[U-Boot] [PATCH 1/2] fs: fat: dynamically allocate memory for temporary buffer

tien.fong.chee at intel.com
2019-01-17T06:52:27Z

From: Stefan Agner <stefan.ag...@toradex.com>

Drop the statically allocated get_contents_vfatname_block and
dynamically allocate a buffer only if required. This saves
64KiB of memory.

Signed-off-by: Stefan Agner <stefan.ag...@toradex.com>
Signed-off-by: Tien Fong Chee <tien.fong.chee@intel.com>
---
fs/fat/fat.c | 19 +++++++++++++------
1 files changed, 13 insertions(+), 6 deletions(-)

diff --git a/fs/fat/fat.c b/fs/fat/fat.c
index 8803fb4..aa4636d 100644
--- a/fs/fat/fat.c
+++ b/fs/fat/fat.c
@@ -307,9 +307,6 @@ get_cluster(fsdata *mydata, __u32 clustnum, __u8 *buffer, unsigned long size)
* into 'buffer'.
* Update the number of bytes read in *gotsize or return -1 on fatal errors.
*/
-__u8 get_contents_vfatname_block[MAX_CLUSTSIZE]
- __aligned(ARCH_DMA_MINALIGN);
-
static int get_contents(fsdata *mydata, dir_entry *dentptr, loff_t pos,
__u8 *buffer, loff_t maxsize, loff_t *gotsize)
{
@@ -320,7 +317,7 @@ static int get_contents(fsdata *mydata, dir_entry *dentptr, loff_t pos,
loff_t actsize;

*gotsize = 0;
- debug("Filesize: %llu bytes\n", filesize);
+ debug("Filesize: %llu bytes, starting at pos %llu\n", filesize, pos);

if (pos >= filesize) {
debug("Read position past EOF: %llu\n", pos);
@@ -352,15 +349,25 @@ static int get_contents(fsdata *mydata, dir_entry *dentptr, loff_t pos,

/* align to beginning of next cluster if any */
if (pos) {
+ __u8 *tmp_buffer;
+
+ tmp_buffer = malloc_cache_aligned(MAX_CLUSTSIZE);
+ if (!tmp_buffer) {
+ debug("Error: allocating buffer\n");
+ return -ENOMEM;
+ }
+
actsize = min(filesize, (loff_t)bytesperclust);
- if (get_cluster(mydata, curclust, get_contents_vfatname_block,
+ if (get_cluster(mydata, curclust, tmp_buffer,
(int)actsize) != 0) {
printf("Error reading cluster\n");
+ free(tmp_buffer);
return -1;
}
filesize -= actsize;
actsize -= pos;
- memcpy(buffer, get_contents_vfatname_block + pos, actsize);
+ memcpy(buffer, tmp_buffer + pos, actsize);
+ free(tmp_buffer);
*gotsize += actsize;
if (!filesize)
return 0;
--
1.7.7.4