram.c | 304 ++++++++++++++++++++++----------------------------
 1 file changed, 132 insertions(+), 172 deletions(-)

diff --git a/drivers/block/z2ram.c b/drivers/block/z2ram.c
index c1d20818e649..4e6c5564f1e8 100644
--- a/drivers/block/z2ram.c
+++ b/drivers/block/z2ram.c
@@ -1,30 +1,31 @@
 /*
-** z2ram - Amiga pseudo-driver to access 16bit-RAM in ZorroII space
-**         as a block device, to be used as a RAM disk or swap space
-** 
-** Copyright (C) 1994 by Ingo Wilken (Ingo.Wilken@informatik.uni-oldenburg.de)
-**
-** ++Geert: support for zorro_unused_z2ram, better range checking
-** ++roman: translate accesses via an array
-** ++Milan: support for ChipRAM usage
-** ++yambo: converted to 2.0 kernel
-** ++yambo: modularized and support added for 3 minor devices including:
-**          MAJOR  MINOR  DESCRIPTION
-**          -----  -----  ----------------------------------------------
-**          37     0       Use Zorro II and Chip ram
-**          37     1       Use only Zorro II ram
-**          37     2       Use only Chip ram
-**          37     4-7     Use memory list entry 1-4 (first is 0)
-** ++jskov: support for 1-4th memory list entry.
-**
-** Permission to use, copy, modify, and distribute this software and its
-** documentation for any purpose and without fee is hereby granted, provided
-** that the above copyright notice appear in all copies and that both that
-** copyright notice and this permission notice appear in supporting
-** documentation.  This software is provided "as is" without express or
-** implied warranty.
-*/
-
+ * z2ram - Amiga pseudo-driver to access 16bit-RAM in ZorroII space
+ *         as a block device, to be used as a RAM disk or swap space
+ *
+ * Copyright (C) 1994 by Ingo Wilken (Ingo.Wilken@informatik.uni-oldenburg.de)
+ *
+ * ++Geert: support for zorro_unused_z2ram, better range checking
+ * ++roman: translate accesses via an array
+ * ++Milan: support for ChipRAM usage
+ * ++yambo: converted to 2.0 kernel
+ * ++yambo: modularized and support added for 3 minor devices including:
+ *          MAJOR  MINOR  DESCRIPTION
+ *          -----  -----  ----------------------------------------------
+ *          37     0       Use Zorro II and Chip ram
+ *          37     1       Use only Zorro II ram
+ *          37     2       Use only Chip ram
+ *          37     4-7     Use memory list entry 1-4 (first is 0)
+ * ++jskov: support for 1-4th memory list entry.
+ *
+ * Permission to use, copy, modify, and distribute this software and its
+ * documentation for any purpose and without fee is hereby granted, provided
+ * that the above copyright notice appear in all copies and that both that
+ * copyright notice and this permission notice appear in supporting
+ * documentation.  This software is provided "as is" without express or
+ * implied warranty.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 #define DEVICE_NAME "Z2RAM"
 
 #include <linux/major.h>
@@ -51,7 +52,7 @@
 #define Z2MINOR_MEMLIST4      (7)
 #define Z2MINOR_COUNT         (8)	/* Move this down when adding a new minor */
 
-#define Z2RAM_CHUNK1024       ( Z2RAM_CHUNKSIZE >> 10 )
+#define Z2RAM_CHUNK1024       (Z2RAM_CHUNKSIZE >> 10)
 
 static DEFINE_MUTEX(z2ram_mutex);
 static u_long *z2ram_map = NULL;
@@ -75,8 +76,7 @@ static blk_status_t z2_queue_rq(struct blk_mq_hw_ctx *hctx,
 	blk_mq_start_request(req);
 
