tracing: fix typos in comments
[safe/jmp/linux-2.6] / kernel / trace / trace.c
index eb453a2..d7c175a 100644 (file)
@@ -31,6 +31,7 @@
 #include <linux/fs.h>
 #include <linux/kprobes.h>
 #include <linux/writeback.h>
+#include <linux/splice.h>
 
 #include <linux/stacktrace.h>
 #include <linux/ring_buffer.h>
@@ -364,6 +365,25 @@ ssize_t trace_seq_to_user(struct trace_seq *s, char __user *ubuf, size_t cnt)
        return cnt;
 }
 
+ssize_t trace_seq_to_buffer(struct trace_seq *s, void *buf, size_t cnt)
+{
+       int len;
+       void *ret;
+
+       if (s->len <= s->readpos)
+               return -EBUSY;
+
+       len = s->len - s->readpos;
+       if (cnt > len)
+               cnt = len;
+       ret = memcpy(buf, s->buffer + s->readpos, cnt);
+       if (!ret)
+               return -EFAULT;
+
+       s->readpos += len;
+       return cnt;
+}
+
 static void
 trace_print_seq(struct seq_file *m, struct trace_seq *s)
 {
@@ -559,6 +579,15 @@ void unregister_tracer(struct tracer *type)
 
  found:
        *t = (*t)->next;
+
+       if (type == current_trace && tracer_enabled) {
+               tracer_enabled = 0;
+               tracing_stop();
+               if (current_trace->stop)
+                       current_trace->stop(&global_trace);
+               current_trace = &nop_trace;
+       }
+
        if (strlen(type->name) != max_tracer_type_len)
                goto out;
 
@@ -776,6 +805,39 @@ tracing_generic_entry_update(struct trace_entry *entry, unsigned long flags,
                (need_resched() ? TRACE_FLAG_NEED_RESCHED : 0);
 }
 
+struct ring_buffer_event *trace_buffer_lock_reserve(struct trace_array *tr,
+                                                   unsigned char type,
+                                                   unsigned long len,
+                                                   unsigned long flags, int pc)
+{
+       struct ring_buffer_event *event;
+
+       event = ring_buffer_lock_reserve(tr->buffer, len);
+       if (event != NULL) {
+               struct trace_entry *ent = ring_buffer_event_data(event);
+
+               tracing_generic_entry_update(ent, flags, pc);
+               ent->type = type;
+       }
+
+       return event;
+}
+static void ftrace_trace_stack(struct trace_array *tr,
+                              unsigned long flags, int skip, int pc);
+static void ftrace_trace_userstack(struct trace_array *tr,
+                                  unsigned long flags, int pc);
+
+void trace_buffer_unlock_commit(struct trace_array *tr,
+                               struct ring_buffer_event *event,
+                               unsigned long flags, int pc)
+{
+       ring_buffer_unlock_commit(tr->buffer, event);
+
+       ftrace_trace_stack(tr, flags, 6, pc);
+       ftrace_trace_userstack(tr, flags, pc);
+       trace_wake_up();
+}
+
 void
 trace_function(struct trace_array *tr,
               unsigned long ip, unsigned long parent_ip, unsigned long flags,
@@ -788,12 +850,11 @@ trace_function(struct trace_array *tr,
        if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled))))
                return;
 
-       event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry));
+       event = trace_buffer_lock_reserve(tr, TRACE_FN, sizeof(*entry),
+                                         flags, pc);
        if (!event)
                return;
        entry   = ring_buffer_event_data(event);
-       tracing_generic_entry_update(&entry->ent, flags, pc);
-       entry->ent.type                 = TRACE_FN;
        entry->ip                       = ip;
        entry->parent_ip                = parent_ip;
        ring_buffer_unlock_commit(tr->buffer, event);
@@ -811,12 +872,11 @@ static void __trace_graph_entry(struct trace_array *tr,
        if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled))))
                return;
 
