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path: root/drivers/block/brd.c
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Diffstat (limited to 'drivers/block/brd.c')
-rw-r--r--drivers/block/brd.c22
1 files changed, 20 insertions, 2 deletions
diff --git a/drivers/block/brd.c b/drivers/block/brd.c
index a8730cc4db10..220c5e18aba0 100644
--- a/drivers/block/brd.c
+++ b/drivers/block/brd.c
@@ -473,6 +473,25 @@ static struct kobject *brd_probe(dev_t dev, int *part, void *data)
return kobj;
}
+static inline void brd_check_and_reset_par(void)
+{
+ if (unlikely(!max_part))
+ max_part = 1;
+
+ /*
+ * make sure 'max_part' can be divided exactly by (1U << MINORBITS),
+ * otherwise, it is possiable to get same dev_t when adding partitions.
+ */
+ if ((1U << MINORBITS) % max_part != 0)
+ max_part = 1UL << fls(max_part);
+
+ if (max_part > DISK_MAX_PARTS) {
+ pr_info("brd: max_part can't be larger than %d, reset max_part = %d.\n",
+ DISK_MAX_PARTS, DISK_MAX_PARTS);
+ max_part = DISK_MAX_PARTS;
+ }
+}
+
static int __init brd_init(void)
{
struct brd_device *brd, *next;
@@ -496,8 +515,7 @@ static int __init brd_init(void)
if (register_blkdev(RAMDISK_MAJOR, "ramdisk"))
return -EIO;
- if (unlikely(!max_part))
- max_part = 1;
+ brd_check_and_reset_par();
for (i = 0; i < rd_nr; i++) {
brd = brd_alloc(i);