[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>

1 files changed, 27 insertions, 0 deletions

diff --git a/fs/jffs2/erase.c b/fs/jffs2/erase.c
index bdab9bc51d65..e9e3c2c330cc 100644
--- 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);