From f4a1d08ce65d7156504f2f0eac26f47dfc9120e6 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Wed, 12 Nov 2014 11:35:48 -0500 Subject: [PATCH] blktrace/tracing: Use trace_seq_has_overflowed() helper function Checking the return code of every trace_seq_printf() operation and having to return early if it overflowed makes the code messy. Using the new trace_seq_has_overflowed() and trace_handle_return() functions allows us to clean up the code. In the future, trace_seq_printf() and friends will be turning into void functions and not returning a value. The trace_seq_has_overflowed() is to be used instead. This cleanup allows that change to take place. Cc: Jens Axboe Reviewed-by: Petr Mladek Signed-off-by: Steven Rostedt --- kernel/trace/blktrace.c | 148 ++++++++++++++++++---------------------- 1 file changed, 66 insertions(+), 82 deletions(-) diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c index c1bd4ada2a04..11b9cb36092b 100644 --- a/kernel/trace/blktrace.c +++ b/kernel/trace/blktrace.c @@ -1142,9 +1142,9 @@ static void get_pdu_remap(const struct trace_entry *ent, r->sector_from = be64_to_cpu(sector_from); } -typedef int (blk_log_action_t) (struct trace_iterator *iter, const char *act); +typedef void (blk_log_action_t) (struct trace_iterator *iter, const char *act); -static int blk_log_action_classic(struct trace_iterator *iter, const char *act) +static void blk_log_action_classic(struct trace_iterator *iter, const char *act) { char rwbs[RWBS_LEN]; unsigned long long ts = iter->ts; @@ -1154,33 +1154,33 @@ static int blk_log_action_classic(struct trace_iterator *iter, const char *act) fill_rwbs(rwbs, t); - return trace_seq_printf(&iter->seq, - "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ", - MAJOR(t->device), MINOR(t->device), iter->cpu, - secs, nsec_rem, iter->ent->pid, act, rwbs); + trace_seq_printf(&iter->seq, + "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ", + MAJOR(t->device), MINOR(t->device), iter->cpu, + secs, nsec_rem, iter->ent->pid, act, rwbs); } -static int blk_log_action(struct trace_iterator *iter, const char *act) +static void blk_log_action(struct trace_iterator *iter, const char *act) { char rwbs[RWBS_LEN]; const struct blk_io_trace *t = te_blk_io_trace(iter->ent); fill_rwbs(rwbs, t); - return trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ", - MAJOR(t->device), MINOR(t->device), act, rwbs); + trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ", + MAJOR(t->device), MINOR(t->device), act, rwbs); } -static int blk_log_dump_pdu(struct trace_seq *s, const struct trace_entry *ent) +static void blk_log_dump_pdu(struct trace_seq *s, const struct trace_entry *ent) { const unsigned char *pdu_buf; int pdu_len; - int i, end, ret; + int i, end; pdu_buf = pdu_start(ent); pdu_len = te_blk_io_trace(ent)->pdu_len; if (!pdu_len) - return 1; + return; /* find the last zero that needs to be printed */ for (end = pdu_len - 1; end >= 0; end--) @@ -1188,119 +1188,107 @@ static int blk_log_dump_pdu(struct trace_seq *s, const struct trace_entry *ent) break; end++; - if (!trace_seq_putc(s, '(')) - return 0; + trace_seq_putc(s, '('); for (i = 0; i < pdu_len; i++) { - ret = trace_seq_printf(s, "%s%02x", - i == 0 ? "" : " ", pdu_buf[i]); - if (!ret) - return ret; + trace_seq_printf(s, "%s%02x", + i == 0 ? "" : " ", pdu_buf[i]); /* * stop when the rest is just zeroes and indicate so * with a ".." appended */ - if (i == end && end != pdu_len - 1) - return trace_seq_puts(s, " ..) "); + if (i == end && end != pdu_len - 1) { + trace_seq_puts(s, " ..) "); + return; + } } - return trace_seq_puts(s, ") "); + trace_seq_puts(s, ") "); } -static int blk_log_generic(struct trace_seq *s, const struct trace_entry *ent) +static void blk_log_generic(struct trace_seq *s, const struct trace_entry *ent) { char cmd[TASK_COMM_LEN]; trace_find_cmdline(ent->pid, cmd); if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) { - int ret; - - ret = trace_seq_printf(s, "%u ", t_bytes(ent)); - if (!ret) - return 0; - ret = blk_log_dump_pdu(s, ent); - if (!ret) - return 0; - return trace_seq_printf(s, "[%s]\n", cmd); + trace_seq_printf(s, "%u ", t_bytes(ent)); + blk_log_dump_pdu(s, ent); + trace_seq_printf(s, "[%s]\n", cmd); } else { if (t_sec(ent)) - return trace_seq_printf(s, "%llu + %u [%s]\n", + trace_seq_printf(s, "%llu + %u [%s]\n", t_sector(ent), t_sec(ent), cmd); - return trace_seq_printf(s, "[%s]\n", cmd); + else + trace_seq_printf(s, "[%s]\n", cmd); } } -static int blk_log_with_error(struct trace_seq *s, +static void blk_log_with_error(struct trace_seq *s, const struct trace_entry *ent) { if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) { - int ret; - - ret = blk_log_dump_pdu(s, ent); - if (ret) - return trace_seq_printf(s, "[%d]\n", t_error(ent)); - return 0; + blk_log_dump_pdu(s, ent); + trace_seq_printf(s, "[%d]\n", t_error(ent)); } else { if (t_sec(ent)) - return trace_seq_printf(s, "%llu + %u [%d]\n", - t_sector(ent), - t_sec(ent), t_error(ent)); - return trace_seq_printf(s, "%llu [%d]\n", - t_sector(ent), t_error(ent)); + trace_seq_printf(s, "%llu + %u [%d]\n", + t_sector(ent), + t_sec(ent), t_error(ent)); + else + trace_seq_printf(s, "%llu [%d]\n", + t_sector(ent), t_error(ent)); } } -static int blk_log_remap(struct trace_seq *s, const struct trace_entry *ent) +static void blk_log_remap(struct trace_seq *s, const struct trace_entry *ent) { struct blk_io_trace_remap r = { .device_from = 0, }; get_pdu_remap(ent, &r); - return trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n", - t_sector(ent), t_sec(ent), - MAJOR(r.device_from), MINOR(r.device_from), - (unsigned long long)r.sector_from); + trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n", + t_sector(ent), t_sec(ent), + MAJOR(r.device_from), MINOR(r.device_from), + (unsigned long long)r.sector_from); } -static int blk_log_plug(struct trace_seq *s, const struct trace_entry *ent) +static void blk_log_plug(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, "[%s]\n", cmd); + trace_seq_printf(s, "[%s]\n", cmd); } -static int blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent) +static void blk_log_unplug(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, "[%s] %llu\n", cmd, get_pdu_int(ent)); + 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) +static void 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), cmd); + trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent), + get_pdu_int(ent), cmd); } -static int blk_log_msg(struct trace_seq *s, const struct trace_entry *ent) +static void blk_log_msg(struct trace_seq *s, const struct trace_entry *ent) { - int ret; const struct blk_io_trace *t = te_blk_io_trace(ent); - ret = trace_seq_putmem(s, t + 1, t->pdu_len); - if (ret) - return trace_seq_putc(s, '\n'); - return ret; + trace_seq_putmem(s, t + 1, t->pdu_len); + trace_seq_putc(s, '\n'); } /* @@ -1339,7 +1327,7 @@ static void blk_tracer_reset(struct trace_array *tr) static const struct { const char *act[2]; - int (*print)(struct trace_seq *s, const struct trace_entry *ent); + void (*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 }, @@ -1364,7 +1352,6 @@ static enum print_line_t print_one_line(struct trace_iterator *iter, struct trace_seq *s = &iter->seq; const struct blk_io_trace *t; u16 what; - int ret; bool long_act; blk_log_action_t *log_action; @@ -1374,21 +1361,18 @@ static enum print_line_t print_one_line(struct trace_iterator *iter, log_action = classic ? &blk_log_action_classic : &blk_log_action; if (t->action == BLK_TN_MESSAGE) { - ret = log_action(iter, long_act ? "message" : "m"); - if (ret) - ret = blk_log_msg(s, iter->ent); - goto out; + log_action(iter, long_act ? "message" : "m"); + blk_log_msg(s, iter->ent); } if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act))) - ret = trace_seq_printf(s, "Unknown action %x\n", what); + trace_seq_printf(s, "Unknown action %x\n", what); else { - ret = log_action(iter, what2act[what].act[long_act]); - if (ret) - ret = what2act[what].print(s, iter->ent); + log_action(iter, what2act[what].act[long_act]); + what2act[what].print(s, iter->ent); } -out: - return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE; + + return trace_handle_return(s); } static enum print_line_t blk_trace_event_print(struct trace_iterator *iter, @@ -1397,7 +1381,7 @@ static enum print_line_t blk_trace_event_print(struct trace_iterator *iter, return print_one_line(iter, false); } -static int blk_trace_synthesize_old_trace(struct trace_iterator *iter) +static void blk_trace_synthesize_old_trace(struct trace_iterator *iter) { struct trace_seq *s = &iter->seq; struct blk_io_trace *t = (struct blk_io_trace *)iter->ent; @@ -1407,18 +1391,18 @@ static int blk_trace_synthesize_old_trace(struct trace_iterator *iter) .time = iter->ts, }; - if (!trace_seq_putmem(s, &old, offset)) - return 0; - return trace_seq_putmem(s, &t->sector, - sizeof(old) - offset + t->pdu_len); + trace_seq_putmem(s, &old, offset); + trace_seq_putmem(s, &t->sector, + sizeof(old) - offset + t->pdu_len); } static enum print_line_t blk_trace_event_print_binary(struct trace_iterator *iter, int flags, struct trace_event *event) { - return blk_trace_synthesize_old_trace(iter) ? - TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE; + blk_trace_synthesize_old_trace(iter); + + return trace_handle_return(&iter->seq); } static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter) -- 2.20.1