]> pilppa.org Git - linux-2.6-omap-h63xx.git/blobdiff - kernel/trace/blktrace.c
blktrace: fix the original blktrace
[linux-2.6-omap-h63xx.git] / kernel / trace / blktrace.c
index d24a10b8411a6673af11b783bea6ec364da89cb7..a7f7ff5db38b9f2cfdc469224102248ce2f95ea1 100644 (file)
 static unsigned int blktrace_seq __read_mostly = 1;
 
 static struct trace_array *blk_tr;
-static int __read_mostly  blk_tracer_enabled;
+static bool blk_tracer_enabled __read_mostly;
 
 /* Select an alternative, minimalistic output than the original one */
-#define TRACE_BLK_OPT_CLASSIC  0x1
+#define TRACE_BLK_OPT_CLASSIC  0x1
 
 static struct tracer_opt blk_tracer_opts[] = {
        /* Default disable the minimalistic output */
@@ -47,10 +47,9 @@ static struct tracer_flags blk_tracer_flags = {
 };
 
 /* Global reference count of probes */
-static DEFINE_MUTEX(blk_probe_mutex);
 static atomic_t blk_probes_ref = ATOMIC_INIT(0);
 
-static int blk_register_tracepoints(void);
+static void blk_register_tracepoints(void);
 static void blk_unregister_tracepoints(void);
 
 /*
@@ -111,7 +110,7 @@ void __trace_note_message(struct blk_trace *bt, const char *fmt, ...)
        unsigned long flags;
        char *buf;
 
-       if (blk_tr) {
+       if (blk_tracer_enabled) {
                va_start(args, fmt);
                ftrace_vprintk(fmt, args);
                va_end(args);
@@ -148,8 +147,8 @@ static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector,
 /*
  * Data direction bit lookup
  */
-static u32 ddir_act[2] __read_mostly = { BLK_TC_ACT(BLK_TC_READ),
-                                        BLK_TC_ACT(BLK_TC_WRITE) };
+static const u32 ddir_act[2] = { BLK_TC_ACT(BLK_TC_READ),
+                                BLK_TC_ACT(BLK_TC_WRITE) };
 
 /* The ilog2() calls fall out because they're constant */
 #define MASK_TC_BIT(rw, __name) ((rw & (1 << BIO_RW_ ## __name)) << \
@@ -170,7 +169,7 @@ static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
        pid_t pid;
        int cpu, pc = 0;
 
-       if (unlikely(bt->trace_state != Blktrace_running ||
+       if (unlikely(bt->trace_state != Blktrace_running &&
                     !blk_tracer_enabled))
                return;
 
@@ -186,7 +185,7 @@ static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
                return;
        cpu = raw_smp_processor_id();
 
-       if (blk_tr) {
+       if (blk_tracer_enabled) {
                tracing_record_cmdline(current);
 
                pc = preempt_count();
@@ -236,7 +235,7 @@ record_it:
                if (pdu_len)
                        memcpy((void *) t + sizeof(*t), pdu_data, pdu_len);
 
-               if (blk_tr) {
+               if (blk_tracer_enabled) {
                        trace_buffer_unlock_commit(blk_tr, event, 0, pc);
                        return;
                }
@@ -256,10 +255,8 @@ static void blk_trace_cleanup(struct blk_trace *bt)
        free_percpu(bt->sequence);
        free_percpu(bt->msg_data);
        kfree(bt);
-       mutex_lock(&blk_probe_mutex);
        if (atomic_dec_and_test(&blk_probes_ref))
                blk_unregister_tracepoints();
-       mutex_unlock(&blk_probe_mutex);
 }
 
 int blk_trace_remove(struct request_queue *q)
@@ -270,8 +267,7 @@ int blk_trace_remove(struct request_queue *q)
        if (!bt)
                return -EINVAL;
 
-       if (bt->trace_state == Blktrace_setup ||
-           bt->trace_state == Blktrace_stopped)
+       if (bt->trace_state != Blktrace_running)
                blk_trace_cleanup(bt);
 
        return 0;
@@ -429,11 +425,15 @@ int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
 
        ret = -ENOENT;
 
