From e159489baa717dbae70f9903770a6a4990865887 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Sun, 9 Jan 2011 23:32:15 +0100 Subject: workqueue: relax lockdep annotation on flush_work() Currently, the lockdep annotation in flush_work() requires exclusive access on the workqueue the target work is queued on and triggers warning if a work is trying to flush another work on the same workqueue; however, this is no longer true as workqueues can now execute multiple works concurrently. This patch adds lock_map_acquire_read() and make process_one_work() hold read access to the workqueue while executing a work and start_flush_work() check for write access if concurrnecy level is one or the workqueue has a rescuer (as only one execution resource - the rescuer - is guaranteed to be available under memory pressure), and read access if higher. This better represents what's going on and removes spurious lockdep warnings which are triggered by fake dependency chain created through flush_work(). * Peter pointed out that flushing another work from a WQ_MEM_RECLAIM wq breaks forward progress guarantee under memory pressure. Condition check accordingly updated. Signed-off-by: Tejun Heo Reported-by: "Rafael J. Wysocki" Tested-by: "Rafael J. Wysocki" Cc: Peter Zijlstra Cc: stable@kernel.org --- include/linux/lockdep.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'include/linux') diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h index 71c09b26c759..9f19430c7d07 100644 --- a/include/linux/lockdep.h +++ b/include/linux/lockdep.h @@ -522,12 +522,15 @@ static inline void print_irqtrace_events(struct task_struct *curr) #ifdef CONFIG_DEBUG_LOCK_ALLOC # ifdef CONFIG_PROVE_LOCKING # define lock_map_acquire(l) lock_acquire(l, 0, 0, 0, 2, NULL, _THIS_IP_) +# define lock_map_acquire_read(l) lock_acquire(l, 0, 0, 2, 2, NULL, _THIS_IP_) # else # define lock_map_acquire(l) lock_acquire(l, 0, 0, 0, 1, NULL, _THIS_IP_) +# define lock_map_acquire_read(l) lock_acquire(l, 0, 0, 2, 1, NULL, _THIS_IP_) # endif # define lock_map_release(l) lock_release(l, 1, _THIS_IP_) #else # define lock_map_acquire(l) do { } while (0) +# define lock_map_acquire_read(l) do { } while (0) # define lock_map_release(l) do { } while (0) #endif -- cgit v1.2.3 From f00c9e44ad1a9660fe8cd3ca15b6cd9497172eab Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Wed, 15 Sep 2010 17:38:58 +0200 Subject: quota: Fix deadlock during path resolution As Al Viro pointed out path resolution during Q_QUOTAON calls to quotactl is prone to deadlocks. We hold s_umount semaphore for reading during the path resolution and resolution itself may need to acquire the semaphore for writing when e. g. autofs mountpoint is passed. Solve the problem by performing the resolution before we get hold of the superblock (and thus s_umount semaphore). The whole thing is complicated by the fact that some filesystems (OCFS2) ignore the path argument. So to distinguish between filesystem which want the path and which do not we introduce new .quota_on_meta callback which does not get the path. OCFS2 then uses this callback instead of old .quota_on. CC: Al Viro CC: Christoph Hellwig CC: Ted Ts'o CC: Joel Becker Signed-off-by: Jan Kara --- include/linux/quota.h | 5 ++++- include/linux/quotaops.h | 4 +--- 2 files changed, 5 insertions(+), 4 deletions(-) (limited to 'include/linux') diff --git a/include/linux/quota.h b/include/linux/quota.h index 94c1f03b50eb..9a85412e0db6 100644 --- a/include/linux/quota.h +++ b/include/linux/quota.h @@ -322,9 +322,12 @@ struct dquot_operations { qsize_t *(*get_reserved_space) (struct inode *); }; +struct path; + /* Operations handling