writeback: s/bdi/wb/ in mm/page-writeback.c
authorTejun Heo <tj@kernel.org>
Fri, 22 May 2015 21:13:29 +0000 (17:13 -0400)
committerJens Axboe <axboe@fb.com>
Tue, 2 Jun 2015 14:33:34 +0000 (08:33 -0600)
Writeback operations will now be per wb (bdi_writeback) instead of
bdi.  Replace the relevant bdi references in symbol names and comments
with wb.  This patch is purely cosmetic and doesn't make any
functional changes.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Jens Axboe <axboe@fb.com>
mm/page-writeback.c

index cd39ee91b7bb569c618055443059be23c00d7e85..78ef5511a1987fb8b74175142056b7b86268cd18 100644 (file)
@@ -595,7 +595,7 @@ static long long pos_ratio_polynom(unsigned long setpoint,
  *
  * (o) global/bdi setpoints
  *
- * We want the dirty pages be balanced around the global/bdi setpoints.
+ * We want the dirty pages be balanced around the global/wb setpoints.
  * When the number of dirty pages is higher/lower than the setpoint, the
  * dirty position control ratio (and hence task dirty ratelimit) will be
  * decreased/increased to bring the dirty pages back to the setpoint.
@@ -605,8 +605,8 @@ static long long pos_ratio_polynom(unsigned long setpoint,
  *     if (dirty < setpoint) scale up   pos_ratio
  *     if (dirty > setpoint) scale down pos_ratio
  *
- *     if (bdi_dirty < bdi_setpoint) scale up   pos_ratio
- *     if (bdi_dirty > bdi_setpoint) scale down pos_ratio
+ *     if (wb_dirty < wb_setpoint) scale up   pos_ratio
+ *     if (wb_dirty > wb_setpoint) scale down pos_ratio
  *
  *     task_ratelimit = dirty_ratelimit * pos_ratio >> RATELIMIT_CALC_SHIFT
  *
@@ -631,7 +631,7 @@ static long long pos_ratio_polynom(unsigned long setpoint,
  *   0 +------------.------------------.----------------------*------------->
  *           freerun^          setpoint^                 limit^   dirty pages
  *
- * (o) bdi control line
+ * (o) wb control line
  *
  *     ^ pos_ratio
  *     |
@@ -657,27 +657,27 @@ static long long pos_ratio_polynom(unsigned long setpoint,
  *     |                      .                           .
  *     |                      .                             .
  *   0 +----------------------.-------------------------------.------------->
- *                bdi_setpoint^                    x_intercept^
+ *                wb_setpoint^                    x_intercept^
  *
- * The bdi control line won't drop below pos_ratio=1/4, so that bdi_dirty can
+ * The wb control line won't drop below pos_ratio=1/4, so that wb_dirty can
  * be smoothly throttled down to normal if it starts high in situations like
  * - start writing to a slow SD card and a fast disk at the same time. The SD
- *   card's bdi_dirty may rush to many times higher than bdi_setpoint.
- * - the bdi dirty thresh drops quickly due to change of JBOD workload
+ *   card's wb_dirty may rush to many times higher than wb_setpoint.
+ * - the wb dirty thresh drops quickly due to change of JBOD workload
  */
 static unsigned long wb_position_ratio(struct bdi_writeback *wb,
                                       unsigned long thresh,
                                       unsigned long bg_thresh,
                                       unsigned long dirty,
-                                      unsigned long bdi_thresh,
-                                      unsigned long bdi_dirty)
+                                      unsigned long wb_thresh,
+                                      unsigned long wb_dirty)
 {
        unsigned long write_bw = wb->avg_write_bandwidth;
        unsigned long freerun = dirty_freerun_ceiling(thresh, bg_thresh);
        unsigned long limit = hard_dirty_limit(thresh);
        unsigned long x_intercept;
        unsigned long setpoint;         /* dirty pages' target balance point */
-       unsigned long bdi_setpoint;
+       unsigned long wb_setpoint;
        unsigned long span;
        long long pos_ratio;            /* for scaling up/down the rate limit */
        long x;
@@ -696,146 +696,145 @@ static unsigned long wb_position_ratio(struct bdi_writeback *wb,
        /*
         * The strictlimit feature is a tool preventing mistrusted filesystems
         * from growing a large number of dirty pages before throttling. For
-        * such filesystems balance_dirty_pages always checks bdi counters
-        * against bdi limits. Even if global "nr_dirty" is under "freerun".
+        * such filesystems balance_dirty_pages always checks wb counters
+        * against wb limits. Even if global "nr_dirty" is under "freerun".
         * This is especially important for fuse which sets bdi->max_ratio to
         * 1% by default. Without strictlimit feature, fuse writeback may
         * consume arbitrary amount of RAM because it is accounted in
         * NR_WRITEBACK_TEMP which is not involved in calculating "nr_dirty".
         *
         * Here, in wb_position_ratio(), we calculate pos_ratio based on
-        * two values: bdi_dirty and bdi_thresh. Let's consider an example:
+        * two values: wb_dirty and wb_thresh. Let's consider an example:
         * total amount of RAM is 16GB, bdi->max_ratio is equal to 1%, global
         * limits are set by default to 10% and 20% (background and throttle).
-        * Then bdi_thresh is 1% of 20% of 16GB. This amounts to ~8K pages.
-        * wb_dirty_limit(wb, bg_thresh) is about ~4K pages. bdi_setpoint is
-        * about ~6K pages (as the average of background and throttle bdi
+        * Then wb_thresh is 1% of 20% of 16GB. This amounts to ~8K pages.
+        * wb_dirty_limit(wb, bg_thresh) is about ~4K pages. wb_setpoint is
+        * about ~6K pages (as the average of background and throttle wb
         * limits). The 3rd order polynomial will provide positive feedback if
-        * bdi_dirty is under bdi_setpoint and vice versa.
+        * wb_dirty is under wb_setpoint and vice versa.
         *
         * Note, that we cannot use global counters in these calculations
-        * because we want to throttle process writing to a strictlimit BDI
+        * because we want to throttle process writing to a strictlimit wb
         * much earlier than global "freerun" is reached (~23MB vs. ~2.3GB
         * in the example above).
         */
        if (unlikely(wb->bdi->capabilities & BDI_CAP_STRICTLIMIT)) {
-               long long bdi_pos_ratio;
-               unsigned long bdi_bg_thresh;
+               long long wb_pos_ratio;
+               unsigned long wb_bg_thresh;
 
