01_blk_tag_map_use_find_first_zero_bit.patch
blk_queue_start_tag() hand-coded searching for the first zero
bit in the tag map. Replace it with find_first_zero_bit().
With this patch, blk_queue_star_tag() doesn't need to fill
remains of tag map with 1, thus allowing it to work properly
with the next remove_real_max_depth patch.
Signed-off-by: Tejun Heo <[EMAIL PROTECTED]>
ll_rw_blk.c | 13 ++++---------
1 files changed, 4 insertions(+), 9 deletions(-)
Index: blk-fixes/drivers/block/ll_rw_blk.c
===================================================================
--- blk-fixes.orig/drivers/block/ll_rw_blk.c 2005-04-20 20:36:35.000000000
+0900
+++ blk-fixes/drivers/block/ll_rw_blk.c 2005-04-20 20:36:36.000000000 +0900
@@ -967,8 +967,7 @@ EXPORT_SYMBOL(blk_queue_end_tag);
int blk_queue_start_tag(request_queue_t *q, struct request *rq)
{
struct blk_queue_tag *bqt = q->queue_tags;
- unsigned long *map = bqt->tag_map;
- int tag = 0;
+ int tag;
if (unlikely((rq->flags & REQ_QUEUED))) {
printk(KERN_ERR
@@ -977,14 +976,10 @@ int blk_queue_start_tag(request_queue_t
BUG();
}
- for (map = bqt->tag_map; *map == -1UL; map++) {
- tag += BLK_TAGS_PER_LONG;
-
- if (tag >= bqt->max_depth)
- return 1;
- }
+ tag = find_first_zero_bit(bqt->tag_map, bqt->max_depth);
+ if (tag >= bqt->max_depth)
+ return 1;
- tag += ffz(*map);
__set_bit(tag, bqt->tag_map);
rq->flags |= REQ_QUEUED;
-
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