requests from userspace */ struct quotactl_ops { - int (*quota_on)(struct super_block *, int, int, char *); + int (*quota_on)(struct super_block *, int, int, struct path *); + int (*quota_on_meta)(struct super_block *, int, int); int (*quota_off)(struct super_block *, int); int (*quota_sync)(struct super_block *, int, int); int (*get_info)(struct super_block *, int, struct if_dqinfo *); diff --git a/include/linux/quotaops.h b/include/linux/quotaops.h index 223b14cd129c..eb354f6f26b3 100644 --- a/include/linux/quotaops.h +++ b/include/linux/quotaops.h @@ -76,11 +76,9 @@ int dquot_mark_dquot_dirty(struct dquot *dquot); int dquot_file_open(struct inode *inode, struct file *file); -int dquot_quota_on(struct super_block *sb, int type, int format_id, - char *path); int dquot_enable(struct inode *inode, int type, int format_id, unsigned int flags); -int dquot_quota_on_path(struct super_block *sb, int type, int format_id, +int dquot_quota_on(struct super_block *sb, int type, int format_id, struct path *path); int dquot_quota_on_mount(struct super_block *sb, char *qf_name, int format_id, int type); -- cgit v1.2.3 From 8d661f1e462d50bd83de87ee628aaf820ce3c66c Mon Sep 17 00:00:00 2001 From: Amitkumar Karwar Date: Tue, 11 Jan 2011 16:14:24 -0800 Subject: ieee80211: correct IEEE80211_ADDBA_PARAM_BUF_SIZE_MASK macro It is defined in include/linux/ieee80211.h. As per IEEE spec. bit6 to bit15 in block ack parameter represents buffer size. So the bitmask should be 0xFFC0. Signed-off-by: Amitkumar Karwar Signed-off-by: Bing Zhao Cc: stable@kernel.org Reviewed-by: Johannes Berg Signed-off-by: John W. Linville --- include/linux/ieee80211.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux') diff --git a/include/linux/ieee80211.h b/include/linux/ieee80211.h index 6042228954a7..294169e31364 100644 --- a/include/linux/ieee80211.h +++ b/include/linux/ieee80211.h @@ -959,7 +959,7 @@ struct ieee80211_ht_info { /* block-ack parameters */ #define IEEE80211_ADDBA_PARAM_POLICY_MASK 0x0002 #define IEEE80211_ADDBA_PARAM_TID_MASK 0x003C -#define IEEE80211_ADDBA_PARAM_BUF_SIZE_MASK 0xFFA0 +#define IEEE80211_ADDBA_PARAM_BUF_SIZE_MASK 0xFFC0 #define IEEE80211_DELBA_PARAM_TID_MASK 0xF000 #define IEEE80211_DELBA_PARAM_INITIATOR_MASK 0x0800 -- cgit v1.2.3 From 2ce802f62ba32a7d95748ac92bf351f76affb6ff Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Thu, 20 Jan 2011 12:06:35 +0100 Subject: lockdep: Move early boot local IRQ enable/disable status to init/main.c During early boot, local IRQ is disabled until IRQ subsystem is properly initialized. During this time, no one should enable local IRQ and some operations which usually are not allowed with IRQ disabled, e.g. operations which might sleep or require communications with other processors, are allowed. lockdep tracked this with early_boot_irqs_off/on() callbacks. As other subsystems need this information too, move it to init/main.c and make it generally available. While at it, toggle the boolean to early_boot_irqs_disabled instead of enabled so that it can be initialized with %false and %true indicates the exceptional condition. Signed-off-by: Tejun Heo Acked-by: Peter Zijlstra Acked-by: Pekka Enberg Cc: Linus Torvalds LKML-Reference: <20110120110635.GB6036@htj.dyndns.org> Signed-off-by: Ingo Molnar --- include/linux/kernel.h | 2 ++ include/linux/lockdep.h | 8 -------- 2 files changed, 2 insertions(+), 8 deletions(-) (limited to 'include/linux') diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 5a9d9059520b..d07d8057e440 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -243,6 +243,8 @@ extern int test_taint(unsigned flag); extern unsigned long get_taint(void); extern