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-rw-r--r--block/genhd.c24
1 files changed, 24 insertions, 0 deletions
diff --git a/block/genhd.c b/block/genhd.c
index 397960cf26a..a9ec910974c 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -256,6 +256,22 @@ void blkdev_show(struct seq_file *seqf, off_t offset)
}
#endif /* CONFIG_PROC_FS */
+/**
+ * register_blkdev - register a new block device
+ *
+ * @major: the requested major device number [1..255]. If @major=0, try to
+ * allocate any unused major number.
+ * @name: the name of the new block device as a zero terminated string
+ *
+ * The @name must be unique within the system.
+ *
+ * The return value depends on the @major input parameter.
+ * - if a major device number was requested in range [1..255] then the
+ * function returns zero on success, or a negative error code
+ * - if any unused major number was requested with @major=0 parameter
+ * then the return value is the allocated major number in range
+ * [1..255] or a negative error code otherwise
+ */
int register_blkdev(unsigned int major, const char *name)
{
struct blk_major_name **n, *p;
@@ -1087,6 +1103,14 @@ dev_t blk_lookup_devt(const char *name, int partno)
if (strcmp(dev_name(dev), name))
continue;
+ if (partno < disk->minors) {
+ /* We need to return the right devno, even
+ * if the partition doesn't exist yet.
+ */
+ devt = MKDEV(MAJOR(dev->devt),
+ MINOR(dev->devt) + partno);
+ break;
+ }
part = disk_get_part(disk, partno);
if (part) {
devt = part_devt(part);