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-rw-r--r--lib/sbitmap.c777
1 files changed, 777 insertions, 0 deletions
diff --git a/lib/sbitmap.c b/lib/sbitmap.c
new file mode 100644
index 000000000..c515072ec
--- /dev/null
+++ b/lib/sbitmap.c
@@ -0,0 +1,777 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2016 Facebook
+ * Copyright (C) 2013-2014 Jens Axboe
+ */
+
+#include <linux/sched.h>
+#include <linux/random.h>
+#include <linux/sbitmap.h>
+#include <linux/seq_file.h>
+
+static int init_alloc_hint(struct sbitmap *sb, gfp_t flags)
+{
+ unsigned depth = sb->depth;
+
+ sb->alloc_hint = alloc_percpu_gfp(unsigned int, flags);
+ if (!sb->alloc_hint)
+ return -ENOMEM;
+
+ if (depth && !sb->round_robin) {
+ int i;
+
+ for_each_possible_cpu(i)
+ *per_cpu_ptr(sb->alloc_hint, i) = prandom_u32_max(depth);
+ }
+ return 0;
+}
+
+static inline unsigned update_alloc_hint_before_get(struct sbitmap *sb,
+ unsigned int depth)
+{
+ unsigned hint;
+
+ hint = this_cpu_read(*sb->alloc_hint);
+ if (unlikely(hint >= depth)) {
+ hint = depth ? prandom_u32_max(depth) : 0;
+ this_cpu_write(*sb->alloc_hint, hint);
+ }
+
+ return hint;
+}
+
+static inline void update_alloc_hint_after_get(struct sbitmap *sb,
+ unsigned int depth,
+ unsigned int hint,
+ unsigned int nr)
+{
+ if (nr == -1) {
+ /* If the map is full, a hint won't do us much good. */
+ this_cpu_write(*sb->alloc_hint, 0);
+ } else if (nr == hint || unlikely(sb->round_robin)) {
+ /* Only update the hint if we used it. */
+ hint = nr + 1;
+ if (hint >= depth - 1)
+ hint = 0;
+ this_cpu_write(*sb->alloc_hint, hint);
+ }
+}
+
+/*
+ * See if we have deferred clears that we can batch move
+ */
+static inline bool sbitmap_deferred_clear(struct sbitmap_word *map)
+{
+ unsigned long mask;
+
+ if (!READ_ONCE(map->cleared))
+ return false;
+
+ /*
+ * First get a stable cleared mask, setting the old mask to 0.
+ */
+ mask = xchg(&map->cleared, 0);
+
+ /*
+ * Now clear the masked bits in our free word
+ */
+ atomic_long_andnot(mask, (atomic_long_t *)&map->word);
+ BUILD_BUG_ON(sizeof(atomic_long_t) != sizeof(map->word));
+ return true;
+}
+
+int sbitmap_init_node(struct sbitmap *sb, unsigned int depth, int shift,
+ gfp_t flags, int node, bool round_robin,
+ bool alloc_hint)
+{
+ unsigned int bits_per_word;
+
+ if (shift < 0)
+ shift = sbitmap_calculate_shift(depth);
+
+ bits_per_word = 1U << shift;
+ if (bits_per_word > BITS_PER_LONG)
+ return -EINVAL;
+
+ sb->shift = shift;
+ sb->depth = depth;
+ sb->map_nr = DIV_ROUND_UP(sb->depth, bits_per_word);
+ sb->round_robin = round_robin;
+
+ if (depth == 0) {
+ sb->map = NULL;
+ return 0;
+ }
+
+ if (alloc_hint) {
+ if (init_alloc_hint(sb, flags))
+ return -ENOMEM;
+ } else {
+ sb->alloc_hint = NULL;
+ }
+
+ sb->map = kvzalloc_node(sb->map_nr * sizeof(*sb->map), flags, node);
+ if (!sb->map) {
+ free_percpu(sb->alloc_hint);
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(sbitmap_init_node);
+
+void sbitmap_resize(struct sbitmap *sb, unsigned int depth)
+{
+ unsigned int bits_per_word = 1U << sb->shift;
+ unsigned int i;
+
+ for (i = 0; i < sb->map_nr; i++)
+ sbitmap_deferred_clear(&sb->map[i]);
+
+ sb->depth = depth;
+ sb->map_nr = DIV_ROUND_UP(sb->depth, bits_per_word);
+}
+EXPORT_SYMBOL_GPL(sbitmap_resize);
+
+static int __sbitmap_get_word(unsigned long *word, unsigned long depth,
+ unsigned int hint, bool wrap)
+{
+ int nr;
+
+ /* don't wrap if starting from 0 */
+ wrap = wrap && hint;
+
+ while (1) {
+ nr = find_next_zero_bit(word, depth, hint);
+ if (unlikely(nr >= depth)) {
+ /*
+ * We started with an offset, and we didn't reset the
+ * offset to 0 in a failure case, so start from 0 to
+ * exhaust the map.
