UBI: Fastmap: Make WL pool size 50% of user pool size

Don't use a fixed size for the WL pool.
Make it instead 50% of the user pool.
We don't make it 100% as it is not as heavily used as the user pool.
Signed-off-by: Richard Weinberger <richard@nod.at>

drivers/mtd/ubi/build.c

@@ -949,7 +949,7 @@ int ubi_attach_mtd_dev(struct mtd_info *mtd, int ubi_num,
 	if (ubi->fm_pool.max_size < UBI_FM_MIN_POOL_SIZE)
 		ubi->fm_pool.max_size = UBI_FM_MIN_POOL_SIZE;
 
-	ubi->fm_wl_pool.max_size = UBI_FM_WL_POOL_SIZE;
+	ubi->fm_wl_pool.max_size = ubi->fm_pool.max_size / 2;
 	ubi->fm_disabled = !fm_autoconvert;
 
 	if (!ubi->fm_disabled && (int)mtd_div_by_eb(ubi->mtd->size, ubi->mtd)

drivers/mtd/ubi/ubi-media.h

@@ -403,8 +403,6 @@ struct ubi_vtbl_record {
 #define UBI_FM_MIN_POOL_SIZE	8
 #define UBI_FM_MAX_POOL_SIZE	256
 
-#define UBI_FM_WL_POOL_SIZE	25
-
 /**
  * struct ubi_fm_sb - UBI fastmap super block
  * @magic: fastmap super block magic number (%UBI_FM_SB_MAGIC)