 	if (start + len > z2ram_size) {
-		pr_err(DEVICE_NAME ": bad access: block=%llu, "
-		       "count=%u\n",
+		pr_err("bad access: block=%llu, count=%u\n",
 		       (unsigned long long)blk_rq_pos(req),
 		       blk_rq_cur_sectors(req));
 		return BLK_STS_IOERR;
@@ -93,9 +93,9 @@ static blk_status_t z2_queue_rq(struct blk_mq_hw_ctx *hctx,
 			size = len;
 		addr += z2ram_map[start >> Z2RAM_CHUNKSHIFT];
 		if (rq_data_dir(req) == READ)
-			memcpy(buffer, (char *)addr, size);
+			memcpy(buffer, (void *)addr, size);
 		else
-			memcpy((char *)addr, buffer, size);
+			memcpy((void *)addr, buffer, size);
 		start += size;
 		len -= size;
 	}
@@ -107,37 +107,29 @@ static blk_status_t z2_queue_rq(struct blk_mq_hw_ctx *hctx,
 
 static void get_z2ram(void)
 {
+	unsigned long vaddr = (unsigned long)ZTWO_VADDR(Z2RAM_START);
 	int i;
 
 	for (i = 0; i < Z2RAM_SIZE / Z2RAM_CHUNKSIZE; i++) {
-		if (test_bit(i, zorro_unused_z2ram)) {
-			z2_count++;
-			z2ram_map[z2ram_size++] =
-			    (unsigned long)ZTWO_VADDR(Z2RAM_START) +
-			    (i << Z2RAM_CHUNKSHIFT);
-			clear_bit(i, zorro_unused_z2ram);
-		}
+		if (!test_and_clear_bit(i, zorro_unused_z2ram))
+			continue;
+		z2_count++;
+		z2ram_map[z2ram_size++] = vaddr + (i << Z2RAM_CHUNKSHIFT);
 	}
-
-	return;
 }
 
 static void get_chipram(void)
 {
-
 	while (amiga_chip_avail() > (Z2RAM_CHUNKSIZE * 4)) {
 		chip_count++;
 		z2ram_map[z2ram_size] =
-		    (u_long) amiga_chip_alloc(Z2RAM_CHUNKSIZE, "z2ram");
+		    (u_long)amiga_chip_alloc(Z2RAM_CHUNKSIZE, "z2ram");
 
-		if (z2ram_map[z2ram_size] == 0) {
+		if (z2ram_map[z2ram_size] == 0)
 			break;
-		}
 
 		z2ram_size++;
 	}
-
-	return;
 }
 
 static int z2_open(struct block_device *bdev, fmode_t mode)
@@ -146,146 +138,120 @@ static int z2_open(struct block_device *bdev, fmode_t mode)
 	int max_z2_map = (Z2RAM_SIZE / Z2RAM_CHUNKSIZE) * sizeof(z2ram_map[0]);
 	int max_chip_map = (amiga_chip_size / Z2RAM_CHUNKSIZE) *
 	    sizeof(z2ram_map[0]);
-	int rc = -ENOMEM;
+	int ret = -ENOMEM;
 
 	device = MINOR(bdev->bd_dev);
 
 	mutex_lock(&z2ram_mutex);
-	if (current_device != -1 && current_device != device) {
-		rc = -EBUSY;
-		goto err_out;
+	if (current_device != -1) {
+		ret = (current_device != device) ? -EBUSY : 0;
+		mutex_unlock(&z2ram_mutex);
+		return ret;
 	}
 
-	if (current_device == -1) {
-		z2_count = 0;
-		chip_count = 0;
-		list_count = 0;
-		z2ram_size = 0;
-
-		/* Use a specific list entry. */
-		if (device >= Z2MINOR_MEMLIST1 && device <= Z2MINOR_MEMLIST4) {
-			int index = device - Z2MINOR_MEMLIST1 + 1;
-			unsigned long size, paddr, vaddr;
-
-			if (index >= m68k_realnum_memory) {
-				printk(KERN_ERR DEVICE_NAME
-				       ": no such entry in z2ram_map\n");
-				goto err_out;
-			}
+	z2_count = 0;
+	chip_count = 0;
+	list_count = 0;
+	z2ram_size = 0;
 