+ */
+ if (hint && wrap) {
+ hint = 0;
+ continue;
+ }
+ return -1;
+ }
+
+ if (!test_and_set_bit_lock(nr, word))
+ break;
+
+ hint = nr + 1;
+ if (hint >= depth - 1)
+ hint = 0;
+ }
+
+ return nr;
+}
+
+static int sbitmap_find_bit_in_index(struct sbitmap *sb, int index,
+ unsigned int alloc_hint)
+{
+ struct sbitmap_word *map = &sb->map[index];
+ int nr;
+
+ do {
+ nr = __sbitmap_get_word(&map->word, __map_depth(sb, index),
+ alloc_hint, !sb->round_robin);
+ if (nr != -1)
+ break;
+ if (!sbitmap_deferred_clear(map))
+ break;
+ } while (1);
+
+ return nr;
+}
+
+static int __sbitmap_get(struct sbitmap *sb, unsigned int alloc_hint)
+{
+ unsigned int i, index;
+ int nr = -1;
+
+ index = SB_NR_TO_INDEX(sb, alloc_hint);
+
+ /*
+ * Unless we're doing round robin tag allocation, just use the
+ * alloc_hint to find the right word index. No point in looping
+ * twice in find_next_zero_bit() for that case.
+ */
+ if (sb->round_robin)
+ alloc_hint = SB_NR_TO_BIT(sb, alloc_hint);
+ else
+ alloc_hint = 0;
+
+ for (i = 0; i < sb->map_nr; i++) {
+ nr = sbitmap_find_bit_in_index(sb, index, alloc_hint);
+ if (nr != -1) {
+ nr += index << sb->shift;
+ break;
+ }
+
+ /* Jump to next index. */
+ alloc_hint = 0;
+ if (++index >= sb->map_nr)
+ index = 0;
+ }
+
+ return nr;
+}
+
+int sbitmap_get(struct sbitmap *sb)
+{
+ int nr;
+ unsigned int hint, depth;
+
+ if (WARN_ON_ONCE(unlikely(!sb->alloc_hint)))
+ return -1;
+
+ depth = READ_ONCE(sb->depth);
+ hint = update_alloc_hint_before_get(sb, depth);
+ nr = __sbitmap_get(sb, hint);
+ update_alloc_hint_after_get(sb, depth, hint, nr);
+
+ return nr;
+}
+EXPORT_SYMBOL_GPL(sbitmap_get);
+
+static int __sbitmap_get_shallow(struct sbitmap *sb,
+ unsigned int alloc_hint,
+ unsigned long shallow_depth)
+{
+ unsigned int i, index;
+ int nr = -1;
+
+ index = SB_NR_TO_INDEX(sb, alloc_hint);
+
+ for (i = 0; i < sb->map_nr; i++) {
+again:
+ nr = __sbitmap_get_word(&sb->map[index].word,
+ min_t(unsigned int,
+ __map_depth(sb, index),
+ shallow_depth),
+ SB_NR_TO_BIT(sb, alloc_hint), true);
+ if (nr != -1) {
+ nr += index << sb->shift;
+ break;
+ }
+
+ if (sbitmap_deferred_clear(&sb->map[index]))
+ goto again;
+
+ /* Jump to next index. */
+ index++;
+ alloc_hint = index << sb->shift;
+
+ if (index >= sb->map_nr) {
+ index = 0;
+ alloc_hint = 0;
+ }
+ }
+
+ return nr;
+}
+
+int sbitmap_get_shallow(struct sbitmap *sb, unsigned long shallow_depth)
+{
+ int nr;
+ unsigned int hint, depth;
+
+ if (WARN_ON_ONCE(unlikely(!sb->alloc_hint)))
+ return -1;
+
+ depth = READ_ONCE(sb->depth);
+ hint = update_alloc_hint_before_get(sb, depth);
+ nr = __sbitmap_get_shallow(sb, hint, shallow_depth);
+ update_alloc_hint_after_get(sb, depth, hint, nr);
+
+ return nr;
+}
+EXPORT_SYMBOL_GPL(sbitmap_get_shallow);
