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>

1 files changed, 9 insertions, 1 deletions

diff --git a/fs/ubifs/orphan.c b/fs/ubifs/orphan.c
index 82009c74b6a3..2cdbd31641d7 100644
--- 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;
 }