fs/fat/fatwrite: Local variable as buffer to store dir_slot entries

fill_dir_slot use get_contents_vfatname_block as a temporary buffer for
constructing a list of dir_slot entries. To save the memory and providing
correct type of memory for above usage, a local buffer with accurate size
declaration is introduced.

The local array size 640 is used because for long file name entry,
each entry use 32 bytes, one entry can store up to 13 characters.
The maximum number of entry possible is 20. So, total size is
32*20=640bytes.

Signed-off-by: Genevieve Chan <ccheauya@altera.com>
Signed-off-by: Tien Fong Chee <tfchee@altera.com>

diff --git a/fs/fat/fat_write.c b/fs/fat/fat_write.c
index 0583af310a56ca586ae6728f7eded14be4519f5a..40a3860e47c9f58d63dc6b813b53fd772bd11c96 100644 (file)
--- a/fs/fat/fat_write.c
+++ b/fs/fat/fat_write.c
@@ -327,7 +327,8 @@ static void flush_dir_table(fsdata *mydata, dir_entry **dentptr);
 static void
 fill_dir_slot(fsdata *mydata, dir_entry **dentptr, const char *l_name)
 {
-       dir_slot *slotptr = (dir_slot *)get_contents_vfatname_block;
+       __u8 temp_dir_slot_buffer[MAX_LFN_SLOT * sizeof(dir_slot)];
+       dir_slot *slotptr = (dir_slot *)temp_dir_slot_buffer;
        __u8 counter = 0, checksum;
        int idx = 0, ret;
 

diff --git a/include/fat.h b/include/fat.h
index 8ec91cda753ba562d9877a1d76a983b17150b5d3..e38f3808af2524463507848b89044f37433f54e8 100644 (file)
--- a/include/fat.h
+++ b/include/fat.h
@@ -33,6 +33,8 @@
 #define FAT16BUFSIZE   (FATBUFSIZE/2)
 #define FAT32BUFSIZE   (FATBUFSIZE/4)
 
+/* Maximum number of entry for long file name according to spec */
+#define MAX_LFN_SLOT   20
 
 /* Filesystem identifiers */
 #define FAT12_SIGN     "FAT12   "