+
+bool sbitmap_any_bit_set(const struct sbitmap *sb)
+{
+ unsigned int i;
+
+ for (i = 0; i < sb->map_nr; i++) {
+ if (sb->map[i].word & ~sb->map[i].cleared)
+ return true;
+ }
+ return false;
+}
+EXPORT_SYMBOL_GPL(sbitmap_any_bit_set);
+
+static unsigned int __sbitmap_weight(const struct sbitmap *sb, bool set)
+{
+ unsigned int i, weight = 0;
+
+ for (i = 0; i < sb->map_nr; i++) {
+ const struct sbitmap_word *word = &sb->map[i];
+ unsigned int word_depth = __map_depth(sb, i);
+
+ if (set)
+ weight += bitmap_weight(&word->word, word_depth);
+ else
+ weight += bitmap_weight(&word->cleared, word_depth);
+ }
+ return weight;
+}
+
+static unsigned int sbitmap_cleared(const struct sbitmap *sb)
+{
+ return __sbitmap_weight(sb, false);
+}
+
+unsigned int sbitmap_weight(const struct sbitmap *sb)
+{
+ return __sbitmap_weight(sb, true) - sbitmap_cleared(sb);
+}
+EXPORT_SYMBOL_GPL(sbitmap_weight);
+
+void sbitmap_show(struct sbitmap *sb, struct seq_file *m)
+{
+ seq_printf(m, "depth=%u\n", sb->depth);
+ seq_printf(m, "busy=%u\n", sbitmap_weight(sb));
+ seq_printf(m, "cleared=%u\n", sbitmap_cleared(sb));
+ seq_printf(m, "bits_per_word=%u\n", 1U << sb->shift);
+ seq_printf(m, "map_nr=%u\n", sb->map_nr);
+}
+EXPORT_SYMBOL_GPL(sbitmap_show);
+
+static inline void emit_byte(struct seq_file *m, unsigned int offset, u8 byte)
+{
+ if ((offset & 0xf) == 0) {
+ if (offset != 0)
+ seq_putc(m, '\n');
+ seq_printf(m, "%08x:", offset);
+ }
+ if ((offset & 0x1) == 0)
+ seq_putc(m, ' ');
+ seq_printf(m, "%02x", byte);
+}
+
+void sbitmap_bitmap_show(struct sbitmap *sb, struct seq_file *m)
+{
+ u8 byte = 0;
+ unsigned int byte_bits = 0;
+ unsigned int offset = 0;
+ int i;
+
+ for (i = 0; i < sb->map_nr; i++) {
+ unsigned long word = READ_ONCE(sb->map[i].word);
+ unsigned long cleared = READ_ONCE(sb->map[i].cleared);
+ unsigned int word_bits = __map_depth(sb, i);
+
+ word &= ~cleared;
+
+ while (word_bits > 0) {
+ unsigned int bits = min(8 - byte_bits, word_bits);
+
+ byte |= (word & (BIT(bits) - 1)) << byte_bits;
+ byte_bits += bits;
+ if (byte_bits == 8) {
+ emit_byte(m, offset, byte);
+ byte = 0;
+ byte_bits = 0;
+ offset++;
+ }
+ word >>= bits;
+ word_bits -= bits;
+ }
+ }
+ if (byte_bits) {
+ emit_byte(m, offset, byte);
+ offset++;
+ }
+ if (offset)
+ seq_putc(m, '\n');
+}
+EXPORT_SYMBOL_GPL(sbitmap_bitmap_show);
+
+static unsigned int sbq_calc_wake_batch(struct sbitmap_queue *sbq,
+ unsigned int depth)
+{
+ unsigned int wake_batch;
+ unsigned int shallow_depth;
+
+ /*
+ * For each batch, we wake up one queue. We need to make sure that our
+ * batch size is small enough that the full depth of the bitmap,
+ * potentially limited by a shallow depth, is enough to wake up all of
+ * the queues.
