ata: libata-scsi: fix ata_dsm_trim_pages() kernel-docgrafted

make htmldocs fails with:

  Documentation/driver-api/libata:604: ./drivers/ata/libata-scsi.c:2301:
  ERROR: Unexpected indentation. [docutils]

The Return: section of ata_dsm_trim_pages() ends its first sentence with
a colon and continues with an indented bullet list. reStructuredText
requires a blank line before an indented block, so docutils chokes on
the list.

Simply adding the missing blank line does not work either: Return: is a
kernel-doc "special section", which is terminated by the first blank
line, so the bullet list would end up in the Description section,
detached from the sentence introducing it.

Spell the two bounds out as prose instead, so that the Return: section
stays self-contained. Documentation-only change.

Fixes: e64e6b5dc867 ("ata: libata-scsi: scale DSM TRIM payload by MAX PAGES PER DSM COMMAND")
Reported-by: Thomas Huth <thuth@redhat.com>
Closes: https://lore.kernel.org/linux-ide/b0a0b8e8-cc4f-4c7b-8bc5-fee0712d405a@redhat.com/
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Link: https://lore.kernel.org/r/20260916130031.29990-2-cassel@kernel.org
Signed-off-by: Niklas Cassel <cassel@kernel.org>

1 files changed, 172 insertions, 0 deletions

diff --git a/tools/writeback/wb_monitor.py b/tools/writeback/wb_monitor.py
new file mode 100644
index 000000000..5e3591f1f
--- /dev/null
+++ b/tools/writeback/wb_monitor.py
@@ -0,0 +1,172 @@
+#!/usr/bin/env drgn
+#
+# Copyright (C) 2024 Kemeng Shi <shikemeng@huaweicloud.com>
+# Copyright (C) 2024 Huawei Inc
+
+desc = """
+This is a drgn script based on wq_monitor.py to monitor writeback info on
+backing dev. For more info on drgn, visit https://github.com/osandov/drgn.
+
+  writeback(kB)     Amount of dirty pages are currently being written back to
+                    disk.
+
+  reclaimable(kB)   Amount of pages are currently reclaimable.
+
+  dirtied(kB)       Amount of pages have been dirtied.
+
+  wrttien(kB)       Amount of dirty pages have been written back to disk.
+
+  avg_wb(kBps)      Smoothly estimated write bandwidth of writing dirty pages
+                    back to disk.
+"""
+
+import signal
+import re
+import time
+import json
+
+import drgn
+from drgn.helpers.linux.list import list_for_each_entry
+
+import argparse
+parser = argparse.ArgumentParser(description=desc,
+                                 formatter_class=argparse.RawTextHelpFormatter)
+parser.add_argument('bdi', metavar='REGEX', nargs='*',
+                    help='Target backing device name patterns (all if empty)')
+parser.add_argument('-i', '--interval', metavar='SECS', type=float, default=1,
+                    help='Monitoring interval (0 to print once and exit)')
+parser.add_argument('-j', '--json', action='store_true',
+                    help='Output in json')
+parser.add_argument('-c', '--cgroup', action='store_true',
+                    help='show writeback of bdi in cgroup')
+args = parser.parse_args()
+
+bdi_list                = prog['bdi_list']
+
+WB_RECLAIMABLE          = prog['WB_RECLAIMABLE']
+WB_WRITEBACK            = prog['WB_WRITEBACK']
+WB_DIRTIED              = prog['WB_DIRTIED']
+WB_WRITTEN              = prog['WB_WRITTEN']
+NR_WB_STAT_ITEMS        = prog['NR_WB_STAT_ITEMS']
+
+PAGE_SHIFT              = prog['PAGE_SHIFT']
+
+def K(x):
+    return x << (PAGE_SHIFT - 10)
+
+class Stats:
+    def dict(self, now):
+        return { 'timestamp'            : now,
+                 'name'                 : self.name,
