[U-Boot] [PATCH] ext2: Cache line aligned partial sector bounce buffer
Currently, if a device read request is done that does not begin or end on a sector boundary a stack allocated bounce buffer is used to perform the read, and then just the part of the sector that is needed is copied into the users buffer. This stack allocation can mean that the bounce buffer will not be aligned to the dcache line size. This is a problem when caches are enabled because unaligned cache invalidates are not safe.
This patch allocates a cache line size aligned sector sized bounce buffer the first time that ext2fs_devread is called.
Signed-off-by: Anton Staaf robotboy@chromium.org Cc: Lukasz Majewski l.majewski@samsung.com Cc: Mike Frysinger vapier@gentoo.org Cc: Dave Liu r63238@freescale.com Cc: Andy Fleming afleming@gmail.com Cc: Albert ARIBAUD albert.u.boot@aribaud.net ---
This patch depends on Lukasz Majewski's dcache line size patch sent to the list in: http://patchwork.ozlabs.org/patch/110501/
fs/ext2/dev.c | 9 ++++++++- 1 files changed, 8 insertions(+), 1 deletions(-)
diff --git a/fs/ext2/dev.c b/fs/ext2/dev.c index 78851d0..4b2aeef 100644 --- a/fs/ext2/dev.c +++ b/fs/ext2/dev.c @@ -26,6 +26,7 @@
#include <common.h> #include <config.h> +#include <malloc.h> #include <ext2fs.h>
static block_dev_desc_t *ext2fs_block_dev_desc; @@ -52,9 +53,15 @@ 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]; + static char *sec_buf; unsigned sectors;
+ if (sec_buf == NULL) + sec_buf = memalign(get_dcache_line_size(), SECTOR_SIZE); + + if (sec_buf == NULL) + return 0; //-ENOMEM + /* * Check partition boundaries */
Ooops, expect a follow up without that last minute addition of a C++ style comment about ENOMEM, sorry...
-Anton
On Mon, Aug 22, 2011 at 1:03 PM, Anton Staaf robotboy@chromium.org wrote:
Currently, if a device read request is done that does not begin or end on a sector boundary a stack allocated bounce buffer is used to perform the read, and then just the part of the sector that is needed is copied into the users buffer. This stack allocation can mean that the bounce buffer will not be aligned to the dcache line size. This is a problem when caches are enabled because unaligned cache invalidates are not safe.
This patch allocates a cache line size aligned sector sized bounce buffer the first time that ext2fs_devread is called.
Signed-off-by: Anton Staaf robotboy@chromium.org Cc: Lukasz Majewski l.majewski@samsung.com Cc: Mike Frysinger vapier@gentoo.org Cc: Dave Liu r63238@freescale.com Cc: Andy Fleming afleming@gmail.com Cc: Albert ARIBAUD albert.u.boot@aribaud.net
This patch depends on Lukasz Majewski's dcache line size patch sent to the list in: http://patchwork.ozlabs.org/patch/110501/
fs/ext2/dev.c | 9 ++++++++- 1 files changed, 8 insertions(+), 1 deletions(-)
diff --git a/fs/ext2/dev.c b/fs/ext2/dev.c index 78851d0..4b2aeef 100644 --- a/fs/ext2/dev.c +++ b/fs/ext2/dev.c @@ -26,6 +26,7 @@
#include <common.h> #include <config.h> +#include <malloc.h> #include <ext2fs.h>
static block_dev_desc_t *ext2fs_block_dev_desc; @@ -52,9 +53,15 @@ 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];
- static char *sec_buf;
unsigned sectors;
- if (sec_buf == NULL)
- sec_buf = memalign(get_dcache_line_size(), SECTOR_SIZE);
- if (sec_buf == NULL)
- return 0; //-ENOMEM
/* * Check partition boundaries */ -- 1.7.3.1
participants (2)
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Anton Staaf -
Anton Staaf