cleanup ubd gendisk registration

cleanup ubd gendisk registration

[Christoph Hellwig]

Hi all,

this series sits on top of Jens' for-5.14/block branch and tries to
convert ubd to the new gendisk and request_queue registration helpers.
As part of that I found that the ide emulation code currently registers
two gendisk for a request_queue which leads to a bunch of problems we've
avoided in other drivers (only the mmc subsystem has a similar issue).
Given that the legacy IDE driver isn't practically used any more and
modern userspace doesn't hard code specific block drivers, so I think
we can just drop it.  Let me know if this is ok.

[PATCH 1/2] ubd: remove the code to register as the legacy IDE driver

[Christoph Hellwig]

With the legacy IDE driver long deprecated, and modern userspace being
much more flexible about dev_t assignments there is no reason to fake
a registration as the legacy IDE driver in ubd.  This registeration
is a little problematic as it registers the same request_queue for
multiple gendisks, so just remove it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 arch/um/drivers/ubd_kern.c | 106 +++++--------------------------------
 1 file changed, 12 insertions(+), 94 deletions(-)

diff --git a/arch/um/drivers/ubd_kern.c b/arch/um/drivers/ubd_kern.c
index 8e0b43cf089f..f508d45f7a69 100644
--- a/arch/um/drivers/ubd_kern.c
+++ b/arch/um/drivers/ubd_kern.c
@@ -125,9 +125,7 @@ static const struct block_device_operations ubd_blops = {
 };
 
 /* Protected by ubd_lock */
-static int fake_major = UBD_MAJOR;
 static struct gendisk *ubd_gendisk[MAX_DEV];
-static struct gendisk *fake_gendisk[MAX_DEV];
 
 #ifdef CONFIG_BLK_DEV_UBD_SYNC
 #define OPEN_FLAGS ((struct openflags) { .r = 1, .w = 1, .s = 1, .c = 0, \
@@ -197,54 +195,19 @@ struct ubd {
 /* Protected by ubd_lock */
 static struct ubd ubd_devs[MAX_DEV] = { [0 ... MAX_DEV - 1] = DEFAULT_UBD };
 
-/* Only changed by fake_ide_setup which is a setup */
-static int fake_ide = 0;
-static struct proc_dir_entry *proc_ide_root = NULL;
-static struct proc_dir_entry *proc_ide = NULL;
-
 static blk_status_t ubd_queue_rq(struct blk_mq_hw_ctx *hctx,
 				 const struct blk_mq_queue_data *bd);
 
-static void make_proc_ide(void)
-{
-	proc_ide_root = proc_mkdir("ide", NULL);
-	proc_ide = proc_mkdir("ide0", proc_ide_root);
-}
-
-static int fake_ide_media_proc_show(struct seq_file *m, void *v)
-{
-	seq_puts(m, "disk\n");
-	return 0;
-}
-
-static void make_ide_entries(const char *dev_name)
-{
-	struct proc_dir_entry *dir, *ent;
-	char name[64];
-
-	if(proc_ide_root == NULL) make_proc_ide();
-
-	dir = proc_mkdir(dev_name, proc_ide);
-	if(!dir) return;
-
-	ent = proc_create_single("media", S_IRUGO, dir,
-			fake_ide_media_proc_show);
-	if(!ent) return;
-	snprintf(name, sizeof(name), "ide0/%s", dev_name);
-	proc_symlink(dev_name, proc_ide_root, name);
-}
-
 static int fake_ide_setup(char *str)
 {
-	fake_ide = 1;
+	pr_warn("The fake_ide option has been removed\n");
 	return 1;
 }
-
 __setup("fake_ide", fake_ide_setup);
 
 __uml_help(fake_ide_setup,
 "fake_ide\n"
-"    Create ide0 entries that map onto ubd devices.\n\n"
+"    Obsolete stub.\n\n"
 );
 
 static int parse_unit(char **ptr)
@@ -296,20 +259,8 @@ static int ubd_setup_common(char *str, int *index_out, char **error_out)
 			return err;
 		}
 
