Messages in this thread Patch in this message | | | Subject | [PATCH for 3.12-rcX] mutex: Avoid gcc version dependent __builtin_constant_p() usage. | From | Tetsuo Handa <> | Date | Thu, 3 Oct 2013 23:02:18 +0900 |
| |
Peter Zijlstra wrote: > On Mon, Sep 09, 2013 at 08:56:53PM +0900, Tetsuo Handa wrote: > > From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> > > Date: Mon, 9 Sep 2013 20:48:13 +0900 > > Subject: [PATCH] mutex: Avoid gcc version dependent __builtin_constant_p() usage. > > > > Commit 040a0a37 "mutex: Add support for wound/wait style locks" used > > "!__builtin_constant_p(p == NULL)" but gcc 3.x cannot handle such expression > > correctly, leading to boot failure when built with CONFIG_DEBUG_MUTEXES=y. > > > > Fix it by explicitly passing a bool which tells whether p != NULL or not. > > > > Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> > > Cc: <stable@kernel.org> [3.11+] > > --- > > kernel/mutex.c | 32 ++++++++++++++++---------------- > > 1 files changed, 16 insertions(+), 16 deletions(-) > > > > diff --git a/kernel/mutex.c b/kernel/mutex.c > > index a52ee7bb..a2b80f1 100644 > > --- a/kernel/mutex.c > > +++ b/kernel/mutex.c > > @@ -408,7 +408,7 @@ ww_mutex_set_context_fastpath(struct ww_mutex *lock, > > static __always_inline int __sched > > __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass, > > struct lockdep_map *nest_lock, unsigned long ip, > > - struct ww_acquire_ctx *ww_ctx) > > + struct ww_acquire_ctx *ww_ctx, const bool use_ww_ctx) > > { > > struct task_struct *task = current; > > struct mutex_waiter waiter; > > @@ -448,7 +448,7 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass, > > struct task_struct *owner; > > struct mspin_node node; > > > > - if (!__builtin_constant_p(ww_ctx == NULL) && ww_ctx->acquired > 0) { > > + if (use_ww_ctx && ww_ctx->acquired > 0) { > > struct ww_mutex *ww; > > > > ww = container_of(lock, struct ww_mutex, base); > > @@ -478,7 +478,7 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass, > > if ((atomic_read(&lock->count) == 1) && > > (atomic_cmpxchg(&lock->count, 1, 0) == 1)) { > > lock_acquired(&lock->dep_map, ip); > > - if (!__builtin_constant_p(ww_ctx == NULL)) { > > + if (use_ww_ctx) { > > struct ww_mutex *ww; > > ww = container_of(lock, struct ww_mutex, base); > > > > @@ -548,7 +548,7 @@ slowpath: > > goto err; > > } > > > > - if (!__builtin_constant_p(ww_ctx == NULL) && ww_ctx->acquired > 0) { > > + if (use_ww_ctx && ww_ctx->acquired > 0) { > > ret = __mutex_lock_check_stamp(lock, ww_ctx); > > if (ret) > > goto err; > > @@ -568,7 +568,7 @@ done: > > mutex_remove_waiter(lock, &waiter, current_thread_info()); > > mutex_set_owner(lock); > > > > - if (!__builtin_constant_p(ww_ctx == NULL)) { > > + if (use_ww_ctx) { > > struct ww_mutex *ww = container_of(lock, > > struct ww_mutex, > > base); > > @@ -618,7 +618,7 @@ mutex_lock_nested(struct mutex *lock, unsigned int subclass) > > { > > might_sleep(); > > __mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, > > - subclass, NULL, _RET_IP_, NULL); > > + subclass, NULL, _RET_IP_, NULL, 0); > > } > > > > EXPORT_SYMBOL_GPL(mutex_lock_nested); > > This is a sad patch, but provided it actually generates similar code I > suppose its the best we can do bar whole sale deprecating gcc-3. >
Can the patch below go to 3.12-rcX (and the patch above to 3.11-stable which does the same thing)?
Regards. ---------- >From a1b01c858143c2c2c92b17e7df096042bfe0df6b Mon Sep 17 00:00:00 2001 From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Date: Tue, 24 Sep 2013 23:44:17 +0900 Subject: [PATCH] mutex: Avoid gcc version dependent __builtin_constant_p() usage.
Commit 040a0a37 "mutex: Add support for wound/wait style locks" used "!__builtin_constant_p(p == NULL)" but gcc 3.x cannot handle such expression correctly, leading to boot failure when built with CONFIG_DEBUG_MUTEXES=y.
Fix it by explicitly passing a bool which tells whether p != NULL or not.
