[JFFS2] Use point(), if available, to check newly erased blocks.

Faster and won't trash the D-cache.

Signed-off-by: Joakim Tjernlund <Joakim.Tjernlund@transmode.se>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

diff --git a/fs/jffs2/erase.c b/fs/jffs2/erase.c
index bdab9bc51d6556b9b401c8c9f8131f01202b089d..e9e3c2c330cc586d3913e9bbcad06088da933525 100644 (file)
--- a/fs/jffs2/erase.c
+++ b/fs/jffs2/erase.c
@@ -317,6 +317,33 @@ static int jffs2_block_check_erase(struct jffs2_sb_info *c, struct jffs2_erasebl
        size_t retlen;
        int ret = -EIO;
 
+       if (c->mtd->point) {
+               unsigned long *wordebuf;
+
+               ret = c->mtd->point(c->mtd, jeb->offset, c->sector_size, &retlen, (unsigned char **)&ebuf);
+               if (ret) {
+                       D1(printk(KERN_DEBUG "MTD point failed %d\n", ret));
+                       goto do_flash_read;
+               }
+               if (retlen < c->sector_size) {
+                       /* Don't muck about if it won't let us point to the whole erase sector */
+                       D1(printk(KERN_DEBUG "MTD point returned len too short: 0x%zx\n", retlen));
+                       c->mtd->unpoint(c->mtd, ebuf, jeb->offset, c->sector_size);
+                       goto do_flash_read;
+               }
+               wordebuf = ebuf-sizeof(*wordebuf);
+               retlen /= sizeof(*wordebuf);
+               do {
+                  if (*++wordebuf != ~0)
+                          break;
+               } while(--retlen);
+               c->mtd->unpoint(c->mtd, ebuf, jeb->offset, c->sector_size);
+               if (retlen)
+                       printk(KERN_WARNING "Newly-erased block contained word 0x%lx at offset 0x%08x\n",
+                              *wordebuf, jeb->offset + c->sector_size-retlen*sizeof(*wordebuf));
+               return 0;
+       }
+ do_flash_read:
        ebuf = kmalloc(PAGE_SIZE, GFP_KERNEL);
        if (!ebuf) {
                printk(KERN_WARNING "Failed to allocate page buffer for verifying erase at 0x%08x. Refiling\n", jeb->offset);