+       mutex_lock(&blk_tree_mutex);
        if (!blk_tree_root) {
                blk_tree_root = debugfs_create_dir("block", NULL);
-               if (!blk_tree_root)
-                       return -ENOMEM;
+               if (!blk_tree_root) {
+                       mutex_unlock(&blk_tree_mutex);
+                       goto err;
+               }
        }
+       mutex_unlock(&blk_tree_mutex);
 
        dir = debugfs_create_dir(buts->name, blk_tree_root);
 
@@ -471,14 +471,6 @@ int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
        bt->pid = buts->pid;
        bt->trace_state = Blktrace_setup;
 
-       mutex_lock(&blk_probe_mutex);
-       if (atomic_add_return(1, &blk_probes_ref) == 1) {
-               ret = blk_register_tracepoints();
-               if (ret)
-                       goto probe_err;
-       }
-       mutex_unlock(&blk_probe_mutex);
-
        ret = -EBUSY;
        old_bt = xchg(&q->blk_trace, bt);
        if (old_bt) {
@@ -486,10 +478,10 @@ int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
                goto err;
        }
 
+       if (atomic_add_return(1, &blk_probes_ref) == 1)
+               blk_register_tracepoints();
+
        return 0;
-probe_err:
-       atomic_dec(&blk_probes_ref);
-       mutex_unlock(&blk_probe_mutex);
 err:
        if (bt) {
                if (bt->msg_file)
@@ -564,7 +556,7 @@ EXPORT_SYMBOL_GPL(blk_trace_startstop);
 /**
  * blk_trace_ioctl: - handle the ioctls associated with tracing
  * @bdev:      the block device
- * @cmd:       the ioctl cmd
+ * @cmd:       the ioctl cmd
  * @arg:       the argument data, if any
  *
  **/
@@ -863,7 +855,7 @@ void blk_add_driver_data(struct request_queue *q,
 }
 EXPORT_SYMBOL_GPL(blk_add_driver_data);
 
-static int blk_register_tracepoints(void)
+static void blk_register_tracepoints(void)
 {
        int ret;
 
@@ -901,7 +893,6 @@ static int blk_register_tracepoints(void)
        WARN_ON(ret);
        ret = register_trace_block_remap(blk_add_trace_remap);
        WARN_ON(ret);
-       return 0;
 }
 
 static void blk_unregister_tracepoints(void)
@@ -934,23 +925,24 @@ static void blk_unregister_tracepoints(void)
 static void fill_rwbs(char *rwbs, const struct blk_io_trace *t)
 {
        int i = 0;
+       int tc = t->action >> BLK_TC_SHIFT;
 
-       if (t->action & BLK_TC_DISCARD)
+       if (tc & BLK_TC_DISCARD)
                rwbs[i++] = 'D';
-       else if (t->action & BLK_TC_WRITE)
+       else if (tc & BLK_TC_WRITE)
                rwbs[i++] = 'W';
        else if (t->bytes)
                rwbs[i++] = 'R';
        else
                rwbs[i++] = 'N';
 
-       if (t->action & BLK_TC_AHEAD)
+       if (tc & BLK_TC_AHEAD)
                rwbs[i++] = 'A';
-       if (t->action & BLK_TC_BARRIER)
+       if (tc & BLK_TC_BARRIER)
                rwbs[i++] = 'B';
-       if (t->action & BLK_TC_SYNC)
+       if (tc & BLK_TC_SYNC)
                rwbs[i++] = 'S';
-       if (t->action & BLK_TC_META)
+       if (tc & BLK_TC_META)
                rwbs[i++] = 'M';
 
        rwbs[i] = '\0';
@@ -979,7 +971,7 @@ static inline unsigned long long t_sector(const struct trace_entry *ent)
 
 static inline __u16 t_error(const struct trace_entry *ent)
 {
-       return te_blk_io_trace(ent)->sector;
+       return te_blk_io_trace(ent)->error;
 }
 
