diff options
| -rw-r--r-- | include/linux/ring_buffer.h | 4 | ||||
| -rw-r--r-- | kernel/trace/ring_buffer.c | 63 | ||||
| -rw-r--r-- | kernel/trace/trace.c | 14 | ||||
| -rw-r--r-- | kernel/trace/trace_kdb.c | 8 |
4 files changed, 18 insertions, 71 deletions
diff --git a/include/linux/ring_buffer.h b/include/linux/ring_buffer.h index cd7f0ae26615..bc90c3c7b5fd 100644 --- a/include/linux/ring_buffer.h +++ b/include/linux/ring_buffer.h @@ -152,9 +152,7 @@ ring_buffer_consume(struct trace_buffer *buffer, int cpu, u64 *ts, unsigned long *lost_events); struct ring_buffer_iter * -ring_buffer_read_prepare(struct trace_buffer *buffer, int cpu, gfp_t flags); -void ring_buffer_read_prepare_sync(void); -void ring_buffer_read_start(struct ring_buffer_iter *iter); +ring_buffer_read_start(struct trace_buffer *buffer, int cpu, gfp_t flags); void ring_buffer_read_finish(struct ring_buffer_iter *iter); struct ring_buffer_event * diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index a99ed4716de9..903d9db75e12 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -5943,24 +5943,20 @@ ring_buffer_consume(struct trace_buffer *buffer, int cpu, u64 *ts, EXPORT_SYMBOL_GPL(ring_buffer_consume); /** - * ring_buffer_read_prepare - Prepare for a non consuming read of the buffer + * ring_buffer_read_start - start a non consuming read of the buffer * @buffer: The ring buffer to read from * @cpu: The cpu buffer to iterate over * @flags: gfp flags to use for memory allocation * - * This performs the initial preparations necessary to iterate - * through the buffer. Memory is allocated, buffer resizing - * is disabled, and the iterator pointer is returned to the caller. - * - * After a sequence of ring_buffer_read_prepare calls, the user is - * expected to make at least one call to ring_buffer_read_prepare_sync. - * Afterwards, ring_buffer_read_start is invoked to get things going - * for real. + * This creates an iterator to allow non-consuming iteration through + * the buffer. If the buffer is disabled for writing, it will produce + * the same information each time, but if the buffer is still writing + * then the first hit of a write will cause the iteration to stop. * - * This overall must be paired with ring_buffer_read_finish. + * Must be paired with ring_buffer_read_finish. */ struct ring_buffer_iter * -ring_buffer_read_prepare(struct trace_buffer *buffer, int cpu, gfp_t flags) +ring_buffer_read_start(struct trace_buffer *buffer, int cpu, gfp_t flags) { struct ring_buffer_per_cpu *cpu_buffer; struct ring_buffer_iter *iter; @@ -5986,51 +5982,12 @@ ring_buffer_read_prepare(struct trace_buffer *buffer, int cpu, gfp_t flags) atomic_inc(&cpu_buffer->resize_disabled); - return iter; -} -EXPORT_SYMBOL_GPL(ring_buffer_read_prepare); - -/** - * ring_buffer_read_prepare_sync - Synchronize a set of prepare calls - * - * All previously invoked ring_buffer_read_prepare calls to prepare - * iterators will be synchronized. Afterwards, read_buffer_read_start - * calls on those iterators are allowed. - */ -void -ring_buffer_read_prepare_sync(void) -{ - synchronize_rcu(); -} -EXPORT_SYMBOL_GPL(ring_buffer_read_prepare_sync); - -/** - * ring_buffer_read_start - start a non consuming read of the buffer - * @iter: The iterator returned by ring_buffer_read_prepare - * - * This finalizes the startup of an iteration through the buffer. - * The iterator comes from a call to ring_buffer_read_prepare and - * an intervening ring_buffer_read_prepare_sync must have been - * performed. - * - * Must be paired with ring_buffer_read_finish. - */ -void -ring_buffer_read_start(struct ring_buffer_iter *iter) -{ - struct ring_buffer_per_cpu *cpu_buffer; - unsigned long flags; - - if (!iter) - return; - - cpu_buffer = iter->cpu_buffer; - - raw_spin_lock_irqsave(&cpu_buffer->reader_lock, flags); + guard(raw_spinlock_irqsave)(&cpu_buffer->reader_lock); arch_spin_lock(&cpu_buffer->lock); rb_iter_reset(iter); arch_spin_unlock(&cpu_buffer->lock); - raw_spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags); + + return iter; } EXPORT_SYMBOL_GPL(ring_buffer_read_start); diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 95ae7c4e5835..7996f26c3f46 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -4735,21 +4735,15 @@ __tracing_open(struct inode *inode, struct file *file, bool snapshot) if (iter->cpu_file == RING_BUFFER_ALL_CPUS) { for_each_tracing_cpu(cpu) { iter->buffer_iter[cpu] = - ring_buffer_read_prepare(iter->array_buffer->buffer, - cpu, GFP_KERNEL); - } - ring_buffer_read_prepare_sync(); - for_each_tracing_cpu(cpu) { - ring_buffer_read_start(iter->buffer_iter[cpu]); + ring_buffer_read_start(iter->array_buffer->buffer, + cpu, GFP_KERNEL); tracing_iter_reset(iter, cpu); } } else { cpu = iter->cpu_file; iter->buffer_iter[cpu] = - ring_buffer_read_prepare(iter->array_buffer->buffer, - cpu, GFP_KERNEL); - ring_buffer_read_prepare_sync(); - ring_buffer_read_start(iter->buffer_iter[cpu]); + ring_buffer_read_start(iter->array_buffer->buffer, + cpu, GFP_KERNEL); tracing_iter_reset(iter, cpu); } diff --git a/kernel/trace/trace_kdb.c b/kernel/trace/trace_kdb.c index d7b135de958a..896ff78b8349 100644 --- a/kernel/trace/trace_kdb.c +++ b/kernel/trace/trace_kdb.c @@ -43,17 +43,15 @@ static void ftrace_dump_buf(int skip_entries, long cpu_file) if (cpu_file == RING_BUFFER_ALL_CPUS) { for_each_tracing_cpu(cpu) { iter.buffer_iter[cpu] = - ring_buffer_read_prepare(iter.array_buffer->buffer, - cpu, GFP_ATOMIC); - ring_buffer_read_start(iter.buffer_iter[cpu]); + ring_buffer_read_start(iter.array_buffer->buffer, + cpu, GFP_ATOMIC); tracing_iter_reset(&iter, cpu); } } else { iter.cpu_file = cpu_file; iter.buffer_iter[cpu_file] = - ring_buffer_read_prepare(iter.array_buffer->buffer, + ring_buffer_read_start(iter.array_buffer->buffer, cpu_file, GFP_ATOMIC); - ring_buffer_read_start(iter.buffer_iter[cpu_file]); tracing_iter_reset(&iter, cpu_file); } |