-			paddr = m68k_memory[index].addr;
-			size = m68k_memory[index].size & ~(Z2RAM_CHUNKSIZE - 1);
+	/* Use a specific list entry. */
+	if (device >= Z2MINOR_MEMLIST1 && device <= Z2MINOR_MEMLIST4) {
+		int index = device - Z2MINOR_MEMLIST1 + 1;
+		unsigned long size, paddr, vaddr;
+
+		if (index >= m68k_realnum_memory) {
+			pr_err("no such entry in z2ram_map\n");
+			goto err_out;
+		}
+
+		paddr = m68k_memory[index].addr;
+		size = m68k_memory[index].size & ~(Z2RAM_CHUNKSIZE - 1);
 
 #ifdef __powerpc__
-			/* FIXME: ioremap doesn't build correct memory tables. */
-			{
-				vfree(vmalloc(size));
-			}
+		/* FIXME: ioremap doesn't build correct memory tables. */
+		{
+			vfree(vmalloc(size));
+		}
 
-			vaddr = (unsigned long)ioremap_wt(paddr, size);
+		vaddr = (unsigned long)ioremap_wt(paddr, size);
 
 #else
-			vaddr =
-			    (unsigned long)z_remap_nocache_nonser(paddr, size);
+		vaddr = (unsigned long)z_remap_nocache_nonser(paddr, size);
 #endif
-			z2ram_map =
-			    kmalloc_array(size / Z2RAM_CHUNKSIZE,
+		z2ram_map = kmalloc_array(size / Z2RAM_CHUNKSIZE,
 					  sizeof(z2ram_map[0]), GFP_KERNEL);
-			if (z2ram_map == NULL) {
-				printk(KERN_ERR DEVICE_NAME
-				       ": cannot get mem for z2ram_map\n");
+		if (!z2ram_map)
+			goto err_out;
+
+		while (size) {
+			z2ram_map[z2ram_size++] = vaddr;
+			size -= Z2RAM_CHUNKSIZE;
+			vaddr += Z2RAM_CHUNKSIZE;
+			list_count++;
+		}
+
+		if (z2ram_size != 0)
+			pr_info("using %iK List Entry %d Memory\n",
+				list_count * Z2RAM_CHUNK1024, index);
+	} else {
+		switch (device) {
+		case Z2MINOR_COMBINED:
+
+			z2ram_map = kmalloc(max_z2_map + max_chip_map,
+					    GFP_KERNEL);
+			if (!z2ram_map)
 				goto err_out;
-			}
 
-			while (size) {
-				z2ram_map[z2ram_size++] = vaddr;
-				size -= Z2RAM_CHUNKSIZE;
-				vaddr += Z2RAM_CHUNKSIZE;
-				list_count++;
-			}
+			get_z2ram();
+			get_chipram();
 