 static __u64 get_pdu_int(const struct trace_entry *ent)
@@ -1027,7 +1019,9 @@ static int blk_log_action_seq(struct trace_seq *s, const struct blk_io_trace *t,
 
 static int blk_log_generic(struct trace_seq *s, const struct trace_entry *ent)
 {
-       const char *cmd = trace_find_cmdline(ent->pid);
+       char cmd[TASK_COMM_LEN];
+
+       trace_find_cmdline(ent->pid, cmd);
 
        if (t_sec(ent))
                return trace_seq_printf(s, "%llu + %u [%s]\n",
@@ -1057,19 +1051,30 @@ static int blk_log_remap(struct trace_seq *s, const struct trace_entry *ent)
 
 static int blk_log_plug(struct trace_seq *s, const struct trace_entry *ent)
 {
-       return trace_seq_printf(s, "[%s]\n", trace_find_cmdline(ent->pid));
+       char cmd[TASK_COMM_LEN];
+
+       trace_find_cmdline(ent->pid, cmd);
+
+       return trace_seq_printf(s, "[%s]\n", cmd);
 }
 
 static int blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent)
 {
-       return trace_seq_printf(s, "[%s] %llu\n", trace_find_cmdline(ent->pid),
-                               get_pdu_int(ent));
+       char cmd[TASK_COMM_LEN];
+
+       trace_find_cmdline(ent->pid, cmd);
+
+       return trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent));
 }
 
 static int blk_log_split(struct trace_seq *s, const struct trace_entry *ent)
 {
+       char cmd[TASK_COMM_LEN];
+
+       trace_find_cmdline(ent->pid, cmd);
+
        return trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent),
-                               get_pdu_int(ent), trace_find_cmdline(ent->pid));
+                               get_pdu_int(ent), cmd);
 }
 
 /*
@@ -1086,11 +1091,8 @@ static void blk_tracer_print_header(struct seq_file *m)
 
 static void blk_tracer_start(struct trace_array *tr)
 {
-       mutex_lock(&blk_probe_mutex);
        if (atomic_add_return(1, &blk_probes_ref) == 1)
-               if (blk_register_tracepoints())
-                       atomic_dec(&blk_probes_ref);
-       mutex_unlock(&blk_probe_mutex);
+               blk_register_tracepoints();
        trace_flags &= ~TRACE_ITER_CONTEXT_INFO;
 }
 
@@ -1098,19 +1100,15 @@ static int blk_tracer_init(struct trace_array *tr)
 {
        blk_tr = tr;
        blk_tracer_start(tr);
-       mutex_lock(&blk_probe_mutex);
-       blk_tracer_enabled++;
-       mutex_unlock(&blk_probe_mutex);
+       blk_tracer_enabled = true;
        return 0;
 }
 
 static void blk_tracer_stop(struct trace_array *tr)
 {
        trace_flags |= TRACE_ITER_CONTEXT_INFO;
-       mutex_lock(&blk_probe_mutex);
        if (atomic_dec_and_test(&blk_probes_ref))
                blk_unregister_tracepoints();
-       mutex_unlock(&blk_probe_mutex);
 }
 
 static void blk_tracer_reset(struct trace_array *tr)
@@ -1118,19 +1116,15 @@ static void blk_tracer_reset(struct trace_array *tr)
        if (!atomic_read(&blk_probes_ref))
                return;
 
-       mutex_lock(&blk_probe_mutex);
-       blk_tracer_enabled--;
-       WARN_ON(blk_tracer_enabled < 0);
-       mutex_unlock(&blk_probe_mutex);
-
+       blk_tracer_enabled = false;
        blk_tracer_stop(tr);
 }
 