-       event = ring_buffer_lock_reserve(global_trace.buffer, sizeof(*entry));
+       event = trace_buffer_lock_reserve(&global_trace, TRACE_GRAPH_ENT,
+                                         sizeof(*entry), flags, pc);
        if (!event)
                return;
        entry   = ring_buffer_event_data(event);
-       tracing_generic_entry_update(&entry->ent, flags, pc);
-       entry->ent.type                 = TRACE_GRAPH_ENT;
        entry->graph_ent                        = *trace;
        ring_buffer_unlock_commit(global_trace.buffer, event);
 }
@@ -832,12 +892,11 @@ static void __trace_graph_return(struct trace_array *tr,
        if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled))))
                return;
 
-       event = ring_buffer_lock_reserve(global_trace.buffer, sizeof(*entry));
+       event = trace_buffer_lock_reserve(&global_trace, TRACE_GRAPH_RET,
+                                         sizeof(*entry), flags, pc);
        if (!event)
                return;
        entry   = ring_buffer_event_data(event);
-       tracing_generic_entry_update(&entry->ent, flags, pc);
-       entry->ent.type                 = TRACE_GRAPH_RET;
        entry->ret                              = *trace;
        ring_buffer_unlock_commit(global_trace.buffer, event);
 }
@@ -861,13 +920,11 @@ static void __ftrace_trace_stack(struct trace_array *tr,
        struct stack_entry *entry;
        struct stack_trace trace;
 
-       event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry));
+       event = trace_buffer_lock_reserve(tr, TRACE_STACK,
+                                         sizeof(*entry), flags, pc);
        if (!event)
                return;
        entry   = ring_buffer_event_data(event);
-       tracing_generic_entry_update(&entry->ent, flags, pc);
-       entry->ent.type         = TRACE_STACK;
-
        memset(&entry->caller, 0, sizeof(entry->caller));
 
        trace.nr_entries        = 0;
@@ -908,12 +965,11 @@ static void ftrace_trace_userstack(struct trace_array *tr,
        if (!(trace_flags & TRACE_ITER_USERSTACKTRACE))
                return;
 
-       event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry));
+       event = trace_buffer_lock_reserve(tr, TRACE_USER_STACK,
+                                         sizeof(*entry), flags, pc);
        if (!event)
                return;
        entry   = ring_buffer_event_data(event);
-       tracing_generic_entry_update(&entry->ent, flags, pc);
-       entry->ent.type         = TRACE_USER_STACK;
 
        memset(&entry->caller, 0, sizeof(entry->caller));
 
@@ -941,20 +997,15 @@ ftrace_trace_special(void *__tr,
        struct trace_array *tr = __tr;
        struct special_entry *entry;
 
-       event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry));
+       event = trace_buffer_lock_reserve(tr, TRACE_SPECIAL,
+                                         sizeof(*entry), 0, pc);
        if (!event)
                return;
        entry   = ring_buffer_event_data(event);
-       tracing_generic_entry_update(&entry->ent, 0, pc);
-       entry->ent.type                 = TRACE_SPECIAL;
        entry->arg1                     = arg1;
        entry->arg2                     = arg2;
        entry->arg3                     = arg3;
-       ring_buffer_unlock_commit(tr->buffer, event);
-       ftrace_trace_stack(tr, 0, 4, pc);
-       ftrace_trace_userstack(tr, 0, pc);
-
-       trace_wake_up();
+       trace_buffer_unlock_commit(tr, event, 0, pc);
 }
 
 void
@@ -973,12 +1024,11 @@ tracing_sched_switch_trace(struct trace_array *tr,
        struct ring_buffer_event *event;
        struct ctx_switch_entry *entry;
 
