linux-kernel - [PATCH v3 5/7] libnvdimm: reduce an unnecessary if branch in nd_region

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Date:   Thu, 20 Aug 2020 10:16:39 +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>
Subject: [PATCH v3 5/7] libnvdimm: reduce an unnecessary if branch in nd_region_activate()

According to the original code logic:
if (!nvdimm->num_flush) {
	flush_data_size += sizeof(void *);
	//nvdimm->num_flush is zero now, add 1) have no side effects
} else {
	flush_data_size += sizeof(void *);
1)	flush_data_size += nvdimm->num_flush * sizeof(void *);
}

Obviously, the above code snippet can be reduced to one statement:
flush_data_size += (nvdimm->num_flush + 1) * sizeof(void *);

No functional change.

Signed-off-by: Zhen Lei <thunder.leizhen@...wei.com>
---
 drivers/nvdimm/region_devs.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/drivers/nvdimm/region_devs.c b/drivers/nvdimm/region_devs.c
index 7cf9c7d857909ce..49be115c9189eff 100644
--- a/drivers/nvdimm/region_devs.c
+++ b/drivers/nvdimm/region_devs.c
@@ -77,11 +77,8 @@ int nd_region_activate(struct nd_region *nd_region)
 		}
 
 		/* at least one null hint slot per-dimm for the "no-hint" case */
-		flush_data_size += sizeof(void *);
+		flush_data_size += (nvdimm->num_flush + 1) * sizeof(void *);
 		num_flush = min_not_zero(num_flush, nvdimm->num_flush);
-		if (!nvdimm->num_flush)
-			continue;
-		flush_data_size += nvdimm->num_flush * sizeof(void *);
 	}
 	nvdimm_bus_unlock(&nd_region->dev);
 
-- 
1.8.3