-static struct {
+static const struct {
        const char *act[2];
-       int        (*print)(struct trace_seq *s, const struct trace_entry *ent);
-} what2act[] __read_mostly = {
-       [__BLK_TA_QUEUE]        = {{  "Q", "queue" },      blk_log_generic },
+       int        (*print)(struct trace_seq *s, const struct trace_entry *ent);
+} what2act[] = {
+       [__BLK_TA_QUEUE]        = {{  "Q", "queue" },      blk_log_generic },
        [__BLK_TA_BACKMERGE]    = {{  "M", "backmerge" },  blk_log_generic },
        [__BLK_TA_FRONTMERGE]   = {{  "F", "frontmerge" }, blk_log_generic },
        [__BLK_TA_GETRQ]        = {{  "G", "getrq" },      blk_log_generic },
@@ -1177,7 +1171,7 @@ static int blk_trace_synthesize_old_trace(struct trace_iterator *iter)
        const int offset = offsetof(struct blk_io_trace, sector);
        struct blk_io_trace old = {
                .magic    = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION,
-               .time     = ns2usecs(iter->ts),
+               .time     = iter->ts,
        };
 
        if (!trace_seq_putmem(s, &old, offset))
@@ -1229,7 +1223,7 @@ static struct tracer blk_tracer __read_mostly = {
 };
 
 static struct trace_event trace_blk_event = {
-       .type           = TRACE_BLK,
+       .type           = TRACE_BLK,
        .trace          = blk_trace_event_print,
        .binary         = blk_trace_event_print_binary,
 };
@@ -1270,99 +1264,29 @@ static int blk_trace_remove_queue(struct request_queue *q)
 static int blk_trace_setup_queue(struct request_queue *q, dev_t dev)
 {
        struct blk_trace *old_bt, *bt = NULL;
-       int ret;
 
-       ret = -ENOMEM;
        bt = kzalloc(sizeof(*bt), GFP_KERNEL);
        if (!bt)
-               goto err;
+               return -ENOMEM;
 
        bt->dev = dev;
        bt->act_mask = (u16)-1;
        bt->end_lba = -1ULL;
-       bt->trace_state = Blktrace_running;
 
        old_bt = xchg(&q->blk_trace, bt);
        if (old_bt != NULL) {
                (void)xchg(&q->blk_trace, old_bt);
                kfree(bt);
-               ret = -EBUSY;
+               return -EBUSY;
        }
+
        return 0;
-err:
-       return ret;
 }
 
 /*
  * sysfs interface to enable and configure tracing
  */
 
-static ssize_t sysfs_blk_trace_enable_show(struct device *dev,
-                                          struct device_attribute *attr,
-                                          char *buf)
-{
-       struct hd_struct *p = dev_to_part(dev);
-       struct block_device *bdev;
-       ssize_t ret = -ENXIO;
-
-       lock_kernel();
-       bdev = bdget(part_devt(p));
-       if (bdev != NULL) {
-               struct request_queue *q = bdev_get_queue(bdev);
-
-               if (q != NULL) {
-                       mutex_lock(&bdev->bd_mutex);
-                       ret = sprintf(buf, "%u\n", !!q->blk_trace);
-                       mutex_unlock(&bdev->bd_mutex);
-               }
-
-               bdput(bdev);
-       }
-
-       unlock_kernel();
-       return ret;
-}
-
-static ssize_t sysfs_blk_trace_enable_store(struct device *dev,
-                                           struct device_attribute *attr,
-                                           const char *buf, size_t count)
-{
-       struct block_device *bdev;
-       struct request_queue *q;
-       struct hd_struct *p;
-       int value;
-       ssize_t ret = -ENXIO;
-
-       if (count == 0 || sscanf(buf, "%d", &value) != 1)
-               goto out;
-
-       lock_kernel();
-       p = dev_to_part(dev);
-       bdev = bdget(part_devt(p));
-       if (bdev == NULL)
-               goto out_unlock_kernel;
-
-       q = bdev_get_queue(bdev);
-       if (q == NULL)
-               goto out_bdput;
-
-       mutex_lock(&bdev->bd_mutex);
-       if (value)
-               ret = blk_trace_setup_queue(q, bdev->bd_dev);
-       else
-               ret = blk_trace_remove_queue(q);
-       mutex_unlock(&bdev->bd_mutex);
-
-       if (ret == 0)
-               ret = count;
-out_bdput:
-       bdput(bdev);
-out_unlock_kernel:
-       unlock_kernel();
-out:
-       return ret;
-}
-
 static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
                                         struct device_attribute *attr,
                                         char *buf);
@@ -1374,8 +1298,7 @@ static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
                    sysfs_blk_trace_attr_show, \
                    sysfs_blk_trace_attr_store)
 
