blk-throttle: add backlink pointer from throtl_grp to throtl_data

Add throtl_grp->td so that the td (throtl_data) a given tg
(throtl_grp) belongs to can be determined, and remove @td argument
from functions which take both @td and @tg as the former now can be
determined from the latter.

This generally simplifies the code and removes a number of cases where
@td is passed as an argument without being actually used.  This will
also help hierarchy support implementation.

While at it, in multi-line conditions, move the logical operators
leading broken lines to the end of the previous line.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Vivek Goyal <vgoyal@redhat.com>

1 files changed, 53 insertions, 53 deletions

diff --git a/block/blk-throttle.c b/block/blk-throttle.c
index e8ef43d3fab3..a489391f9153 100644
--- a/block/blk-throttle.c
+++ b/block/blk-throttle.c
@@ -57,6 +57,9 @@ struct throtl_grp {
         /* active throtl group service_queue member */
         struct rb_node rb_node;
 
+        /* throtl_data this group belongs to */
+        struct throtl_data *td;
+
         /*
          * Dispatch time in jiffies. This is the estimated time when group
          * will unthrottle and is ready to dispatch more bio. It is used as
@@ -140,11 +143,11 @@ static inline struct throtl_grp *td_root_tg(struct throtl_data *td)
         return blkg_to_tg(td->queue->root_blkg);
 }
 
-#define throtl_log_tg(td, tg, fmt, args...)     do {                    \
+#define throtl_log_tg(tg, fmt, args...) do {                            \
         char __pbuf[128];                                               \
                                                                         \
         blkg_path(tg_to_blkg(tg), __pbuf, sizeof(__pbuf));              \
-        blk_add_trace_msg((td)->queue, "throtl %s " fmt, __pbuf, ##args); \
+        blk_add_trace_msg((tg)->td->queue, "throtl %s " fmt, __pbuf, ##args); \
 } while (0)
 
 #define throtl_log(td, fmt, args...)    \
@@ -193,6 +196,7 @@ static void throtl_pd_init(struct blkcg_gq *blkg)
         unsigned long flags;
 
         RB_CLEAR_NODE(&tg->rb_node);
+        tg->td = blkg->q->td;
         bio_list_init(&tg->bio_lists[0]);
         bio_list_init(&tg->bio_lists[1]);
 
@@ -401,36 +405,34 @@ static void throtl_schedule_next_dispatch(struct throtl_data *td)
                 throtl_schedule_delayed_work(td, sq->first_pending_disptime - jiffies);
 }
 
-static inline void
-throtl_start_new_slice(struct throtl_data *td, struct throtl_grp *tg, bool rw)
+static inline void throtl_start_new_slice(struct throtl_grp *tg, bool rw)
 {
         tg->bytes_disp[rw] = 0;
         tg->io_disp[rw] = 0;
         tg->slice_start[rw] = jiffies;
         tg->slice_end[rw] = jiffies + throtl_slice;
-        throtl_log_tg(td, tg, "[%c] new slice start=%lu end=%lu jiffies=%lu",
+        throtl_log_tg(tg, "[%c] new slice start=%lu end=%lu jiffies=%lu",
                         rw == READ ? 'R' : 'W', tg->slice_start[rw],
                         tg->slice_end[rw], jiffies);
 }
 
-static inline void throtl_set_slice_end(struct throtl_data *td,
-                struct throtl_grp *tg, bool rw, unsigned long jiffy_end)
+static inline void throtl_set_slice_end(struct throtl_grp *tg, bool rw,
+                                        unsigned long jiffy_end)
 {
         tg->slice_end[rw] = roundup(jiffy_end, throtl_slice);
 }
 
-static inline void throtl_extend_slice(struct throtl_data *td,
-                struct throtl_grp *tg, bool rw, unsigned long jiffy_end)
+static inline void throtl_extend_slice(struct throtl_grp *tg, bool rw,
+                                       unsigned long jiffy_end)
 {
         tg->slice_end[rw] = roundup(jiffy_end, throtl_slice);
-        throtl_log_tg(td, tg, "[%c] extend slice start=%lu end=%lu jiffies=%lu",
+        throtl_log_tg(tg, "[%c] extend slice start=%lu end=%lu jiffies=%lu",
                         rw == READ ? 'R' : 'W', tg->slice_start[rw],
                         tg->slice_end[rw], jiffies);
 }
 
