Commit 252c651a authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Jens Axboe
Browse files

blk-cgroup: stop using seq_get_buf 



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: default avatarChristoph Hellwig <hch@lst.de>
Acked-by: default avatarTejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20210810152623.1796144-2-hch@lst.de


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 49cb5168

block/blk-cgroup.c

+6 −24
Original line number Diff line number Diff line
@@ -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)

block/blk-iocost.c

+9 −14
Original line number Diff line number Diff line
@@ -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",

		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 pos;

	return true;

}



static u64 ioc_weight_prfill(struct seq_file *sf, struct blkg_policy_data *pd,

block/blk-iolatency.c

+19 −19
Original line number Diff line number Diff line
@@ -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",

		seq_printf(s, " 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",

	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",

		seq_printf(s, " depth=max avg_lat=%llu win=%llu",

			avg_lat, cur_win);



	return scnprintf(buf, size, " depth=%u avg_lat=%llu win=%llu",

	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)

block/mq-deadline-cgroup.c

+3 −5
Original line number Diff line number Diff line
@@ -52,7 +52,7 @@ struct dd_blkcg *dd_blkcg_from_bio(struct bio *bio) 
	return dd_blkcg_from_pd(pd);

}



static size_t dd_pd_stat(struct blkg_policy_data *pd, char *buf, size_t size)

static bool dd_pd_stat(struct blkg_policy_data *pd, struct seq_file *s)

{

	static const char *const prio_class_name[] = {

		[IOPRIO_CLASS_NONE]	= "NONE",
@@ -61,12 +61,10 @@ static size_t dd_pd_stat(struct blkg_policy_data *pd, char *buf, size_t size) 
		[IOPRIO_CLASS_IDLE]	= "IDLE",

	};

	struct dd_blkcg *blkcg = dd_blkcg_from_pd(pd);

	int res = 0;

	u8 prio;



	for (prio = 0; prio < ARRAY_SIZE(blkcg->stats->stats); prio++)

		res += scnprintf(buf + res, size - res,

			" [%s] dispatched=%u inserted=%u merged=%u",

		seq_printf(s, " [%s] dispatched=%u inserted=%u merged=%u",

			prio_class_name[prio],

			ddcg_sum(blkcg, dispatched, prio) +

			ddcg_sum(blkcg, merged, prio) -
@@ -75,7 +73,7 @@ static size_t dd_pd_stat(struct blkg_policy_data *pd, char *buf, size_t size) 
			ddcg_sum(blkcg, completed, prio),

			ddcg_sum(blkcg, merged, prio));



	return res;

	return true;

}



static struct blkg_policy_data *dd_pd_alloc(gfp_t gfp, struct request_queue *q,

include/linux/blk-cgroup.h

+2 −2
Original line number Diff line number Diff line
@@ -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;