UBI: factorize code used to manipulate volumes at attach time

Volume creation/search code is duplicated in a few places (fastmap and
non fastmap code). Create some helpers to factorize the code.

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

3 files changed, 112 insertions, 67 deletions

diff --git a/drivers/mtd/ubi/attach.c b/drivers/mtd/ubi/attach.c
index 95138ae2062f..6d34cd7b0263 100644
--- a/drivers/mtd/ubi/attach.c
+++ b/drivers/mtd/ubi/attach.c
@@ -95,6 +95,92 @@ static int self_check_ai(struct ubi_device *ubi, struct ubi_attach_info *ai);
 static struct ubi_ec_hdr *ech;
 static struct ubi_vid_hdr *vidh;
 
+#define AV_FIND         BIT(0)
+#define AV_ADD          BIT(1)
+#define AV_FIND_OR_ADD  (AV_FIND | AV_ADD)
+
+/**
+ * find_or_add_av - internal function to find a volume, add a volume or do
+ *                  both (find and add if missing).
+ * @ai: attaching information
+ * @vol_id: the requested volume ID
+ * @flags: a combination of the %AV_FIND and %AV_ADD flags describing the
+ *         expected operation. If only %AV_ADD is set, -EEXIST is returned
+ *         if the volume already exists. If only %AV_FIND is set, NULL is
+ *         returned if the volume does not exist. And if both flags are
+ *         set, the helper first tries to find an existing volume, and if
+ *         it does not exist it creates a new one.
+ * @created: in value used to inform the caller whether it"s a newly created
+ *           volume or not.
+ *
+ * This function returns a pointer to a volume description or an ERR_PTR if
+ * the operation failed. It can also return NULL if only %AV_FIND is set and
+ * the volume does not exist.
+ */
+static struct ubi_ainf_volume *find_or_add_av(struct ubi_attach_info *ai,
+                                              int vol_id, unsigned int flags,
+                                              bool *created)
+{
+        struct ubi_ainf_volume *av;
+        struct rb_node **p = &ai->volumes.rb_node, *parent = NULL;
+
+        /* Walk the volume RB-tree to look if this volume is already present */
+        while (*p) {
+                parent = *p;
+                av = rb_entry(parent, struct ubi_ainf_volume, rb);
+
+                if (vol_id == av->vol_id) {
+                        *created = false;
+
+                        if (!(flags & AV_FIND))
+                                return ERR_PTR(-EEXIST);
+
+                        return av;
+                }
+
+                if (vol_id > av->vol_id)
+                        p = &(*p)->rb_left;
+                else
+                        p = &(*p)->rb_right;
+        }
+
+        if (!(flags & AV_ADD))
+                return NULL;
+
+        /* The volume is absent - add it */
+        av = kzalloc(sizeof(*av), GFP_KERNEL);
+        if (!av)
+                return ERR_PTR(-ENOMEM);
+
+        av->vol_id = vol_id;
+
+        if (vol_id > ai->highest_vol_id)
+                ai->highest_vol_id = vol_id;
+
+        rb_link_node(&av->rb, parent, p);
+        rb_insert_color(&av->rb, &ai->volumes);
+        ai->vols_found += 1;
+        *created = true;
+        dbg_bld("added volume %d", vol_id);
+        return av;
+}
+
+/**
+ * ubi_find_or_add_av - search for a volume in the attaching information and
+ *                      add one if it does not exist.
+ * @ai: attaching information
+ * @vol_id: the requested volume ID
+ * @created: whether the volume has been created or not
+ *
+ * This function returns a pointer to the new volume description or an
+ * ERR_PTR if the operation failed.
+ */
+static struct ubi_ainf_volume *ubi_find_or_add_av(struct ubi_attach_info *ai,
+                                                  int vol_id, bool *created)
+{
+        return find_or_add_av(ai, vol_id, AV_FIND_OR_ADD, created);
+}
+
 /**
  * add_to_list - add physical eraseblock to a list.
  * @ai: attaching information
@@ -294,44 +380,20 @@ static struct ubi_ainf_volume *add_volume(struct ubi_attach_info *ai,
                                           const struct ubi_vid_hdr *vid_hdr)
 {
         struct ubi_ainf_volume *av;
-        struct rb_node **p = &ai->volumes.rb_node, *parent = NULL;
+        bool created;
 
         ubi_assert(vol_id == be32_to_cpu(vid_hdr->vol_id));
 
