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authorAnton Staaf <robotboy@chromium.org>2011-06-08 15:15:00 -0700
committerSimon Glass <sjg@chromium.org>2011-08-29 10:39:19 -0700
commitf97bdd6f0eba1ec18fa70cd059f9b8d504f9c8c2 (patch)
tree2aa027a0e1b6001c41c90ef14dbe4f9f72d63153 /fs
parentb28c3c2179de844442fc1c8fcc090a3582f471d0 (diff)
ext2: Simplify partial sector access logic
Previously reading or writing zero full sectors (reading the end of one sector and the beginning of the next for example) was special cased and involved stack allocating a second sector buffer. This change uses the same code path for this case as well as when there are a non-zero number of full sectors to access. The result is easier to read and reduces the maximum stack used. BUG=None TEST=run "ext2ls mmc 0:3" on Seaboard Change-Id: Iac92172bf40724302292a2a9695cb61029b02ae7 Reviewed-on: http://gerrit.chromium.org/gerrit/2327 Reviewed-by: Anton Staaf <robotboy@chromium.org> Tested-by: Anton Staaf <robotboy@chromium.org>
Diffstat (limited to 'fs')
-rw-r--r--fs/ext2/dev.c42
1 files changed, 15 insertions, 27 deletions
diff --git a/fs/ext2/dev.c b/fs/ext2/dev.c
index 4365b3b882a..78851d0a5d0 100644
--- a/fs/ext2/dev.c
+++ b/fs/ext2/dev.c
@@ -53,7 +53,7 @@ int ext2fs_set_blk_dev(block_dev_desc_t *rbdd, int part)
int ext2fs_devread(int sector, int byte_offset, int byte_len, char *buf)
{
char sec_buf[SECTOR_SIZE];
- unsigned block_len;
+ unsigned sectors;
/*
* Check partition boundaries
@@ -98,35 +98,23 @@ int ext2fs_devread(int sector, int byte_offset, int byte_len, char *buf)
sector++;
}
- if (byte_len == 0)
- return 1;
-
/* read sector aligned part */
- block_len = byte_len & ~(SECTOR_SIZE - 1);
-
- if (block_len == 0) {
- u8 p[SECTOR_SIZE];
-
- block_len = SECTOR_SIZE;
- ext2fs_block_dev_desc->block_read(ext2fs_block_dev_desc->dev,
- part_info.start + sector,
- 1, (unsigned long *)p);
- memcpy(buf, p, byte_len);
- return 1;
- }
+ sectors = byte_len / SECTOR_SIZE;
+
+ if (sectors > 0) {
+ if (ext2fs_block_dev_desc->block_read(
+ ext2fs_block_dev_desc->dev,
+ part_info.start + sector,
+ sectors,
+ (unsigned long *) buf) != sectors) {
+ printf(" ** %s read error - block\n", __func__);
+ return 0;
+ }
- if (ext2fs_block_dev_desc->block_read(ext2fs_block_dev_desc->dev,
- part_info.start + sector,
- block_len / SECTOR_SIZE,
- (unsigned long *) buf) !=
- block_len / SECTOR_SIZE) {
- printf(" ** %s read error - block\n", __func__);
- return 0;
+ buf += sectors * SECTOR_SIZE;
+ byte_len -= sectors * SECTOR_SIZE;
+ sector += sectors;
}
- block_len = byte_len & ~(SECTOR_SIZE - 1);
- buf += block_len;
- byte_len -= block_len;
- sector += block_len / SECTOR_SIZE;
if (byte_len != 0) {
/* read rest of data which are not in whole sector */