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authorJingbo Xu <jefflexu@linux.alibaba.com>2023-12-19 17:25:07 +0300
committerAndrew Morton <akpm@linux-foundation.org>2023-12-29 22:06:47 +0300
commite0646b7590084a5bf3b056d3ad871d9379d2c25a (patch)
tree7dd7c742f1943c2b36df9c444d7ba5a5167679a0 /mm/page-writeback.c
parentefa7df3e3bb5da8e6abbe37727417f32a37fba47 (diff)
downloadlinux-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.c1
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) {