int root_mountflags; +extern bool early_boot_irqs_disabled; + /* Values used for system_state */ extern enum system_states { SYSTEM_BOOTING, diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h index 71c09b26c759..f638fd78d106 100644 --- a/include/linux/lockdep.h +++ b/include/linux/lockdep.h @@ -436,16 +436,8 @@ do { \ #endif /* CONFIG_LOCKDEP */ #ifdef CONFIG_TRACE_IRQFLAGS -extern void early_boot_irqs_off(void); -extern void early_boot_irqs_on(void); extern void print_irqtrace_events(struct task_struct *curr); #else -static inline void early_boot_irqs_off(void) -{ -} -static inline void early_boot_irqs_on(void) -{ -} static inline void print_irqtrace_events(struct task_struct *curr) { } -- cgit v1.2.3 From ca3e021417eed30ec2b64ce88eb0acf64aa9bc29 Mon Sep 17 00:00:00 2001 From: KAMEZAWA Hiroyuki Date: Thu, 20 Jan 2011 14:44:24 -0800 Subject: memcg: fix USED bit handling at uncharge in THP Now, under THP: at charge: - PageCgroupUsed bit is set to all page_cgroup on a hugepage. ....set to 512 pages. at uncharge - PageCgroupUsed bit is unset on the head page. So, some pages will remain with "Used" bit. This patch fixes that Used bit is set only to the head page. Used bits for tail pages will be set at splitting if necessary. This patch adds this lock order: compound_lock() -> page_cgroup_move_lock(). [akpm@linux-foundation.org: fix warning] Signed-off-by: KAMEZAWA Hiroyuki Cc: Daisuke Nishimura Cc: Balbir Singh Cc: Johannes Weiner Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/memcontrol.h | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'include/linux') diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index 6a576f989437..f512e189be5a 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -146,6 +146,10 @@ unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order, gfp_t gfp_mask); u64 mem_cgroup_get_limit(struct mem_cgroup *mem); +#ifdef CONFIG_TRANSPARENT_HUGEPAGE +void mem_cgroup_split_huge_fixup(struct page *head, struct page *tail); +#endif + #else /* CONFIG_CGROUP_MEM_RES_CTLR */ struct mem_cgroup; @@ -335,6 +339,11 @@ u64 mem_cgroup_get_limit(struct mem_cgroup *mem) return 0; } +static inline void mem_cgroup_split_huge_fixup(struct page *head, + struct page *tail) +{ +} + #endif /* CONFIG_CGROUP_MEM_CONT */ #endif /* _LINUX_MEMCONTROL_H */ -- cgit v1.2.3 From 2d6d9fd3a54a28c6f67f26eb6c74803307a1b11e Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Wed, 19 Jan 2011 22:27:14 +0100 Subject: ACPI: Introduce acpi_os_ioremap() Commit ca9b600be38c ("ACPI / PM: Make suspend_nvs_save() use acpi_os_map_memory()") attempted to prevent the code in osl.c and nvs.c from using different ioremap() variants by making the latter use acpi_os_map_memory() for mapping the NVS pages. However, that also requires acpi_os_unmap_memory() to be used for unmapping them, which causes synchronize_rcu() to be executed many times in a row unnecessarily and introduces substantial delays during resume on some systems. Instead of using acpi_os_map_memory() for mapping the NVS pages in nvs.c introduce acpi_os_ioremap() calling ioremap_cache() and make the code in both osl.c and nvs.c use it. Reported-by: Jeff Chua Signed-off-by: Rafael J. Wysocki Signed-off-by: Linus Torvalds --- include/linux/acpi.h | 3 --- include/linux/acpi_io.h | 16 ++++++++++++++++ 2 files changed, 16 insertions(+), 3 deletions(-) create mode 100644 include/linux/acpi_io.h (limited to 'include/linux') diff --git a/include/linux/acpi.h b/include/linux/acpi.h index eb176bb1b15b..a2e910e01293 100644 --- a/include/linux/acpi.h +++ b/include/linux/acpi.h @@ -306,9 +306,6 @@ extern acpi_status acpi_pci_osc_control_set(acpi_handle