ubi fastmap memory leak

[wang.bo116 at zte.com.cn]

Hello，
        When use ubi fastmap,i think there is a memory leak in 
"ubi_attach" function.Think about this scene：
 
        1. In "ubi_attach" function, "alloc_ai" function called to alloc a 
slab cache named "ubi_aeb_slab_cache".
        Then use "ai->aeb_slab_cache" to record the cache. 
 
        2. ubi_attach -> scan_fast -> ubi_scan_fastmap -> 
ubi_attach_fastmap,
        in "ubi_attach_fastmap" function, slab cache named 
"ubi_ainf_peb_slab" will be alloced. 
        Because of this slab cache also recorded in "ai->aeb_slab_cache", 
so, in fact it overwrite the previously one.
 
        3. When "destroy_ai" called , it only free "ubi_ainf_peb_slab".

        I made a patch base on Linux 3.9-rc6, it fix this problem use a 
temporary ai for fastmap scan.
        During my test, this patch like work good.
 
 
--- attach.c    2013-04-08 03:49:54.000000000 +0000
+++ attach1.c   2013-04-11 11:29:00.239412000 +0000
@@ -90,6 +90,7 @@
 #include "ubi.h"
 
 static int self_check_ai(struct ubi_device *ubi, struct ubi_attach_info 
*ai);
+static struct ubi_attach_info *alloc_ai(const char *slab_name);
 
 /* Temporary variables used during scanning */
 static struct ubi_ec_hdr *ech;
@@ -1314,9 +1315,14 @@ static int scan_fast(struct ubi_device *
 {
        int err, pnum, fm_anchor = -1;
        unsigned long long max_sqnum = 0;
-
+       struct ubi_attach_info *fastmap_temp_ai = NULL;
+ 
        err = -ENOMEM;
 
+       fastmap_temp_ai = alloc_ai("ubi_scan_fastmap_slab_cache");
+       if (!fastmap_temp_ai)
+               goto out;
+
        ech = kzalloc(ubi->ec_hdr_alsize, GFP_KERNEL);
        if (!ech)
                goto out;
@@ -1331,7 +1337,7 @@ static int scan_fast(struct ubi_device *
                cond_resched();
 
                dbg_gen("process PEB %d", pnum);
-               err = scan_peb(ubi, ai, pnum, &vol_id, &sqnum);
+               err = scan_peb(ubi, fastmap_temp_ai, pnum, &vol_id, 
&sqnum);
                if (err < 0)
                        goto out_vidh;
 
@@ -1343,6 +1349,7 @@ static int scan_fast(struct ubi_device *
 
        ubi_free_vid_hdr(ubi, vidh);
        kfree(ech);
+       destroy_ai(fastmap_temp_ai);
 
        if (fm_anchor < 0)
                return UBI_NO_FASTMAP;
@@ -1351,6 +1358,7 @@ static int scan_fast(struct ubi_device *
 
 out_vidh:
        ubi_free_vid_hdr(ubi, vidh);
+       destroy_ai(fastmap_temp_ai);
 out_ech:
        kfree(ech);
 out:
@@ -1419,7 +1427,7 @@ int ubi_attach(struct ubi_device *ubi, i
                                        return -ENOMEM;
                        }
 
-                       err = scan_all(ubi, ai, UBI_FM_MAX_START);
+                       err = scan_all(ubi, ai, 0);
                }
        }
 #else

 
 
 
--- fastmap.c   2013-04-08 03:49:54.000000000 +0000
+++ fastmap1.c  2013-04-11 03:22:54.432000000 +0000
@@ -559,7 +559,8 @@ static int ubi_attach_fastmap(struct ubi
        ai->volumes = RB_ROOT;
        ai->min_ec = UBI_MAX_ERASECOUNTER;
 
-       ai->aeb_slab_cache = kmem_cache_create("ubi_ainf_peb_slab",
+       if(!ai->aeb_slab_cache)
+               ai->aeb_slab_cache = 
kmem_cache_create("ubi_ainf_peb_slab",
                                               sizeof(struct 
ubi_ainf_peb),
                                               0, 0, NULL);
        if (!ai->aeb_slab_cache) {