-       event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry));
+       event = trace_buffer_lock_reserve(tr, TRACE_CTX,
+                                         sizeof(*entry), flags, pc);
        if (!event)
                return;
        entry   = ring_buffer_event_data(event);
-       tracing_generic_entry_update(&entry->ent, flags, pc);
-       entry->ent.type                 = TRACE_CTX;
        entry->prev_pid                 = prev->pid;
        entry->prev_prio                = prev->prio;
        entry->prev_state               = prev->state;
@@ -986,9 +1036,7 @@ tracing_sched_switch_trace(struct trace_array *tr,
        entry->next_prio                = next->prio;
        entry->next_state               = next->state;
        entry->next_cpu = task_cpu(next);
-       ring_buffer_unlock_commit(tr->buffer, event);
-       ftrace_trace_stack(tr, flags, 5, pc);
-       ftrace_trace_userstack(tr, flags, pc);
+       trace_buffer_unlock_commit(tr, event, flags, pc);
 }
 
 void
@@ -1000,12 +1048,11 @@ tracing_sched_wakeup_trace(struct trace_array *tr,
        struct ring_buffer_event *event;
        struct ctx_switch_entry *entry;
 
-       event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry));
+       event = trace_buffer_lock_reserve(tr, TRACE_WAKE,
+                                         sizeof(*entry), flags, pc);
        if (!event)
                return;
        entry   = ring_buffer_event_data(event);
-       tracing_generic_entry_update(&entry->ent, flags, pc);
-       entry->ent.type                 = TRACE_WAKE;
        entry->prev_pid                 = curr->pid;
        entry->prev_prio                = curr->prio;
        entry->prev_state               = curr->state;
@@ -1013,11 +1060,7 @@ tracing_sched_wakeup_trace(struct trace_array *tr,
        entry->next_prio                = wakee->prio;
        entry->next_state               = wakee->state;
        entry->next_cpu                 = task_cpu(wakee);
-       ring_buffer_unlock_commit(tr->buffer, event);
-       ftrace_trace_stack(tr, flags, 6, pc);
-       ftrace_trace_userstack(tr, flags, pc);
-
-       trace_wake_up();
+       trace_buffer_unlock_commit(tr, event, flags, pc);
 }
 
 void
@@ -1505,7 +1548,7 @@ static enum print_line_t print_bin_fmt(struct trace_iterator *iter)
 
        if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
                SEQ_PUT_FIELD_RET(s, entry->pid);
-               SEQ_PUT_FIELD_RET(s, entry->cpu);
+               SEQ_PUT_FIELD_RET(s, iter->cpu);
                SEQ_PUT_FIELD_RET(s, iter->ts);
        }
 
@@ -1920,7 +1963,7 @@ tracing_trace_options_read(struct file *filp, char __user *ubuf,
        struct tracer_opt *trace_opts = current_trace->flags->opts;
 
 
-       /* calulate max size */
+       /* calculate max size */
        for (i = 0; trace_options[i]; i++) {
                len += strlen(trace_options[i]);
                len += 3; /* "no" and space */
@@ -2157,6 +2200,12 @@ tracing_set_trace_read(struct file *filp, char __user *ubuf,
        return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
 }
 
+int tracer_init(struct tracer *t, struct trace_array *tr)
+{
+       tracing_reset_online_cpus(tr);
+       return t->init(tr);
+}
+
 static int tracing_set_tracer(const char *buf)
 {
        struct trace_array *tr = &global_trace;
@@ -2181,7 +2230,7 @@ static int tracing_set_tracer(const char *buf)
 
        current_trace = t;
        if (t->init) {
-               ret = t->init(tr);
+               ret = tracer_init(t, tr);
                if (ret)
                        goto out;
        }
@@ -2339,37 +2388,15 @@ tracing_poll_pipe(struct file *filp, poll_table *poll_table)
        }
 }
 
-/*
- * Consumer reader.
- */
-static ssize_t
-tracing_read_pipe(struct file *filp, char __user *ubuf,
-                 size_t cnt, loff_t *ppos)
+/* Must be called with trace_types_lock mutex held. */
+static int tracing_wait_pipe(struct file *filp)
 {
        struct trace_iterator *iter = filp->private_data;
-       ssize_t sret;
-
-       /* return any leftover data */
-       sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
-       if (sret != -EBUSY)
-               return sret;
 
