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| author | Wen Yang <wenyang@linux.alibaba.com> | 2020-01-20 18:04:43 +0800 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2020-01-22 10:34:11 -0700 |
| commit | 554d21efb0d2e102a14f8c4b6bdfbcfbe54b3c65 (patch) | |
| tree | 0e784efc85671e7bb4e4668d115bacba43ebf54a /block/bfq-wf2q.c | |
| parent | b7f22d993f51c64d79b7fd7ad2c060e3fdc006c0 (diff) | |
| download | lwn-554d21efb0d2e102a14f8c4b6bdfbcfbe54b3c65.tar.gz lwn-554d21efb0d2e102a14f8c4b6bdfbcfbe54b3c65.zip | |
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/bfq-wf2q.c')
| -rw-r--r-- | block/bfq-wf2q.c | 5 |
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); } /** |