-		mutex_lock(&ubd_lock);
-		if (fake_major != UBD_MAJOR) {
-			*error_out = "Can't assign a fake major twice";
-			goto out1;
-		}
-
-		fake_major = major;
-
-		printk(KERN_INFO "Setting extra ubd major number to %d\n",
-		       major);
-		err = 0;
-	out1:
-		mutex_unlock(&ubd_lock);
-		return err;
+		pr_warn("fake major not supported any more\n");
+		return 0;
 	}
 
 	n = parse_unit(&str);
@@ -917,7 +868,6 @@ static const struct attribute_group *ubd_attr_groups[] = {
 static int ubd_disk_register(int major, u64 size, int unit,
 			     struct gendisk **disk_out)
 {
-	struct device *parent = NULL;
 	struct gendisk *disk;
 
 	disk = alloc_disk(1 << UBD_SHIFT);
@@ -928,24 +878,17 @@ static int ubd_disk_register(int major, u64 size, int unit,
 	disk->first_minor = unit << UBD_SHIFT;
 	disk->fops = &ubd_blops;
 	set_capacity(disk, size / 512);
-	if (major == UBD_MAJOR)
-		sprintf(disk->disk_name, "ubd%c", 'a' + unit);
-	else
-		sprintf(disk->disk_name, "ubd_fake%d", unit);
-
-	/* sysfs register (not for ide fake devices) */
-	if (major == UBD_MAJOR) {
-		ubd_devs[unit].pdev.id   = unit;
-		ubd_devs[unit].pdev.name = DRIVER_NAME;
-		ubd_devs[unit].pdev.dev.release = ubd_device_release;
-		dev_set_drvdata(&ubd_devs[unit].pdev.dev, &ubd_devs[unit]);
-		platform_device_register(&ubd_devs[unit].pdev);
-		parent = &ubd_devs[unit].pdev.dev;
-	}
+	sprintf(disk->disk_name, "ubd%c", 'a' + unit);
+
+	ubd_devs[unit].pdev.id   = unit;
+	ubd_devs[unit].pdev.name = DRIVER_NAME;
+	ubd_devs[unit].pdev.dev.release = ubd_device_release;
+	dev_set_drvdata(&ubd_devs[unit].pdev.dev, &ubd_devs[unit]);
+	platform_device_register(&ubd_devs[unit].pdev);
 
 	disk->private_data = &ubd_devs[unit];
 	disk->queue = ubd_devs[unit].queue;
-	device_add_disk(parent, disk, ubd_attr_groups);
+	device_add_disk(&ubd_devs[unit].pdev.dev, disk, ubd_attr_groups);
 
 	*disk_out = disk;
 	return 0;
@@ -1001,17 +944,6 @@ static int ubd_add(int n, char **error_out)
 		goto out_cleanup_tags;
 	}
 
-	if (fake_major != UBD_MAJOR)
-		ubd_disk_register(fake_major, ubd_dev->size, n,
-				  &fake_gendisk[n]);
-
-	/*
-	 * Perhaps this should also be under the "if (fake_major)" above
-	 * using the fake_disk->disk_name
-	 */
-	if (fake_ide)
-		make_ide_entries(ubd_gendisk[n]->disk_name);
-
 	err = 0;
 out:
 	return err;
@@ -1126,12 +1058,6 @@ static int ubd_remove(int n, char **error_out)
 		put_disk(disk);
 	}
 
-	if(fake_gendisk[n] != NULL){
-		del_gendisk(fake_gendisk[n]);
-		put_disk(fake_gendisk[n]);
-		fake_gendisk[n] = NULL;
-	}
-
 	err = 0;
 	platform_device_unregister(&ubd_dev->pdev);
 out:
@@ -1188,14 +1114,6 @@ static int __init ubd_init(void)
 	if (register_blkdev(UBD_MAJOR, "ubd"))
 		return -1;
 
-	if (fake_major != UBD_MAJOR) {
-		char name[sizeof("ubd_nnn\0")];
-
-		snprintf(name, sizeof(name), "ubd_%d", fake_major);
-		if (register_blkdev(fake_major, "ubd"))
-			return -1;
-	}
-
 	irq_req_buffer = kmalloc_array(UBD_REQ_BUFFER_SIZE,
 				       sizeof(struct io_thread_req *),
 				       GFP_KERNEL
-- 
2.30.2

