From: Russell King - ARM Linux <linux-lFZ/pmaqli7XmaaqVzeoHQ@public.gmane.org> To: Leo Yan <leo.yan-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org> Cc: Wei Xu <xuwei5-C8/M+/jPZTeaMJb+Lgu22Q@public.gmane.org>, Dan Zhao <dan.zhao-C8/M+/jPZTeaMJb+Lgu22Q@public.gmane.org>, zhenwei.wang-C8/M+/jPZTeaMJb+Lgu22Q@public.gmane.org, Haojian Zhuang <haojian.zhuang-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>, Bintian Wang <bintian.wang-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>, mturquette-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org Subject: Re: [PATCH 3/4] clk: hisi: add stub clk driver Date: Thu, 26 Mar 2015 14:22:26 +0000 [thread overview] Message-ID: <20150326142226.GJ8656@n2100.arm.linux.org.uk> (raw) In-Reply-To: <1427368419-22222-4-git-send-email-leo.yan-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org> On Thu, Mar 26, 2015 at 07:13:38PM +0800, Leo Yan wrote: > +static unsigned long hisi_stub_clk_recalc_rate(struct clk_hw *hw, > + unsigned long parent_rate) > +{ ... > + BUG_ON(!stub_clk->lock); ... > +static int hisi_stub_clk_set_rate(struct clk_hw *hw, unsigned long rate, > + unsigned long parent_rate) > +{ ... > + BUG_ON(!stub_clk->lock); ... > +static long hisi_stub_clk_round_rate(struct clk_hw *hw, unsigned long rate, > + unsigned long *parent_rate) > +{ ... > + BUG_ON(!stub_clk->lock); ... > +static struct clk_ops hisi_stub_clk_ops = { > + .recalc_rate = hisi_stub_clk_recalc_rate, > + .round_rate = hisi_stub_clk_round_rate, > + .set_rate = hisi_stub_clk_set_rate, > +}; ... > +static struct clk *_register_stub_clk(struct device *dev, unsigned int id, > + const char *name, const char *parent_name, unsigned long flags, > + spinlock_t *lock) > +{ > + struct hisi_stub_clk *stub_clk; > + struct clk *clk; > + struct clk_init_data init; > + > + stub_clk = kzalloc(sizeof(*stub_clk), GFP_KERNEL); > + if (!stub_clk) { > + pr_err("%s: fail to alloc stub clk!\n", __func__); > + return ERR_PTR(-ENOMEM); > + } > + > + init.name = name; > + init.ops = &hisi_stub_clk_ops; > + init.parent_names = parent_name ? &parent_name : NULL; > + init.num_parents = parent_name ? 1 : 0; > + init.flags = flags; > + > + stub_clk->hw.init = &init; > + stub_clk->id = id; > + stub_clk->lock = lock; Under what scenario is it safe to call _register_stub_clk() with a NULL lock argument? If lock is NULL, then every function callable via the ops structure will bug. Rather than doing a test in each method function, do it in _register_stub_clk() - this means we aren't waiting for a NULL pointer deref when one of these method functions gets called. -- FTTC broadband for 0.8mile line: currently at 10.5Mbps down 400kbps up according to speedtest.net. -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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From: linux@arm.linux.org.uk (Russell King - ARM Linux) To: linux-arm-kernel@lists.infradead.org Subject: [PATCH 3/4] clk: hisi: add stub clk driver Date: Thu, 26 Mar 2015 14:22:26 +0000 [thread overview] Message-ID: <20150326142226.GJ8656@n2100.arm.linux.org.uk> (raw) In-Reply-To: <1427368419-22222-4-git-send-email-leo.yan@linaro.org> On Thu, Mar 26, 2015 at 07:13:38PM +0800, Leo Yan wrote: > +static unsigned long hisi_stub_clk_recalc_rate(struct