 			if (z2ram_size != 0)
-				printk(KERN_INFO DEVICE_NAME
-				       ": using %iK List Entry %d Memory\n",
-				       list_count * Z2RAM_CHUNK1024, index);
-		} else
-			switch (device) {
-			case Z2MINOR_COMBINED:
-
-				z2ram_map =
-				    kmalloc(max_z2_map + max_chip_map,
-					    GFP_KERNEL);
-				if (z2ram_map == NULL) {
-					printk(KERN_ERR DEVICE_NAME
-					       ": cannot get mem for z2ram_map\n");
-					goto err_out;
-				}
-
-				get_z2ram();
-				get_chipram();
-
-				if (z2ram_size != 0)
-					printk(KERN_INFO DEVICE_NAME
-					       ": using %iK Zorro II RAM and %iK Chip RAM (Total %dK)\n",
-					       z2_count * Z2RAM_CHUNK1024,
-					       chip_count * Z2RAM_CHUNK1024,
-					       (z2_count +
-						chip_count) * Z2RAM_CHUNK1024);
-
-				break;
-
-			case Z2MINOR_Z2ONLY:
-				z2ram_map = kmalloc(max_z2_map, GFP_KERNEL);
-				if (z2ram_map == NULL) {
-					printk(KERN_ERR DEVICE_NAME
-					       ": cannot get mem for z2ram_map\n");
-					goto err_out;
-				}
-
-				get_z2ram();
-
-				if (z2ram_size != 0)
-					printk(KERN_INFO DEVICE_NAME
-					       ": using %iK of Zorro II RAM\n",
-					       z2_count * Z2RAM_CHUNK1024);
-
-				break;
-
-			case Z2MINOR_CHIPONLY:
-				z2ram_map = kmalloc(max_chip_map, GFP_KERNEL);
-				if (z2ram_map == NULL) {
-					printk(KERN_ERR DEVICE_NAME
-					       ": cannot get mem for z2ram_map\n");
-					goto err_out;
-				}
-
-				get_chipram();
-
-				if (z2ram_size != 0)
-					printk(KERN_INFO DEVICE_NAME
-					       ": using %iK Chip RAM\n",
-					       chip_count * Z2RAM_CHUNK1024);
-
-				break;
-
-			default:
-				rc = -ENODEV;
+				pr_info("using %iK Zorro II RAM and %iK Chip RAM (Total %dK)\n",
+					z2_count * Z2RAM_CHUNK1024,
+					chip_count * Z2RAM_CHUNK1024,
+					(z2_count + chip_count) * Z2RAM_CHUNK1024);
+
+			break;
+
+		case Z2MINOR_Z2ONLY:
+			z2ram_map = kmalloc(max_z2_map, GFP_KERNEL);
+			if (!z2ram_map)
+				goto err_out;
+
+			get_z2ram();
+
+			if (z2ram_size != 0)
+				pr_info("using %iK of Zorro II RAM\n",
+					z2_count * Z2RAM_CHUNK1024);
+			break;
+
+		case Z2MINOR_CHIPONLY:
+			z2ram_map = kmalloc(max_chip_map, GFP_KERNEL);
+			if (!z2ram_map)
 				goto err_out;
 
-				break;
-			}
+			get_chipram();
 
-		if (z2ram_size == 0) {
-			printk(KERN_NOTICE DEVICE_NAME
-			       ": no unused ZII/Chip RAM found\n");
-			goto err_out_kfree;
+			if (z2ram_size != 0)
+				pr_info("using %iK Chip RAM\n",
+					chip_count * Z2RAM_CHUNK1024);
+			break;
+
+		default:
+			ret = -ENODEV;
+			goto err_out;
 		}
+	}
 
-		current_device = device;
-		z2ram_size <<= Z2RAM_CHUNKSHIFT;
-		set_capacity(z2ram_gendisk[device], z2ram_size >> 9);
+	if (z2ram_size == 0) {
+		pr_notice("no unused ZII/Chip RAM found\n");
+		goto err_out_kfree;
 	}
 
+	current_device = device;
+	z2ram_size <<= Z2RAM_CHUNKSHIFT;
+	set_capacity(z2ram_gendisk[device], z2ram_size >> 9);
+
 	mutex_unlock(&z2ram_mutex);
 	return 0;
 
@@ -293,7 +259,7 @@ static int z2_open(struct block_device *bdev, fmode_t mode)
 	kfree(z2ram_map);
 err_out:
 	mutex_unlock(&z2ram_mutex);
-	return rc;
+	return ret;
 }
 
 static void z2_release(struct gendisk *disk, fmode_t mode)
@@ -401,24 +367,18 @@ static void __exit z2_exit(void)
 	if (current_device != -1) {
 		i = 0;
 
-		for (j = 0; j < z2_count; j++) {
+		for (j = 0; j < z2_count; j++)
 			set_bit(i++, zorro_unused_z2ram);
-		}
 
 		for (j = 0; j < chip_count; j++) {
-			if (z2ram_map[i]) {
+			if (z2ram_map[i])
 				amiga_chip_free((void *)z2ram_map[i++]);
-			}
 		}
 
-		if (z2ram_map != NULL) {
-			kfree(z2ram_map);
-		}
+		kfree(z2ram_map);
 	}
-
-	return;
 }
 
 module_init(z2_init);
 module_exit(z2_exit);
-MODULE_LICENSE("GPL");
+MODULE_LICENSE("GPL and additional rights");

Re: [PATCH] z2ram: MODULE_LICENSE update and neatening

[James Bottomley]

On Thu, 2020-10-29 at 17:11 -0700, Joe Perches wrote:
> This file still does not have an SPDX line.  What should it be?

