path: root/Documentation/block
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authorMike Christie <michaelc@cs.wisc.edu>2006-03-08 11:19:51 +0100
committerJens Axboe <axboe@nelson.home.kernel.dk>2006-03-27 09:29:01 +0200
commit28832e83379afd0b0e83b78ac317290c79ebd496 (patch)
tree5b6acaed05134e0558f08546aca99d74d30f97e9 /Documentation/block
parent5d5d7727a8cde78f798ecf04bac8031eff536f9d (diff)
[PATCH] update max_sectors documentation
The max_sectors has been split into max_hw_sectors and max_sectors for some time. A patch to have blk_queue_max_sectors enforce this was sent by me and it broke IDE. This patch updates the documentation. Signed-off-by: Jens Axboe <axboe@suse.de>
Diffstat (limited to 'Documentation/block')
1 files changed, 12 insertions, 2 deletions
diff --git a/Documentation/block/biodoc.txt b/Documentation/block/biodoc.txt
index 8e63831971d5..f989a9e839b4 100644
--- a/Documentation/block/biodoc.txt
+++ b/Documentation/block/biodoc.txt
@@ -132,8 +132,18 @@ Some new queue property settings:
limit. No highmem default.
blk_queue_max_sectors(q, max_sectors)
- Maximum size request you can handle in units of 512 byte
- sectors. 255 default.
+ Sets two variables that limit the size of the request.
+ - The request queue's max_sectors, which is a soft size in
+ in units of 512 byte sectors, and could be dynamically varied
+ by the core kernel.
+ - The request queue's max_hw_sectors, which is a hard limit
+ and reflects the maximum size request a driver can handle
+ in units of 512 byte sectors.
+ The default for both max_sectors and max_hw_sectors is
+ 255. The upper limit of max_sectors is 1024.
blk_queue_max_phys_segments(q, max_segments)
Maximum physical segments you can handle in a request. 128