From 142a80ffc3b537a9c45acd2444a42a77f147c602 Mon Sep 17 00:00:00 2001
From: Ilya Yanok <yanok@emcraft.com>
Date: Thu, 13 Nov 2008 19:49:36 +0300
Subject: [PATCH] jffs2: cache data_crc results
As we moved data_crc() invocation from jffs2_1pass_build_lists() to
jffs2_1pass_read_inode() data_crc is going to be calculated on each
inode access. This patch adds caching of data_crc() results. There
is no significant improvement in speed (because of flash access
caching added in previous patch I think, crc in RAM is really fast)
but this patch impacts memory usage -- every b_node structure uses
12 bytes instead of 8.
Signed-off-by: Alexey Neyman <avn@emcraft.com>
Signed-off-by: Ilya Yanok <yanok@emcraft.com>
---
fs/jffs2/jffs2_1pass.c | 5 ++++-
fs/jffs2/jffs2_private.h | 1 +
2 files changed, 5 insertions(+), 1 deletion(-)
diff --git a/fs/jffs2/jffs2_1pass.c b/fs/jffs2/jffs2_1pass.c
index 4e49a056694..be7c1a190b5 100644
--- a/fs/jffs2/jffs2_1pass.c
+++ b/fs/jffs2/jffs2_1pass.c
@@ -765,7 +765,10 @@ jffs2_1pass_read_inode(struct b_lists *pL, u32 inode, char *dest)
put_fl_mem(jNode, pL->readbuf);
continue;
}
- if (!data_crc(jNode)) {
+ if (b->datacrc == CRC_UNKNOWN)
+ b->datacrc = data_crc(jNode) ?
+ CRC_OK : CRC_BAD;
+ if (b->datacrc == CRC_BAD) {
put_fl_mem(jNode, pL->readbuf);
continue;
}
diff --git a/fs/jffs2/jffs2_private.h b/fs/jffs2/jffs2_private.h
index 3633deaaf83..658b3252190 100644
--- a/fs/jffs2/jffs2_private.h
+++ b/fs/jffs2/jffs2_private.h
@@ -7,6 +7,7 @@
struct b_node {
u32 offset;
struct b_node *next;
+ enum { CRC_UNKNOWN = 0, CRC_OK, CRC_BAD } datacrc;
};
struct b_list {
--
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