linux-kernel - [PATCH 03/10] qnx4fs: use memweight()

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Sun, 20 May 2012 22:23:16 +0900
From:	Akinobu Mita <akinobu.mita@...il.com>
To:	linux-kernel@...r.kernel.org, akpm@...ux-foundation.org
Cc:	Akinobu Mita <akinobu.mita@...il.com>,
	Anders Larsen <al@...rsen.net>
Subject: [PATCH 03/10] qnx4fs: use memweight()

Use memweight() to count the total number of bits clear in memory area.

Signed-off-by: Akinobu Mita <akinobu.mita@...il.com>
Cc: Anders Larsen <al@...rsen.net>
---
 fs/qnx4/bitmap.c |   24 +++++-------------------
 1 files changed, 5 insertions(+), 19 deletions(-)

diff --git a/fs/qnx4/bitmap.c b/fs/qnx4/bitmap.c
index 22e0d60..fc04ef1 100644
--- a/fs/qnx4/bitmap.c
+++ b/fs/qnx4/bitmap.c
@@ -17,23 +17,6 @@
 #include <linux/bitops.h>
 #include "qnx4.h"
 
-static void count_bits(register const char *bmPart, register int size,
-		       int *const tf)
-{
-	char b;
-	int tot = *tf;
-
-	if (size > QNX4_BLOCK_SIZE) {
-		size = QNX4_BLOCK_SIZE;
-	}
-	do {
-		b = *bmPart++;
-		tot += 8 - hweight8(b);
-		size--;
-	} while (size != 0);
-	*tf = tot;
-}
-
 unsigned long qnx4_count_free_blocks(struct super_block *sb)
 {
 	int start = le32_to_cpu(qnx4_sb(sb)->BitMap->di_first_xtnt.xtnt_blk) - 1;
@@ -44,13 +27,16 @@ unsigned long qnx4_count_free_blocks(struct super_block *sb)
 	struct buffer_head *bh;
 
 	while (total < size) {
+		int bytes = min(size - total, QNX4_BLOCK_SIZE);
+
 		if ((bh = sb_bread(sb, start + offset)) == NULL) {
 			printk(KERN_ERR "qnx4: I/O error in counting free blocks\n");
 			break;
 		}
-		count_bits(bh->b_data, size - total, &total_free);
+		total_free += bytes * BITS_PER_BYTE-
+				memweight(bh->b_data, bytes);
 		brelse(bh);
-		total += QNX4_BLOCK_SIZE;
+		total += bytes;
 		offset++;
 	}
 
-- 
1.7.7.6

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/