+ *
+ * Each full word of the bitmap has bits_per_word bits, and there might
+ * be a partial word. There are depth / bits_per_word full words and
+ * depth % bits_per_word bits left over. In bitwise arithmetic:
+ *
+ * bits_per_word = 1 << shift
+ * depth / bits_per_word = depth >> shift
+ * depth % bits_per_word = depth & ((1 << shift) - 1)
+ *
+ * Each word can be limited to sbq->min_shallow_depth bits.
+ */
+ shallow_depth = min(1U << sbq->sb.shift, sbq->min_shallow_depth);
+ depth = ((depth >> sbq->sb.shift) * shallow_depth +
+ min(depth & ((1U << sbq->sb.shift) - 1), shallow_depth));
+ wake_batch = clamp_t(unsigned int, depth / SBQ_WAIT_QUEUES, 1,
+ SBQ_WAKE_BATCH);
+
+ return wake_batch;
+}
+
+int sbitmap_queue_init_node(struct sbitmap_queue *sbq, unsigned int depth,
+ int shift, bool round_robin, gfp_t flags, int node)
+{
+ int ret;
+ int i;
+
+ ret = sbitmap_init_node(&sbq->sb, depth, shift, flags, node,
+ round_robin, true);
+ if (ret)
+ return ret;
+
+ sbq->min_shallow_depth = UINT_MAX;
+ sbq->wake_batch = sbq_calc_wake_batch(sbq, depth);
+ atomic_set(&sbq->wake_index, 0);
+ atomic_set(&sbq->ws_active, 0);
+ atomic_set(&sbq->completion_cnt, 0);
+ atomic_set(&sbq->wakeup_cnt, 0);
+
+ sbq->ws = kzalloc_node(SBQ_WAIT_QUEUES * sizeof(*sbq->ws), flags, node);
+ if (!sbq->ws) {
+ sbitmap_free(&sbq->sb);
+ return -ENOMEM;
+ }
+
+ for (i = 0; i < SBQ_WAIT_QUEUES; i++)
+ init_waitqueue_head(&sbq->ws[i].wait);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(sbitmap_queue_init_node);
+
+static void sbitmap_queue_update_wake_batch(struct sbitmap_queue *sbq,
+ unsigned int depth)
+{
+ unsigned int wake_batch;
+
+ wake_batch = sbq_calc_wake_batch(sbq, depth);
+ if (sbq->wake_batch != wake_batch)
+ WRITE_ONCE(sbq->wake_batch, wake_batch);
+}
+
+void sbitmap_queue_recalculate_wake_batch(struct sbitmap_queue *sbq,
+ unsigned int users)
+{
+ unsigned int wake_batch;
+ unsigned int depth = (sbq->sb.depth + users - 1) / users;
+
+ wake_batch = clamp_val(depth / SBQ_WAIT_QUEUES,
+ 1, SBQ_WAKE_BATCH);
+
+ WRITE_ONCE(sbq->wake_batch, wake_batch);
+}
+EXPORT_SYMBOL_GPL(sbitmap_queue_recalculate_wake_batch);
+
+void sbitmap_queue_resize(struct sbitmap_queue *sbq, unsigned int depth)
+{
+ sbitmap_queue_update_wake_batch(sbq, depth);
+ sbitmap_resize(&sbq->sb, depth);
+}
+EXPORT_SYMBOL_GPL(sbitmap_queue_resize);
+
+int __sbitmap_queue_get(struct sbitmap_queue *sbq)
+{
+ return sbitmap_get(&sbq->sb);
