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authorTejun Heo <tj@kernel.org>2008-08-25 14:47:22 +0400
committerJens Axboe <jens.axboe@oracle.com>2008-10-09 10:56:06 +0400
commitbcce3de1be61e424deef35d1e86e86a35c4b6e65 (patch)
treecfdefb52bc37c61dfac160951a9beb86d5cd9ba0 /include/linux/major.h
parentc9959059161ddd7bf4670cf47367033d6b2f79c4 (diff)
downloadlinux-bcce3de1be61e424deef35d1e86e86a35c4b6e65.tar.xz
block: implement extended dev numbers
Implement extended device numbers. A block driver can tell block layer that it wants to use extended device numbers. After the usual minor space is used up, block layer automatically allocates devt's from EXT_BLOCK_MAJOR. Currently only one major number is allocated for this but as the allocation is strictly on-demand, ~1mil minor space under it should suffice unless the system actually has more than ~1mil partitions and if that ever happens adding more majors to the extended devt area is easy. Due to internal implementation issues, the first partition can't be allocated on the extended area. In other words, genhd->minors should at least be 1. This limitation will be lifted by later changes. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'include/linux/major.h')
-rw-r--r--include/linux/major.h2
1 files changed, 2 insertions, 0 deletions
diff --git a/include/linux/major.h b/include/linux/major.h
index 53d5fafd85c3..88249452b935 100644
--- a/include/linux/major.h
+++ b/include/linux/major.h
@@ -170,4 +170,6 @@
#define VIOTAPE_MAJOR 230
+#define BLOCK_EXT_MAJOR 259
+
#endif