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From: Zhen Lei <thunder.leizhen@huawei.com>
To: Oliver O'Halloran <oohall@gmail.com>,
	Dan Williams <dan.j.williams@intel.com>,
	Vishal Verma <vishal.l.verma@intel.com>,
	"Dave Jiang" <dave.jiang@intel.com>,
	Ira Weiny <ira.weiny@intel.com>,
	Markus Elfring <Markus.Elfring@web.de>,
	linux-nvdimm <linux-nvdimm@lists.01.org>,
	linux-kernel <linux-kernel@vger.kernel.org>
Cc: Zhen Lei <thunder.leizhen@huawei.com>
Subject: [PATCH v2 3/4] libnvdimm/bus: simplify walk_to_nvdimm_bus()
Date: Wed, 19 Aug 2020 10:05:02 +0800	[thread overview]
Message-ID: <20200819020503.3079-4-thunder.leizhen@huawei.com> (raw)
In-Reply-To: <20200819020503.3079-1-thunder.leizhen@huawei.com>

I first want to move dev_WARN_ONCE() after "if (dev)" branch, but further
I find the "if (dev)" can only be true when is_nvdimm_bus(dev) successed.

No functional change. In fact, the compiler can optimize it correctly. I
run "size drivers/nvdimm/bus.o" and find nothing has changed. So it's
just source code level optimization, make us can read it faster.

Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
---
 drivers/nvdimm/bus.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/nvdimm/bus.c b/drivers/nvdimm/bus.c
index 955265656b96c73..1d89114cb6ab93e 100644
--- a/drivers/nvdimm/bus.c
+++ b/drivers/nvdimm/bus.c
@@ -316,10 +316,9 @@ struct nvdimm_bus *walk_to_nvdimm_bus(struct device *nd_dev)
 
 	for (dev = nd_dev; dev; dev = dev->parent)
 		if (is_nvdimm_bus(dev))
-			break;
-	dev_WARN_ONCE(nd_dev, !dev, "invalid dev, not on nd bus\n");
-	if (dev)
-		return to_nvdimm_bus(dev);
+			return to_nvdimm_bus(dev);
+
+	dev_WARN_ONCE(nd_dev, 1, "invalid dev, not on nd bus\n");
 	return NULL;
 }
 
-- 
1.8.3

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  parent reply	other threads:[~2020-08-19  2:05 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-19  2:04 [PATCH v2 0/4] bugfix and optimize for drivers/nvdimm Zhen Lei
2020-08-19  2:05 ` [PATCH v2 1/4] libnvdimm: fix memmory leaks in of_pmem.c Zhen Lei
2020-08-19 12:28   ` [PATCH v2 1/4] libnvdimm: Fix memory " Markus Elfring
2020-08-19 13:34     ` Leizhen (ThunderTown)
2020-08-19 13:35     ` Oliver O'Halloran
2020-08-19 14:18       ` Leizhen (ThunderTown)
2020-08-19 13:37   ` [PATCH v2 1/4] libnvdimm: fix memmory " Oliver O'Halloran
2020-08-19 14:19     ` Leizhen (ThunderTown)
2020-08-19  2:05 ` [PATCH v2 2/4] libnvdimm: add sanity check for provider_name in of_pmem_region_probe() Zhen Lei
2020-08-19  2:05 ` Zhen Lei [this message]
2020-08-19 12:40   ` [PATCH v2 3/4] libnvdimm/bus: simplify walk_to_nvdimm_bus() Markus Elfring
2020-08-19 13:35     ` Leizhen (ThunderTown)
2020-08-19  2:05 ` [PATCH v2 4/4] libnvdimm/region: reduce an unnecessary if branch in nd_region_create() Zhen Lei
2020-08-19 12:20 ` [PATCH v2 0/4] bug fix and optimize for drivers/nvdimm Markus Elfring
2020-08-19 13:30   ` Leizhen (ThunderTown)

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