[PATCH] blk-throttle: Only use seq_printf() in tg_prfill_limit()

John Garry
2024-03-27T09:40:48Z

Currently tg_prfill_limit() uses a combination of snprintf() and strcpy()
to generate the values parts of the limits string, before passing them as
arguments to seq_printf().

Convert to use only a sequence of seq_printf() calls per argument, which is
simpler.

Suggested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: John Garry <john.g.garry@oracle.com>

diff --git a/block/blk-throttle.c b/block/blk-throttle.c
index f4850a6f860b..c515e1a96fad 100644
--- a/block/blk-throttle.c
+++ b/block/blk-throttle.c
@@ -1494,11 +1494,8 @@ static u64 tg_prfill_limit(struct seq_file *sf, struct blkg_policy_data *pd,
{
struct throtl_grp *tg = pd_to_tg(pd);
const char *dname = blkg_dev_name(pd->blkg);
- char bufs[4][21] = { "max", "max", "max", "max" };
u64 bps_dft;
unsigned int iops_dft;
- char idle_time[26] = "";
- char latency_time[26] = "";

if (!dname)
return 0;
@@ -1520,35 +1517,39 @@ static u64 tg_prfill_limit(struct seq_file *sf, struct blkg_policy_data *pd,
tg->latency_target_conf == DFL_LATENCY_TARGET)))
return 0;

- if (tg->bps_conf[READ][off] != U64_MAX)
- snprintf(bufs[0], sizeof(bufs[0]), "%llu",
- tg->bps_conf[READ][off]);
- if (tg->bps_conf[WRITE][off] != U64_MAX)
- snprintf(bufs[1], sizeof(bufs[1]), "%llu",
- tg->bps_conf[WRITE][off]);
- if (tg->iops_conf[READ][off] != UINT_MAX)
- snprintf(bufs[2], sizeof(bufs[2]), "%u",
- tg->iops_conf[READ][off]);
- if (tg->iops_conf[WRITE][off] != UINT_MAX)
- snprintf(bufs[3], sizeof(bufs[3]), "%u",
- tg->iops_conf[WRITE][off]);
+ seq_printf(sf, "%s", dname);
+ if (tg->bps_conf[READ][off] == U64_MAX)
+ seq_printf(sf, " rbps=max");
+ else
+ seq_printf(sf, " rbps=%llu", tg->bps_conf[READ][off]);
+
+ if (tg->bps_conf[WRITE][off] == U64_MAX)
+ seq_printf(sf, " wbps=max");
+ else
+ seq_printf(sf, " wbps=%llu", tg->bps_conf[WRITE][off]);
+
+ if (tg->iops_conf[READ][off] == UINT_MAX)
+ seq_printf(sf, " riops=max");
+ else
+ seq_printf(sf, " riops=%u", tg->iops_conf[READ][off]);
+
+ if (tg->iops_conf[WRITE][off] == UINT_MAX)
+ seq_printf(sf, " wiops=max");
+ else
+ seq_printf(sf, " wiops=%u", tg->iops_conf[WRITE][off]);
+
if (off == LIMIT_LOW) {
if (tg->idletime_threshold_conf == ULONG_MAX)
- strcpy(idle_time, " idle=max");
+ seq_printf(sf, " idle=max");
else
- snprintf(idle_time, sizeof(idle_time), " idle=%lu",
- tg->idletime_threshold_conf);
+ seq_printf(sf, " idle=%lu", tg->idletime_threshold_conf);

if (tg->latency_target_conf == ULONG_MAX)
- strcpy(latency_time, " latency=max");
+ seq_printf(sf, " latency=max");
else
- snprintf(latency_time, sizeof(latency_time),
- " latency=%lu", tg->latency_target_conf);
+ seq_printf(sf, " latency=%lu", tg->latency_target_conf);
}
-
- seq_printf(sf, "%s rbps=%s wbps=%s riops=%s wiops=%s%s%s\n",
- dname, bufs[0], bufs[1], bufs[2], bufs[3], idle_time,
- latency_time);
+ seq_printf(sf, "\n");
return 0;
}

--
2.31.1