[PATCH 2/2] ubd: use blk_mq_alloc_disk and blk_cleanup_disk

[Christoph Hellwig]

Use blk_mq_alloc_disk and blk_cleanup_disk to simplify the gendisk and
request_queue allocation.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 arch/um/drivers/ubd_kern.c | 44 ++++++++++++--------------------------
 1 file changed, 14 insertions(+), 30 deletions(-)

diff --git a/arch/um/drivers/ubd_kern.c b/arch/um/drivers/ubd_kern.c
index f508d45f7a69..0b86aa1b12f1 100644
--- a/arch/um/drivers/ubd_kern.c
+++ b/arch/um/drivers/ubd_kern.c
@@ -825,7 +825,6 @@ static void ubd_device_release(struct device *dev)
 {
 	struct ubd *ubd_dev = dev_get_drvdata(dev);
 
-	blk_cleanup_queue(ubd_dev->queue);
 	blk_mq_free_tag_set(&ubd_dev->tag_set);
 	*ubd_dev = ((struct ubd) DEFAULT_UBD);
 }
@@ -865,17 +864,12 @@ static const struct attribute_group *ubd_attr_groups[] = {
 	NULL,
 };
 
-static int ubd_disk_register(int major, u64 size, int unit,
-			     struct gendisk **disk_out)
+static void ubd_disk_register(int major, u64 size, int unit,
+			      struct gendisk *disk)
 {
-	struct gendisk *disk;
-
-	disk = alloc_disk(1 << UBD_SHIFT);
-	if(disk == NULL)
-		return -ENOMEM;
-
 	disk->major = major;
 	disk->first_minor = unit << UBD_SHIFT;
+	disk->minors = 1 << UBD_SHIFT;
 	disk->fops = &ubd_blops;
 	set_capacity(disk, size / 512);
 	sprintf(disk->disk_name, "ubd%c", 'a' + unit);
@@ -889,9 +883,6 @@ static int ubd_disk_register(int major, u64 size, int unit,
 	disk->private_data = &ubd_devs[unit];
 	disk->queue = ubd_devs[unit].queue;
 	device_add_disk(&ubd_devs[unit].pdev.dev, disk, ubd_attr_groups);
-
-	*disk_out = disk;
-	return 0;
 }
 
 #define ROUND_BLOCK(n) ((n + (SECTOR_SIZE - 1)) & (-SECTOR_SIZE))
@@ -903,6 +894,7 @@ static const struct blk_mq_ops ubd_mq_ops = {
 static int ubd_add(int n, char **error_out)
 {
 	struct ubd *ubd_dev = &ubd_devs[n];
+	struct gendisk *disk;
 	int err = 0;
 
 	if(ubd_dev->file == NULL)
@@ -927,32 +919,24 @@ static int ubd_add(int n, char **error_out)
 	if (err)
 		goto out;
 
-	ubd_dev->queue = blk_mq_init_queue(&ubd_dev->tag_set);
-	if (IS_ERR(ubd_dev->queue)) {
-		err = PTR_ERR(ubd_dev->queue);
+	disk = blk_mq_alloc_disk(&ubd_dev->tag_set, ubd_dev);
+	if (IS_ERR(disk)) {
+		err = PTR_ERR(disk);
 		goto out_cleanup_tags;
 	}
+	ubd_dev->queue = disk->queue;
 
-	ubd_dev->queue->queuedata = ubd_dev;
 	blk_queue_write_cache(ubd_dev->queue, true, false);
-
 	blk_queue_max_segments(ubd_dev->queue, MAX_SG);
 	blk_queue_segment_boundary(ubd_dev->queue, PAGE_SIZE - 1);
-	err = ubd_disk_register(UBD_MAJOR, ubd_dev->size, n, &ubd_gendisk[n]);
-	if(err){
-		*error_out = "Failed to register device";
-		goto out_cleanup_tags;
-	}
-
-	err = 0;
-out:
-	return err;
+	ubd_disk_register(UBD_MAJOR, ubd_dev->size, n, disk);
+	ubd_gendisk[n] = disk;
+	return 0;
 
