From: John L. Hammond <john.hammond@intel.com>
Date: Mon, 13 May 2013 16:42:36 +0000 (-0500)
Subject: LU-2979 lprocfs: use stats counter index for *pos
X-Git-Tag: 2.4.0-RC1~8
X-Git-Url: https://git.whamcloud.com/?p=fs%2Flustre-release.git;a=commitdiff_plain;h=6fe7c32906f67f43d815c884ed8a902bb2333992;ds=sidebyside

LU-2979 lprocfs: use stats counter index for *pos

In lprocfs_stats_seq_{start,next,show,stop}() encode the counter index
(rather than the counter address) into *pos. Doing so simplifies these
functions and fixes a bug in the case of per-CPU stats where no stats
would be displayed at all if no events had yet occurred on CPU 0.

Signed-off-by: John L. Hammond <john.hammond@intel.com>
Change-Id: Id50f8ae480e151f8e16382db27eef8025ef69f15
Reviewed-on: http://review.whamcloud.com/6328
Tested-by: Hudson
Reviewed-by: wangdi <di.wang@intel.com>
Reviewed-by: Bobi Jam <bobijam@gmail.com>
Reviewed-by: Emoly Liu <emoly.liu@intel.com>
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Keith Mannthey <keith.mannthey@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>
---

diff --git a/lustre/obdclass/lprocfs_status.c b/lustre/obdclass/lprocfs_status.c
index 5ce7661..97d4107 100644
--- a/lustre/obdclass/lprocfs_status.c
+++ b/lustre/obdclass/lprocfs_status.c
@@ -1380,10 +1380,9 @@ static ssize_t lprocfs_stats_seq_write(struct file *file, const char *buf,
 
 static void *lprocfs_stats_seq_start(struct seq_file *p, loff_t *pos)
 {
-        struct lprocfs_stats *stats = p->private;
-        /* return 1st cpu location */
-        return (*pos >= stats->ls_num) ? NULL :
-		lprocfs_stats_counter_get(stats, 0, *pos);
+	struct lprocfs_stats *stats = p->private;
+
+	return (*pos < stats->ls_num) ? pos : NULL;
 }
 
 static void lprocfs_stats_seq_stop(struct seq_file *p, void *v)
@@ -1392,70 +1391,61 @@ static void lprocfs_stats_seq_stop(struct seq_file *p, void *v)
 
 static void *lprocfs_stats_seq_next(struct seq_file *p, void *v, loff_t *pos)
 {
-        struct lprocfs_stats *stats = p->private;
-        ++*pos;
-        return (*pos >= stats->ls_num) ? NULL :
-		lprocfs_stats_counter_get(stats, 0, *pos);
+	(*pos)++;
+
+	return lprocfs_stats_seq_start(p, pos);
 }
 
 /* seq file export of one lprocfs counter */
 static int lprocfs_stats_seq_show(struct seq_file *p, void *v)
 {
 	struct lprocfs_stats		*stats	= p->private;
-	struct lprocfs_counter		*cntr	= v;
-	struct lprocfs_counter		ret;
-	struct lprocfs_counter_header	*header;
-	int				entry_size;
-	int				idx;
-	int				rc	= 0;
+	struct lprocfs_counter_header	*hdr;
+	struct lprocfs_counter		 ctr;
+	int				 idx	= *(loff_t *)v;
+	int				 rc	= 0;
 
-	if (cntr == &(stats->ls_percpu[0])->lp_cntr[0]) {
+	if (idx == 0) {
 		struct timeval now;
+
 		cfs_gettimeofday(&now);
 		rc = seq_printf(p, "%-25s %lu.%lu secs.usecs\n",
 				"snapshot_time", now.tv_sec, now.tv_usec);
 		if (rc < 0)
 			return rc;
 	}
-	entry_size = sizeof(*cntr);
-	if (stats->ls_flags & LPROCFS_STATS_FLAG_IRQ_SAFE)
-		entry_size += sizeof(__s64);
-	idx = ((void *)cntr - (void *)&(stats->ls_percpu[0])->lp_cntr[0]) /
-		entry_size;
 
-	header = &stats->ls_cnt_header[idx];
-	lprocfs_stats_collect(stats, idx, &ret);
+	hdr = &stats->ls_cnt_header[idx];
+	lprocfs_stats_collect(stats, idx, &ctr);
 
-	if (ret.lc_count == 0)
+	if (ctr.lc_count == 0)
 		goto out;
 
-	rc = seq_printf(p, "%-25s "LPD64" samples [%s]", header->lc_name,
-			ret.lc_count, header->lc_units);
-
+	rc = seq_printf(p, "%-25s "LPD64" samples [%s]", hdr->lc_name,
+			ctr.lc_count, hdr->lc_units);
 	if (rc < 0)
 		goto out;
 
-	if ((header->lc_config & LPROCFS_CNTR_AVGMINMAX) &&
-	    (ret.lc_count > 0)) {
+	if ((hdr->lc_config & LPROCFS_CNTR_AVGMINMAX) && ctr.lc_count > 0) {
 		rc = seq_printf(p, " "LPD64" "LPD64" "LPD64,
-				ret.lc_min, ret.lc_max, ret.lc_sum);
+				ctr.lc_min, ctr.lc_max, ctr.lc_sum);
 		if (rc < 0)
 			goto out;
-		if (header->lc_config & LPROCFS_CNTR_STDDEV)
-			rc = seq_printf(p, " "LPD64, ret.lc_sumsquare);
+		if (hdr->lc_config & LPROCFS_CNTR_STDDEV)
+			rc = seq_printf(p, " "LPD64, ctr.lc_sumsquare);
 		if (rc < 0)
 			goto out;
 	}
 	rc = seq_printf(p, "\n");
- out:
+out:
 	return (rc < 0) ? rc : 0;
 }
 
 struct seq_operations lprocfs_stats_seq_sops = {
-        start: lprocfs_stats_seq_start,
-        stop:  lprocfs_stats_seq_stop,
-        next:  lprocfs_stats_seq_next,
-        show:  lprocfs_stats_seq_show,
+	.start	= lprocfs_stats_seq_start,
+	.stop	= lprocfs_stats_seq_stop,
+	.next	= lprocfs_stats_seq_next,
+	.show	= lprocfs_stats_seq_show,
 };
 
 static int lprocfs_stats_seq_open(struct inode *inode, struct file *file)