handle, u32 *mask, u32 req); extern void acpi_early_init(void); -int acpi_os_map_generic_address(struct acpi_generic_address *addr); -void acpi_os_unmap_generic_address(struct acpi_generic_address *addr); - #else /* !CONFIG_ACPI */ #define acpi_disabled 1 diff --git a/include/linux/acpi_io.h b/include/linux/acpi_io.h new file mode 100644 index 000000000000..7180013a4a3a --- /dev/null +++ b/include/linux/acpi_io.h @@ -0,0 +1,16 @@ +#ifndef _ACPI_IO_H_ +#define _ACPI_IO_H_ + +#include +#include + +static inline void __iomem *acpi_os_ioremap(acpi_physical_address phys, + acpi_size size) +{ + return ioremap_cache(phys, size); +} + +int acpi_os_map_generic_address(struct acpi_generic_address *addr); +void acpi_os_unmap_generic_address(struct acpi_generic_address *addr); + +#endif -- cgit v1.2.3 From 1c77ff22f539ceaa64ea43d6a26d867e84602cb7 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Wed, 19 Jan 2011 19:41:35 +0100 Subject: genirq: Remove __do_IRQ All architectures are finally converted. Remove the cruft. Signed-off-by: Thomas Gleixner Cc: Richard Henderson Cc: Mike Frysinger Cc: David Howells Cc: Tony Luck Cc: Greg Ungerer Cc: Michal Simek Acked-by: David Howells Cc: Kyle McMartin Acked-by: Benjamin Herrenschmidt Cc: Chen Liqin Cc: "David S. Miller" Cc: Chris Metcalf Cc: Jeff Dike --- include/linux/irqdesc.h | 14 -------------- 1 file changed, 14 deletions(-) (limited to 'include/linux') diff --git a/include/linux/irqdesc.h b/include/linux/irqdesc.h index 6a64c6fa81af..c1a95b7b58de 100644 --- a/include/linux/irqdesc.h +++ b/include/linux/irqdesc.h @@ -100,13 +100,6 @@ static inline struct irq_desc *move_irq_desc(struct irq_desc *desc, int node) #define get_irq_desc_data(desc) ((desc)->irq_data.handler_data) #define get_irq_desc_msi(desc) ((desc)->irq_data.msi_desc) -/* - * Monolithic do_IRQ implementation. - */ -#ifndef CONFIG_GENERIC_HARDIRQS_NO__DO_IRQ -extern unsigned int __do_IRQ(unsigned int irq); -#endif - /* * Architectures call this to let the generic IRQ layer * handle an interrupt. If the descriptor is attached to an @@ -115,14 +108,7 @@ extern unsigned int __do_IRQ(unsigned int irq); */ static inline void generic_handle_irq_desc(unsigned int irq, struct irq_desc *desc) { -#ifdef CONFIG_GENERIC_HARDIRQS_NO__DO_IRQ desc->handle_irq(irq, desc); -#else - if (likely(desc->handle_irq)) - desc->handle_irq(irq, desc); - else - __do_IRQ(irq); -#endif } static inline void generic_handle_irq(unsigned int irq) -- cgit v1.2.3 From 3dece370ecc7c6152b3fdd21c6de28179f6e643d Mon Sep 17 00:00:00 2001 From: Michal Simek Date: Fri, 21 Jan 2011 08:49:56 +0100 Subject: mm: System without MMU do not need pte_mkwrite The patch "thp: export maybe_mkwrite" (commit 14fd403f2146) breaks systems without MMU. Error log: CC arch/microblaze/mm/init.o In file included from include/linux/mman.h:14, from arch/microblaze/mm/consistent.c:24: include/linux/mm.h: In function 'maybe_mkwrite': include/linux/mm.h:482: error: implicit declaration of function 'pte_mkwrite' include/linux/mm.h:482: error: incompatible types in assignment Signed-off-by: Michal Simek CC: Andrea Arcangeli Reviewed-by: Rik van Riel CC: Andrew Morton CC: Ingo Molnar Signed-off-by: Linus Torvalds --- include/linux/mm.