+                 'writeback'            : self.stats[WB_WRITEBACK],
+                 'reclaimable'          : self.stats[WB_RECLAIMABLE],
+                 'dirtied'              : self.stats[WB_DIRTIED],
+                 'written'              : self.stats[WB_WRITTEN],
+                 'avg_wb'               : self.avg_bw, }
+
+    def table_header_str():
+        return f'{"":>16} {"writeback":>10} {"reclaimable":>12} ' \
+                f'{"dirtied":>9} {"written":>9} {"avg_bw":>9}'
+
+    def table_row_str(self):
+        out = f'{self.name[-16:]:16} ' \
+              f'{self.stats[WB_WRITEBACK]:10} ' \
+              f'{self.stats[WB_RECLAIMABLE]:12} ' \
+              f'{self.stats[WB_DIRTIED]:9} ' \
+              f'{self.stats[WB_WRITTEN]:9} ' \
+              f'{self.avg_bw:9} '
+        return out
+
+    def show_header():
+        if Stats.table_fmt:
+            print()
+            print(Stats.table_header_str())
+
+    def show_stats(self):
+        if Stats.table_fmt:
+            print(self.table_row_str())
+        else:
+            print(self.dict(Stats.now))
+
+class WbStats(Stats):
+    def __init__(self, wb):
+        bdi_name = wb.bdi.dev_name.string_().decode()
+        # avoid to use bdi.wb.memcg_css which is only defined when
+        # CONFIG_CGROUP_WRITEBACK is enabled
+        if wb == wb.bdi.wb.address_of_():
+            ino = "1"
+        else:
+            ino = str(wb.memcg_css.cgroup.kn.id.value_())
+        self.name = bdi_name + '_' + ino
+
+        self.stats = [0] * NR_WB_STAT_ITEMS
+        for i in range(NR_WB_STAT_ITEMS):
+            if wb.stat[i].count >= 0:
+                self.stats[i] = int(K(wb.stat[i].count))
+            else:
+                self.stats[i] = 0
+
+        self.avg_bw = int(K(wb.avg_write_bandwidth))
+
+class BdiStats(Stats):
+    def __init__(self, bdi):
+        self.name = bdi.dev_name.string_().decode()
+        self.stats = [0] * NR_WB_STAT_ITEMS
+        self.avg_bw = 0
+
+    def collectStats(self, wb_stats):
+        for i in range(NR_WB_STAT_ITEMS):
+            self.stats[i] += wb_stats.stats[i]
+
+        self.avg_bw += wb_stats.avg_bw
+
+exit_req = False
+
+def sigint_handler(signr, frame):
+    global exit_req
+    exit_req = True
+
+def main():
+    # handle args
+    Stats.table_fmt = not args.json
+    interval = args.interval
+    cgroup = args.cgroup
+
+    re_str = None
+    if args.bdi:
+        for r in args.bdi:
+            if re_str is None:
+                re_str = r
+            else:
+                re_str += '|' + r
+
+    filter_re = re.compile(re_str) if re_str else None
+
+    # monitoring loop
+    signal.signal(signal.SIGINT, sigint_handler)
+
+    while not exit_req:
+        Stats.now = time.time()
+
+        Stats.show_header()
+        for bdi in list_for_each_entry('struct backing_dev_info', bdi_list.address_of_(), 'bdi_list'):
+            bdi_stats = BdiStats(bdi)
+            if filter_re and not filter_re.search(bdi_stats.name):
+                continue
+
+            for wb in list_for_each_entry('struct bdi_writeback', bdi.wb_list.address_of_(), 'bdi_node'):
+                wb_stats = WbStats(wb)
+                bdi_stats.collectStats(wb_stats)
+                if cgroup:
+                    wb_stats.show_stats()
+
+            bdi_stats.show_stats()
+            if cgroup and Stats.table_fmt:
+                print()
+
+        if interval == 0:
+            break
+        time.sleep(interval)
+
+if __name__ == "__main__":
+    main()