-               if (bdi_dirty < 8)
+               if (wb_dirty < 8)
                        return min_t(long long, pos_ratio * 2,
                                     2 << RATELIMIT_CALC_SHIFT);
 
-               if (bdi_dirty >= bdi_thresh)
+               if (wb_dirty >= wb_thresh)
                        return 0;
 
-               bdi_bg_thresh = div_u64((u64)bdi_thresh * bg_thresh, thresh);
-               bdi_setpoint = dirty_freerun_ceiling(bdi_thresh,
-                                                    bdi_bg_thresh);
+               wb_bg_thresh = div_u64((u64)wb_thresh * bg_thresh, thresh);
+               wb_setpoint = dirty_freerun_ceiling(wb_thresh, wb_bg_thresh);
 
-               if (bdi_setpoint == 0 || bdi_setpoint == bdi_thresh)
+               if (wb_setpoint == 0 || wb_setpoint == wb_thresh)
                        return 0;
 
-               bdi_pos_ratio = pos_ratio_polynom(bdi_setpoint, bdi_dirty,
-                                                 bdi_thresh);
+               wb_pos_ratio = pos_ratio_polynom(wb_setpoint, wb_dirty,
+                                                wb_thresh);
 
                /*
-                * Typically, for strictlimit case, bdi_setpoint << setpoint
-                * and pos_ratio >> bdi_pos_ratio. In the other words global
+                * Typically, for strictlimit case, wb_setpoint << setpoint
+                * and pos_ratio >> wb_pos_ratio. In the other words global
                 * state ("dirty") is not limiting factor and we have to
-                * make decision based on bdi counters. But there is an
+                * make decision based on wb counters. But there is an
                 * important case when global pos_ratio should get precedence:
                 * global limits are exceeded (e.g. due to activities on other
-                * BDIs) while given strictlimit BDI is below limit.
+                * wb's) while given strictlimit wb is below limit.
                 *
-                * "pos_ratio * bdi_pos_ratio" would work for the case above,
+                * "pos_ratio * wb_pos_ratio" would work for the case above,
                 * but it would look too non-natural for the case of all
-                * activity in the system coming from a single strictlimit BDI
+                * activity in the system coming from a single strictlimit wb
                 * with bdi->max_ratio == 100%.
                 *
                 * Note that min() below somewhat changes the dynamics of the
                 * control system. Normally, pos_ratio value can be well over 3
-                * (when globally we are at freerun and bdi is well below bdi
+                * (when globally we are at freerun and wb is well below wb
                 * setpoint). Now the maximum pos_ratio in the same situation
                 * is 2. We might want to tweak this if we observe the control
                 * system is too slow to adapt.
                 */
-               return min(pos_ratio, bdi_pos_ratio);
+               return min(pos_ratio, wb_pos_ratio);
        }
 
