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ext2: Simplify partial sector access logic

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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.

Signed-off-by: Anton Staaf <robotboy@chromium.org>
Cc: Andy Fleming <afleming@freescale.com>
Acked-by: Detlev Zundel <dzu@denx.de>
This commit is contained in:
Anton Staaf 2011-06-13 11:40:40 +00:00 committed by Wolfgang Denk
parent 9bac35f57b
commit d961c188b2
1 changed files with 14 additions and 26 deletions
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40
fs/ext2/dev.c
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@ -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
@ -98,36 +98,24 @@ 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);
sectors = byte_len / SECTOR_SIZE;
if (block_len == 0) {
u8 p[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;
}
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;
buf += sectors * SECTOR_SIZE;
byte_len -= sectors * SECTOR_SIZE;
sector += sectors;
}
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;
}
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 */
if (ext2fs_block_dev_desc->