It's old style MIT with a slight variation:

https://fedoraproject.org/wiki/Licensing:MIT#Old_Style

James

Re: [PATCH] z2ram: MODULE_LICENSE update and neatening

[Joe Perches]

On Thu, 2020-10-29 at 18:01 -0700, James Bottomley wrote:
> On Thu, 2020-10-29 at 17:11 -0700, Joe Perches wrote:
> > This file still does not have an SPDX line.  What should it be?
> 
> It's old style MIT with a slight variation:
> 
> https://fedoraproject.org/wiki/Licensing:MIT#Old_Style

Yes, it's quite similar.
But ", and sell" does not exist in this variant.

So I believe its use of MODULE_LICENSE("GPL") is not correct and
that MODULE_LICENSE("GPL and additional rights") might be the best
available option.

MIT Old style:

Permission to use, copy, modify, distribute, and sell this software and its
documentation for any purpose is hereby granted without fee, provided that
the above copyright notice appear in all copies and that both that
copyright notice and this permission notice appear in supporting
documentation.  No representations are made about the suitability of this
software for any purpose.  It is provided "as is" without express or
implied warranty.

License in the file:

 * Permission to use, copy, modify, and distribute this software and its
 * documentation for any purpose and without fee is hereby granted, provided
 * that the above copyright notice appear in all copies and that both that
 * copyright notice and this permission notice appear in supporting
 * documentation.  This software is provided "as is" without express or
 * implied warranty.

[PATCH 18/18] block: switch gendisk lookup to a simple xarray

[Christoph Hellwig]

Now that bdev_map is only used for finding gendisks, we can use
a simple xarray instead of the regions tracking structure for it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 block/genhd.c         | 208 ++++++++----------------------------------
 include/linux/genhd.h |   7 --
 2 files changed, 37 insertions(+), 178 deletions(-)

diff --git a/block/genhd.c b/block/genhd.c
index e78c95cf3c00a9..439b444cac2038 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -27,15 +27,7 @@
 
 static struct kobject *block_depr;
 
-struct bdev_map {
-	struct bdev_map *next;
-	dev_t dev;
-	unsigned long range;
-	struct module *owner;
-	struct kobject *(*probe)(dev_t, int *, void *);
-	int (*lock)(dev_t, void *);
-	void *data;
-} *bdev_map[255];
+static DEFINE_XARRAY(bdev_map);
 static DEFINE_MUTEX(bdev_map_lock);
 
 /* for extended dynamic devt allocation, currently only one major is used */
@@ -646,85 +638,26 @@ static char *bdevt_str(dev_t devt, char *buf)
 	return buf;
 }
 
-/*
- * Register device numbers dev..(dev+range-1)
- * range must be nonzero
- * The hash chain is sorted on range, so that subranges can override.
- */
-void blk_register_region(dev_t devt, unsigned long range, struct module *module,
-			 struct kobject *(*probe)(dev_t, int *, void *),
-			 int (*lock)(dev_t, void *), void *data)
-{
-	unsigned n = MAJOR(devt + range - 1) - MAJOR(devt) + 1;
-	unsigned index = MAJOR(devt);
-	unsigned i;
-	struct bdev_map *p;
-
-	n = min(n, 255u);
-	p = kmalloc_array(n, sizeof(struct bdev_map), GFP_KERNEL);
-	if (p == NULL)
-		return;
-
-	for (i = 0; i < n; i++, p++) {
-		p->owner = module;
-		p->probe = probe;
-		p->lock = lock;
-		p->dev = devt;
-		p->range = range;
-		p->data = data;
-	}
+static void blk_register_region(struct gendisk *disk)
+{
+	int i;
 
