[PATCH 03/15] md: factor out a mddev_alloc_unit helper from mddev_find
From: Christoph Hellwig <hch@lst.de>
Date: 2021-03-30 16:18:46
Also in:
linux-raid, linux-s390, linux-scsi
Subsystem:
software raid (multiple disks) support, the rest · Maintainers:
Song Liu, Yu Kuai, Linus Torvalds
Split out a self contained helper to find a free minor for the md "unit" number. Signed-off-by: Christoph Hellwig <hch@lst.de> --- drivers/md/md.c | 47 +++++++++++++++++++++++++++-------------------- 1 file changed, 27 insertions(+), 20 deletions(-)
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 9556724fdb0848..f329d5b3c931d4 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c@@ -745,6 +745,27 @@ static struct mddev *mddev_find_locked(dev_t unit) return NULL; } +/* find an unused unit number */ +static dev_t mddev_alloc_unit(void) +{ + static int next_minor = 512; + int start = next_minor; + bool is_free = 0; + dev_t dev = 0; + + while (!is_free) { + dev = MKDEV(MD_MAJOR, next_minor); + next_minor++; + if (next_minor > MINORMASK) + next_minor = 0; + if (next_minor == start) + return 0; /* Oh dear, all in use. */ + is_free = !mddev_find_locked(dev); + } + + return dev; +} + static struct mddev *mddev_find(dev_t unit) { struct mddev *mddev, *new = NULL;
@@ -771,27 +792,13 @@ static struct mddev *mddev_find(dev_t unit) return new; } } else if (new) { - /* find an unused unit number */ - static int next_minor = 512; - int start = next_minor; - int is_free = 0; - int dev = 0; - while (!is_free) { - dev = MKDEV(MD_MAJOR, next_minor); - next_minor++; - if (next_minor > MINORMASK) - next_minor = 0; - if (next_minor == start) { - /* Oh dear, all in use. */ - spin_unlock(&all_mddevs_lock); - kfree(new); - return NULL; - } - - is_free = !mddev_find_locked(dev); + new->unit = mddev_alloc_unit(); + if (!new->unit) { + spin_unlock(&all_mddevs_lock); + kfree(new); + return NULL; } - new->unit = dev; - new->md_minor = MINOR(dev); + new->md_minor = MINOR(new->unit); new->hold_active = UNTIL_STOP; list_add(&new->all_mddevs, &all_mddevs); spin_unlock(&all_mddevs_lock);
--
2.30.1