From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Gleixner Subject: [RFC patch 31/41] dm persistent data: Simplify stack trace handling Date: Wed, 10 Apr 2019 12:28:25 +0200 Message-ID: <20190410103646.401662030@linutronix.de> References: <20190410102754.387743324@linutronix.de> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Return-path: Sender: linux-kernel-owner@vger.kernel.org To: LKML Cc: Josh Poimboeuf , x86@kernel.org, Andy Lutomirski , Steven Rostedt , Alexander Potapenko , dm-devel@redhat.com, Mike Snitzer , Alasdair Kergon List-Id: dm-devel.ids Replace the indirection through struct stack_trace with an invocation of the storage array based interface. This results in less storage space and indirection. Signed-off-by: Thomas Gleixner Cc: dm-devel@redhat.com Cc: Mike Snitzer Cc: Alasdair Kergon --- drivers/md/persistent-data/dm-block-manager.c | 19 +++++++++---------- 1 file changed, 9 insertions(+), 10 deletions(-) --- a/drivers/md/persistent-data/dm-block-manager.c +++ b/drivers/md/persistent-data/dm-block-manager.c @@ -35,7 +35,10 @@ #define MAX_HOLDERS 4 #define MAX_STACK 10 -typedef unsigned long stack_entries[MAX_STACK]; +struct stack_store { + unsigned int nr_entries; + unsigned long entries[MAX_STACK]; +}; struct block_lock { spinlock_t lock; @@ -44,8 +47,7 @@ struct block_lock { struct task_struct *holders[MAX_HOLDERS]; #ifdef CONFIG_DM_DEBUG_BLOCK_STACK_TRACING - struct stack_trace traces[MAX_HOLDERS]; - stack_entries entries[MAX_HOLDERS]; + struct stack_store traces[MAX_HOLDERS]; #endif }; @@ -73,7 +75,7 @@ static void __add_holder(struct block_lo { unsigned h = __find_holder(lock, NULL); #ifdef CONFIG_DM_DEBUG_BLOCK_STACK_TRACING - struct stack_trace *t; + struct stack_store *t; #endif get_task_struct(task); @@ -81,11 +83,7 @@ static void __add_holder(struct block_lo #ifdef CONFIG_DM_DEBUG_BLOCK_STACK_TRACING t = lock->traces + h; - t->nr_entries = 0; - t->max_entries = MAX_STACK; - t->entries = lock->entries[h]; - t->skip = 2; - save_stack_trace(t); + t->nr_entries = stack_trace_save(t->entries, MAX_STACK, 2); #endif } @@ -106,7 +104,8 @@ static int __check_holder(struct block_l DMERR("recursive lock detected in metadata"); #ifdef CONFIG_DM_DEBUG_BLOCK_STACK_TRACING DMERR("previously held here:"); - print_stack_trace(lock->traces + i, 4); + stack_trace_print(lock->traces[i].entries, + lock->traces[i].nr_entries, 4); DMERR("subsequent acquisition attempted here:"); dump_stack();