+}
+EXPORT_SYMBOL_GPL(__sbitmap_queue_get);
+
+unsigned long __sbitmap_queue_get_batch(struct sbitmap_queue *sbq, int nr_tags,
+ unsigned int *offset)
+{
+ struct sbitmap *sb = &sbq->sb;
+ unsigned int hint, depth;
+ unsigned long index, nr;
+ int i;
+
+ if (unlikely(sb->round_robin))
+ return 0;
+
+ depth = READ_ONCE(sb->depth);
+ hint = update_alloc_hint_before_get(sb, depth);
+
+ index = SB_NR_TO_INDEX(sb, hint);
+
+ for (i = 0; i < sb->map_nr; i++) {
+ struct sbitmap_word *map = &sb->map[index];
+ unsigned long get_mask;
+ unsigned int map_depth = __map_depth(sb, index);
+
+ sbitmap_deferred_clear(map);
+ if (map->word == (1UL << (map_depth - 1)) - 1)
+ goto next;
+
+ nr = find_first_zero_bit(&map->word, map_depth);
+ if (nr + nr_tags <= map_depth) {
+ atomic_long_t *ptr = (atomic_long_t *) &map->word;
+ unsigned long val;
+
+ get_mask = ((1UL << nr_tags) - 1) << nr;
+ val = READ_ONCE(map->word);
+ while (!atomic_long_try_cmpxchg(ptr, &val,
+ get_mask | val))
+ ;
+ get_mask = (get_mask & ~val) >> nr;
+ if (get_mask) {
+ *offset = nr + (index << sb->shift);
+ update_alloc_hint_after_get(sb, depth, hint,
+ *offset + nr_tags - 1);
+ return get_mask;
+ }
+ }
+next:
+ /* Jump to next index. */
+ if (++index >= sb->map_nr)
+ index = 0;
+ }
+
+ return 0;
+}
+
+int sbitmap_queue_get_shallow(struct sbitmap_queue *sbq,
+ unsigned int shallow_depth)
+{
+ WARN_ON_ONCE(shallow_depth < sbq->min_shallow_depth);
+
+ return sbitmap_get_shallow(&sbq->sb, shallow_depth);
+}
+EXPORT_SYMBOL_GPL(sbitmap_queue_get_shallow);
+
+void sbitmap_queue_min_shallow_depth(struct sbitmap_queue *sbq,
+ unsigned int min_shallow_depth)
+{
+ sbq->min_shallow_depth = min_shallow_depth;
+ sbitmap_queue_update_wake_batch(sbq, sbq->sb.depth);
+}
+EXPORT_SYMBOL_GPL(sbitmap_queue_min_shallow_depth);
+
+static void __sbitmap_queue_wake_up(struct sbitmap_queue *sbq, int nr)
+{
+ int i, wake_index;
+
+ if (!atomic_read(&sbq->ws_active))
+ return;
+
+ wake_index = atomic_read(&sbq->wake_index);
+ for (i = 0; i < SBQ_WAIT_QUEUES; i++) {
+ struct sbq_wait_state *ws = &sbq->ws[wake_index];
+
+ /*
+ * Advance the index before checking the current queue.
+ * It improves fairness, by ensuring the queue doesn't
+ * need to be fully emptied before trying to wake up
+ * from the next one.
+ */
+ wake_index = sbq_index_inc(wake_index);
+
+ /*
+ * It is sufficient to wake up at least one waiter to
+ * guarantee forward progress.
