From: Christoph Hellwig <hch@lst.de>
Date: Tue, 10 Aug 2021 17:26:23 +0200
Subject: [PATCH] blk-cgroup: stop using seq_get_buf
Git-commit: 252c651a4c854b328445a536bd1892e999103fca
Patch-mainline: v5.15-rc1
References: jsc#PED-1183
seq_get_buf is a crutch that undoes all the memory safety of the
seq_file interface. Use the normal seq_printf interfaces instead.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20210810152623.1796144-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Acked-by: Hannes Reinecke <hare@suse.com>
---
block/blk-cgroup.c | 30 ++++++------------------------
block/blk-iocost.c | 23 +++++++++--------------
block/blk-iolatency.c | 38 +++++++++++++++++++-------------------
include/linux/blk-cgroup.h | 4 ++--
5 files changed, 39 insertions(+), 64 deletions(-)
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 52aa0540ccaf..b8ec47dcce42 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -877,8 +877,6 @@ static void blkcg_print_one_stat(struct blkcg_gq *blkg, struct seq_file *s)
bool has_stats = false;
const char *dname;
unsigned seq;
- char *buf;
- size_t size = seq_get_buf(s, &buf), off = 0;
int i;
if (!blkg->online)
@@ -888,13 +886,7 @@ static void blkcg_print_one_stat(struct blkcg_gq *blkg, struct seq_file *s)
if (!dname)
return;
- /*
- * Hooray string manipulation, count is the size written NOT
- * INCLUDING THE \0, so size is now count+1 less than what we
- * had before, but we want to start writing the next bit from
- * the \0 so we only add count to buf.
- */
- off += scnprintf(buf+off, size-off, "%s ", dname);
+ seq_printf(s, "%s ", dname);
do {
seq = u64_stats_fetch_begin(&bis->sync);
@@ -909,40 +901,30 @@ static void blkcg_print_one_stat(struct blkcg_gq *blkg, struct seq_file *s)
if (rbytes || wbytes || rios || wios) {
has_stats = true;
- off += scnprintf(buf+off, size-off,
- "rbytes=%llu wbytes=%llu rios=%llu wios=%llu dbytes=%llu dios=%llu",
+ seq_printf(s, "rbytes=%llu wbytes=%llu rios=%llu wios=%llu dbytes=%llu dios=%llu",
rbytes, wbytes, rios, wios,
dbytes, dios);
}
if (blkcg_debug_stats && atomic_read(&blkg->use_delay)) {
has_stats = true;
- off += scnprintf(buf+off, size-off, " use_delay=%d delay_nsec=%llu",
+ seq_printf(s, " use_delay=%d delay_nsec=%llu",
atomic_read(&blkg->use_delay),
atomic64_read(&blkg->delay_nsec));
}
for (i = 0; i < BLKCG_MAX_POLS; i++) {
struct blkcg_policy *pol = blkcg_policy[i];
- size_t written;
if (!blkg->pd[i] || !pol->pd_stat_fn)
continue;
- written = pol->pd_stat_fn(blkg->pd[i], buf+off, size-off);
- if (written)
+ if (pol->pd_stat_fn(blkg->pd[i], s))
has_stats = true;
- off += written;
}
- if (has_stats) {
- if (off < size - 1) {
- off += scnprintf(buf+off, size-off, "\n");
- seq_commit(s, off);
- } else {
- seq_commit(s, -1);
- }
- }
+ if (has_stats)
+ seq_printf(s, "\n");
}
static int blkcg_print_stat(struct seq_file *sf, void *v)
diff --git a/block/blk-iocost.c b/block/blk-iocost.c
index 5fac3757e6e0..89b21a360b2c 100644
--- a/block/blk-iocost.c
+++ b/block/blk-iocost.c
@@ -2988,34 +2988,29 @@ static void ioc_pd_free(struct blkg_policy_data *pd)
kfree(iocg);
}
-static size_t ioc_pd_stat(struct blkg_policy_data *pd, char *buf, size_t size)
+static bool ioc_pd_stat(struct blkg_policy_data *pd, struct seq_file *s)
{
struct ioc_gq *iocg = pd_to_iocg(pd);
struct ioc *ioc = iocg->ioc;
- size_t pos = 0;
if (!ioc->enabled)
- return 0;
+ return false;
if (iocg->level == 0) {
unsigned vp10k = DIV64_U64_ROUND_CLOSEST(
ioc->vtime_base_rate * 10000,
VTIME_PER_USEC);
- pos += scnprintf(buf + pos, size - pos, " cost.vrate=%u.%02u",
- vp10k / 100, vp10k % 100);
+ seq_printf(s, " cost.vrate=%u.%02u", vp10k / 100, vp10k % 100);
