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authorWen Yang <wenyang@linux.alibaba.com>2020-01-20 13:04:43 +0300
committerJens Axboe <axboe@kernel.dk>2020-01-22 20:34:11 +0300
commit554d21efb0d2e102a14f8c4b6bdfbcfbe54b3c65 (patch)
tree0e784efc85671e7bb4e4668d115bacba43ebf54a /block
parentb7f22d993f51c64d79b7fd7ad2c060e3fdc006c0 (diff)
downloadlinux-554d21efb0d2e102a14f8c4b6bdfbcfbe54b3c65.tar.xz
block, bfq: improve arithmetic division in bfq_delta()
do_div() does a 64-by-32 division. Use div64_ul() instead of it if the divisor is unsigned long, to avoid truncation to 32-bit. And as a nice side effect also cleans up the function a bit. Signed-off-by: Wen Yang <wenyang@linux.alibaba.com> Cc: Paolo Valente <paolo.valente@linaro.org> Cc: Jens Axboe <axboe@fb.com> Cc: linux-block@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block')
-rw-r--r--block/bfq-wf2q.c5
1 files changed, 1 insertions, 4 deletions
diff --git a/block/bfq-wf2q.c b/block/bfq-wf2q.c
index 05f0bf4a1144..ffe9ce9faa89 100644
--- a/block/bfq-wf2q.c
+++ b/block/bfq-wf2q.c
@@ -277,10 +277,7 @@ struct bfq_queue *bfq_entity_to_bfqq(struct bfq_entity *entity)
*/
static u64 bfq_delta(unsigned long service, unsigned long weight)
{
- u64 d = (u64)service << WFQ_SERVICE_SHIFT;
-
- do_div(d, weight);
- return d;
+ return div64_ul((u64)service << WFQ_SERVICE_SHIFT, weight);
}
/**