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[188.155.176.92]) by smtp.gmail.com with ESMTPSA id 7-20020a170906308700b00722e7e26d22sm1556075ejv.58.2022.06.21.23.50.41 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 21 Jun 2022 23:50:42 -0700 (PDT) Message-ID: Date: Wed, 22 Jun 2022 08:50:41 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.10.0 Subject: Re: [PATCH] memory/tegra: Add missing of_node_get() in tegra_emc_find_node_by_ram_code Content-Language: en-US To: Liang He , thierry.reding@gmail.com, jonathanh@nvidia.com Cc: linux-kernel@vger.kernel.org, linux-tegra@vger.kernel.org References: <20220622042824.4094625-1-windhl@126.com> From: Krzysztof Kozlowski In-Reply-To: <20220622042824.4094625-1-windhl@126.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 22/06/2022 06:28, Liang He wrote: > of_find_node_by_name() will decrease the refcount of its first arg and > we need to add a of_node_put() to keep refcount balance. We do NOT need to add an of_node_put? Anyway why do you add of_node_get which is not explained here? > > Besides, during the 'for' loop execution, the refcount of 'np' will be > automatically increased and decreased. There is no need to call > of_node_put() again. > > Signed-off-by: Liang He > --- > drivers/memory/tegra/tegra20-emc.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/memory/tegra/tegra20-emc.c b/drivers/memory/tegra/tegra20-emc.c > index 25ba3c5e4ad6..e43a5f8e188e 100644 > --- a/drivers/memory/tegra/tegra20-emc.c > +++ b/drivers/memory/tegra/tegra20-emc.c > @@ -477,6 +477,7 @@ tegra_emc_find_node_by_ram_code(struct tegra_emc *emc) > > ram_code = tegra_read_ram_code(); > > + of_get_node(dev->of_node); > for (np = of_find_node_by_name(dev->of_node, "emc-tables"); np; > np = of_find_node_by_name(np, "emc-tables")) { > err = of_property_read_u32(np, "nvidia,ram-code", &value); > @@ -484,6 +485,7 @@ tegra_emc_find_node_by_ram_code(struct tegra_emc *emc) > struct device_node *lpddr2_np; > bool cfg_mismatches = false; > > + of_node_get(np); > lpddr2_np = of_find_node_by_name(np, "lpddr2"); > if (lpddr2_np) { > const struct lpddr2_info *info; > @@ -521,7 +523,6 @@ tegra_emc_find_node_by_ram_code(struct tegra_emc *emc) > } > > if (cfg_mismatches) { > - of_node_put(np); > continue; > } > } Best regards, Krzysztof