 /* Determine if previously allocated or extended slice is complete or not */
-static bool
-throtl_slice_used(struct throtl_data *td, struct throtl_grp *tg, bool rw)
+static bool throtl_slice_used(struct throtl_grp *tg, bool rw)
 {
         if (time_in_range(jiffies, tg->slice_start[rw], tg->slice_end[rw]))
                 return 0;
@@ -439,8 +441,7 @@ throtl_slice_used(struct throtl_data *td, struct throtl_grp *tg, bool rw)
 }
 
 /* Trim the used slices and adjust slice start accordingly */
-static inline void
-throtl_trim_slice(struct throtl_data *td, struct throtl_grp *tg, bool rw)
+static inline void throtl_trim_slice(struct throtl_grp *tg, bool rw)
 {
         unsigned long nr_slices, time_elapsed, io_trim;
         u64 bytes_trim, tmp;
@@ -452,7 +453,7 @@ throtl_trim_slice(struct throtl_data *td, struct throtl_grp *tg, bool rw)
          * renewed. Don't try to trim the slice if slice is used. A new
          * slice will start when appropriate.
          */
-        if (throtl_slice_used(td, tg, rw))
+        if (throtl_slice_used(tg, rw))
                 return;
 
         /*
@@ -463,7 +464,7 @@ throtl_trim_slice(struct throtl_data *td, struct throtl_grp *tg, bool rw)
          * is bad because it does not allow new slice to start.
          */
 
-        throtl_set_slice_end(td, tg, rw, jiffies + throtl_slice);
+        throtl_set_slice_end(tg, rw, jiffies + throtl_slice);
 
         time_elapsed = jiffies - tg->slice_start[rw];
 
@@ -492,14 +493,14 @@ throtl_trim_slice(struct throtl_data *td, struct throtl_grp *tg, bool rw)
 
         tg->slice_start[rw] += nr_slices * throtl_slice;
 
-        throtl_log_tg(td, tg, "[%c] trim slice nr=%lu bytes=%llu io=%lu"
+        throtl_log_tg(tg, "[%c] trim slice nr=%lu bytes=%llu io=%lu"
                         " start=%lu end=%lu jiffies=%lu",
                         rw == READ ? 'R' : 'W', nr_slices, bytes_trim, io_trim,
                         tg->slice_start[rw], tg->slice_end[rw], jiffies);
 }
 
-static bool tg_with_in_iops_limit(struct throtl_data *td, struct throtl_grp *tg,
-                struct bio *bio, unsigned long *wait)
+static bool tg_with_in_iops_limit(struct throtl_grp *tg, struct bio *bio,
+                                  unsigned long *wait)
 {
         bool rw = bio_data_dir(bio);
         unsigned int io_allowed;
@@ -548,8 +549,8 @@ static bool tg_with_in_iops_limit(struct throtl_data *td, struct throtl_grp *tg,
         return 0;
 }
 
-static bool tg_with_in_bps_limit(struct throtl_data *td, struct throtl_grp *tg,
-                struct bio *bio, unsigned long *wait)
+static bool tg_with_in_bps_limit(struct throtl_grp *tg, struct bio *bio,
+                                 unsigned long *wait)
 {
         bool rw = bio_data_dir(bio);
         u64 bytes_allowed, extra_bytes, tmp;
@@ -600,8 +601,8 @@ static bool tg_no_rule_group(struct throtl_grp *tg, bool rw) {
  * Returns whether one can dispatch a bio or not. Also returns approx number
  * of jiffies to wait before this bio is with-in IO rate and can be dispatched
  */
-static bool tg_may_dispatch(struct throtl_data *td, struct throtl_grp *tg,
-                                struct bio *bio, unsigned long *wait)
+static bool tg_may_dispatch(struct throtl_grp *tg, struct bio *bio,
+                            unsigned long *wait)
 {
         bool rw = bio_data_dir(bio);
         unsigned long bps_wait = 0, iops_wait = 0, max_wait = 0;
@@ -626,15 +627,15 @@ static bool tg_may_dispatch(struct throtl_data *td, struct throtl_grp *tg,
          * existing slice to make sure it is at least throtl_slice interval
          * long since now.
          */
-        if (throtl_slice_used(td, tg, rw))
-                throtl_start_new_slice(td, tg, rw);
+        if (throtl_slice_used(tg, rw))
+                throtl_start_new_slice(tg, rw);
         else {
                 if (time_before(tg->slice_end[rw], jiffies + throtl_slice))
-                        throtl_extend_slice(td, tg, rw, jiffies + throtl_slice);
+                        throtl_extend_slice(tg, rw, jiffies + throtl_slice);
         }
 