 out_cleanup_tags:
 	blk_mq_free_tag_set(&ubd_dev->tag_set);
-	if (!(IS_ERR(ubd_dev->queue)))
-		blk_cleanup_queue(ubd_dev->queue);
-	goto out;
+out:
+	return err;
 }
 
 static int ubd_config(char *str, char **error_out)
@@ -1055,7 +1039,7 @@ static int ubd_remove(int n, char **error_out)
 	ubd_gendisk[n] = NULL;
 	if(disk != NULL){
 		del_gendisk(disk);
-		put_disk(disk);
+		blk_cleanup_disk(disk);
 	}
 
 	err = 0;
-- 
2.30.2

Re: [PATCH 1/2] ubd: remove the code to register as the legacy IDE driver

[Anton Ivanov]

On 14/06/2021 07:07, Christoph Hellwig wrote:
> With the legacy IDE driver long deprecated, and modern userspace being
> much more flexible about dev_t assignments there is no reason to fake
> a registration as the legacy IDE driver in ubd.  This registeration
> is a little problematic as it registers the same request_queue for
> multiple gendisks, so just remove it.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>   arch/um/drivers/ubd_kern.c | 106 +++++--------------------------------
>   1 file changed, 12 insertions(+), 94 deletions(-)
> 
> diff --git a/arch/um/drivers/ubd_kern.c b/arch/um/drivers/ubd_kern.c
> index 8e0b43cf089f..f508d45f7a69 100644
> --- a/arch/um/drivers/ubd_kern.c
> +++ b/arch/um/drivers/ubd_kern.c
> @@ -125,9 +125,7 @@ static const struct block_device_operations ubd_blops = {
>   };
>   
>   /* Protected by ubd_lock */
> -static int fake_major = UBD_MAJOR;
>   static struct gendisk *ubd_gendisk[MAX_DEV];
> -static struct gendisk *fake_gendisk[MAX_DEV];
>   
>   #ifdef CONFIG_BLK_DEV_UBD_SYNC
>   #define OPEN_FLAGS ((struct openflags) { .r = 1, .w = 1, .s = 1, .c = 0, \
> @@ -197,54 +195,19 @@ struct ubd {
>   /* Protected by ubd_lock */
>   static struct ubd ubd_devs[MAX_DEV] = { [0 ... MAX_DEV - 1] = DEFAULT_UBD };
>   
> -/* Only changed by fake_ide_setup which is a setup */
> -static int fake_ide = 0;
> -static struct proc_dir_entry *proc_ide_root = NULL;
> -static struct proc_dir_entry *proc_ide = NULL;
> -
>   static blk_status_t ubd_queue_rq(struct blk_mq_hw_ctx *hctx,
>   				 const struct blk_mq_queue_data *bd);
>   
> -static void make_proc_ide(void)
> -{
> -	proc_ide_root = proc_mkdir("ide", NULL);
> -	proc_ide = proc_mkdir("ide0", proc_ide_root);
> -}
> -
> -static int fake_ide_media_proc_show(struct seq_file *m, void *v)
> -{
> -	seq_puts(m, "disk\n");
> -	return 0;
> -}
> -
> -static void make_ide_entries(const char *dev_name)
> -{
> -	struct proc_dir_entry *dir, *ent;
> -	char name[64];
> -
> -	if(proc_ide_root == NULL) make_proc_ide();
> -
> -	dir = proc_mkdir(dev_name, proc_ide);
> -	if(!dir) return;
> -
> -	ent = proc_create_single("media", S_IRUGO, dir,
> -			fake_ide_media_proc_show);
> -	if(!ent) return;
> -	snprintf(name, sizeof(name), "ide0/%s", dev_name);
> -	proc_symlink(dev_name, proc_ide_root, name);
> -}
> -
>   static int fake_ide_setup(char *str)
>   {
> -	fake_ide = 1;
> +	pr_warn("The fake_ide option has been removed\n");
>   	return 1;
>   }
> -
>   __setup("fake_ide", fake_ide_setup);
>   
>   __uml_help(fake_ide_setup,
>   "fake_ide\n"
> -"    Create ide0 entries that map onto ubd devices.\n\n"
> +"    Obsolete stub.\n\n"
>   );
>   
>   static int parse_unit(char **ptr)
> @@ -296,20 +259,8 @@ static int ubd_setup_common(char *str, int *index_out, char **error_out)