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/linux') diff --git a/include/linux/mm.h b/include/linux/mm.h index 956a35532f47..f6385fc17ad4 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -470,6 +470,7 @@ static inline void set_compound_order(struct page *page, unsigned long order) page[1].lru.prev = (void *)order; } +#ifdef CONFIG_MMU /* * Do pte_mkwrite, but only if the vma says VM_WRITE. We do this when * servicing faults for write access. In the normal case, do always want @@ -482,6 +483,7 @@ static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma) pte = pte_mkwrite(pte); return pte; } +#endif /* * Multiple processes may "see" the same page. E.g. for untouched -- cgit v1.2.3 From e94965ed5beb23c6fabf7ed31f625e66d7ff28de Mon Sep 17 00:00:00 2001 From: Dmitry Torokhov Date: Wed, 15 Dec 2010 14:00:19 -0800 Subject: module: show version information for built-in modules in sysfs Currently only drivers that are built as modules have their versions shown in /sys/module//version, but this information might also be useful for built-in drivers as well. This especially important for drivers that do not define any parameters - such drivers, if built-in, are completely invisible from userspace. This patch changes MODULE_VERSION() macro so that in case when we are compiling built-in module, version information is stored in a separate section. Kernel then uses this data to create 'version' sysfs attribute in the same fashion it creates attributes for module parameters. Signed-off-by: Dmitry Torokhov Signed-off-by: Rusty Russell --- include/linux/module.h | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+) (limited to 'include/linux') diff --git a/include/linux/module.h b/include/linux/module.h index 8b17fd8c790d..50efcd3ae850 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -58,6 +58,12 @@ struct module_attribute { void (*free)(struct module *); }; +struct module_version_attribute { + struct module_attribute mattr; + const char *module_name; + const char *version; +}; + struct module_kobject { struct kobject kobj; @@ -161,7 +167,28 @@ extern struct module __this_module; Using this automatically adds a checksum of the .c files and the local headers in "srcversion". */ + +#ifdef MODULE #define MODULE_VERSION(_version) MODULE_INFO(version, _version) +#else +#define MODULE_VERSION(_version) \ + extern ssize_t __modver_version_show(struct module_attribute *, \ + struct module *, char *); \ + static struct module_version_attribute __modver_version_attr \ + __used \ + __attribute__ ((__section__ ("__modver"),aligned(sizeof(void *)))) \ + = { \ + .mattr = { \ + .attr = { \ + .name = "version", \ + .mode = S_IRUGO, \ + }, \ + .show = __modver_version_show, \ + }, \ + .module_name = KBUILD_MODNAME, \ + .version = _version, \ + } +#endif /* Optional firmware file (or files) needed by the module * format is simply firmware file name. Multiple firmware -- cgit v1.2.3 From 3b90a5b292321b2acac3921f77046ae195aef53f Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Mon, 24 Jan 2011 14:32:51 -0600 Subject: module: fix linker error for MODULE_VERSION when !MODULE and CONFIG_SYSFS=n lib/built-in.o:(__modver+0x8): undefined reference to `__modver_version_show' lib/built-in.o:(__modver+0x2c): undefined reference to `__modver_version_show' Simplest to just not emit anything: if they've disabled SYSFS they probably want the smallest kernel possible. Reported-by: Randy Dunlap Signed-off-by: Rusty Russell --- include/linux/module.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux') diff --git a/include/linux/module.h b/include/linux/module.h index 50efcd3ae850..e7c6385c6683 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -168,7 +168,7 @@ extern struct module __this_module; local headers in "srcversion". */ -#ifdef MODULE +#if defined(MODULE) || !defined(CONFIG_SYSFS) #define MODULE_VERSION(_version) MODULE_INFO(version, _version) #else #define MODULE_VERSION(_version) \ -- cgit v1.2.3 From b75be4204e7871869b2c268c00783703197aaa7d Mon Sep 17 00:00:00 2001 From: Linus Walleij Date: Wed, 5 Jan 