From 302cfee150291c6cd85b1ca197d062d0b423d09c Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Thu, 29 Oct 2020 15:58:36 +0100 Subject: [PATCH] floppy: use a separate gendisk for each media format 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 Signed-off-by: Jens Axboe --- 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 7df79ae..dfe1dfc 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); -- 2.7.4