From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-ID: <1371015544.8250.182.camel@pasglop> Subject: [PATCH] of: Fix locking vs. interrupts From: Benjamin Herrenschmidt To: Thomas Gleixner Date: Wed, 12 Jun 2013 15:39:04 +1000 Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Cc: devicetree-discuss@lists.ozlabs.org, linuxppc-dev , David Miller , Linux Kernel list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , The OF code uses irqsafe locks everywhere except in a handful of functions for no obvious reasons. Since the conversion from the old rwlocks, this now triggers lockdep warnings when used at interrupt time. At least one driver (ibmvscsi) seems to be doing that from softirq context. This converts the few non-irqsafe locks into irqsafe ones, making them consistent with the rest of the code. Signed-off-by: Benjamin Herrenschmidt CC: [v3.9+] --- Note: It's silly to access the device-tree at interrupt time in most cases, and we should probably fix ibmvscsi, but for the time being, let's fix the obvious bug. Thomas, this can probably still go into 3.10... If not, I've CCed stable. diff --git a/arch/sparc/kernel/prom_common.c b/arch/sparc/kernel/prom_common.c index 9f20566..79cc0d1 100644 --- a/arch/sparc/kernel/prom_common.c +++ b/arch/sparc/kernel/prom_common.c @@ -54,6 +54,7 @@ EXPORT_SYMBOL(of_set_property_mutex); int of_set_property(struct device_node *dp, const char *name, void *val, int len) { struct property **prevp; + unsigned long flags; void *new_val; int err; @@ -64,7 +65,7 @@ int of_set_property(struct device_node *dp, const char *name, void *val, int len err = -ENODEV; mutex_lock(&of_set_property_mutex); - raw_spin_lock(&devtree_lock); + raw_spin_lock_irqsave(&devtree_lock, flags); prevp = &dp->properties; while (*prevp) { struct property *prop = *prevp; @@ -91,7 +92,7 @@ int of_set_property(struct device_node *dp, const char *name, void *val, int len } prevp = &(*prevp)->next; } - raw_spin_unlock(&devtree_lock); + raw_spin_unlock_irqrestore(&devtree_lock, flags); mutex_unlock(&of_set_property_mutex); /* XXX Upate procfs if necessary... */ diff --git a/drivers/of/base.c b/drivers/of/base.c index f53b992..951452c 100644 --- a/drivers/of/base.c +++ b/drivers/of/base.c @@ -192,14 +192,15 @@ EXPORT_SYMBOL(of_find_property); struct device_node *of_find_all_nodes(struct device_node *prev) { struct device_node *np; + unsigned long flags; - raw_spin_lock(&devtree_lock); + raw_spin_lock_irqsave(&devtree_lock, flags); np = prev ? prev->allnext : of_allnodes; for (; np != NULL; np = np->allnext) if (of_node_get(np)) break; of_node_put(prev); - raw_spin_unlock(&devtree_lock); + raw_spin_unlock_irqrestore(&devtree_lock, flags); return np; } EXPORT_SYMBOL(of_find_all_nodes); @@ -421,8 +422,9 @@ struct device_node *of_get_next_available_child(const struct device_node *node, struct device_node *prev) { struct device_node *next; + unsigned long flags; - raw_spin_lock(&devtree_lock); + raw_spin_lock_irqsave(&devtree_lock, flags); next = prev ? prev->sibling : node->child; for (; next; next = next->sibling) { if (!__of_device_is_available(next)) @@ -431,7 +433,7 @@ struct device_node *of_get_next_available_child(const struct device_node *node, break; } of_node_put(prev); - raw_spin_unlock(&devtree_lock); + raw_spin_unlock_irqrestore(&devtree_lock, flags); return next; } EXPORT_SYMBOL(of_get_next_available_child); @@ -735,13 +737,14 @@ EXPORT_SYMBOL_GPL(of_modalias_node); struct device_node *of_find_node_by_phandle(phandle handle) { struct device_node *np; + unsigned long flags; - raw_spin_lock(&devtree_lock); + raw_spin_lock_irqsave(&devtree_lock, flags); for (np = of_allnodes; np; np = np->allnext) if (np->phandle == handle) break; of_node_get(np); - raw_spin_unlock(&devtree_lock); + raw_spin_unlock_irqrestore(&devtree_lock, flags); return np; } EXPORT_SYMBOL(of_find_node_by_phandle); From