From 436da3cd233e7166b5ce9293dbd28092cf37bcc9 Mon Sep 17 00:00:00 2001
From: "u-boot@lakedaemon.net" <u-boot@lakedaemon.net>
Date: Wed, 28 Mar 2012 04:37:11 +0000
Subject: [PATCH] ext2load: increase read speed
This patch dramatically drops the amount of time u-boot needs to read a
file from an ext2 partition. On a typical 2 to 5 MB file (kernels and
initrds) it goes from tens of seconds to a couple seconds.
All we are doing here is grouping contiguous blocks into one read.
Boot tested on Globalscale Technologies Dreamplug (Kirkwood ARM SoC)
with three different files. sha1sums were calculated in Linux
userspace, and then confirmed after ext2load.
Signed-off-by: Jason Cooper <u-boot@lakedaemon.net>
Tested-by: Eric Nelson <eric.nelson@boundarydevices.com>
Tested-by: Thierry Reding <thierry.reding@avionic-design.de>
---
fs/ext2/ext2fs.c | 26 ++++++++++++++++++++++++--
1 file changed, 24 insertions(+), 2 deletions(-)
diff --git a/fs/ext2/ext2fs.c b/fs/ext2/ext2fs.c
index f621741e40..f1fce48a39 100644
--- a/fs/ext2/ext2fs.c
+++ b/fs/ext2/ext2fs.c
@@ -420,7 +420,6 @@ int ext2fs_read_file
if (blknr < 0) {
return (-1);
}
- blknr = blknr << log2blocksize;
/* Last block. */
if (i == blockcnt - 1) {
@@ -438,6 +437,29 @@ int ext2fs_read_file
blockend -= skipfirst;
}
+ /* grab middle blocks in one go */
+ if (i != pos / blocksize && i != blockcnt - 1 && blockcnt > 3) {
+ int oldblk = blknr;
+ int blocknxt;
+ while (i < blockcnt - 1) {
+ blocknxt = ext2fs_read_block(node, i + 1);
+ if (blocknxt == (oldblk + 1)) {
+ oldblk = blocknxt;
+ i++;
+ } else {
+ blocknxt = ext2fs_read_block(node, i);
+ break;
+ }
+ }
+
+ if (oldblk == blknr)
+ blockend = blocksize;
+ else
+ blockend = (1 + blocknxt - blknr) * blocksize;
+ }
+
+ blknr = blknr << log2blocksize;
+
/* If the block number is 0 this block is not stored on disk but
is zero filled instead. */
if (blknr) {
@@ -450,7 +472,7 @@ int ext2fs_read_file
} else {
memset (buf, 0, blocksize - skipfirst);
}
- buf += blocksize - skipfirst;
+ buf += blockend - skipfirst;
}
return (len);
}
--
2.39.5