>   			return err;
>   		}
>   
> -		mutex_lock(&ubd_lock);
> -		if (fake_major != UBD_MAJOR) {
> -			*error_out = "Can't assign a fake major twice";
> -			goto out1;
> -		}
> -
> -		fake_major = major;
> -
> -		printk(KERN_INFO "Setting extra ubd major number to %d\n",
> -		       major);
> -		err = 0;
> -	out1:
> -		mutex_unlock(&ubd_lock);
> -		return err;
> +		pr_warn("fake major not supported any more\n");
> +		return 0;
>   	}
>   
>   	n = parse_unit(&str);
> @@ -917,7 +868,6 @@ static const struct attribute_group *ubd_attr_groups[] = {
>   static int ubd_disk_register(int major, u64 size, int unit,
>   			     struct gendisk **disk_out)
>   {
> -	struct device *parent = NULL;
>   	struct gendisk *disk;
>   
>   	disk = alloc_disk(1 << UBD_SHIFT);
> @@ -928,24 +878,17 @@ static int ubd_disk_register(int major, u64 size, int unit,
>   	disk->first_minor = unit << UBD_SHIFT;
>   	disk->fops = &ubd_blops;
>   	set_capacity(disk, size / 512);
> -	if (major == UBD_MAJOR)
> -		sprintf(disk->disk_name, "ubd%c", 'a' + unit);
> -	else
> -		sprintf(disk->disk_name, "ubd_fake%d", unit);
> -
> -	/* sysfs register (not for ide fake devices) */
> -	if (major == UBD_MAJOR) {
> -		ubd_devs[unit].pdev.id   = unit;
> -		ubd_devs[unit].pdev.name = DRIVER_NAME;
> -		ubd_devs[unit].pdev.dev.release = ubd_device_release;
> -		dev_set_drvdata(&ubd_devs[unit].pdev.dev, &ubd_devs[unit]);
> -		platform_device_register(&ubd_devs[unit].pdev);
> -		parent = &ubd_devs[unit].pdev.dev;
> -	}
> +	sprintf(disk->disk_name, "ubd%c", 'a' + unit);
> +
> +	ubd_devs[unit].pdev.id   = unit;
> +	ubd_devs[unit].pdev.name = DRIVER_NAME;
> +	ubd_devs[unit].pdev.dev.release = ubd_device_release;
> +	dev_set_drvdata(&ubd_devs[unit].pdev.dev, &ubd_devs[unit]);
> +	platform_device_register(&ubd_devs[unit].pdev);
>   
>   	disk->private_data = &ubd_devs[unit];
>   	disk->queue = ubd_devs[unit].queue;
> -	device_add_disk(parent, disk, ubd_attr_groups);
> +	device_add_disk(&ubd_devs[unit].pdev.dev, disk, ubd_attr_groups);
>   
>   	*disk_out = disk;
>   	return 0;
> @@ -1001,17 +944,6 @@ static int ubd_add(int n, char **error_out)
>   		goto out_cleanup_tags;
>   	}
>   
> -	if (fake_major != UBD_MAJOR)
> -		ubd_disk_register(fake_major, ubd_dev->size, n,
> -				  &fake_gendisk[n]);
> -
> -	/*
> -	 * Perhaps this should also be under the "if (fake_major)" above
> -	 * using the fake_disk->disk_name
> -	 */
> -	if (fake_ide)
> -		make_ide_entries(ubd_gendisk[n]->disk_name);
> -
>   	err = 0;
>   out:
>   	return err;
> @@ -1126,12 +1058,6 @@ static int ubd_remove(int n, char **error_out)
>   		put_disk(disk);
>   	}
>   
> -	if(fake_gendisk[n] != NULL){
> -		del_gendisk(fake_gendisk[n]);
> -		put_disk(fake_gendisk[n]);
> -		fake_gendisk[n] = NULL;
> -	}
> -
>   	err = 0;
>   	platform_device_unregister(&ubd_dev->pdev);
>   out:
> @@ -1188,14 +1114,6 @@ static int __init ubd_init(void)
>   	if (register_blkdev(UBD_MAJOR, "ubd"))
>   		return -1;
>   
> -	if (fake_major != UBD_MAJOR) {
> -		char name[sizeof("ubd_nnn\0")];
> -
> -		snprintf(name, sizeof(name), "ubd_%d", fake_major);
> -		if (register_blkdev(fake_major, "ubd"))
> -			return -1;
> -	}
> -
>   	irq_req_buffer = kmalloc_array(UBD_REQ_BUFFER_SIZE,
>   				       sizeof(struct io_thread_req *),
>   				       GFP_KERNEL
> 