mboxrd@z Thu Jan 1 00:00:00 1970 From: Benjamin Herrenschmidt Subject: [PATCH] of: Fix locking vs. interrupts Date: Wed, 12 Jun 2013 15:39:04 +1000 Message-ID: <1371015544.8250.182.camel@pasglop> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: Sender: linux-kernel-owner@vger.kernel.org To: Thomas Gleixner Cc: David Miller , linuxppc-dev , Linux Kernel list , devicetree-discuss@lists.ozlabs.org List-Id: devicetree@vger.kernel.org The OF code uses irqsafe locks everywhere except in a handful of functions for no obvious reasons. Since the conversion from the old rwlocks, this now triggers lockdep warnings when used at interrupt time. At least one driver (ibmvscsi) seems to be doing that from softirq context. This converts the few non-irqsafe locks into irqsafe ones, making them consistent with the rest of the code. Signed-off-by: Benjamin Herrenschmidt CC: [v3.9+] --- Note: It's silly to access the device-tree at interrupt time in most cases, and we should probably fix ibmvscsi, but for the time being, let's fix the obvious bug. Thomas, this can probably still go into 3.10... If not, I've CCed stable. diff --git a/arch/sparc/kernel/prom_common.c b/arch/sparc/kernel/prom_common.c index 9f20566..79cc0d1 100644 --- a/arch/sparc/kernel/prom_common.c +++ b/arch/sparc/kernel/prom_common.c @@ -54,6 +54,7 @@ EXPORT_SYMBOL(of_set_property_mutex); int of_set_property(struct device_node *dp, const char *name, void *val, int len) { struct property **prevp; + unsigned long flags; void *new_val; int err; @@ -64,7 +65,7 @@ int of_set_property(struct device_node *dp, const char *name, void *val, int len err = -ENODEV; mutex_lock(&of_set_property_mutex); - raw_spin_lock(&devtree_lock); + raw_spin_lock_irqsave(&devtree_lock, flags); prevp = &dp->properties; while (*prevp) { struct property *prop = *prevp; @@ -91,7 +92,7 @@ int of_set_property(struct device_node *dp, const char *name, void *val, int len } prevp = &(*prevp)->next; } - raw_spin_unlock(&devtree_lock); + raw_spin_unlock_irqrestore(&devtree_lock, flags); mutex_unlock(&of_set_property_mutex); /* XXX Upate procfs if necessary... */ diff --git a/drivers/of/base.c b/drivers/of/base.c index f53b992..951452c 100644 --- a/drivers/of/base.c +++ b/drivers/of/base.c @@ -192,14 +192,15 @@ EXPORT_SYMBOL(of_find_property); struct device_node *of_find_all_nodes(struct device_node *prev) { struct device_node *np; + unsigned long flags; - raw_spin_lock(&devtree_lock); + raw_spin_lock_irqsave(&devtree_lock, flags); np = prev ? prev->allnext : of_allnodes; for (; np != NULL; np = np->allnext) if (of_node_get(np)) break; of_node_put(prev); - raw_spin_unlock(&devtree_lock); + raw_spin_unlock_irqrestore(&devtree_lock, flags); return np; } EXPORT_SYMBOL(of_find_all_nodes); @@ -421,8 +422,9 @@ struct device_node *of_get_next_available_child(const struct device_node *node, struct device_node *prev) { struct device_node *next; + unsigned long flags; - raw_spin_lock(&devtree_lock); + raw_spin_lock_irqsave(&devtree_lock, flags); next = prev ? prev->sibling : node->child; for (; next; next = next->sibling) { if (!__of_device_is_available(next)) @@ -431,7 +433,7 @@ struct device_node *of_get_next_available_child(const struct device_node *node, break; } of_node_put(prev); - raw_spin_unlock(&devtree_lock); + raw_spin_unlock_irqrestore(&devtree_lock, flags); return next; } EXPORT_SYMBOL(of_get_next_available_child); @@ -735,13 +737,14 @@ EXPORT_SYMBOL_GPL(of_modalias_node); struct device_node *of_find_node_by_phandle(phandle handle) { struct device_node *np; + unsigned long flags; - raw_spin_lock(&devtree_lock); + raw_spin_lock_irqsave(&devtree_lock, flags); for (np = of_allnodes; np; np = np->allnext) if (np->phandle == handle) break; of_node_get(np); - raw_spin_unlock(&devtree_lock); + raw_spin_unlock_irqrestore(&devtree_lock, flags); return np; } EXPORT_SYMBOL(of_find_node_by_phandle);