linux-kernel - [PATCH 4.19 182/220] lightnvm: pblk: fix write amplificiation calculation

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Message-Id: <20191122100927.382284687@linuxfoundation.org>
Date:   Fri, 22 Nov 2019 11:29:07 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Hans Holmberg <hans.holmberg@...xlabs.com>,
        Matias Bjørling <mb@...htnvm.io>,
        Jens Axboe <axboe@...nel.dk>, Sasha Levin <sashal@...nel.org>
Subject: [PATCH 4.19 182/220] lightnvm: pblk: fix write amplificiation calculation

From: Hans Holmberg <hans.holmberg@...xlabs.com>

[ Upstream commit 765462fa4c4d0fd3eb718f2ba14cb04c35219854 ]

When the user data counter exceeds 32 bits, the write amplification
calculation does not provide the right value. Fix this by using
div64_u64 in stead of div64.

Fixes: 76758390f83e ("lightnvm: pblk: export write amplification counters to sysfs")
Signed-off-by: Hans Holmberg <hans.holmberg@...xlabs.com>
Signed-off-by: Matias Bjørling <mb@...htnvm.io>
Signed-off-by: Jens Axboe <axboe@...nel.dk>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/lightnvm/pblk-sysfs.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/lightnvm/pblk-sysfs.c b/drivers/lightnvm/pblk-sysfs.c
index 8d2ed510c04b3..bdc86ee4c7793 100644
--- a/drivers/lightnvm/pblk-sysfs.c
+++ b/drivers/lightnvm/pblk-sysfs.c
@@ -343,7 +343,6 @@ static ssize_t pblk_get_write_amp(u64 user, u64 gc, u64 pad,
 {
 	int sz;
 
-
 	sz = snprintf(page, PAGE_SIZE,
 			"user:%lld gc:%lld pad:%lld WA:",
 			user, gc, pad);
@@ -355,7 +354,7 @@ static ssize_t pblk_get_write_amp(u64 user, u64 gc, u64 pad,
 		u32 wa_frac;
 
 		wa_int = (user + gc + pad) * 100000;
-		wa_int = div_u64(wa_int, user);
+		wa_int = div64_u64(wa_int, user);
 		wa_int = div_u64_rem(wa_int, 100000, &wa_frac);
 
 		sz += snprintf(page + sz, PAGE_SIZE - sz, "%llu.%05u\n",
-- 
2.20.1