        /*
         * We have computed basic pos_ratio above based on global situation. If
-        * the bdi is over/under its share of dirty pages, we want to scale
+        * the wb is over/under its share of dirty pages, we want to scale
         * pos_ratio further down/up. That is done by the following mechanism.
         */
 
        /*
-        * bdi setpoint
+        * wb setpoint
         *
-        *        f(bdi_dirty) := 1.0 + k * (bdi_dirty - bdi_setpoint)
+        *        f(wb_dirty) := 1.0 + k * (wb_dirty - wb_setpoint)
         *
-        *                        x_intercept - bdi_dirty
+        *                        x_intercept - wb_dirty
         *                     := --------------------------
-        *                        x_intercept - bdi_setpoint
+        *                        x_intercept - wb_setpoint
         *
-        * The main bdi control line is a linear function that subjects to
+        * The main wb control line is a linear function that subjects to
         *
-        * (1) f(bdi_setpoint) = 1.0
-        * (2) k = - 1 / (8 * write_bw)  (in single bdi case)
-        *     or equally: x_intercept = bdi_setpoint + 8 * write_bw
+        * (1) f(wb_setpoint) = 1.0
+        * (2) k = - 1 / (8 * write_bw)  (in single wb case)
+        *     or equally: x_intercept = wb_setpoint + 8 * write_bw
         *
-        * For single bdi case, the dirty pages are observed to fluctuate
+        * For single wb case, the dirty pages are observed to fluctuate
         * regularly within range
-        *        [bdi_setpoint - write_bw/2, bdi_setpoint + write_bw/2]
+        *        [wb_setpoint - write_bw/2, wb_setpoint + write_bw/2]
         * for various filesystems, where (2) can yield in a reasonable 12.5%
         * fluctuation range for pos_ratio.
         *
-        * For JBOD case, bdi_thresh (not bdi_dirty!) could fluctuate up to its
+        * For JBOD case, wb_thresh (not wb_dirty!) could fluctuate up to its
         * own size, so move the slope over accordingly and choose a slope that
-        * yields 100% pos_ratio fluctuation on suddenly doubled bdi_thresh.
+        * yields 100% pos_ratio fluctuation on suddenly doubled wb_thresh.
         */
-       if (unlikely(bdi_thresh > thresh))
-               bdi_thresh = thresh;
+       if (unlikely(wb_thresh > thresh))
+               wb_thresh = thresh;
        /*
-        * It's very possible that bdi_thresh is close to 0 not because the
+        * It's very possible that wb_thresh is close to 0 not because the
         * device is slow, but that it has remained inactive for long time.
         * Honour such devices a reasonable good (hopefully IO efficient)
         * threshold, so that the occasional writes won't be blocked and active
         * writes can rampup the threshold quickly.
         */
-       bdi_thresh = max(bdi_thresh, (limit - dirty) / 8);
+       wb_thresh = max(wb_thresh, (limit - dirty) / 8);
        /*
-        * scale global setpoint to bdi's:
-        *      bdi_setpoint = setpoint * bdi_thresh / thresh
+        * scale global setpoint to wb's:
+        *      wb_setpoint = setpoint * wb_thresh / thresh
         */
-       x = div_u64((u64)bdi_thresh << 16, thresh + 1);
-       bdi_setpoint = setpoint * (u64)x >> 16;
+       x = div_u64((u64)wb_thresh << 16, thresh + 1);
+       wb_setpoint = setpoint * (u64)x >> 16;
        /*
-        * Use span=(8*write_bw) in single bdi case as indicated by
-        * (thresh - bdi_thresh ~= 0) and transit to bdi_thresh in JBOD case.
+        * Use span=(8*write_bw) in single wb case as indicated by
+        * (thresh - wb_thresh ~= 0) and transit to wb_thresh in JBOD case.
         *
-        *        bdi_thresh                    thresh - bdi_thresh
-        * span = ---------- * (8 * write_bw) + ------------------- * bdi_thresh
-        *          thresh                            thresh
+        *        wb_thresh                    thresh - wb_thresh
+        * span = --------- * (8 * write_bw) + ------------------ * wb_thresh
+        *         thresh                           thresh
         */
-       span = (thresh - bdi_thresh + 8 * write_bw) * (u64)x >> 16;
-       x_intercept = bdi_setpoint + span;
+       span = (thresh - wb_thresh + 8 * write_bw) * (u64)x >> 16;
+       x_intercept = wb_setpoint + span;
 