}
- pos += scnprintf(buf + pos, size - pos, " cost.usage=%llu",
- iocg->last_stat.usage_us);
+ seq_printf(s, " cost.usage=%llu", iocg->last_stat.usage_us);
if (blkcg_debug_stats)
- pos += scnprintf(buf + pos, size - pos,
- " cost.wait=%llu cost.indebt=%llu cost.indelay=%llu",
- iocg->last_stat.wait_us,
- iocg->last_stat.indebt_us,
- iocg->last_stat.indelay_us);
-
- return pos;
+ seq_printf(s, " cost.wait=%llu cost.indebt=%llu cost.indelay=%llu",
+ iocg->last_stat.wait_us,
+ iocg->last_stat.indebt_us,
+ iocg->last_stat.indelay_us);
+ return true;
}
static u64 ioc_weight_prfill(struct seq_file *sf, struct blkg_policy_data *pd,
diff --git a/block/blk-iolatency.c b/block/blk-iolatency.c
index 81be0096411d..4c06fafb7411 100644
--- a/block/blk-iolatency.c
+++ b/block/blk-iolatency.c
@@ -886,8 +886,7 @@ static int iolatency_print_limit(struct seq_file *sf, void *v)
return 0;
}
-static size_t iolatency_ssd_stat(struct iolatency_grp *iolat, char *buf,
- size_t size)
+static bool iolatency_ssd_stat(struct iolatency_grp *iolat, struct seq_file *s)
{
struct latency_stat stat;
int cpu;
@@ -902,39 +901,40 @@ static size_t iolatency_ssd_stat(struct iolatency_grp *iolat, char *buf,
preempt_enable();
if (iolat->rq_depth.max_depth == UINT_MAX)
- return scnprintf(buf, size, " missed=%llu total=%llu depth=max",
- (unsigned long long)stat.ps.missed,
- (unsigned long long)stat.ps.total);
- return scnprintf(buf, size, " missed=%llu total=%llu depth=%u",
- (unsigned long long)stat.ps.missed,
- (unsigned long long)stat.ps.total,
- iolat->rq_depth.max_depth);
+ seq_printf(s, " missed=%llu total=%llu depth=max",
+ (unsigned long long)stat.ps.missed,
+ (unsigned long long)stat.ps.total);
+ else
+ seq_printf(s, " missed=%llu total=%llu depth=%u",
+ (unsigned long long)stat.ps.missed,
+ (unsigned long long)stat.ps.total,
+ iolat->rq_depth.max_depth);
+ return true;
}
-static size_t iolatency_pd_stat(struct blkg_policy_data *pd, char *buf,
- size_t size)
+static bool iolatency_pd_stat(struct blkg_policy_data *pd, struct seq_file *s)
{
struct iolatency_grp *iolat = pd_to_lat(pd);
unsigned long long avg_lat;
unsigned long long cur_win;
if (!blkcg_debug_stats)
- return 0;
+ return false;
if (iolat->ssd)
- return iolatency_ssd_stat(iolat, buf, size);
+ return iolatency_ssd_stat(iolat, s);
avg_lat = div64_u64(iolat->lat_avg, NSEC_PER_USEC);
cur_win = div64_u64(iolat->cur_win_nsec, NSEC_PER_MSEC);
if (iolat->rq_depth.max_depth == UINT_MAX)
- return scnprintf(buf, size, " depth=max avg_lat=%llu win=%llu",
- avg_lat, cur_win);
-
- return scnprintf(buf, size, " depth=%u avg_lat=%llu win=%llu",
- iolat->rq_depth.max_depth, avg_lat, cur_win);
+ seq_printf(s, " depth=max avg_lat=%llu win=%llu",
+ avg_lat, cur_win);
+ else
+ seq_printf(s, " depth=%u avg_lat=%llu win=%llu",
+ iolat->rq_depth.max_depth, avg_lat, cur_win);
+ return true;
}
-
static struct blkg_policy_data *iolatency_pd_alloc(gfp_t gfp,
struct request_queue *q,
struct blkcg *blkcg)
diff --git a/include/linux/blk-cgroup.h b/include/linux/blk-cgroup.h
index 37048438872c..b4de2010fba5 100644
--- a/include/linux/blk-cgroup.h
+++ b/include/linux/blk-cgroup.h
@@ -152,8 +152,8 @@ typedef void (blkcg_pol_online_pd_fn)(struct blkg_policy_data *pd);
typedef void (blkcg_pol_offline_pd_fn)(struct blkg_policy_data *pd);
typedef void (blkcg_pol_free_pd_fn)(struct blkg_policy_data *pd);
typedef void (blkcg_pol_reset_pd_stats_fn)(struct blkg_policy_data *pd);
-typedef size_t (blkcg_pol_stat_pd_fn)(struct blkg_policy_data *pd, char *buf,
- size_t size);
+typedef bool (blkcg_pol_stat_pd_fn)(struct blkg_policy_data *pd,
+ struct seq_file *s);
struct blkcg_policy {
int plid;
--
2.35.3