linux-kernel - [PATCH v2 1/1] libnvdimm: slightly simplify available_slots

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Date:   Sat, 19 Sep 2020 19:11:12 +0800
From:   Zhen Lei <thunder.leizhen@...wei.com>
To:     Oliver O'Halloran <oohall@...il.com>,
        Dan Williams <dan.j.williams@...el.com>,
        Vishal Verma <vishal.l.verma@...el.com>,
        "Dave Jiang" <dave.jiang@...el.com>,
        Ira Weiny <ira.weiny@...el.com>,
        Markus Elfring <Markus.Elfring@....de>,
        linux-nvdimm <linux-nvdimm@...ts.01.org>,
        linux-kernel <linux-kernel@...r.kernel.org>
CC:     Zhen Lei <thunder.leizhen@...wei.com>,
        Libin <huawei.libin@...wei.com>,
        Kefeng Wang <wangkefeng.wang@...wei.com>
Subject: [PATCH v2 1/1] libnvdimm: slightly simplify available_slots_show()

The type of "nfree" is u32, so "nfree - 1" can only be overflowed when
"nfree" is zero. Replace "if (nfree - 1 > nfree)" with "if (nfree == 0)"
seems more clear. And remove the assignment "nfree = 0", no need for it.

Signed-off-by: Zhen Lei <thunder.leizhen@...wei.com>
---
v1 --> v2:
No change, just sent separately

v1:
https://lkml.org/lkml/2020/8/19/1465

 drivers/nvdimm/dimm_devs.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/nvdimm/dimm_devs.c b/drivers/nvdimm/dimm_devs.c
index b59032e0859b7f3..d6835f127d83055 100644
--- a/drivers/nvdimm/dimm_devs.c
+++ b/drivers/nvdimm/dimm_devs.c
@@ -347,10 +347,9 @@ static ssize_t available_slots_show(struct device *dev,
 
 	nvdimm_bus_lock(dev);
 	nfree = nd_label_nfree(ndd);
-	if (nfree - 1 > nfree) {
+	if (nfree == 0)
 		dev_WARN_ONCE(dev, 1, "we ate our last label?\n");
-		nfree = 0;
-	} else
+	else
 		nfree--;
 	rc = sprintf(buf, "%d\n", nfree);
 	nvdimm_bus_unlock(dev);
-- 
1.8.3