| Message ID | 20200903080119.441674-15-hch@lst.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [01/19] char_dev: replace cdev_map with an xarray | expand |
Hi, On 9/3/20 11:01 AM, Christoph Hellwig wrote: > 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> Tested-by: Denis Efremov <efremov@linux.com> The patch looks ok as it is. Two nitpicks below if you will send next revision. > --- > 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 a563b023458a8b..f07d97558cb698 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. */ > @@ -4109,7 +4110,7 @@ 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; > @@ -4577,15 +4578,58 @@ 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; ITYPE(MINOR(dev))? > + > + 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) > @@ -4607,33 +4651,25 @@ 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; > > @@ -4641,9 +4677,6 @@ 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; > @@ -4671,7 +4704,7 @@ 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; > @@ -4682,7 +4715,7 @@ 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 */ > @@ -4759,10 +4792,8 @@ 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; > @@ -4770,30 +4801,27 @@ 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; > } > @@ -5004,9 +5032,8 @@ 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); > > @@ -5016,10 +5043,16 @@ 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]); > > /* > @@ -5027,10 +5060,17 @@ 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]) We can omit NULL check for put_disk(). > + put_disk(disks[drive][i]); > + } Regards, Denis
On 9/3/20 10:01 AM, Christoph Hellwig wrote: > 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(-) > Reviewed-by: Hannes Reinecke <hare@suse.de> Cheers, Hannes
diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c index a563b023458a8b..f07d97558cb698 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. */ @@ -4109,7 +4110,7 @@ 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; @@ -4577,15 +4578,58 @@ 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) @@ -4607,33 +4651,25 @@ 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; @@ -4641,9 +4677,6 @@ 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; @@ -4671,7 +4704,7 @@ 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; @@ -4682,7 +4715,7 @@ 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 */ @@ -4759,10 +4792,8 @@ 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; @@ -4770,30 +4801,27 @@ 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; } @@ -5004,9 +5032,8 @@ 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); @@ -5016,10 +5043,16 @@ 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]); /* @@ -5027,10 +5060,17 @@ 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);
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(-)