Re: [PATCH 06/19] block: add an optional probe callback to major_names
On 9/3/20 10:01 AM, Christoph Hellwig wrote: 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 --- block/genhd.c | 21 ++--- include/linux/genhd.h | 5 - 2 files changed, 22 insertions(+), 4 deletions(-) Reviewed-by: Hannes Reinecke Cheers, Hannes -- Dr. Hannes ReineckeKernel Storage Architect h...@suse.de +49 911 74053 688 SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg HRB 36809 (AG Nürnberg), Geschäftsführer: Felix Imendörffer
[PATCH 06/19] block: add an optional probe callback to major_names
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 --- 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 d9ecc751fc956c..3abd764443a6af 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(_names_lock); return ret; } - -EXPORT_SYMBOL(register_blkdev); +EXPORT_SYMBOL(__register_blkdev); void unregister_blkdev(unsigned int major, const char *name) { @@ -1035,6 +1037,19 @@ 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(_names_lock); + for (n = _names[major_to_index(major)]; *n; n = &(*n)->next) { + if ((*n)->major == major && (*n)->probe) { + (*n)->probe(devt); + mutex_unlock(_names_lock); + return; + } + } + mutex_unlock(_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 c618b27292fcc8..a808afe80a4fec 100644 --- a/include/linux/genhd.h +++ b/include/linux/genhd.h @@ -367,7 +367,10 @@ 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 06/19] block: add an optional probe callback to major_names
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 --- 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 00164304317cfa..4cbeff3ec1ef5a 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -402,6 +402,7 @@ 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); @@ -444,7 +445,8 @@ 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; @@ -483,6 +485,7 @@ 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); @@ -505,8 +508,7 @@ int register_blkdev(unsigned int major, const char *name) mutex_unlock(_names_lock); return ret; } - -EXPORT_SYMBOL(register_blkdev); +EXPORT_SYMBOL(__register_blkdev); void unregister_blkdev(unsigned int major, const char *name) { @@ -1037,6 +1039,19 @@ 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(_names_lock); + for (n = _names[major_to_index(major)]; *n; n = &(*n)->next) { + if ((*n)->major == major && (*n)->probe) { + (*n)->probe(devt); + mutex_unlock(_names_lock); + return; + } + } + mutex_unlock(_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 4ab853461dff25..c0bde190a3dd0c 100644 --- a/include/linux/genhd.h +++ b/include/linux/genhd.h @@ -369,7 +369,10 @@ 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); int revalidate_disk(struct gendisk *disk); -- 2.28.0
[PATCH 06/19] block: add an optional probe callback to major_names
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 --- 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 00164304317cfa..4cbeff3ec1ef5a 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -402,6 +402,7 @@ 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); @@ -444,7 +445,8 @@ 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; @@ -483,6 +485,7 @@ 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); @@ -505,8 +508,7 @@ int register_blkdev(unsigned int major, const char *name) mutex_unlock(_names_lock); return ret; } - -EXPORT_SYMBOL(register_blkdev); +EXPORT_SYMBOL(__register_blkdev); void unregister_blkdev(unsigned int major, const char *name) { @@ -1037,6 +1039,19 @@ 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(_names_lock); + for (n = _names[major_to_index(major)]; *n; n = &(*n)->next) { + if ((*n)->major == major && (*n)->probe) { + (*n)->probe(devt); + mutex_unlock(_names_lock); + return; + } + } + mutex_unlock(_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 4ab853461dff25..c0bde190a3dd0c 100644 --- a/include/linux/genhd.h +++ b/include/linux/genhd.h @@ -369,7 +369,10 @@ 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); int revalidate_disk(struct gendisk *disk); -- 2.28.0