fs/fat: Reduce stack usage

We have limited stack in SPL builds.  Drop itrblock and move to
malloc/free of itr to move this off of the stack.  As part of this fix a
double-free issue in fat_size().

Signed-off-by: Tom Rini <trini@konsulko.com>
---
Rework to use malloc/free as moving this to a global overflows some SH
targets.

diff --git a/fs/fat/fat.c b/fs/fat/fat.c
index f0284398b41dbed60869deeabadc9407b7e65b80..36a309c73c2713f73a8f7f4f873b6e0d7ae21d68 100644 (file)
--- a/fs/fat/fat.c
+++ b/fs/fat/fat.c
@@ -1034,24 +1034,27 @@ int file_fat_detectfs(void)
 int fat_exists(const char *filename)
 {
        fsdata fsdata;
-       fat_itr itrblock, *itr = &itrblock;
+       fat_itr *itr;
        int ret;
 
+       itr = malloc(sizeof(fat_itr));
        ret = fat_itr_root(itr, &fsdata);
        if (ret)
                return 0;
 
        ret = fat_itr_resolve(itr, filename, TYPE_ANY);
        free(fsdata.fatbuf);
+       free(itr);
        return ret == 0;
 }
 
 int fat_size(const char *filename, loff_t *size)
 {
        fsdata fsdata;
-       fat_itr itrblock, *itr = &itrblock;
+       fat_itr *itr;
        int ret;
 
+       itr = malloc(sizeof(fat_itr));
        ret = fat_itr_root(itr, &fsdata);
        if (ret)
                return ret;
@@ -1072,8 +1075,9 @@ int fat_size(const char *filename, loff_t *size)
        }
 
        *size = FAT2CPU32(itr->dent->size);
-out:
        free(fsdata.fatbuf);
+out:
+       free(itr);
        return ret;
 }
 
@@ -1081,9 +1085,10 @@ int file_fat_read_at(const char *filename, loff_t pos, void *buffer,
                     loff_t maxsize, loff_t *actread)
 {
        fsdata fsdata;
-       fat_itr itrblock, *itr = &itrblock;
+       fat_itr *itr;
        int ret;
 
+       itr = malloc(sizeof(fat_itr));
        ret = fat_itr_root(itr, &fsdata);
        if (ret)
                return ret;
@@ -1097,6 +1102,7 @@ int file_fat_read_at(const char *filename, loff_t pos, void *buffer,
 
 out:
        free(fsdata.fatbuf);
+       free(itr);
        return ret;
 }