[PATCH][next] bcache: Use 64-bit arithmetic instead of 32-bit

From: Gustavo A. R. Silva
Date: Fri Feb 12 2021 - 08:10:41 EST


Cast multiple variables to (int64_t) in order to give the compiler
complete information about the proper arithmetic to use. Notice that
these variables are being used in contexts that expect expressions of
type int64_t (64 bit, signed). And currently, such expressions are
being evaluated using 32-bit arithmetic.

Fixes: d0cf9503e908 ("octeontx2-pf: ethtool fec mode support")
Addresses-Coverity-ID: 1501724 ("Unintentional integer overflow")
Addresses-Coverity-ID: 1501725 ("Unintentional integer overflow")
Addresses-Coverity-ID: 1501726 ("Unintentional integer overflow")
Signed-off-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx>
---
drivers/md/bcache/writeback.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/md/bcache/writeback.c b/drivers/md/bcache/writeback.c
index 82d4e0880a99..4fb635c0baa0 100644
--- a/drivers/md/bcache/writeback.c
+++ b/drivers/md/bcache/writeback.c
@@ -110,13 +110,13 @@ static void __update_writeback_rate(struct cached_dev *dc)
int64_t fps;

if (c->gc_stats.in_use <= BCH_WRITEBACK_FRAGMENT_THRESHOLD_MID) {
- fp_term = dc->writeback_rate_fp_term_low *
+ fp_term = (int64_t)dc->writeback_rate_fp_term_low *
(c->gc_stats.in_use - BCH_WRITEBACK_FRAGMENT_THRESHOLD_LOW);
} else if (c->gc_stats.in_use <= BCH_WRITEBACK_FRAGMENT_THRESHOLD_HIGH) {
- fp_term = dc->writeback_rate_fp_term_mid *
+ fp_term = (int64_t)dc->writeback_rate_fp_term_mid *
(c->gc_stats.in_use - BCH_WRITEBACK_FRAGMENT_THRESHOLD_MID);
} else {
- fp_term = dc->writeback_rate_fp_term_high *
+ fp_term = (int64_t)dc->writeback_rate_fp_term_high *
(c->gc_stats.in_use - BCH_WRITEBACK_FRAGMENT_THRESHOLD_HIGH);
}
fps = div_s64(dirty, dirty_buckets) * fp_term;
--
2.27.0