2011 13:27:04 +0100 Subject: param: add null statement to compiled-in module params Add an unused struct declaration statement requiring a terminating semicolon to the compile-in case to provoke an error if __MODULE_INFO() is used without the terminating semicolon. Previously MODULE_ALIAS("foo") (no semicolon) compiled fine if MODULE was not selected. Cc: Dan Carpenter Signed-off-by: Linus Walleij Signed-off-by: Rusty Russell --- include/linux/moduleparam.h | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'include/linux') diff --git a/include/linux/moduleparam.h b/include/linux/moduleparam.h index 112adf8bd47d..07b41951e3fa 100644 --- a/include/linux/moduleparam.h +++ b/include/linux/moduleparam.h @@ -16,15 +16,17 @@ /* Chosen so that structs with an unsigned long line up. */ #define MAX_PARAM_PREFIX_LEN (64 - sizeof(unsigned long)) -#ifdef MODULE #define ___module_cat(a,b) __mod_ ## a ## b #define __module_cat(a,b) ___module_cat(a,b) +#ifdef MODULE #define __MODULE_INFO(tag, name, info) \ static const char __module_cat(name,__LINE__)[] \ __used __attribute__((section(".modinfo"), unused, aligned(1))) \ = __stringify(tag) "=" info #else /* !MODULE */ -#define __MODULE_INFO(tag, name, info) +/* This struct is here for syntactic coherency, it is not used */ +#define __MODULE_INFO(tag, name, info) \ + struct __module_cat(name,__LINE__) {} #endif #define __MODULE_PARM_TYPE(name, _type) \ __MODULE_INFO(parmtype, name##type, #name ":" _type) -- cgit v1.2.3 From 7ef88ad561457c0346355dfd1f53e503ddfde719 Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Mon, 24 Jan 2011 14:45:10 -0600 Subject: BUILD_BUG_ON: make it handle more cases BUILD_BUG_ON used to use the optimizer to do code elimination or fail at link time; it was changed to first the size of a negative array (a nicer compile time error), then (in 8c87df457cb58fe75b9b893007917cf8095660a0) to a bitfield. This forced us to change some non-constant cases to MAYBE_BUILD_BUG_ON(); as Jan points out in that commit, it didn't work as intended anyway. bitfields: needs a literal constant at parse time, and can't be put under "if (__builtin_constant_p(x))" for example. negative array: can handle anything, but if the compiler can't tell it's a constant, silently has no effect. link time: breaks link if the compiler can't determine the value, but the linker output is not usually as informative as a compiler error. If we use the negative-array-size method *and* the link time trick, we get the ability to use BUILD_BUG_ON() under __builtin_constant_p() branches, and maximal ability for the compiler to detect errors at build time. We also document it thoroughly. Signed-off-by: Rusty Russell Cc: Jan Beulich Acked-by: Hollis Blanchard --- include/linux/kernel.h | 33 +++++++++++++++++++++++++++------ 1 file changed, 27 insertions(+), 6 deletions(-) (limited to 'include/linux') diff --git a/include/linux/kernel.h b/include/linux/kernel.h index d07d8057e440..864712f3653d 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -575,12 +575,6 @@ struct sysinfo { char _f[20-2*sizeof(long)-sizeof(int)]; /* Padding: libc5 uses this.. */ }; -/* Force a compilation error if condition is true */ -#define BUILD_BUG_ON(condition) ((void)BUILD_BUG_ON_ZERO(condition)) - -/* Force a compilation error if condition is constant and true */ -#define MAYBE_BUILD_BUG_ON(cond) ((void)sizeof(char[1 - 2 * !!(cond)])) - /* Force a compilation error if a constant expression is not a power of 2 */ #define BUILD_BUG_ON_NOT_POWER_OF_2(n) \ BUILD_BUG_ON((n) == 0 || (((n) & ((n) - 1)) != 0)) @@ -592,6 +586,33 @@ struct sysinfo { #define BUILD_BUG_ON_ZERO(e) (sizeof(struct { int:-!!