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> --- kernel/mutex.c | 32 ++++++++++++++++---------------- 1 files changed, 16 insertions(+), 16 deletions(-)
diff --git a/kernel/mutex.c b/kernel/mutex.c index 6d647ae..d24105b 100644 --- a/kernel/mutex.c +++ b/kernel/mutex.c @@ -410,7 +410,7 @@ ww_mutex_set_context_fastpath(struct ww_mutex *lock, static __always_inline int __sched __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass, struct lockdep_map *nest_lock, unsigned long ip, - struct ww_acquire_ctx *ww_ctx) + struct ww_acquire_ctx *ww_ctx, const bool use_ww_ctx) { struct task_struct *task = current; struct mutex_waiter waiter; @@ -450,7 +450,7 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass, struct task_struct *owner; struct mspin_node node; - if (!__builtin_constant_p(ww_ctx == NULL) && ww_ctx->acquired > 0) { + if (use_ww_ctx && ww_ctx->acquired > 0) { struct ww_mutex *ww; ww = container_of(lock, struct ww_mutex, base); @@ -480,7 +480,7 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass, if ((atomic_read(&lock->count) == 1) && (atomic_cmpxchg(&lock->count, 1, 0) == 1)) { lock_acquired(&lock->dep_map, ip); - if (!__builtin_constant_p(ww_ctx == NULL)) { + if (use_ww_ctx) { struct ww_mutex *ww; ww = container_of(lock, struct ww_mutex, base); @@ -551,7 +551,7 @@ slowpath: goto err; } - if (!__builtin_constant_p(ww_ctx == NULL) && ww_ctx->acquired > 0) { + if (use_ww_ctx && ww_ctx->acquired > 0) { ret = __mutex_lock_check_stamp(lock, ww_ctx); if (ret) goto err; @@ -575,7 +575,7 @@ skip_wait: lock_acquired(&lock->dep_map, ip); mutex_set_owner(lock); - if (!__builtin_constant_p(ww_ctx == NULL)) { + if (use_ww_ctx) { struct ww_mutex *ww = container_of(lock, struct ww_mutex, base); struct mutex_waiter *cur; @@ -615,7 +615,7 @@ mutex_lock_nested(struct mutex *lock, unsigned int subclass) { might_sleep(); __mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, - subclass, NULL, _RET_IP_, NULL); + subclass, NULL, _RET_IP_, NULL, 0); } EXPORT_SYMBOL_GPL(mutex_lock_nested); @@ -625,7 +625,7 @@ _mutex_lock_nest_lock(struct mutex *lock, struct lockdep_map *nest) { might_sleep(); __mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, - 0, nest, _RET_IP_, NULL); + 0, nest, _RET_IP_, NULL, 0); } EXPORT_SYMBOL_GPL(_mutex_lock_nest_lock); @@ -635,7 +635,7 @@ mutex_lock_killable_nested(struct mutex *lock, unsigned int subclass) { might_sleep(); return __mutex_lock_common(lock, TASK_KILLABLE, - subclass, NULL, _RET_IP_, NULL); + subclass, NULL, _RET_IP_, NULL, 0); } EXPORT_SYMBOL_GPL(mutex_lock_killable_nested); @@ -644,7 +644,7 @@ mutex_lock_interruptible_nested(struct mutex *lock, unsigned int subclass) { might_sleep(); return __mutex_lock_common(lock, TASK_INTERRUPTIBLE, - subclass, NULL, _RET_IP_, NULL); + subclass, NULL, _RET_IP_, NULL, 0); } EXPORT_SYMBOL_GPL(mutex_lock_interruptible_nested); @@ -682,7 +682,7 @@ __ww_mutex_lock(struct ww_mutex *lock, struct ww_acquire_ctx *ctx) might_sleep(); ret = __mutex_lock_common(&lock->base, TASK_UNINTERRUPTIBLE, - 0, &ctx->dep_map, _RET_IP_, ctx); + 0, &ctx->dep_map, _RET_IP_, ctx, 1); if (!ret && ctx->acquired > 1) return ww_mutex_deadlock_injection(lock, ctx); @@ -697,7 +697,7 @@ __ww_mutex_lock_interruptible(struct ww_mutex *lock, struct ww_acquire_ctx *ctx) might_sleep(); ret = __mutex_lock_common(&lock->base, TASK_INTERRUPTIBLE, - 0, &ctx->dep_map, _RET_IP_, ctx); + 0, &ctx->dep_map, _RET_IP_, ctx, 1); if (!ret && ctx->acquired > 1) return ww_mutex_deadlock_injection(lock, ctx); @@ -809,28 +809,28 @@ __mutex_lock_slowpath(atomic_t *lock_count) struct mutex *lock = container_of(lock_count, struct mutex, count); __mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, 0, - NULL, _RET_IP_, NULL); + NULL, _RET_IP_, NULL, 0); } static noinline int __sched __mutex_lock_killable_slowpath(struct mutex *lock) { return __mutex_lock_common(lock, TASK_KILLABLE, 0, - NULL, _RET_IP_, NULL); + NULL, _RET_IP_, NULL, 0); } static noinline int __sched __mutex_lock_interruptible_slowpath(struct mutex *lock) { return __mutex_lock_common(lock, TASK_INTERRUPTIBLE, 0, - NULL, _RET_IP_, NULL); + NULL, _RET_IP_, NULL, 0); } static noinline int __sched __ww_mutex_lock_slowpath(struct ww_mutex *lock, struct ww_acquire_ctx *ctx) { return __mutex_lock_common(&lock->base, TASK_UNINTERRUPTIBLE, 0, - NULL, _RET_IP_, ctx); + NULL, _RET_IP_, ctx, 1); } static noinline int __sched @@ -838,7 +838,7 @@ __ww_mutex_lock_interruptible_slowpath(struct ww_mutex *lock, struct ww_acquire_ctx *ctx) { return __mutex_lock_common(&lock->base, TASK_INTERRUPTIBLE, 0, - NULL, _RET_IP_, ctx); + NULL, _RET_IP_, ctx, 1); } #endif -- 1.7.1
| |