-       if (bdi_dirty < x_intercept - span / 4) {
-               pos_ratio = div64_u64(pos_ratio * (x_intercept - bdi_dirty),
-                                   x_intercept - bdi_setpoint + 1);
+       if (wb_dirty < x_intercept - span / 4) {
+               pos_ratio = div64_u64(pos_ratio * (x_intercept - wb_dirty),
+                                   x_intercept - wb_setpoint + 1);
        } else
                pos_ratio /= 4;
 
        /*
-        * bdi reserve area, safeguard against dirty pool underrun and disk idle
+        * wb reserve area, safeguard against dirty pool underrun and disk idle
         * It may push the desired control point of global dirty pages higher
         * than setpoint.
         */
-       x_intercept = bdi_thresh / 2;
-       if (bdi_dirty < x_intercept) {
-               if (bdi_dirty > x_intercept / 8)
-                       pos_ratio = div_u64(pos_ratio * x_intercept, bdi_dirty);
+       x_intercept = wb_thresh / 2;
+       if (wb_dirty < x_intercept) {
+               if (wb_dirty > x_intercept / 8)
+                       pos_ratio = div_u64(pos_ratio * x_intercept, wb_dirty);
                else
                        pos_ratio *= 8;
        }
@@ -943,17 +942,17 @@ static void global_update_bandwidth(unsigned long thresh,
 }
 
 /*
- * Maintain bdi->dirty_ratelimit, the base dirty throttle rate.
+ * Maintain wb->dirty_ratelimit, the base dirty throttle rate.
  *
- * Normal bdi tasks will be curbed at or below it in long term.
+ * Normal wb tasks will be curbed at or below it in long term.
  * Obviously it should be around (write_bw / N) when there are N dd tasks.
  */
 static void wb_update_dirty_ratelimit(struct bdi_writeback *wb,
                                      unsigned long thresh,
                                      unsigned long bg_thresh,
                                      unsigned long dirty,
-                                     unsigned long bdi_thresh,
-                                     unsigned long bdi_dirty,
+                                     unsigned long wb_thresh,
+                                     unsigned long wb_dirty,
                                      unsigned long dirtied,
                                      unsigned long elapsed)
 {
@@ -976,7 +975,7 @@ static void wb_update_dirty_ratelimit(struct bdi_writeback *wb,
        dirty_rate = (dirtied - wb->dirtied_stamp) * HZ / elapsed;
 
        pos_ratio = wb_position_ratio(wb, thresh, bg_thresh, dirty,
-                                     bdi_thresh, bdi_dirty);
+                                     wb_thresh, wb_dirty);
        /*
         * task_ratelimit reflects each dd's dirty rate for the past 200ms.
         */
@@ -986,7 +985,7 @@ static void wb_update_dirty_ratelimit(struct bdi_writeback *wb,
 
        /*
         * A linear estimation of the "balanced" throttle rate. The theory is,
-        * if there are N dd tasks, each throttled at task_ratelimit, the bdi's
+        * if there are N dd tasks, each throttled at task_ratelimit, the wb's
         * dirty_rate will be measured to be (N * task_ratelimit). So the below
         * formula will yield the balanced rate limit (write_bw / N).
         *
@@ -1025,7 +1024,7 @@ static void wb_update_dirty_ratelimit(struct bdi_writeback *wb,
        /*
         * We could safely do this and return immediately:
         *
-        *      bdi->dirty_ratelimit = balanced_dirty_ratelimit;
+        *      wb->dirty_ratelimit = balanced_dirty_ratelimit;
         *
         * However to get a more stable dirty_ratelimit, the below elaborated
         * code makes use of task_ratelimit to filter out singular points and
@@ -1059,22 +1058,22 @@ static void wb_update_dirty_ratelimit(struct bdi_writeback *wb,
        step = 0;
 
