On 2021-01-05 18:27, Greg KH wrote:
Oops, forgot the big problem that I noticed:

On Mon, Jan 04, 2021 at 07:15:51PM -0800, Can Guo wrote:
+static ssize_t monitor_show(struct device *dev, struct device_attribute *attr,
+                           char *buf)
+{
+       struct ufs_hba *hba = dev_get_drvdata(dev);
+       struct ufs_qcom_host *host = ufshcd_get_variant(hba);
+       struct ufs_qcom_perf_monitor *mon = &host->monitor;
+       unsigned long nr_sec_rd, nr_sec_wr, busy_us_rd, busy_us_wr;
+ unsigned long lat_max_rd, lat_min_rd, lat_sum_rd, lat_avg_rd, nr_req_rd; + unsigned long lat_max_wr, lat_min_wr, lat_sum_wr, lat_avg_wr, nr_req_wr;
+       bool is_enabled;
+
+       /*
+        * Don't lock the host lock since user needs to cat the entry very
+        * frequently during performance test, otherwise it may impact the
+        * performance.
+        */
+       is_enabled = mon->enabled;
+       if (!is_enabled)
+               goto print_usage;
+
+       nr_sec_rd = mon->nr_sec_rw[READ];
+       nr_sec_wr = mon->nr_sec_rw[WRITE];
+       busy_us_rd = ktime_to_us(mon->total_busy[READ]);
+       busy_us_wr = ktime_to_us(mon->total_busy[WRITE]);
+
+       nr_req_rd = mon->nr_req[READ];
+       lat_max_rd = ktime_to_us(mon->lat_max[READ]);
+       lat_min_rd = ktime_to_us(mon->lat_min[READ]);
+       lat_sum_rd = ktime_to_us(mon->lat_sum[READ]);
+       lat_avg_rd = lat_sum_rd / nr_req_rd;
+
+       nr_req_wr = mon->nr_req[WRITE];
+       lat_max_wr = ktime_to_us(mon->lat_max[WRITE]);
+       lat_min_wr = ktime_to_us(mon->lat_min[WRITE]);
+       lat_sum_wr = ktime_to_us(mon->lat_sum[WRITE]);
+       lat_avg_wr = lat_sum_wr / nr_req_wr;
+
+ return scnprintf(buf, PAGE_SIZE, "Read %lu %s %lu us, %lu %s max %lu | min %lu | avg %lu | sum %lu\nWrite %lu %s %lu us, %lu %s max %lu | min %lu | avg %lu | sum %lu\n",
+                nr_sec_rd, "sectors (in 512 bytes) in ", busy_us_rd,
+                nr_req_rd, "read reqs completed, latencies in us: ",
+                lat_max_rd, lat_min_rd, lat_avg_rd, lat_sum_rd,
+                nr_sec_wr, "sectors (in 512 bytes) in ", busy_us_wr,
+                nr_req_wr, "write reqs completed, latencies in us: ",
+                lat_max_wr, lat_min_wr, lat_avg_wr, lat_sum_wr);

sysfs is one-value-per-file, not
throw-everything-in-one-file-and-hope-userspace-can-parse-it.

This is not acceptable at all.  Why not just use debugfs for stats like
this?

Also, use sysfs_emit() for any new sysfs files please.

thanks,

greg k-h

Hi Greg,

Thanks for the comments, I will rework the change to make it right.

Regards,
Can Guo.

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