 	mutex_lock(&bdev_map_lock);
-	for (i = 0, p -= n; i < n; i++, p++, index++) {
-		struct bdev_map **s = &bdev_map[index % 255];
-		while (*s && (*s)->range < range)
-			s = &(*s)->next;
-		p->next = *s;
-		*s = p;
+	for (i = 0; i < disk->minors; i++) {
+		if (xa_insert(&bdev_map, disk_devt(disk) + i, disk, GFP_KERNEL))
+			WARN_ON_ONCE(1);
 	}
 	mutex_unlock(&bdev_map_lock);
 }
-EXPORT_SYMBOL(blk_register_region);
 
-void blk_unregister_region(dev_t devt, unsigned long range)
+static void blk_unregister_region(struct gendisk *disk)
 {
-	unsigned n = MAJOR(devt + range - 1) - MAJOR(devt) + 1;
-	unsigned index = MAJOR(devt);
-	unsigned i;
-	struct bdev_map *found = NULL;
+	int i;
 
 	mutex_lock(&bdev_map_lock);
-	for (i = 0; i < min(n, 255u); i++, index++) {
-		struct bdev_map **s;
-		for (s = &bdev_map[index % 255]; *s; s = &(*s)->next) {
-			struct bdev_map *p = *s;
-			if (p->dev == devt && p->range == range) {
-				*s = p->next;
-				if (!found)
-					found = p;
-				break;
-			}
-		}
-	}
+	for (i = 0; i < disk->minors; i++)
+		xa_erase(&bdev_map, disk_devt(disk) + i);
 	mutex_unlock(&bdev_map_lock);
-	kfree(found);
-}
-EXPORT_SYMBOL(blk_unregister_region);
-
-static struct kobject *exact_match(dev_t devt, int *partno, void *data)
-{
-	struct gendisk *p = data;
-
-	return &disk_to_dev(p)->kobj;
-}
-
-static int exact_lock(dev_t devt, void *data)
-{
-	struct gendisk *p = data;
-
-	if (!get_disk_and_module(p))
-		return -1;
-	return 0;
 }
 
 static void disk_scan_partitions(struct gendisk *disk)
@@ -870,8 +803,7 @@ static void __device_add_disk(struct device *parent, struct gendisk *disk,
 		ret = bdi_register(bdi, "%u:%u", MAJOR(devt), MINOR(devt));
 		WARN_ON(ret);
 		bdi_set_owner(bdi, dev);
-		blk_register_region(disk_devt(disk), disk->minors, NULL,
-				    exact_match, exact_lock, disk);
+		blk_register_region(disk);
 	}
 	register_disk(parent, disk, groups);
 	if (register_queue)
@@ -984,7 +916,7 @@ void del_gendisk(struct gendisk *disk)
 	blk_unregister_queue(disk);
 	
 	if (!(disk->flags & GENHD_FL_HIDDEN))
-		blk_unregister_region(disk_devt(disk), disk->minors);
+		blk_unregister_region(disk);
 	/*
 	 * Remove gendisk pointer from idr so that it cannot be looked up
 	 * while RCU period before freeing gendisk is running to prevent
@@ -1050,54 +982,22 @@ static void request_gendisk_module(dev_t devt)
 		request_module("block-major-%d", MAJOR(devt));
 }
 
-static struct gendisk *lookup_gendisk(dev_t dev, int *partno)
+static bool get_disk_and_module(struct gendisk *disk)
 {
-	struct kobject *kobj;
-	struct bdev_map *p;
-	unsigned long best = ~0UL;
-
-retry:
-	mutex_lock(&bdev_map_lock);
-	for (p = bdev_map[MAJOR(dev) % 255]; p; p = p->next) {
-		struct kobject *(*probe)(dev_t, int *, void *);
-		struct module *owner;
-		void *data;
-
-		if (p->dev > dev || p->dev + p->range - 1 < dev)
-			continue;
-		if (p->range - 1 >= best)
-			break;
-		if (!try_module_get(p->owner))
-			continue;
-		owner = p->owner;
-		data = p->data;
-		probe = p->probe;
-		best = p->range - 1;
-		*partno = dev - p->dev;
-
-		if (!probe) {
-			mutex_unlock(&bdev_map_lock);
-			module_put(owner);
-			request_gendisk_module(dev);
-			goto retry;
-		}
+	struct module *owner;
 