clk_hw *hw, > + unsigned long parent_rate) > +{ ... > + BUG_ON(!stub_clk->lock); ... > +static int hisi_stub_clk_set_rate(struct clk_hw *hw, unsigned long rate, > + unsigned long parent_rate) > +{ ... > + BUG_ON(!stub_clk->lock); ... > +static long hisi_stub_clk_round_rate(struct clk_hw *hw, unsigned long rate, > + unsigned long *parent_rate) > +{ ... > + BUG_ON(!stub_clk->lock); ... > +static struct clk_ops hisi_stub_clk_ops = { > + .recalc_rate = hisi_stub_clk_recalc_rate, > + .round_rate = hisi_stub_clk_round_rate, > + .set_rate = hisi_stub_clk_set_rate, > +}; ... > +static struct clk *_register_stub_clk(struct device *dev, unsigned int id, > + const char *name, const char *parent_name, unsigned long flags, > + spinlock_t *lock) > +{ > + struct hisi_stub_clk *stub_clk; > + struct clk *clk; > + struct clk_init_data init; > + > + stub_clk = kzalloc(sizeof(*stub_clk), GFP_KERNEL); > + if (!stub_clk) { > + pr_err("%s: fail to alloc stub clk!\n", __func__); > + return ERR_PTR(-ENOMEM); > + } > + > + init.name = name; > + init.ops = &hisi_stub_clk_ops; > + init.parent_names = parent_name ? &parent_name : NULL; > + init.num_parents = parent_name ? 1 : 0; > + init.flags = flags; > + > + stub_clk->hw.init = &init; > + stub_clk->id = id; > + stub_clk->lock = lock; Under what scenario is it safe to call _register_stub_clk() with a NULL lock argument? If lock is NULL, then every function callable via the ops structure will bug. Rather than doing a test in each method function, do it in _register_stub_clk() - this means we aren't waiting for a NULL pointer deref when one of these method functions gets called. -- FTTC broadband for 0.8mile line: currently at 10.5Mbps down 400kbps up according to speedtest.net.
next prev parent reply other threads:[~2015-03-26 14:22 UTC|newest] Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top 2015-03-26 11:13 [PATCH 0/4] clk: hisilicon: support stub clock Leo Yan 2015-03-26 11:13 ` Leo Yan [not found] ` <1427368419-22222-1-git-send-email-leo.yan-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org> 2015-03-26 11:13 ` [PATCH 1/4] clk: hisi: add API for allocation clk data struct Leo Yan 2015-03-26 11:13 ` Leo Yan [not found] ` <1427368419-22222-2-git-send-email-leo.yan-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org> 2015-03-26 14:18 ` Russell King - ARM Linux 2015-03-26 14:18 ` Russell King - ARM Linux [not found] ` <20150326141834.GI8656-l+eeeJia6m9vn6HldHNs0ANdhmdF6hFW@public.gmane.org> 2015-03-27 1:48 ` Leo Yan 2015-03-27 1:48 ` Leo Yan 2015-03-26 11:13 ` [PATCH 2/4] dt-bindings: clk: hisilicon: Document stub clock driver Leo Yan 2015-03-26 11:13 ` Leo Yan 2015-03-26 11:13 ` [PATCH 3/4] clk: hisi: add stub clk driver Leo Yan 2015-03-26 11:13 ` Leo Yan [not found] ` <1427368419-22222-4-git-send-email-leo.yan-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org> 2015-03-26 14:22 ` Russell King - ARM Linux [this message] 2015-03-26 14:22 ` Russell King - ARM Linux [not found] ` <20150326142226.GJ8656-l+eeeJia6m9vn6HldHNs0ANdhmdF6hFW@public.gmane.org> 2015-03-27 2:08 ` Leo Yan 2015-03-27 2:08 ` Leo Yan 2015-03-26 11:13 ` [PATCH 4/4] clk: hisi: add stub clock register function Leo Yan 2015-03-26 11:13 ` Leo Yan
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