UBI: use the whole MTD device size to get bad_peb_limit

[karo-tx-linux.git] / drivers / mtd / ubi / build.c

diff --git a/drivers/mtd/ubi/build.c b/drivers/mtd/ubi/build.c
index ce311aa75a75edec971bd168005a46d3868170d2..9980441a8886b303ffae064620257d43f440ce48 100644 (file)
--- a/drivers/mtd/ubi/build.c
+++ b/drivers/mtd/ubi/build.c
@@ -36,6 +36,7 @@
 #include <linux/namei.h>
 #include <linux/stat.h>
 #include <linux/miscdevice.h>
+#include <linux/mtd/partitions.h>
 #include <linux/log2.h>
 #include <linux/kthread.h>
 #include <linux/kernel.h>
@@ -610,11 +611,25 @@ static int io_init(struct ubi_device *ubi)
        if (mtd_can_have_bb(ubi->mtd)) {
                ubi->bad_allowed = 1;
                if (CONFIG_MTD_UBI_BEB_LIMIT > 0) {
-                       int percent = CONFIG_MTD_UBI_BEB_LIMIT;
-                       int limit = mult_frac(ubi->peb_count, percent, 100);
+                       int per1024 = CONFIG_MTD_UBI_BEB_LIMIT;
+                       int limit, device_pebs;
+                       uint64_t device_size;
+
+                       /*
+                        * Here we are using size of the entire flash chip and
+                        * not just the MTD partition size because the maximum
+                        * number of bad eraseblocks is a percentage of the
+                        * whole device and bad eraseblocks are not fairly
+                        * distributed over the flash chip. So the worst case
+                        * is that all the bad eraseblocks of the chip are in
+                        * the MTD partition we are attaching (ubi->mtd).
+                        */
+                       device_size = mtd_get_device_size(ubi->mtd);
+                       device_pebs = mtd_div_by_eb(device_size, ubi->mtd);
+                       limit = mult_frac(device_pebs, per1024, 1024);
 
                        /* Round it up */
-                       if (mult_frac(limit, 100, percent) < ubi->peb_count)
+                       if (mult_frac(limit, 1024, per1024) < device_pebs)
                                limit += 1;
                        ubi->bad_peb_limit = limit;
                }