-        if (tg_with_in_bps_limit(td, tg, bio, &bps_wait)
-            && tg_with_in_iops_limit(td, tg, bio, &iops_wait)) {
+        if (tg_with_in_bps_limit(tg, bio, &bps_wait) &&
+            tg_with_in_iops_limit(tg, bio, &iops_wait)) {
                 if (wait)
                         *wait = 0;
                 return 1;
@@ -646,7 +647,7 @@ static bool tg_may_dispatch(struct throtl_data *td, struct throtl_grp *tg,
                 *wait = max_wait;
 
         if (time_before(tg->slice_end[rw], jiffies + max_wait))
-                throtl_extend_slice(td, tg, rw, jiffies + max_wait);
+                throtl_extend_slice(tg, rw, jiffies + max_wait);
 
         return 0;
 }
@@ -707,10 +708,10 @@ static void tg_update_disptime(struct throtl_data *td, struct throtl_grp *tg)
         struct bio *bio;
 
         if ((bio = bio_list_peek(&tg->bio_lists[READ])))
-                tg_may_dispatch(td, tg, bio, &read_wait);
+                tg_may_dispatch(tg, bio, &read_wait);
 
         if ((bio = bio_list_peek(&tg->bio_lists[WRITE])))
-                tg_may_dispatch(td, tg, bio, &write_wait);
+                tg_may_dispatch(tg, bio, &write_wait);
 
         min_wait = min(read_wait, write_wait);
         disptime = jiffies + min_wait;
@@ -721,8 +722,8 @@ static void tg_update_disptime(struct throtl_data *td, struct throtl_grp *tg)
         throtl_enqueue_tg(td, tg);
 }
 
-static void tg_dispatch_one_bio(struct throtl_data *td, struct throtl_grp *tg,
-                                bool rw, struct bio_list *bl)
+static void tg_dispatch_one_bio(struct throtl_grp *tg, bool rw,
+                                struct bio_list *bl)
 {
         struct bio *bio;
 
@@ -731,18 +732,17 @@ static void tg_dispatch_one_bio(struct throtl_data *td, struct throtl_grp *tg,
         /* Drop bio reference on blkg */
         blkg_put(tg_to_blkg(tg));
 
-        BUG_ON(td->nr_queued[rw] <= 0);
-        td->nr_queued[rw]--;
+        BUG_ON(tg->td->nr_queued[rw] <= 0);
+        tg->td->nr_queued[rw]--;
 
         throtl_charge_bio(tg, bio);
         bio_list_add(bl, bio);
         bio->bi_rw |= REQ_THROTTLED;
 
-        throtl_trim_slice(td, tg, rw);
+        throtl_trim_slice(tg, rw);
 }
 
-static int throtl_dispatch_tg(struct throtl_data *td, struct throtl_grp *tg,
-                                struct bio_list *bl)
+static int throtl_dispatch_tg(struct throtl_grp *tg, struct bio_list *bl)
 {
         unsigned int nr_reads = 0, nr_writes = 0;
         unsigned int max_nr_reads = throtl_grp_quantum*3/4;
@@ -751,20 +751,20 @@ static int throtl_dispatch_tg(struct throtl_data *td, struct throtl_grp *tg,
 
         /* Try to dispatch 75% READS and 25% WRITES */
 
-        while ((bio = bio_list_peek(&tg->bio_lists[READ]))
-                && tg_may_dispatch(td, tg, bio, NULL)) {
+        while ((bio = bio_list_peek(&tg->bio_lists[READ])) &&
+               tg_may_dispatch(tg, bio, NULL)) {
 