        /*
-        * For strictlimit case, calculations above were based on bdi counters
+        * For strictlimit case, calculations above were based on wb counters
         * and limits (starting from pos_ratio = wb_position_ratio() and up to
         * balanced_dirty_ratelimit = task_ratelimit * write_bw / dirty_rate).
-        * Hence, to calculate "step" properly, we have to use bdi_dirty as
-        * "dirty" and bdi_setpoint as "setpoint".
+        * Hence, to calculate "step" properly, we have to use wb_dirty as
+        * "dirty" and wb_setpoint as "setpoint".
         *
-        * We rampup dirty_ratelimit forcibly if bdi_dirty is low because
-        * it's possible that bdi_thresh is close to zero due to inactivity
+        * We rampup dirty_ratelimit forcibly if wb_dirty is low because
+        * it's possible that wb_thresh is close to zero due to inactivity
         * of backing device (see the implementation of wb_dirty_limit()).
         */
        if (unlikely(wb->bdi->capabilities & BDI_CAP_STRICTLIMIT)) {
-               dirty = bdi_dirty;
-               if (bdi_dirty < 8)
-                       setpoint = bdi_dirty + 1;
+               dirty = wb_dirty;
+               if (wb_dirty < 8)
+                       setpoint = wb_dirty + 1;
                else
-                       setpoint = (bdi_thresh +
+                       setpoint = (wb_thresh +
                                    wb_dirty_limit(wb, bg_thresh)) / 2;
        }
 
@@ -1116,8 +1115,8 @@ void __wb_update_bandwidth(struct bdi_writeback *wb,
                           unsigned long thresh,
                           unsigned long bg_thresh,
                           unsigned long dirty,
-                          unsigned long bdi_thresh,
-                          unsigned long bdi_dirty,
+                          unsigned long wb_thresh,
+                          unsigned long wb_dirty,
                           unsigned long start_time)
 {
        unsigned long now = jiffies;
@@ -1144,7 +1143,7 @@ void __wb_update_bandwidth(struct bdi_writeback *wb,
        if (thresh) {
                global_update_bandwidth(thresh, dirty, now);
                wb_update_dirty_ratelimit(wb, thresh, bg_thresh, dirty,
-                                         bdi_thresh, bdi_dirty,
+                                         wb_thresh, wb_dirty,
                                          dirtied, elapsed);
        }
        wb_update_write_bandwidth(wb, elapsed, written);
@@ -1159,15 +1158,15 @@ static void wb_update_bandwidth(struct bdi_writeback *wb,
                                unsigned long thresh,
                                unsigned long bg_thresh,
                                unsigned long dirty,
-                               unsigned long bdi_thresh,
-                               unsigned long bdi_dirty,
+                               unsigned long wb_thresh,
+                               unsigned long wb_dirty,
                                unsigned long start_time)
 {
        if (time_is_after_eq_jiffies(wb->bw_time_stamp + BANDWIDTH_INTERVAL))
                return;
        spin_lock(&wb->list_lock);
        __wb_update_bandwidth(wb, thresh, bg_thresh, dirty,
-                             bdi_thresh, bdi_dirty, start_time);
+                             wb_thresh, wb_dirty, start_time);
        spin_unlock(&wb->list_lock);
 }
 
@@ -1189,7 +1188,7 @@ static unsigned long dirty_poll_interval(unsigned long dirty,
 }
 
 static unsigned long wb_max_pause(struct bdi_writeback *wb,
-                                     unsigned long bdi_dirty)
+                                 unsigned long wb_dirty)
 {
        unsigned long bw = wb->avg_write_bandwidth;
        unsigned long t;
@@ -1201,7 +1200,7 @@ static unsigned long wb_max_pause(struct bdi_writeback *wb,
         *
         * 8 serves as the safety ratio.
         */
-       t = bdi_dirty / (1 + bw / roundup_pow_of_two(1 + HZ / 8));
+       t = wb_dirty / (1 + bw / roundup_pow_of_two(1 + HZ / 8));
        t++;
 
        return min_t(unsigned long, t, MAX_PAUSE);
@@ -1285,31 +1284,31 @@ static long wb_min_pause(struct bdi_writeback *wb,
 static inline void wb_dirty_limits(struct bdi_writeback *wb,
                                   unsigned long dirty_thresh,
                                   unsigned long background_thresh,
-                                  unsigned long *bdi_dirty,
-                                  unsigned long *bdi_thresh,
-                                  unsigned long *bdi_bg_thresh)
+                                  unsigned long *wb_dirty,
+                                  unsigned long *wb_thresh,
+                                  unsigned long *wb_bg_thresh)
 {
        unsigned long wb_reclaimable;
 
