UBIFS: allocate orphans scan buffer on demand

Instead of using pre-allocated 'c->dbg->buf' buffer in
'dbg_scan_orphans()', dynamically allocate it when needed. The intend
is to get rid of the pre-allocated 'c->dbg->buf' buffer and save
128KiB of RAM (or more if PEB size is larger). Indeed, currently we
allocate this memory even if the user never enables any self-check,
which is wasteful.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

diff --git a/fs/ubifs/orphan.c b/fs/ubifs/orphan.c
index 82009c74b6a32e7faad97dba0d0e67b98e5bdc5d..2cdbd31641d7eff40681cae07547935f443d7b0f 100644 (file)
--- a/fs/ubifs/orphan.c
+++ b/fs/ubifs/orphan.c
@@ -892,15 +892,22 @@ static int dbg_read_orphans(struct check_info *ci, struct ubifs_scan_leb *sleb)
 static int dbg_scan_orphans(struct ubifs_info *c, struct check_info *ci)
 {
        int lnum, err = 0;
+       void *buf;
 
        /* Check no-orphans flag and skip this if no orphans */
        if (c->no_orphs)
                return 0;
 
+       buf = __vmalloc(c->leb_size, GFP_KERNEL | GFP_NOFS, PAGE_KERNEL);
+       if (!buf) {
+               ubifs_err("cannot allocate memory to check orphans");
+               return 0;
+       }
+
        for (lnum = c->orph_first; lnum <= c->orph_last; lnum++) {
                struct ubifs_scan_leb *sleb;
 
-               sleb = ubifs_scan(c, lnum, 0, c->dbg->buf, 0);
+               sleb = ubifs_scan(c, lnum, 0, buf, 0);
                if (IS_ERR(sleb)) {
                        err = PTR_ERR(sleb);
                        break;
@@ -912,6 +919,7 @@ static int dbg_scan_orphans(struct ubifs_info *c, struct check_info *ci)
                        break;
        }
 
+       vfree(buf);
        return err;
 }