From: Yu Kuai <yukuai3@xxxxxxxxxx>
sysfs entry /sys/block/[device]/queue/wbt_lat_usec will be created even
if CONFIG_BLK_WBT is disabled, while read and write will always fail.
It doesn't make sense to create a sysfs entry that can't be accessed,
so don't create such entry.
Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
---
block/blk-sysfs.c | 143 ++++++++++++++++++++++++----------------------
block/blk-wbt.h | 19 ------
2 files changed, 74 insertions(+), 88 deletions(-)
diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
index a64208583853..6c1c4ba66bc0 100644
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -47,19 +47,6 @@ queue_var_store(unsigned long *var, const char *page, size_t count)
return count;
}
-static ssize_t queue_var_store64(s64 *var, const char *page)
-{
- int err;
- s64 v;
-
- err = kstrtos64(page, 10, &v);
- if (err < 0)
- return err;
-
- *var = v;
- return 0;
-}
-
static ssize_t queue_requests_show(struct request_queue *q, char *page)
{
return queue_var_show(q->nr_requests, page);
@@ -451,61 +438,6 @@ static ssize_t queue_io_timeout_store(struct request_queue *q, const char *page,
return count;
}
-static ssize_t queue_wb_lat_show(struct request_queue *q, char *page)
-{
- if (!wbt_rq_qos(q))
- return -EINVAL;
-
- if (wbt_disabled(q))
- return sprintf(page, "0\n");
-
- return sprintf(page, "%llu\n", div_u64(wbt_get_min_lat(q), 1000));
-}
-
-static ssize_t queue_wb_lat_store(struct request_queue *q, const char *page,
- size_t count)
-{
- struct rq_qos *rqos;
- ssize_t ret;
- s64 val;
-
- ret = queue_var_store64(&val, page);
- if (ret < 0)
- return ret;
- if (val < -1)
- return -EINVAL;
-
- rqos = wbt_rq_qos(q);
- if (!rqos) {
- ret = wbt_init(q->disk);
- if (ret)
- return ret;
- }
-
- if (val == -1)
- val = wbt_default_latency_nsec(q);
- else if (val >= 0)
- val *= 1000ULL;
-
- if (wbt_get_min_lat(q) == val)
- return count;
-
- /*
- * Ensure that the queue is idled, in case the latency update
- * ends up either enabling or disabling wbt completely. We can't
- * have IO inflight if that happens.
- */
- blk_mq_freeze_queue(q);
- blk_mq_quiesce_queue(q);
-
- wbt_set_min_lat(q, val);
-
- blk_mq_unquiesce_queue(q);
- blk_mq_unfreeze_queue(q);
-
- return count;
-}
-
static ssize_t queue_wc_show(struct request_queue *q, char *page)
{
if (test_bit(QUEUE_FLAG_WC, &q->queue_flags))
@@ -598,7 +530,6 @@ QUEUE_RW_ENTRY(queue_wc, "write_cache");
QUEUE_RO_ENTRY(queue_fua, "fua");
QUEUE_RO_ENTRY(queue_dax, "dax");
QUEUE_RW_ENTRY(queue_io_timeout, "io_timeout");
-QUEUE_RW_ENTRY(queue_wb_lat, "wbt_lat_usec");
QUEUE_RO_ENTRY(queue_virt_boundary_mask, "virt_boundary_mask");
QUEUE_RO_ENTRY(queue_dma_alignment, "dma_alignment");
@@ -617,6 +548,78 @@ QUEUE_RW_ENTRY(queue_iostats, "iostats");
QUEUE_RW_ENTRY(queue_random, "add_random");
QUEUE_RW_ENTRY(queue_stable_writes, "stable_writes");
+#ifdef CONFIG_BLK_WBT
+static ssize_t queue_var_store64(s64 *var, const char *page)
+{
+ int err;
+ s64 v;
+
+ err = kstrtos64(page, 10, &v);
+ if (err < 0)
+ return err;
+
+ *var = v;
+ return 0;
+}
+
+static ssize_t queue_wb_lat_show(struct request_queue *q, char *page)
+{
+ if (!wbt_rq_qos(q))
+ return -EINVAL;
+
+ if (wbt_disabled(q))
+ return sprintf(page, "0\n");
+
+ return sprintf(page, "%llu\n", div_u64(wbt_get_min_lat(q), 1000));
+}
+
+static ssize_t queue_wb_lat_store(struct request_queue *q, const char *page,
+ size_t count)
+{
+ struct rq_qos *rqos;
+ ssize_t ret;
+ s64 val;
+
+ ret = queue_var_store64(&val, page);
+ if (ret < 0)
+ return ret;
+ if (val < -1)
+ return -EINVAL;
+
+ rqos = wbt_rq_qos(q);
+ if (!rqos) {
+ ret = wbt_init(q->disk);
+ if (ret)
+ return ret;
+ }
+
+ if (val == -1)
+ val = wbt_default_latency_nsec(q);
+ else if (val >= 0)
+ val *= 1000ULL;
+
+ if (wbt_get_min_lat(q) == val)
+ return count;
+
+ /*
+ * Ensure that the queue is idled, in case the latency update
+ * ends up either enabling or disabling wbt completely. We can't
+ * have IO inflight if that happens.
+ */
+ blk_mq_freeze_queue(q);
+ blk_mq_quiesce_queue(q);
+
+ wbt_set_min_lat(q, val);
+
+ blk_mq_unquiesce_queue(q);
+ blk_mq_unfreeze_queue(q);
+
+ return count;
+}
+
+QUEUE_RW_ENTRY(queue_wb_lat, "wbt_lat_usec");
+#endif
+
static struct attribute *queue_attrs[] = {
&queue_requests_entry.attr,
&queue_ra_entry.attr,
@@ -655,7 +658,9 @@ static struct attribute *queue_attrs[] = {
&queue_wc_entry.attr,
&queue_fua_entry.attr,
&queue_dax_entry.attr,
+#ifdef CONFIG_BLK_WBT
&queue_wb_lat_entry.attr,
+#endif
&queue_poll_delay_entry.attr,
&queue_io_timeout_entry.attr,
#ifdef CONFIG_BLK_DEV_THROTTLING_LOW
diff --git a/block/blk-wbt.h b/block/blk-wbt.h
index ba6cca5849a6..8a029e138f7a 100644
--- a/block/blk-wbt.h
+++ b/block/blk-wbt.h
@@ -18,10 +18,6 @@ u64 wbt_default_latency_nsec(struct request_queue *);
#else
-static inline int wbt_init(struct gendisk *disk)
-{
- return -EINVAL;
-}
static inline void wbt_disable_default(struct gendisk *disk)
{
}
@@ -31,21 +27,6 @@ static inline void wbt_enable_default(struct gendisk *disk)
static inline void wbt_set_write_cache(struct request_queue *q, bool wc)
{
}
-static inline u64 wbt_get_min_lat(struct request_queue *q)
-{
- return 0;
-}
-static inline void wbt_set_min_lat(struct request_queue *q, u64 val)
-{
-}
-static inline u64 wbt_default_latency_nsec(struct request_queue *q)
-{
- return 0;
-}
-static inline bool wbt_disabled(struct request_queue *q)
-{
- return true;
-}
#endif /* CONFIG_BLK_WBT */
--
2.39.2