        /*
-        * bdi_thresh is not treated as some limiting factor as
+        * wb_thresh is not treated as some limiting factor as
         * dirty_thresh, due to reasons
-        * - in JBOD setup, bdi_thresh can fluctuate a lot
+        * - in JBOD setup, wb_thresh can fluctuate a lot
         * - in a system with HDD and USB key, the USB key may somehow
-        *   go into state (bdi_dirty >> bdi_thresh) either because
-        *   bdi_dirty starts high, or because bdi_thresh drops low.
+        *   go into state (wb_dirty >> wb_thresh) either because
+        *   wb_dirty starts high, or because wb_thresh drops low.
         *   In this case we don't want to hard throttle the USB key
-        *   dirtiers for 100 seconds until bdi_dirty drops under
-        *   bdi_thresh. Instead the auxiliary bdi control line in
+        *   dirtiers for 100 seconds until wb_dirty drops under
+        *   wb_thresh. Instead the auxiliary wb control line in
         *   wb_position_ratio() will let the dirtier task progress
-        *   at some rate <= (write_bw / 2) for bringing down bdi_dirty.
+        *   at some rate <= (write_bw / 2) for bringing down wb_dirty.
         */
-       *bdi_thresh = wb_dirty_limit(wb, dirty_thresh);
+       *wb_thresh = wb_dirty_limit(wb, dirty_thresh);
 
-       if (bdi_bg_thresh)
-               *bdi_bg_thresh = dirty_thresh ? div_u64((u64)*bdi_thresh *
-                                                       background_thresh,
-                                                       dirty_thresh) : 0;
+       if (wb_bg_thresh)
+               *wb_bg_thresh = dirty_thresh ? div_u64((u64)*wb_thresh *
+                                                      background_thresh,
+                                                      dirty_thresh) : 0;
 
        /*
         * In order to avoid the stacked BDI deadlock we need
@@ -1321,12 +1320,12 @@ static inline void wb_dirty_limits(struct bdi_writeback *wb,
         * actually dirty; with m+n sitting in the percpu
         * deltas.
         */
-       if (*bdi_thresh < 2 * wb_stat_error(wb)) {
+       if (*wb_thresh < 2 * wb_stat_error(wb)) {
                wb_reclaimable = wb_stat_sum(wb, WB_RECLAIMABLE);
-               *bdi_dirty = wb_reclaimable + wb_stat_sum(wb, WB_WRITEBACK);
+               *wb_dirty = wb_reclaimable + wb_stat_sum(wb, WB_WRITEBACK);
        } else {
                wb_reclaimable = wb_stat(wb, WB_RECLAIMABLE);
-               *bdi_dirty = wb_reclaimable + wb_stat(wb, WB_WRITEBACK);
+               *wb_dirty = wb_reclaimable + wb_stat(wb, WB_WRITEBACK);
        }
 }
 
@@ -1360,9 +1359,9 @@ static void balance_dirty_pages(struct address_space *mapping,
 
        for (;;) {
                unsigned long now = jiffies;
-               unsigned long uninitialized_var(bdi_thresh);
+               unsigned long uninitialized_var(wb_thresh);
                unsigned long thresh;
-               unsigned long uninitialized_var(bdi_dirty);
+               unsigned long uninitialized_var(wb_dirty);
                unsigned long dirty;
                unsigned long bg_thresh;
 
@@ -1380,10 +1379,10 @@ static void balance_dirty_pages(struct address_space *mapping,
 
                if (unlikely(strictlimit)) {
                        wb_dirty_limits(wb, dirty_thresh, background_thresh,
-                                       &bdi_dirty, &bdi_thresh, &bg_thresh);
+                                       &wb_dirty, &wb_thresh, &bg_thresh);
 