-		if (p->lock && p->lock(dev, data) < 0) {
-			module_put(owner);
-			continue;
-		}
-		mutex_unlock(&bdev_map_lock);
-		kobj = probe(dev, partno, data);
-		/* Currently ->owner protects _only_ ->probe() itself. */
+	if (!disk->fops)
+		return false;
+	owner = disk->fops->owner;
+	if (owner && !try_module_get(owner))
+		return false;
+	if (!kobject_get_unless_zero(&disk_to_dev(disk)->kobj)) {
 		module_put(owner);
-		if (kobj)
-			return dev_to_disk(kobj_to_dev(kobj));
-		goto retry;
+		return false;
 	}
-	mutex_unlock(&bdev_map_lock);
-	return NULL;
-}
+	return true;
 
+}
 
 /**
  * get_gendisk - get partitioning information for a given device
@@ -1116,7 +1016,19 @@ struct gendisk *get_gendisk(dev_t devt, int *partno)
 	might_sleep();
 
 	if (MAJOR(devt) != BLOCK_EXT_MAJOR) {
-		disk = lookup_gendisk(devt, partno);
+		mutex_lock(&bdev_map_lock);
+		disk = xa_load(&bdev_map, devt);
+		if (!disk) {
+			mutex_unlock(&bdev_map_lock);
+			request_gendisk_module(devt);
+			mutex_lock(&bdev_map_lock);
+			disk = xa_load(&bdev_map, devt);
+		}
+		if (disk && !get_disk_and_module(disk))
+			disk = NULL;
+		if (disk)
+			*partno = devt - disk_devt(disk);
+		mutex_unlock(&bdev_map_lock);
 	} else {
 		struct hd_struct *part;
 
@@ -1320,21 +1232,6 @@ static const struct seq_operations partitions_op = {
 };
 #endif
 
-static void bdev_map_init(void)
-{
-	struct bdev_map *base;
-	int i;
-
-	base = kzalloc(sizeof(*base), GFP_KERNEL);
-	if (!base)
-		panic("cannot allocate bdev_map");
-
-	base->dev = 1;
-	base->range = ~0 ;
-	for (i = 0; i < 255; i++)
-		bdev_map[i] = base;
-}
-
 static int __init genhd_device_init(void)
 {
 	int error;
@@ -1343,7 +1240,6 @@ static int __init genhd_device_init(void)
 	error = class_register(&block_class);
 	if (unlikely(error))
 		return error;
-	bdev_map_init();
 	blk_dev_init();
 
 	register_blkdev(BLOCK_EXT_MAJOR, "blkext");
@@ -1892,35 +1788,6 @@ struct gendisk *__alloc_disk_node(int minors, int node_id)
 }
 EXPORT_SYMBOL(__alloc_disk_node);
 
-/**
- * get_disk_and_module - increments the gendisk and gendisk fops module refcount
- * @disk: the struct gendisk to increment the refcount for
- *
- * This increments the refcount for the struct gendisk, and the gendisk's
- * fops module owner.
- *
- * Context: Any context.
- */
-struct kobject *get_disk_and_module(struct gendisk *disk)
-{
-	struct module *owner;
-	struct kobject *kobj;
-
-	if (!disk->fops)
-		return NULL;
-	owner = disk->fops->owner;
-	if (owner && !try_module_get(owner))
-		return NULL;
-	kobj = kobject_get_unless_zero(&disk_to_dev(disk)->kobj);
-	if (kobj == NULL) {
-		module_put(owner);
-		return NULL;
-	}
-	return kobj;
-
-}
-EXPORT_SYMBOL(get_disk_and_module);
-
 /**
  * put_disk - decrements the gendisk refcount
  * @disk: the struct gendisk to decrement the refcount for
@@ -1957,7 +1824,6 @@ void put_disk_and_module(struct gendisk *disk)
 		module_put(owner);
 	}
 }
-EXPORT_SYMBOL(put_disk_and_module);
 