Acked-By: Anton Ivanov <anton.ivanov@cambridgegreys.com>

-- 
Anton R. Ivanov
Cambridgegreys Limited. Registered in England. Company Number 10273661
https://www.cambridgegreys.com/

Re: [PATCH 2/2] ubd: use blk_mq_alloc_disk and blk_cleanup_disk

[Anton Ivanov]

On 14/06/2021 07:07, Christoph Hellwig wrote:
> Use blk_mq_alloc_disk and blk_cleanup_disk to simplify the gendisk and
> request_queue allocation.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>   arch/um/drivers/ubd_kern.c | 44 ++++++++++++--------------------------
>   1 file changed, 14 insertions(+), 30 deletions(-)
> 
> diff --git a/arch/um/drivers/ubd_kern.c b/arch/um/drivers/ubd_kern.c
> index f508d45f7a69..0b86aa1b12f1 100644
> --- a/arch/um/drivers/ubd_kern.c
> +++ b/arch/um/drivers/ubd_kern.c
> @@ -825,7 +825,6 @@ static void ubd_device_release(struct device *dev)
>   {
>   	struct ubd *ubd_dev = dev_get_drvdata(dev);
>   
> -	blk_cleanup_queue(ubd_dev->queue);
>   	blk_mq_free_tag_set(&ubd_dev->tag_set);
>   	*ubd_dev = ((struct ubd) DEFAULT_UBD);
>   }
> @@ -865,17 +864,12 @@ static const struct attribute_group *ubd_attr_groups[] = {
>   	NULL,
>   };
>   
> -static int ubd_disk_register(int major, u64 size, int unit,
> -			     struct gendisk **disk_out)
> +static void ubd_disk_register(int major, u64 size, int unit,
> +			      struct gendisk *disk)
>   {
> -	struct gendisk *disk;
> -
> -	disk = alloc_disk(1 << UBD_SHIFT);
> -	if(disk == NULL)
> -		return -ENOMEM;
> -
>   	disk->major = major;
>   	disk->first_minor = unit << UBD_SHIFT;
> +	disk->minors = 1 << UBD_SHIFT;
>   	disk->fops = &ubd_blops;
>   	set_capacity(disk, size / 512);
>   	sprintf(disk->disk_name, "ubd%c", 'a' + unit);
> @@ -889,9 +883,6 @@ static int ubd_disk_register(int major, u64 size, int unit,
>   	disk->private_data = &ubd_devs[unit];
>   	disk->queue = ubd_devs[unit].queue;
>   	device_add_disk(&ubd_devs[unit].pdev.dev, disk, ubd_attr_groups);
> -
> -	*disk_out = disk;
> -	return 0;
>   }
>   
>   #define ROUND_BLOCK(n) ((n + (SECTOR_SIZE - 1)) & (-SECTOR_SIZE))
> @@ -903,6 +894,7 @@ static const struct blk_mq_ops ubd_mq_ops = {
>   static int ubd_add(int n, char **error_out)
>   {
>   	struct ubd *ubd_dev = &ubd_devs[n];
> +	struct gendisk *disk;
>   	int err = 0;
>   
>   	if(ubd_dev->file == NULL)
> @@ -927,32 +919,24 @@ static int ubd_add(int n, char **error_out)
>   	if (err)
>   		goto out;
>   
> -	ubd_dev->queue = blk_mq_init_queue(&ubd_dev->tag_set);
> -	if (IS_ERR(ubd_dev->queue)) {
> -		err = PTR_ERR(ubd_dev->queue);
> +	disk = blk_mq_alloc_disk(&ubd_dev->tag_set, ubd_dev);
> +	if (IS_ERR(disk)) {
> +		err = PTR_ERR(disk);
>   		goto out_cleanup_tags;
>   	}
> +	ubd_dev->queue = disk->queue;
>   
> -	ubd_dev->queue->queuedata = ubd_dev;
>   	blk_queue_write_cache(ubd_dev->queue, true, false);
> -
>   	blk_queue_max_segments(ubd_dev->queue, MAX_SG);
>   	blk_queue_segment_boundary(ubd_dev->queue, PAGE_SIZE - 1);
> -	err = ubd_disk_register(UBD_MAJOR, ubd_dev->size, n, &ubd_gendisk[n]);
> -	if(err){
> -		*error_out = "Failed to register device";
> -		goto out_cleanup_tags;
> -	}
> -
> -	err = 0;
> -out:
> -	return err;
> +	ubd_disk_register(UBD_MAJOR, ubd_dev->size, n, disk);
> +	ubd_gendisk[n] = disk;
> +	return 0;
>   
>   out_cleanup_tags:
>   	blk_mq_free_tag_set(&ubd_dev->tag_set);
> -	if (!(IS_ERR(ubd_dev->queue)))
> -		blk_cleanup_queue(ubd_dev->queue);
> -	goto out;
> +out:
> +	return err;
>   }
>   
>   static int ubd_config(char *str, char **error_out)
> @@ -1055,7 +1039,7 @@ static int ubd_remove(int n, char **error_out)
>   	ubd_gendisk[n] = NULL;
>   	if(disk != NULL){
>   		del_gendisk(disk);
> -		put_disk(disk);
> +		blk_cleanup_disk(disk);
>   	}
>   
>   	err = 0;
> 