-                       dirty = bdi_dirty;
-                       thresh = bdi_thresh;
+                       dirty = wb_dirty;
+                       thresh = wb_thresh;
                } else {
                        dirty = nr_dirty;
                        thresh = dirty_thresh;
@@ -1393,10 +1392,10 @@ static void balance_dirty_pages(struct address_space *mapping,
                /*
                 * Throttle it only when the background writeback cannot
                 * catch-up. This avoids (excessively) small writeouts
-                * when the bdi limits are ramping up in case of !strictlimit.
+                * when the wb limits are ramping up in case of !strictlimit.
                 *
-                * In strictlimit case make decision based on the bdi counters
-                * and limits. Small writeouts when the bdi limits are ramping
+                * In strictlimit case make decision based on the wb counters
+                * and limits. Small writeouts when the wb limits are ramping
                 * up are the price we consciously pay for strictlimit-ing.
                 */
                if (dirty <= dirty_freerun_ceiling(thresh, bg_thresh)) {
@@ -1412,24 +1411,23 @@ static void balance_dirty_pages(struct address_space *mapping,
 
                if (!strictlimit)
                        wb_dirty_limits(wb, dirty_thresh, background_thresh,
-                                       &bdi_dirty, &bdi_thresh, NULL);
+                                       &wb_dirty, &wb_thresh, NULL);
 
-               dirty_exceeded = (bdi_dirty > bdi_thresh) &&
+               dirty_exceeded = (wb_dirty > wb_thresh) &&
                                 ((nr_dirty > dirty_thresh) || strictlimit);
                if (dirty_exceeded && !wb->dirty_exceeded)
                        wb->dirty_exceeded = 1;
 
                wb_update_bandwidth(wb, dirty_thresh, background_thresh,
-                                   nr_dirty, bdi_thresh, bdi_dirty,
-                                   start_time);
+                                   nr_dirty, wb_thresh, wb_dirty, start_time);
 
                dirty_ratelimit = wb->dirty_ratelimit;
                pos_ratio = wb_position_ratio(wb, dirty_thresh,
                                              background_thresh, nr_dirty,
-                                             bdi_thresh, bdi_dirty);
+                                             wb_thresh, wb_dirty);
                task_ratelimit = ((u64)dirty_ratelimit * pos_ratio) >>
                                                        RATELIMIT_CALC_SHIFT;
-               max_pause = wb_max_pause(wb, bdi_dirty);
+               max_pause = wb_max_pause(wb, wb_dirty);
                min_pause = wb_min_pause(wb, max_pause,
                                         task_ratelimit, dirty_ratelimit,
                                         &nr_dirtied_pause);
@@ -1455,8 +1453,8 @@ static void balance_dirty_pages(struct address_space *mapping,
                                                  dirty_thresh,
                                                  background_thresh,
                                                  nr_dirty,
-                                                 bdi_thresh,
-                                                 bdi_dirty,
+                                                 wb_thresh,
+                                                 wb_dirty,
                                                  dirty_ratelimit,
                                                  task_ratelimit,
                                                  pages_dirtied,
@@ -1484,8 +1482,8 @@ pause:
                                          dirty_thresh,
                                          background_thresh,
                                          nr_dirty,
-                                         bdi_thresh,
-                                         bdi_dirty,
+                                         wb_thresh,
+                                         wb_dirty,
                                          dirty_ratelimit,
                                          task_ratelimit,
                                          pages_dirtied,
@@ -1508,15 +1506,15 @@ pause:
 
                /*
                 * In the case of an unresponding NFS server and the NFS dirty
-                * pages exceeds dirty_thresh, give the other good bdi's a pipe
+                * pages exceeds dirty_thresh, give the other good wb's a pipe
                 * to go through, so that tasks on them still remain responsive.
                 *
                 * In theory 1 page is enough to keep the comsumer-producer
                 * pipe going: the flusher cleans 1 page => the task dirties 1
-                * more page. However bdi_dirty has accounting errors.  So use
+                * more page. However wb_dirty has accounting errors.  So use
                 * the larger and more IO friendly wb_stat_error.
                 */
-               if (bdi_dirty <= wb_stat_error(wb))
+               if (wb_dirty <= wb_stat_error(wb))
                        break;
 
                if (fatal_signal_pending(current))