(e); })) #define BUILD_BUG_ON_NULL(e) ((void *)sizeof(struct { int:-!!(e); })) +/** + * BUILD_BUG_ON - break compile if a condition is true. + * @cond: the condition which the compiler should know is false. + * + * If you have some code which relies on certain constants being equal, or + * other compile-time-evaluated condition, you should use BUILD_BUG_ON to + * detect if someone changes it. + * + * The implementation uses gcc's reluctance to create a negative array, but + * gcc (as of 4.4) only emits that error for obvious cases (eg. not arguments + * to inline functions). So as a fallback we use the optimizer; if it can't + * prove the condition is false, it will cause a link error on the undefined + * "__build_bug_on_failed". This error message can be harder to track down + * though, hence the two different methods. + */ +#ifndef __OPTIMIZE__ +#define BUILD_BUG_ON(condition) ((void)sizeof(char[1 - 2*!!(condition)])) +#else +extern int __build_bug_on_failed; +#define BUILD_BUG_ON(condition) \ + do { \ + ((void)sizeof(char[1 - 2*!!(condition)])); \ + if (condition) __build_bug_on_failed = 1; \ + } while(0) +#endif +#define MAYBE_BUILD_BUG_ON(condition) BUILD_BUG_ON(condition) + /* Trap pasters of __FUNCTION__ at compile-time */ #define __FUNCTION__ (__func__) -- cgit v1.2.3 From 1765e3a4933ea0870fabd755feffc5473c4363ce Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Mon, 24 Jan 2011 14:45:10 -0600 Subject: Remove MAYBE_BUILD_BUG_ON Now BUILD_BUG_ON() can handle optimizable constants, we don't need MAYBE_BUILD_BUG_ON any more. Signed-off-by: Rusty Russell --- include/linux/gfp.h | 2 +- include/linux/kernel.h | 1 - include/linux/kmemcheck.h | 2 +- include/linux/virtio_config.h | 5 ++++- 4 files changed, 6 insertions(+), 4 deletions(-) (limited to 'include/linux') diff --git a/include/linux/gfp.h b/include/linux/gfp.h index a3b148a91874..0b84c61607e8 100644 --- a/include/linux/gfp.h +++ b/include/linux/gfp.h @@ -249,7 +249,7 @@ static inline enum zone_type gfp_zone(gfp_t flags) ((1 << ZONES_SHIFT) - 1); if (__builtin_constant_p(bit)) - MAYBE_BUILD_BUG_ON((GFP_ZONE_BAD >> bit) & 1); + BUILD_BUG_ON((GFP_ZONE_BAD >> bit) & 1); else { #ifdef CONFIG_DEBUG_VM BUG_ON((GFP_ZONE_BAD >> bit) & 1); diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 864712f3653d..e2f4d6af2125 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -611,7 +611,6 @@ extern int __build_bug_on_failed; if (condition) __build_bug_on_failed = 1; \ } while(0) #endif -#define MAYBE_BUILD_BUG_ON(condition) BUILD_BUG_ON(condition) /* Trap pasters of __FUNCTION__ at compile-time */ #define __FUNCTION__ (__func__) diff --git a/include/linux/kmemcheck.h b/include/linux/kmemcheck.h index 08d7dc4ddf40..39f8453239f7 100644 --- a/include/linux/kmemcheck.h +++ b/include/linux/kmemcheck.h @@ -76,7 +76,7 @@ bool kmemcheck_is_obj_initialized(unsigned long addr, size_t size); \ _n = (long) &((ptr)->name##_end) \ - (long) &((ptr)->name##_begin); \ - MAYBE_BUILD_BUG_ON(_n < 0); \ + BUILD_BUG_ON(_n < 0); \ \ kmemcheck_mark_initialized(&((ptr)->name##_begin), _n); \ } while (0) diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h index 0093dd7c1d6f..800617b4ddd5 100644 --- a/include/linux/virtio_config.h +++ b/include/linux/virtio_config.h @@ -109,7 +109,10 @@ static inline bool virtio_has_feature(const struct virtio_device *vdev, unsigned int fbit) { /* Did you forget to fix assumptions on max features? */ - MAYBE_BUILD_BUG_ON(fbit >= 32); + if (__builtin_constant_p(fbit)) + BUILD_BUG_ON(fbit >= 32); + else + BUG_ON(fbit >= 32); if (fbit < VIRTIO_TRANSPORT_F_START) virtio_check_driver_offered_feature(vdev, fbit); -- cgit v1.2.3