v4.19.13 snapshot.
diff --git a/drivers/md/bcache/util.c b/drivers/md/bcache/util.c
new file mode 100644
index 0000000..20eddea
--- /dev/null
+++ b/drivers/md/bcache/util.c
@@ -0,0 +1,283 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * random utiility code, for bcache but in theory not specific to bcache
+ *
+ * Copyright 2010, 2011 Kent Overstreet <kent.overstreet@gmail.com>
+ * Copyright 2012 Google, Inc.
+ */
+
+#include <linux/bio.h>
+#include <linux/blkdev.h>
+#include <linux/ctype.h>
+#include <linux/debugfs.h>
+#include <linux/module.h>
+#include <linux/seq_file.h>
+#include <linux/types.h>
+#include <linux/sched/clock.h>
+
+#include "util.h"
+
+#define simple_strtoint(c, end, base) simple_strtol(c, end, base)
+#define simple_strtouint(c, end, base) simple_strtoul(c, end, base)
+
+#define STRTO_H(name, type) \
+int bch_ ## name ## _h(const char *cp, type *res) \
+{ \
+ int u = 0; \
+ char *e; \
+ type i = simple_ ## name(cp, &e, 10); \
+ \
+ switch (tolower(*e)) { \
+ default: \
+ return -EINVAL; \
+ case 'y': \
+ case 'z': \
+ u++; \
+ /* fall through */ \
+ case 'e': \
+ u++; \
+ /* fall through */ \
+ case 'p': \
+ u++; \
+ /* fall through */ \
+ case 't': \
+ u++; \
+ /* fall through */ \
+ case 'g': \
+ u++; \
+ /* fall through */ \
+ case 'm': \
+ u++; \
+ /* fall through */ \
+ case 'k': \
+ u++; \
+ if (e++ == cp) \
+ return -EINVAL; \
+ /* fall through */ \
+ case '\n': \
+ case '\0': \
+ if (*e == '\n') \
+ e++; \
+ } \
+ \
+ if (*e) \
+ return -EINVAL; \
+ \
+ while (u--) { \
+ if ((type) ~0 > 0 && \
+ (type) ~0 / 1024 <= i) \
+ return -EINVAL; \
+ if ((i > 0 && ANYSINT_MAX(type) / 1024 < i) || \
+ (i < 0 && -ANYSINT_MAX(type) / 1024 > i)) \
+ return -EINVAL; \
+ i *= 1024; \
+ } \
+ \
+ *res = i; \
+ return 0; \
+} \
+
+STRTO_H(strtoint, int)
+STRTO_H(strtouint, unsigned int)
+STRTO_H(strtoll, long long)
+STRTO_H(strtoull, unsigned long long)
+
+/**
+ * bch_hprint - formats @v to human readable string for sysfs.
+ * @buf: the (at least 8 byte) buffer to format the result into.
+ * @v: signed 64 bit integer
+ *
+ * Returns the number of bytes used by format.
+ */
+ssize_t bch_hprint(char *buf, int64_t v)
+{
+ static const char units[] = "?kMGTPEZY";
+ int u = 0, t;
+
+ uint64_t q;
+
+ if (v < 0)
+ q = -v;
+ else
+ q = v;
+
+ /* For as long as the number is more than 3 digits, but at least
+ * once, shift right / divide by 1024. Keep the remainder for
+ * a digit after the decimal point.
+ */
+ do {
+ u++;
+
+ t = q & ~(~0 << 10);
+ q >>= 10;
+ } while (q >= 1000);
+
+ if (v < 0)
+ /* '-', up to 3 digits, '.', 1 digit, 1 character, null;
+ * yields 8 bytes.