-static DEVICE_ATTR(enable, S_IRUGO | S_IWUSR,
-                  sysfs_blk_trace_enable_show, sysfs_blk_trace_enable_store);
+static BLK_TRACE_DEVICE_ATTR(enable);
 static BLK_TRACE_DEVICE_ATTR(act_mask);
 static BLK_TRACE_DEVICE_ATTR(pid);
 static BLK_TRACE_DEVICE_ATTR(start_lba);
@@ -1395,53 +1318,85 @@ struct attribute_group blk_trace_attr_group = {
        .attrs = blk_trace_attrs,
 };
 
-static int blk_str2act_mask(const char *str)
+static const struct {
+       int mask;
+       const char *str;
+} mask_maps[] = {
+       { BLK_TC_READ,          "read"          },
+       { BLK_TC_WRITE,         "write"         },
+       { BLK_TC_BARRIER,       "barrier"       },
+       { BLK_TC_SYNC,          "sync"          },
+       { BLK_TC_QUEUE,         "queue"         },
+       { BLK_TC_REQUEUE,       "requeue"       },
+       { BLK_TC_ISSUE,         "issue"         },
+       { BLK_TC_COMPLETE,      "complete"      },
+       { BLK_TC_FS,            "fs"            },
+       { BLK_TC_PC,            "pc"            },
+       { BLK_TC_AHEAD,         "ahead"         },
+       { BLK_TC_META,          "meta"          },
+       { BLK_TC_DISCARD,       "discard"       },
+       { BLK_TC_DRV_DATA,      "drv_data"      },
+};
+
+static int blk_trace_str2mask(const char *str)
 {
+       int i;
        int mask = 0;
-       char *copy = kstrdup(str, GFP_KERNEL), *s;
+       char *s, *token;
 
-       if (copy == NULL)
+       s = kstrdup(str, GFP_KERNEL);
+       if (s == NULL)
                return -ENOMEM;
-
-       s = strstrip(copy);
+       s = strstrip(s);
 
        while (1) {
-               char *sep = strchr(s, ',');
-
-               if (sep != NULL)
-                       *sep = '\0';
-
-               if (strcasecmp(s, "barrier") == 0)
-                       mask |= BLK_TC_BARRIER;
-               else if (strcasecmp(s, "complete") == 0)
-                       mask |= BLK_TC_COMPLETE;
-               else if (strcasecmp(s, "fs") == 0)
-                       mask |= BLK_TC_FS;
-               else if (strcasecmp(s, "issue") == 0)
-                       mask |= BLK_TC_ISSUE;
-               else if (strcasecmp(s, "pc") == 0)
-                       mask |= BLK_TC_PC;
-               else if (strcasecmp(s, "queue") == 0)
-                       mask |= BLK_TC_QUEUE;
-               else if (strcasecmp(s, "read") == 0)
-                       mask |= BLK_TC_READ;
-               else if (strcasecmp(s, "requeue") == 0)
-                       mask |= BLK_TC_REQUEUE;
-               else if (strcasecmp(s, "sync") == 0)
-                       mask |= BLK_TC_SYNC;
-               else if (strcasecmp(s, "write") == 0)
-                       mask |= BLK_TC_WRITE;
-
-               if (sep == NULL)
+               token = strsep(&s, ",");
+               if (token == NULL)
                        break;
 