+ */
+ if (waitqueue_active(&ws->wait) &&
+ wake_up_nr(&ws->wait, nr))
+ break;
+ }
+
+ if (wake_index != atomic_read(&sbq->wake_index))
+ atomic_set(&sbq->wake_index, wake_index);
+}
+
+void sbitmap_queue_wake_up(struct sbitmap_queue *sbq, int nr)
+{
+ unsigned int wake_batch = READ_ONCE(sbq->wake_batch);
+ unsigned int wakeups;
+
+ if (!atomic_read(&sbq->ws_active))
+ return;
+
+ atomic_add(nr, &sbq->completion_cnt);
+ wakeups = atomic_read(&sbq->wakeup_cnt);
+
+ do {
+ if (atomic_read(&sbq->completion_cnt) - wakeups < wake_batch)
+ return;
+ } while (!atomic_try_cmpxchg(&sbq->wakeup_cnt,
+ &wakeups, wakeups + wake_batch));
+
+ __sbitmap_queue_wake_up(sbq, wake_batch);
+}
+EXPORT_SYMBOL_GPL(sbitmap_queue_wake_up);
+
+static inline void sbitmap_update_cpu_hint(struct sbitmap *sb, int cpu, int tag)
+{
+ if (likely(!sb->round_robin && tag < sb->depth))
+ data_race(*per_cpu_ptr(sb->alloc_hint, cpu) = tag);
+}
+
+void sbitmap_queue_clear_batch(struct sbitmap_queue *sbq, int offset,
+ int *tags, int nr_tags)
+{
+ struct sbitmap *sb = &sbq->sb;
+ unsigned long *addr = NULL;
+ unsigned long mask = 0;
+ int i;
+
+ smp_mb__before_atomic();
+ for (i = 0; i < nr_tags; i++) {
+ const int tag = tags[i] - offset;
+ unsigned long *this_addr;
+
+ /* since we're clearing a batch, skip the deferred map */
+ this_addr = &sb->map[SB_NR_TO_INDEX(sb, tag)].word;
+ if (!addr) {
+ addr = this_addr;
+ } else if (addr != this_addr) {
+ atomic_long_andnot(mask, (atomic_long_t *) addr);
+ mask = 0;
+ addr = this_addr;
+ }
+ mask |= (1UL << SB_NR_TO_BIT(sb, tag));
+ }
+
+ if (mask)
+ atomic_long_andnot(mask, (atomic_long_t *) addr);
+
+ smp_mb__after_atomic();
+ sbitmap_queue_wake_up(sbq, nr_tags);
+ sbitmap_update_cpu_hint(&sbq->sb, raw_smp_processor_id(),
+ tags[nr_tags - 1] - offset);
+}
+
+void sbitmap_queue_clear(struct sbitmap_queue *sbq, unsigned int nr,
+ unsigned int cpu)
+{
+ /*
+ * Once the clear bit is set, the bit may be allocated out.
+ *
+ * Orders READ/WRITE on the associated instance(such as request
+ * of blk_mq) by this bit for avoiding race with re-allocation,
+ * and its pair is the memory barrier implied in __sbitmap_get_word.
+ *
+ * One invariant is that the clear bit has to be zero when the bit
+ * is in use.
+ */
+ smp_mb__before_atomic();
+ sbitmap_deferred_clear_bit(&sbq->sb, nr);
+
+ /*
+ * Pairs with the memory barrier in set_current_state() to ensure the
+ * proper ordering of clear_bit_unlock()/waitqueue_active() in the waker
+ * and test_and_set_bit_lock()/prepare_to_wait()/finish_wait() in the
+ * waiter. See the comment on waitqueue_active().
+ */
+ smp_mb__after_atomic();
+ sbitmap_queue_wake_up(sbq, 1);
+ sbitmap_update_cpu_hint(&sbq->sb, cpu, nr);
+}
+EXPORT_SYMBOL_GPL(sbitmap_queue_clear);
+
+void sbitmap_queue_wake_all(struct sbitmap_queue *sbq)
+{
+ int i, wake_index;
+
+ /*
+ * Pairs with the memory barrier in set_current_state() like in
+ * sbitmap_queue_wake_up().