-       trace_seq_reset(&iter->seq);
-
-       mutex_lock(&trace_types_lock);
-       if (iter->trace->read) {
-               sret = iter->trace->read(iter, filp, ubuf, cnt, ppos);
-               if (sret)
-                       goto out;
-       }
-
-waitagain:
-       sret = 0;
        while (trace_empty(iter)) {
 
                if ((filp->f_flags & O_NONBLOCK)) {
-                       sret = -EAGAIN;
-                       goto out;
+                       return -EAGAIN;
                }
 
                /*
@@ -2394,12 +2421,11 @@ waitagain:
                iter->tr->waiter = NULL;
 
                if (signal_pending(current)) {
-                       sret = -EINTR;
-                       goto out;
+                       return -EINTR;
                }
 
                if (iter->trace != current_trace)
-                       goto out;
+                       return 0;
 
                /*
                 * We block until we read something and tracing is disabled.
@@ -2416,9 +2442,43 @@ waitagain:
                continue;
        }
 
+       return 1;
+}
+
+/*
+ * Consumer reader.
+ */
+static ssize_t
+tracing_read_pipe(struct file *filp, char __user *ubuf,
+                 size_t cnt, loff_t *ppos)
+{
+       struct trace_iterator *iter = filp->private_data;
+       ssize_t sret;
+
+       /* return any leftover data */
+       sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
+       if (sret != -EBUSY)
+               return sret;
+
+       trace_seq_reset(&iter->seq);
+
+       mutex_lock(&trace_types_lock);
+       if (iter->trace->read) {
+               sret = iter->trace->read(iter, filp, ubuf, cnt, ppos);
+               if (sret)
+                       goto out;
+       }
+
+waitagain:
+       sret = tracing_wait_pipe(filp);
+       if (sret <= 0)
+               goto out;
+
        /* stop when tracing is finished */
-       if (trace_empty(iter))
+       if (trace_empty(iter)) {
+               sret = 0;
                goto out;
+       }
 
        if (cnt >= PAGE_SIZE)
                cnt = PAGE_SIZE - 1;
@@ -2439,8 +2499,8 @@ waitagain:
                        iter->seq.len = len;
                        break;
                }
-
-               trace_consume(iter);
+               if (ret != TRACE_TYPE_NO_CONSUME)
+                       trace_consume(iter);
 
                if (iter->seq.len >= cnt)
                        break;
@@ -2464,6 +2524,135 @@ out:
        return sret;
 }
 