+ */
+ return sprintf(buf, "-%llu.%i%c", q, t * 10 / 1024, units[u]);
+ else
+ return sprintf(buf, "%llu.%i%c", q, t * 10 / 1024, units[u]);
+}
+
+bool bch_is_zero(const char *p, size_t n)
+{
+ size_t i;
+
+ for (i = 0; i < n; i++)
+ if (p[i])
+ return false;
+ return true;
+}
+
+int bch_parse_uuid(const char *s, char *uuid)
+{
+ size_t i, j, x;
+
+ memset(uuid, 0, 16);
+
+ for (i = 0, j = 0;
+ i < strspn(s, "-0123456789:ABCDEFabcdef") && j < 32;
+ i++) {
+ x = s[i] | 32;
+
+ switch (x) {
+ case '0'...'9':
+ x -= '0';
+ break;
+ case 'a'...'f':
+ x -= 'a' - 10;
+ break;
+ default:
+ continue;
+ }
+
+ if (!(j & 1))
+ x <<= 4;
+ uuid[j++ >> 1] |= x;
+ }
+ return i;
+}
+
+void bch_time_stats_update(struct time_stats *stats, uint64_t start_time)
+{
+ uint64_t now, duration, last;
+
+ spin_lock(&stats->lock);
+
+ now = local_clock();
+ duration = time_after64(now, start_time)
+ ? now - start_time : 0;
+ last = time_after64(now, stats->last)
+ ? now - stats->last : 0;
+
+ stats->max_duration = max(stats->max_duration, duration);
+
+ if (stats->last) {
+ ewma_add(stats->average_duration, duration, 8, 8);
+
+ if (stats->average_frequency)
+ ewma_add(stats->average_frequency, last, 8, 8);
+ else
+ stats->average_frequency = last << 8;
+ } else {
+ stats->average_duration = duration << 8;
+ }
+
+ stats->last = now ?: 1;
+
+ spin_unlock(&stats->lock);
+}
+
+/**
+ * bch_next_delay() - update ratelimiting statistics and calculate next delay
+ * @d: the struct bch_ratelimit to update
+ * @done: the amount of work done, in arbitrary units
+ *
+ * Increment @d by the amount of work done, and return how long to delay in
+ * jiffies until the next time to do some work.
+ */
+uint64_t bch_next_delay(struct bch_ratelimit *d, uint64_t done)
+{
+ uint64_t now = local_clock();
+
+ d->next += div_u64(done * NSEC_PER_SEC, atomic_long_read(&d->rate));
+
+ /* Bound the time. Don't let us fall further than 2 seconds behind
+ * (this prevents unnecessary backlog that would make it impossible
+ * to catch up). If we're ahead of the desired writeback rate,
+ * don't let us sleep more than 2.5 seconds (so we can notice/respond
+ * if the control system tells us to speed up!).
+ */
+ if (time_before64(now + NSEC_PER_SEC * 5LLU / 2LLU, d->next))
+ d->next = now + NSEC_PER_SEC * 5LLU / 2LLU;
+
+ if (time_after64(now - NSEC_PER_SEC * 2, d->next))
+ d->next = now - NSEC_PER_SEC * 2;
+
+ return time_after64(d->next, now)
+ ? div_u64(d->next - now, NSEC_PER_SEC / HZ)
+ : 0;
+}
+
+/*
+ * Generally it isn't good to access .bi_io_vec and .bi_vcnt directly,
+ * the preferred way is bio_add_page, but in this case, bch_bio_map()
+ * supposes that the bvec table is empty, so it is safe to access
+ * .bi_vcnt & .bi_io_vec in this way even after multipage bvec is
+ * supported.
+ */
+void bch_bio_map(struct bio *bio, void *base)
+{
+ size_t size = bio->bi_iter.bi_size;
+ struct bio_vec *bv = bio->bi_io_vec;
+
+ BUG_ON(!bio->bi_iter.bi_size);
+ BUG_ON(bio->bi_vcnt);
+
+ bv->bv_offset = base ? offset_in_page(base) : 0;
+ goto start;
+
+ for (; size; bio->bi_vcnt++, bv++) {
+ bv->bv_offset = 0;
+start: bv->bv_len = min_t(size_t, PAGE_SIZE - bv->bv_offset,
+ size);
+ if (base) {
+ bv->bv_page = is_vmalloc_addr(base)
+ ? vmalloc_to_page(base)
+ : virt_to_page(base);
+
+ base += bv->bv_len;
+ }
+
+ size -= bv->bv_len;
+ }
+}
+
+/**
+ * bch_bio_alloc_pages - allocates a single page for each bvec in a bio
+ * @bio: bio to allocate pages for
+ * @gfp_mask: flags for allocation
+ *
+ * Allocates pages up to @bio->bi_vcnt.
+ *
+ * Returns 0 on success, -ENOMEM on failure. On failure, any allocated pages are
+ * freed.
+ */
+int bch_bio_alloc_pages(struct bio *bio, gfp_t gfp_mask)
+{
+ int i;
+ struct bio_vec *bv;
+
+ bio_for_each_segment_all(bv, bio, i) {
+ bv->bv_page = alloc_page(gfp_mask);
+ if (!bv->bv_page) {
+ while (--bv >= bio->bi_io_vec)
+ __free_page(bv->bv_page);
+ return -ENOMEM;
+ }
+ }
+
+ return 0;
+}