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| author | Jingbo Xu <jefflexu@linux.alibaba.com> | 2023-12-19 17:25:07 +0300 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2023-12-29 22:06:47 +0300 |
| commit | e0646b7590084a5bf3b056d3ad871d9379d2c25a (patch) | |
| tree | 7dd7c742f1943c2b36df9c444d7ba5a5167679a0 /mm/page-writeback.c | |
| parent | efa7df3e3bb5da8e6abbe37727417f32a37fba47 (diff) | |
| download | linux-e0646b7590084a5bf3b056d3ad871d9379d2c25a.tar.xz | |
mm: fix arithmetic for bdi min_ratio
Since now bdi->min_ratio is part per million, fix the wrong arithmetic.
Otherwise it will fail with -EINVAL when setting a reasonable min_ratio,
as it tries to set min_ratio to (min_ratio * BDI_RATIO_SCALE) in
percentage unit, which exceeds 100% anyway.
# cat /sys/class/bdi/253\:0/min_ratio
0
# cat /sys/class/bdi/253\:0/max_ratio
100
# echo 1 > /sys/class/bdi/253\:0/min_ratio
-bash: echo: write error: Invalid argument
Link: https://lkml.kernel.org/r/20231219142508.86265-2-jefflexu@linux.alibaba.com
Fixes: 8021fb3232f2 ("mm: split off __bdi_set_min_ratio() function")
Signed-off-by: Jingbo Xu <jefflexu@linux.alibaba.com>
Reported-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Stefan Roesch <shr@devkernel.io>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/page-writeback.c')
| -rw-r--r-- | mm/page-writeback.c | 1 |
1 files changed, 0 insertions, 1 deletions
diff --git a/mm/page-writeback.c b/mm/page-writeback.c index ee2fd6a6af40..2140382dd768 100644 --- a/mm/page-writeback.c +++ b/mm/page-writeback.c @@ -692,7 +692,6 @@ static int __bdi_set_min_ratio(struct backing_dev_info *bdi, unsigned int min_ra if (min_ratio > 100 * BDI_RATIO_SCALE) return -EINVAL; - min_ratio *= BDI_RATIO_SCALE; spin_lock_bh(&bdi_lock); if (min_ratio > bdi->max_ratio) { |