-                tg_dispatch_one_bio(td, tg, bio_data_dir(bio), bl);
+                tg_dispatch_one_bio(tg, bio_data_dir(bio), bl);
                 nr_reads++;
 
                 if (nr_reads >= max_nr_reads)
                         break;
         }
 
-        while ((bio = bio_list_peek(&tg->bio_lists[WRITE]))
-                && tg_may_dispatch(td, tg, bio, NULL)) {
+        while ((bio = bio_list_peek(&tg->bio_lists[WRITE])) &&
+               tg_may_dispatch(tg, bio, NULL)) {
 
-                tg_dispatch_one_bio(td, tg, bio_data_dir(bio), bl);
+                tg_dispatch_one_bio(tg, bio_data_dir(bio), bl);
                 nr_writes++;
 
                 if (nr_writes >= max_nr_writes)
@@ -791,7 +791,7 @@ static int throtl_select_dispatch(struct throtl_data *td, struct bio_list *bl)
 
                 throtl_dequeue_tg(td, tg);
 
-                nr_disp += throtl_dispatch_tg(td, tg, bl);
+                nr_disp += throtl_dispatch_tg(tg, bl);
 
                 if (tg->nr_queued[0] || tg->nr_queued[1])
                         tg_update_disptime(td, tg);
@@ -933,7 +933,7 @@ static int tg_set_conf(struct cgroup *cgrp, struct cftype *cft, const char *buf,
         else
                 *(unsigned int *)((void *)tg + cft->private) = ctx.v;
 
-        throtl_log_tg(td, tg, "limit change rbps=%llu wbps=%llu riops=%u wiops=%u",
+        throtl_log_tg(tg, "limit change rbps=%llu wbps=%llu riops=%u wiops=%u",
                       tg->bps[READ], tg->bps[WRITE],
                       tg->iops[READ], tg->iops[WRITE]);
 
@@ -945,8 +945,8 @@ static int tg_set_conf(struct cgroup *cgrp, struct cftype *cft, const char *buf,
          * that a group's limit are dropped suddenly and we don't want to
          * account recently dispatched IO with new low rate.
          */
-        throtl_start_new_slice(td, tg, 0);
-        throtl_start_new_slice(td, tg, 1);
+        throtl_start_new_slice(tg, 0);
+        throtl_start_new_slice(tg, 1);
 
         if (tg->flags & THROTL_TG_PENDING) {
                 tg_update_disptime(td, tg);
@@ -1076,7 +1076,7 @@ bool blk_throtl_bio(struct request_queue *q, struct bio *bio)
         }
 
         /* Bio is with-in rate limit of group */
-        if (tg_may_dispatch(td, tg, bio, NULL)) {
+        if (tg_may_dispatch(tg, bio, NULL)) {
                 throtl_charge_bio(tg, bio);
 
                 /*
@@ -1090,12 +1090,12 @@ bool blk_throtl_bio(struct request_queue *q, struct bio *bio)
                  *
                  * So keep on trimming slice even if bio is not queued.
                  */
-                throtl_trim_slice(td, tg, rw);
+                throtl_trim_slice(tg, rw);
                 goto out_unlock;
         }
 
 queue_bio:
-        throtl_log_tg(td, tg, "[%c] bio. bdisp=%llu sz=%u bps=%llu"
+        throtl_log_tg(tg, "[%c] bio. bdisp=%llu sz=%u bps=%llu"
                         " iodisp=%u iops=%u queued=%d/%d",
                         rw == READ ? 'R' : 'W',
                         tg->bytes_disp[rw], bio->bi_size, tg->bps[rw],
@@ -1142,9 +1142,9 @@ void blk_throtl_drain(struct request_queue *q)
                 throtl_dequeue_tg(td, tg);
 
                 while ((bio = bio_list_peek(&tg->bio_lists[READ])))
-                        tg_dispatch_one_bio(td, tg, bio_data_dir(bio), &bl);
+                        tg_dispatch_one_bio(tg, bio_data_dir(bio), &bl);
                 while ((bio = bio_list_peek(&tg->bio_lists[WRITE])))
-                        tg_dispatch_one_bio(td, tg, bio_data_dir(bio), &bl);
+                        tg_dispatch_one_bio(tg, bio_data_dir(bio), &bl);
         }
         spin_unlock_irq(q->queue_lock);