-               s = sep + 1;
+               if (*token == '\0')
+                       continue;
+
+               for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
+                       if (strcasecmp(token, mask_maps[i].str) == 0) {
+                               mask |= mask_maps[i].mask;
+                               break;
+                       }
+               }
+               if (i == ARRAY_SIZE(mask_maps)) {
+                       mask = -EINVAL;
+                       break;
+               }
        }
-       kfree(copy);
+       kfree(s);
 
        return mask;
 }
 
+static ssize_t blk_trace_mask2str(char *buf, int mask)
+{
+       int i;
+       char *p = buf;
+
+       for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
+               if (mask & mask_maps[i].mask) {
+                       p += sprintf(p, "%s%s",
+                                   (p == buf) ? "" : ",", mask_maps[i].str);
+               }
+       }
+       *p++ = '\n';
+
+       return p - buf;
+}
+
+static struct request_queue *blk_trace_get_queue(struct block_device *bdev)
+{
+       if (bdev->bd_disk == NULL)
+               return NULL;
+
+       return bdev_get_queue(bdev);
+}
+
 static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
                                         struct device_attribute *attr,
                                         char *buf)
@@ -1456,20 +1411,29 @@ static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
        if (bdev == NULL)
                goto out_unlock_kernel;
 
-       q = bdev_get_queue(bdev);
+       q = blk_trace_get_queue(bdev);
        if (q == NULL)
                goto out_bdput;
+
        mutex_lock(&bdev->bd_mutex);
+
+       if (attr == &dev_attr_enable) {
+               ret = sprintf(buf, "%u\n", !!q->blk_trace);
+               goto out_unlock_bdev;
+       }
+
        if (q->blk_trace == NULL)
                ret = sprintf(buf, "disabled\n");
        else if (attr == &dev_attr_act_mask)
-               ret = sprintf(buf, "%#x\n", q->blk_trace->act_mask);
+               ret = blk_trace_mask2str(buf, q->blk_trace->act_mask);
        else if (attr == &dev_attr_pid)
                ret = sprintf(buf, "%u\n", q->blk_trace->pid);
        else if (attr == &dev_attr_start_lba)
                ret = sprintf(buf, "%llu\n", q->blk_trace->start_lba);
        else if (attr == &dev_attr_end_lba)
                ret = sprintf(buf, "%llu\n", q->blk_trace->end_lba);
+
+out_unlock_bdev:
        mutex_unlock(&bdev->bd_mutex);
 out_bdput:
        bdput(bdev);
@@ -1486,7 +1450,7 @@ static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
        struct request_queue *q;
        struct hd_struct *p;
        u64 value;
-       ssize_t ret = -ENXIO;
+       ssize_t ret = -EINVAL;
 
        if (count == 0)
                goto out;
@@ -1494,24 +1458,36 @@ static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
        if (attr == &dev_attr_act_mask) {
                if (sscanf(buf, "%llx", &value) != 1) {
                        /* Assume it is a list of trace category names */
-                       value = blk_str2act_mask(buf);
-                       if (value < 0)
+                       ret = blk_trace_str2mask(buf);
+                       if (ret < 0)
                                goto out;
+                       value = ret;
                }
        } else if (sscanf(buf, "%llu", &value) != 1)
                goto out;
 
+       ret = -ENXIO;
+
        lock_kernel();
        p = dev_to_part(dev);
        bdev = bdget(part_devt(p));
        if (bdev == NULL)
                goto out_unlock_kernel;
 
-       q = bdev_get_queue(bdev);
+       q = blk_trace_get_queue(bdev);
        if (q == NULL)
                goto out_bdput;
 
        mutex_lock(&bdev->bd_mutex);
+
+       if (attr == &dev_attr_enable) {
+               if (value)
+                       ret = blk_trace_setup_queue(q, bdev->bd_dev);
+               else
+                       ret = blk_trace_remove_queue(q);
+               goto out_unlock_bdev;
+       }
+
        ret = 0;
        if (q->blk_trace == NULL)
                ret = blk_trace_setup_queue(q, bdev->bd_dev);
@@ -1525,13 +1501,15 @@ static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
                        q->blk_trace->start_lba = value;
                else if (attr == &dev_attr_end_lba)
                        q->blk_trace->end_lba = value;
-               ret = count;
        }
+
+out_unlock_bdev:
        mutex_unlock(&bdev->bd_mutex);
 out_bdput:
        bdput(bdev);
 out_unlock_kernel:
        unlock_kernel();
 out:
-       return ret;
+       return ret ? ret : count;
 }
+