From a7b7d85d8da39ab57b13b5ef4043bdde7db80719 Mon Sep 17 00:00:00 2001
From: bapt <bapt@FreeBSD.org>
Date: Mon, 11 Dec 2017 14:54:42 +0000
Subject: [PATCH] Remove hard coded number of lun definition

The number of lun exposed is now exposed via sysctl by the kernel.
Use that number in ctlstat instead of the hardcoded version
Add a backward compatibility in case the sysctl(2) request fails.

This also allows ctlstat -l 1118 to actually work when having more than
1024 luns.

Reviewed by:	avg, manu (both before the backward compatibility addition)
Approved by:	avg, manu (both before the backward compatibility addition)
MFC after:	2 weeks
Sponsored by:	Gandi.net
Differential Revision:	https://reviews.freebsd.org/D13446
---
 usr.bin/ctlstat/ctlstat.c | 28 +++++++++++++++++-----------
 1 file changed, 17 insertions(+), 11 deletions(-)

diff --git a/usr.bin/ctlstat/ctlstat.c b/usr.bin/ctlstat/ctlstat.c
index 0ec9e632ee80..34e340faddea 100644
--- a/usr.bin/ctlstat/ctlstat.c
+++ b/usr.bin/ctlstat/ctlstat.c
@@ -74,12 +74,7 @@ __FBSDID("$FreeBSD$");
  */
 #define	CTL_STAT_NUM_ITEMS	256
 
-/*
- * The default number of LUN selection bits we allocate.  This is large
- * because we don't currently increase it if the user specifies a LUN
- * number of 1024 or larger.
- */
-#define	CTL_STAT_BITS		1024L
+static int ctl_stat_bits;
 
 static const char *ctlstat_opts = "Cc:Ddhjl:n:p:tw:";
 static const char *ctlstat_usage = "Usage:  ctlstat [-CDdjht] [-l lunnum]"
@@ -127,7 +122,7 @@ struct ctlstat_context {
 	struct ctl_cpu_stats cur_cpu, prev_cpu;
 	uint64_t cur_total_jiffies, prev_total_jiffies;
 	uint64_t cur_idle, prev_idle;
-	bitstr_t bit_decl(item_mask, CTL_STAT_BITS);
+	bitstr_t *item_mask;
 	int cur_items, prev_items;
 	int cur_alloc, prev_alloc;
 	int numdevs;
@@ -431,7 +426,7 @@ ctlstat_standard(struct ctlstat_context *ctx) {
 					(F_TIMEVAL(ctx) != 0) ? "      " : "");
 				n = 3;
 			} else {
-				for (i = n = 0; i < min(CTL_STAT_BITS,
+				for (i = n = 0; i < min(ctl_stat_bits,
 				     ctx->cur_items); i++) {
 					int item;
 
@@ -539,7 +534,7 @@ ctlstat_standard(struct ctlstat_context *ctx) {
 				dmas_per_sec[i], mbsec[i]);
 		}
 	} else {
-		for (i = n = 0; i < min(CTL_STAT_BITS, ctx->cur_items); i++) {
+		for (i = n = 0; i < min(ctl_stat_bits, ctx->cur_items); i++) {
 			long double mbsec, kb_per_transfer;
 			long double transfers_per_sec;
 			long double ms_per_transfer;
@@ -582,6 +577,7 @@ main(int argc, char **argv)
 	int c;
 	int count, waittime;
 	int fd, retval;
+	size_t size;
 	struct ctlstat_context ctx;
 	struct ctl_io_stats *tmp_stats;
 
@@ -596,6 +592,16 @@ main(int argc, char **argv)
 	ctx.flags |= CTLSTAT_FLAG_FIRST_RUN;
 	ctx.flags |= CTLSTAT_FLAG_HEADER;
 
+	size = sizeof(ctl_stat_bits);
+	if (sysctlbyname("kern.cam.ctl.max_luns", &ctl_stat_bits, &size, NULL,
+	    0) == -1) {
+		/* Backward compatibility for where the sysctl wasn't exposed */
+		ctl_stat_bits = 1024;
+	}
+	ctx.item_mask = bit_alloc(ctl_stat_bits);
+	if (ctx.item_mask == NULL)
+		err(1, "bit_alloc() failed");
+
 	while ((c = getopt(argc, argv, ctlstat_opts)) != -1) {
 		switch (c) {
 		case 'C':
@@ -622,7 +628,7 @@ main(int argc, char **argv)
 			int cur_lun;
 
 			cur_lun = atoi(optarg);
-			if (cur_lun > CTL_STAT_BITS)
+			if (cur_lun > ctl_stat_bits)
 				errx(1, "Invalid LUN number %d", cur_lun);
 
 			if (!F_MASK(&ctx))
@@ -641,7 +647,7 @@ main(int argc, char **argv)
 			int cur_port;
 
 			cur_port = atoi(optarg);
-			if (cur_port > CTL_STAT_BITS)
+			if (cur_port > ctl_stat_bits)
 				errx(1, "Invalid port number %d", cur_port);
 
 			if (!F_MASK(&ctx))