 static void set_disk_ro_uevent(struct gendisk *gd, int ro)
 {
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index 14b1bc7dea21d8..77c3489991f42e 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -340,15 +340,8 @@ int blk_add_partitions(struct gendisk *disk, struct block_device *bdev);
 int blk_drop_partitions(struct block_device *bdev);
 
 extern struct gendisk *__alloc_disk_node(int minors, int node_id);
-extern struct kobject *get_disk_and_module(struct gendisk *disk);
 extern void put_disk(struct gendisk *disk);
 extern void put_disk_and_module(struct gendisk *disk);
-extern void blk_register_region(dev_t devt, unsigned long range,
-			struct module *module,
-			struct kobject *(*probe)(dev_t, int *, void *),
-			int (*lock)(dev_t, void *),
-			void *data);
-extern void blk_unregister_region(dev_t devt, unsigned long range);
 
 #define alloc_disk_node(minors, node_id)				\
 ({									\
-- 
2.28.0

Re: simplify gendisk lookup and remove struct block_device aliases v4

[Christoph Hellwig]

Jens, can you take a look and possibly pick this series up?

On Thu, Oct 29, 2020 at 03:58:23PM +0100, Christoph Hellwig wrote:
> Hi all,
> 
> this series removes the annoying struct block_device aliases, which can
> happen for a bunch of old floppy drivers (and z2ram).  In that case
> multiple struct block device instances for different dev_t's can point
> to the same gendisk, without being partitions.  The cause for that
> is the probe/get callback registered through blk_register_regions.
> 
> This series removes blk_register_region entirely, splitting it it into
> a simple xarray lookup of registered gendisks, and a probe callback
> stored in the major_names array that can be used for modprobe overrides
> or creating devices on demands when no gendisk is found.  The old
> remapping is gone entirely, and instead the 4 remaining drivers just
> register a gendisk for each operating mode.  In case of the two drivers
> that have lots of aliases that is done on-demand using the new probe
> callback, while for the other two I simply register all at probe time
> to keep things simple.
> 
> Note that the m68k drivers are compile tested only.
> 
> Changes since v3:
>  - keep kobj_map for char dev lookup for now, as the testbot found
>    some very strange and unexplained regressions, so I'll get back to
>    this later separately
>  - fix a commit message typo
> 
> Changes since v2:
>  - fix a wrong variable passed to ERR_PTR in the floppy driver
>  - slightly adjust the del_gendisk cleanups to prepare for the next
>    series touching this area
> 
> Changes since v1:
>  - add back a missing kobject_put in the cdev code
>  - improve the xarray delete loops
---end quoted text---

Re: simplify gendisk lookup and remove struct block_device aliases v4

[Jens Axboe]

On 10/29/20 8:58 AM, Christoph Hellwig wrote:
> Hi all,
> 
> this series removes the annoying struct block_device aliases, which can
> happen for a bunch of old floppy drivers (and z2ram).  In that case
> multiple struct block device instances for different dev_t's can point
> to the same gendisk, without being partitions.  The cause for that
> is the probe/get callback registered through blk_register_regions.
> 
> This series removes blk_register_region entirely, splitting it it into
> a simple xarray lookup of registered gendisks, and a probe callback
> stored in the major_names array that can be used for modprobe overrides
> or creating devices on demands when no gendisk is found.  The old
> remapping is gone entirely, and instead the 4 remaining drivers just
> register a gendisk for each operating mode.  In case of the two drivers
> that have lots of aliases that is done on-demand using the new probe
> callback, while for the other two I simply register all at probe time
> to keep things simple.
> 
> Note that the m68k drivers are compile tested only.

Applied, thanks.

-- 
Jens Axboe