From: Jens Axboe <axboe@suse.de>
Date: Fri, 7 Oct 2005 08:50:56 +0000 (+0200)
Subject: [PATCH] blkparse_fmt: Check for repeated zeroes in pdu
X-Git-Tag: blktrace-0.99~25
X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=1d6376a5e39ed9d13969f4217da386e49e028906;p=blktrace.git

[PATCH] blkparse_fmt: Check for repeated zeroes in pdu

We can stop dumping the pdu (typically the cdb) if the rest is just
zeroes, append a .. to show that is the case. Saves screen space.
---

diff --git a/blkparse_fmt.c b/blkparse_fmt.c
index c445d0d..8031a8e 100644
--- a/blkparse_fmt.c
+++ b/blkparse_fmt.c
@@ -79,6 +79,16 @@ static inline void fill_rwbs(char *rwbs, struct blk_io_trace *t)
 	rwbs[i] = '\0';
 }
 
+static int pdu_rest_is_zero(unsigned char *pdu, int len)
+{
+	int i = 0;
+
+	while (!pdu[i] && i < len)
+		i++;
+
+	return i == len;
+}
+
 static char *dump_pdu(unsigned char *pdu_buf, int pdu_len)
 {
 	static char p[4096];
@@ -92,6 +102,16 @@ static char *dump_pdu(unsigned char *pdu_buf, int pdu_len)
 			len += sprintf(p + len, " ");
 
 		len += sprintf(p + len, "%02x", pdu_buf[i]);
+
+		/*
+		 * usually dump for cdb dumps where we can see lots of
+		 * zeroes, stop when the rest is just zeroes and indicate
+		 * so with a .. appended
+		 */
+		if (!pdu_buf[i] && pdu_rest_is_zero(pdu_buf + i, pdu_len - i)) {
+			sprintf(p + len, " ..");
+			break;
+		}
 	}
 
 	return p;