This does not build for me when applied to master:


arch/um/drivers/ubd_kern.c: In function ‘ubd_add’:
arch/um/drivers/ubd_kern.c:922:9: error: implicit declaration of function ‘blk_mq_alloc_disk’; did you mean ‘blk_mq_alloc_request’? [-Werror=implicit-function-declaration]
   disk = blk_mq_alloc_disk(&ubd_dev->tag_set, ubd_dev);
          ^~~~~~~~~~~~~~~~~
          blk_mq_alloc_request
arch/um/drivers/ubd_kern.c:922:7: warning: assignment to ‘struct gendisk *’ from ‘int’ makes pointer from integer without a cast [-Wint-conversion]
   disk = blk_mq_alloc_disk(&ubd_dev->tag_set, ubd_dev);
        ^
arch/um/drivers/ubd_kern.c: In function ‘ubd_remove’:
arch/um/drivers/ubd_kern.c:1042:3: error: implicit declaration of function ‘blk_cleanup_disk’; did you mean ‘blk_cleanup_queue’? [-Werror=implicit-function-declaration]
    blk_cleanup_disk(disk);

-- 
Anton R. Ivanov
Cambridgegreys Limited. Registered in England. Company Number 10273661
https://www.cambridgegreys.com/

Re: [PATCH 2/2] ubd: use blk_mq_alloc_disk and blk_cleanup_disk

[Christoph Hellwig]

On Mon, Jun 14, 2021 at 09:26:58AM +0100, Anton Ivanov wrote:
> This does not build for me when applied to master:

Yes, as mentioned in the cover letter it needs for-5.14/block branch
from here:

   git://git.kernel.dk/linux-block for-5.14/block

Gitweb:

   https://git.kernel.dk/cgit/linux-block/log/?h=for-5.14/block

Re: cleanup ubd gendisk registration

[Jens Axboe]

On 6/14/21 12:07 AM, Christoph Hellwig wrote:
> Hi all,
> 
> this series sits on top of Jens' for-5.14/block branch and tries to
> convert ubd to the new gendisk and request_queue registration helpers.
> As part of that I found that the ide emulation code currently registers
> two gendisk for a request_queue which leads to a bunch of problems we've
> avoided in other drivers (only the mmc subsystem has a similar issue).
> Given that the legacy IDE driver isn't practically used any more and
> modern userspace doesn't hard code specific block drivers, so I think
> we can just drop it.  Let me know if this is ok.

Applied, thanks.

-- 
Jens Axboe