Merge tag 'v5.0-rc7' into patchwork

Linux 5.0-rc7

* tag 'v5.0-rc7': (1667 commits)
  Linux 5.0-rc7
  Input: elan_i2c - add ACPI ID for touchpad in Lenovo V330-15ISK
  Input: st-keyscan - fix potential zalloc NULL dereference
  Input: apanel - switch to using brightness_set_blocking()
  powerpc/64s: Fix possible corruption on big endian due to pgd/pud_present()
  efi/arm: Revert "Defer persistent reservations until after paging_init()"
  arm64, mm, efi: Account for GICv3 LPI tables in static memblock reserve table
  sunrpc: fix 4 more call sites that were using stack memory with a scatterlist
  include/linux/module.h: copy __init/__exit attrs to init/cleanup_module
  Compiler Attributes: add support for __copy (gcc >= 9)
  lib/crc32.c: mark crc32_le_base/__crc32c_le_base aliases as __pure
  auxdisplay: ht16k33: fix potential user-after-free on module unload
  x86/platform/UV: Use efi_runtime_lock to serialise BIOS calls
  i2c: bcm2835: Clear current buffer pointers and counts after a transfer
  i2c: cadence: Fix the hold bit setting
  drm: Use array_size() when creating lease
  dm thin: fix bug where bio that overwrites thin block ignores FUA
  Revert "exec: load_script: don't blindly truncate shebang string"
  Revert "gfs2: read journal in large chunks to locate the head"
  net: ethernet: freescale: set FEC ethtool regs version
  ...

Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

1 files changed, 48 insertions, 8 deletions

diff --git a/block/blk-iolatency.c b/block/blk-iolatency.c
index fc714ef402a6..2620baa1f699 100644
--- a/block/blk-iolatency.c
+++ b/block/blk-iolatency.c
@@ -72,6 +72,7 @@
 #include <linux/sched/loadavg.h>
 #include <linux/sched/signal.h>
 #include <trace/events/block.h>
+#include <linux/blk-mq.h>
 #include "blk-rq-qos.h"
 #include "blk-stat.h"
 
@@ -591,6 +592,7 @@ static void blkcg_iolatency_done_bio(struct rq_qos *rqos, struct bio *bio)
 	u64 now = ktime_to_ns(ktime_get());
 	bool issue_as_root = bio_issue_as_root_blkg(bio);
 	bool enabled = false;
+	int inflight = 0;
 
 	blkg = bio->bi_blkg;
 	if (!blkg || !bio_flagged(bio, BIO_TRACKED))
@@ -601,6 +603,9 @@ static void blkcg_iolatency_done_bio(struct rq_qos *rqos, struct bio *bio)
 		return;
 
 	enabled = blk_iolatency_enabled(iolat->blkiolat);
+	if (!enabled)
+		return;
+
 	while (blkg && blkg->parent) {
 		iolat = blkg_to_lat(blkg);
 		if (!iolat) {
@@ -609,8 +614,9 @@ static void blkcg_iolatency_done_bio(struct rq_qos *rqos, struct bio *bio)
 		}
 		rqw = &iolat->rq_wait;
 
-		atomic_dec(&rqw->inflight);
-		if (!enabled || iolat->min_lat_nsec == 0)
+		inflight = atomic_dec_return(&rqw->inflight);
+		WARN_ON_ONCE(inflight < 0);
+		if (iolat->min_lat_nsec == 0)
 			goto next;
 		iolatency_record_time(iolat, &bio->bi_issue, now,
 				      issue_as_root);
@@ -754,10 +760,13 @@ int blk_iolatency_init(struct request_queue *q)
 	return 0;
 }
 
-static void iolatency_set_min_lat_nsec(struct blkcg_gq *blkg, u64 val)
+/*
+ * return 1 for enabling iolatency, return -1 for disabling iolatency, otherwise
+ * return 0.
+ */
+static int iolatency_set_min_lat_nsec(struct blkcg_gq *blkg, u64 val)
 {
 	struct iolatency_grp *iolat = blkg_to_lat(blkg);
-	struct blk_iolatency *blkiolat = iolat->blkiolat;
 	u64 oldval = iolat->min_lat_nsec;
 
 	iolat->min_lat_nsec = val;
@@ -766,9 +775,10 @@ static void iolatency_set_min_lat_nsec(struct blkcg_gq *blkg, u64 val)
 				    BLKIOLATENCY_MAX_WIN_SIZE);
 
 	if (!oldval && val)
-		atomic_inc(&blkiolat->enabled);
+		return 1;
 	if (oldval && !val)
-		atomic_dec(&blkiolat->enabled);
+		return -1;
+	return 0;
 }
 
 static void iolatency_clear_scaling(struct blkcg_gq *blkg)
@@ -800,6 +810,7 @@ static ssize_t iolatency_set_limit(struct kernfs_open_file *of, char *buf,
 	u64 lat_val = 0;
 	u64 oldval;
 	int ret;
+	int enable = 0;
 
 	ret = blkg_conf_prep(blkcg, &blkcg_policy_iolatency, buf, &ctx);
 	if (ret)
@@ -834,7 +845,12 @@ static ssize_t iolatency_set_limit(struct kernfs_open_file *of, char *buf,
 	blkg = ctx.blkg;
 	oldval = iolat->min_lat_nsec;
 
-	iolatency_set_min_lat_nsec(blkg, lat_val);
+	enable = iolatency_set_min_lat_nsec(blkg, lat_val);
+	if (enable) {
+		WARN_ON_ONCE(!blk_get_queue(blkg->q));
+		blkg_get(blkg);
+	}
+
 	if (oldval != iolat->min_lat_nsec) {
 		iolatency_clear_scaling(blkg);
 	}
@@ -842,6 +858,24 @@ static ssize_t iolatency_set_limit(struct kernfs_open_file *of, char *buf,
 	ret = 0;
 out:
 	blkg_conf_finish(&ctx);
+	if (ret == 0 && enable) {
+		struct iolatency_grp *tmp = blkg_to_lat(blkg);
+		struct blk_iolatency *blkiolat = tmp->blkiolat;
+
+		blk_mq_freeze_queue(blkg->q);
+
+		if (enable == 1)
+			atomic_inc(&blkiolat->enabled);
+		else if (enable == -1)
+			atomic_dec(&blkiolat->enabled);
+		else
+			WARN_ON_ONCE(1);
+
+		blk_mq_unfreeze_queue(blkg->q);
+
+		blkg_put(blkg);
+		blk_put_queue(blkg->q);
+	}
 	return ret ?: nbytes;
 }
 
@@ -977,8 +1011,14 @@ static void iolatency_pd_offline(struct blkg_policy_data *pd)
 {
 	struct iolatency_grp *iolat = pd_to_lat(pd);
 	struct blkcg_gq *blkg = lat_to_blkg(iolat);
+	struct blk_iolatency *blkiolat = iolat->blkiolat;
+	int ret;
 
-	iolatency_set_min_lat_nsec(blkg, 0);
+	ret = iolatency_set_min_lat_nsec(blkg, 0);
+	if (ret == 1)
+		atomic_inc(&blkiolat->enabled);
+	if (ret == -1)
+		atomic_dec(&blkiolat->enabled);
 	iolatency_clear_scaling(blkg);
 }