+ */
+ smp_mb();
+ wake_index = atomic_read(&sbq->wake_index);
+ for (i = 0; i < SBQ_WAIT_QUEUES; i++) {
+ struct sbq_wait_state *ws = &sbq->ws[wake_index];
+
+ if (waitqueue_active(&ws->wait))
+ wake_up(&ws->wait);
+
+ wake_index = sbq_index_inc(wake_index);
+ }
+}
+EXPORT_SYMBOL_GPL(sbitmap_queue_wake_all);
+
+void sbitmap_queue_show(struct sbitmap_queue *sbq, struct seq_file *m)
+{
+ bool first;
+ int i;
+
+ sbitmap_show(&sbq->sb, m);
+
+ seq_puts(m, "alloc_hint={");
+ first = true;
+ for_each_possible_cpu(i) {
+ if (!first)
+ seq_puts(m, ", ");
+ first = false;
+ seq_printf(m, "%u", *per_cpu_ptr(sbq->sb.alloc_hint, i));
+ }
+ seq_puts(m, "}\n");
+
+ seq_printf(m, "wake_batch=%u\n", sbq->wake_batch);
+ seq_printf(m, "wake_index=%d\n", atomic_read(&sbq->wake_index));
+ seq_printf(m, "ws_active=%d\n", atomic_read(&sbq->ws_active));
+
+ seq_puts(m, "ws={\n");
+ for (i = 0; i < SBQ_WAIT_QUEUES; i++) {
+ struct sbq_wait_state *ws = &sbq->ws[i];
+ seq_printf(m, "\t{.wait=%s},\n",
+ waitqueue_active(&ws->wait) ? "active" : "inactive");
+ }
+ seq_puts(m, "}\n");
+
+ seq_printf(m, "round_robin=%d\n", sbq->sb.round_robin);
+ seq_printf(m, "min_shallow_depth=%u\n", sbq->min_shallow_depth);
+}
+EXPORT_SYMBOL_GPL(sbitmap_queue_show);
+
+void sbitmap_add_wait_queue(struct sbitmap_queue *sbq,
+ struct sbq_wait_state *ws,
+ struct sbq_wait *sbq_wait)
+{
+ if (!sbq_wait->sbq) {
+ sbq_wait->sbq = sbq;
+ atomic_inc(&sbq->ws_active);
+ add_wait_queue(&ws->wait, &sbq_wait->wait);
+ }
+}
+EXPORT_SYMBOL_GPL(sbitmap_add_wait_queue);
+
+void sbitmap_del_wait_queue(struct sbq_wait *sbq_wait)
+{
+ list_del_init(&sbq_wait->wait.entry);
+ if (sbq_wait->sbq) {
+ atomic_dec(&sbq_wait->sbq->ws_active);
+ sbq_wait->sbq = NULL;
+ }
+}
+EXPORT_SYMBOL_GPL(sbitmap_del_wait_queue);
+
+void sbitmap_prepare_to_wait(struct sbitmap_queue *sbq,
+ struct sbq_wait_state *ws,
+ struct sbq_wait *sbq_wait, int state)
+{
+ if (!sbq_wait->sbq) {
+ atomic_inc(&sbq->ws_active);
+ sbq_wait->sbq = sbq;
+ }
+ prepare_to_wait_exclusive(&ws->wait, &sbq_wait->wait, state);
+}
+EXPORT_SYMBOL_GPL(sbitmap_prepare_to_wait);
+
+void sbitmap_finish_wait(struct sbitmap_queue *sbq, struct sbq_wait_state *ws,
+ struct sbq_wait *sbq_wait)
+{
+ finish_wait(&ws->wait, &sbq_wait->wait);
+ if (sbq_wait->sbq) {
+ atomic_dec(&sbq->ws_active);
+ sbq_wait->sbq = NULL;
+ }
+}
+EXPORT_SYMBOL_GPL(sbitmap_finish_wait);
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-23 23:16:45 +0000