[PATCH 5.12 411/677] bcache: Use 64-bit arithmetic instead of 32-bit

From: Greg Kroah-Hartman
Date: Wed May 12 2021 - 14:55:12 EST


From: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx>

[ Upstream commit 62594f189e81caffa6a3bfa2fdb08eec2e347c76 ]

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>
Signed-off-by: Coly Li <colyli@xxxxxxx>
Link: https://lore.kernel.org/r/20210411134316.80274-7-colyli@xxxxxxx
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@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;
--
2.30.2