+static void tracing_pipe_buf_release(struct pipe_inode_info *pipe,
+                                    struct pipe_buffer *buf)
+{
+       __free_page(buf->page);
+}
+
+static void tracing_spd_release_pipe(struct splice_pipe_desc *spd,
+                                    unsigned int idx)
+{
+       __free_page(spd->pages[idx]);
+}
+
+static struct pipe_buf_operations tracing_pipe_buf_ops = {
+       .can_merge              = 0,
+       .map                    = generic_pipe_buf_map,
+       .unmap                  = generic_pipe_buf_unmap,
+       .confirm                = generic_pipe_buf_confirm,
+       .release                = tracing_pipe_buf_release,
+       .steal                  = generic_pipe_buf_steal,
+       .get                    = generic_pipe_buf_get,
+};
+
+static size_t
+tracing_fill_pipe_page(struct page *pages, size_t rem,
+                       struct trace_iterator *iter)
+{
+       size_t count;
+       int ret;
+
+       /* Seq buffer is page-sized, exactly what we need. */
+       for (;;) {
+               count = iter->seq.len;
+               ret = print_trace_line(iter);
+               count = iter->seq.len - count;
+               if (rem < count) {
+                       rem = 0;
+                       iter->seq.len -= count;
+                       break;
+               }
+               if (ret == TRACE_TYPE_PARTIAL_LINE) {
+                       iter->seq.len -= count;
+                       break;
+               }
+
+               trace_consume(iter);
+               rem -= count;
+               if (!find_next_entry_inc(iter)) {
+                       rem = 0;
+                       iter->ent = NULL;
+                       break;
+               }
+       }
+
+       return rem;
+}
+
+static ssize_t tracing_splice_read_pipe(struct file *filp,
+                                       loff_t *ppos,
+                                       struct pipe_inode_info *pipe,
+                                       size_t len,
+                                       unsigned int flags)
+{
+       struct page *pages[PIPE_BUFFERS];
+       struct partial_page partial[PIPE_BUFFERS];
+       struct trace_iterator *iter = filp->private_data;
+       struct splice_pipe_desc spd = {
+               .pages          = pages,
+               .partial        = partial,
+               .nr_pages       = 0, /* This gets updated below. */
+               .flags          = flags,
+               .ops            = &tracing_pipe_buf_ops,
+               .spd_release    = tracing_spd_release_pipe,
+       };
+       ssize_t ret;
+       size_t rem;
+       unsigned int i;
+
+       mutex_lock(&trace_types_lock);
+
+       if (iter->trace->splice_read) {
+               ret = iter->trace->splice_read(iter, filp,
+                                              ppos, pipe, len, flags);
+               if (ret)
+                       goto out_err;
+       }
+
+       ret = tracing_wait_pipe(filp);
+       if (ret <= 0)
+               goto out_err;
+
+       if (!iter->ent && !find_next_entry_inc(iter)) {
+               ret = -EFAULT;
+               goto out_err;
+       }
+
+       /* Fill as many pages as possible. */
+       for (i = 0, rem = len; i < PIPE_BUFFERS && rem; i++) {
+               pages[i] = alloc_page(GFP_KERNEL);
+               if (!pages[i])
+                       break;
+
+               rem = tracing_fill_pipe_page(pages[i], rem, iter);
+
+               /* Copy the data into the page, so we can start over. */
+               ret = trace_seq_to_buffer(&iter->seq,
+                                         page_address(pages[i]),
+                                         iter->seq.len);
+               if (ret < 0) {
+                       __free_page(pages[i]);
+                       break;
+               }
+               partial[i].offset = 0;
+               partial[i].len = iter->seq.len;
+
+               trace_seq_reset(&iter->seq);
+       }
+
+       mutex_unlock(&trace_types_lock);
+
+       spd.nr_pages = i;
+
+       return splice_to_pipe(pipe, &spd);
+
+out_err:
+       mutex_unlock(&trace_types_lock);
+
+       return ret;
+}
+
 static ssize_t
 tracing_entries_read(struct file *filp, char __user *ubuf,
                     size_t cnt, loff_t *ppos)
@@ -2627,6 +2816,7 @@ static struct file_operations tracing_pipe_fops = {
        .open           = tracing_open_pipe,
        .poll           = tracing_poll_pipe,
        .read           = tracing_read_pipe,
+       .splice_read    = tracing_splice_read_pipe,
        .release        = tracing_release_pipe,
 };
 
@@ -2825,12 +3015,10 @@ int trace_vprintk(unsigned long ip, int depth, const char *fmt, va_list args)
        trace_buf[len] = 0;
 
        size = sizeof(*entry) + len + 1;
-       event = ring_buffer_lock_reserve(tr->buffer, size);
+       event = trace_buffer_lock_reserve(tr, TRACE_PRINT, size, irq_flags, pc);
        if (!event)
                goto out_unlock;
        entry = ring_buffer_event_data(event);
-       tracing_generic_entry_update(&entry->ent, irq_flags, pc);
-       entry->ent.type                 = TRACE_PRINT;
        entry->ip                       = ip;
        entry->depth                    = depth;