-        /* Walk the volume RB-tree to look if this volume is already present */
-        while (*p) {
-                parent = *p;
-                av = rb_entry(parent, struct ubi_ainf_volume, rb);
-
-                if (vol_id == av->vol_id)
-                        return av;
+        av = ubi_find_or_add_av(ai, vol_id, &created);
+        if (IS_ERR(av) || !created)
+                return av;
 
-                if (vol_id > av->vol_id)
-                        p = &(*p)->rb_left;
-                else
-                        p = &(*p)->rb_right;
-        }
-
-        /* The volume is absent - add it */
-        av = kmalloc(sizeof(struct ubi_ainf_volume), GFP_KERNEL);
-        if (!av)
-                return ERR_PTR(-ENOMEM);
-
-        av->highest_lnum = av->leb_count = 0;
-        av->vol_id = vol_id;
-        av->root = RB_ROOT;
         av->used_ebs = be32_to_cpu(vid_hdr->used_ebs);
         av->data_pad = be32_to_cpu(vid_hdr->data_pad);
         av->compat = vid_hdr->compat;
         av->vol_type = vid_hdr->vol_type == UBI_VID_DYNAMIC ? UBI_DYNAMIC_VOLUME
                                                             : UBI_STATIC_VOLUME;
-        if (vol_id > ai->highest_vol_id)
-                ai->highest_vol_id = vol_id;
 
-        rb_link_node(&av->rb, parent, p);
-        rb_insert_color(&av->rb, &ai->volumes);
-        ai->vols_found += 1;
-        dbg_bld("added volume %d", vol_id);
         return av;
 }
 
@@ -629,6 +691,21 @@ int ubi_add_to_av(struct ubi_device *ubi, struct ubi_attach_info *ai, int pnum,
 }
 
 /**
+ * ubi_add_av - add volume to the attaching information.
+ * @ai: attaching information
+ * @vol_id: the requested volume ID
+ *
+ * This function returns a pointer to the new volume description or an
+ * ERR_PTR if the operation failed.
+ */
+struct ubi_ainf_volume *ubi_add_av(struct ubi_attach_info *ai, int vol_id)
+{
+        bool created;
+
+        return find_or_add_av(ai, vol_id, AV_ADD, &created);
+}
+
+/**
  * ubi_find_av - find volume in the attaching information.
  * @ai: attaching information
  * @vol_id: the requested volume ID
@@ -639,22 +716,10 @@ int ubi_add_to_av(struct ubi_device *ubi, struct ubi_attach_info *ai, int pnum,
 struct ubi_ainf_volume *ubi_find_av(const struct ubi_attach_info *ai,
                                     int vol_id)
 {
-        struct ubi_ainf_volume *av;
-        struct rb_node *p = ai->volumes.rb_node;
-
-        while (p) {
-                av = rb_entry(p, struct ubi_ainf_volume, rb);
-
-                if (vol_id == av->vol_id)
-                        return av;
-
-                if (vol_id > av->vol_id)
-                        p = p->rb_left;
-                else
-                        p = p->rb_right;
-        }
+        bool created;
 
-        return NULL;
+        return find_or_add_av((struct ubi_attach_info *)ai, vol_id, AV_FIND,
+                              &created);
 }
 
 /**
diff --git a/drivers/mtd/ubi/fastmap.c b/drivers/mtd/ubi/fastmap.c
index a6ed78d14055..bae80699c2f2 100644
--- a/drivers/mtd/ubi/fastmap.c
+++ b/drivers/mtd/ubi/fastmap.c
@@ -186,40 +186,19 @@ static struct ubi_ainf_volume *add_vol(struct ubi_attach_info *ai, int vol_id,
                                        int last_eb_bytes)
 {
         struct ubi_ainf_volume *av;
-        struct rb_node **p = &ai->volumes.rb_node, *parent = NULL;
 
-        while (*p) {
-                parent = *p;
-                av = rb_entry(parent, struct ubi_ainf_volume, rb);
-
-                if (vol_id > av->vol_id)
-                        p = &(*p)->rb_left;
-                else if (vol_id < av->vol_id)
-                        p = &(*p)->rb_right;
-                else
-                        return ERR_PTR(-EINVAL);
-        }
+        av = ubi_add_av(ai, vol_id);
+        if (IS_ERR(av))
+                return av;
 
-        av = kmalloc(sizeof(struct ubi_ainf_volume), GFP_KERNEL);
-        if (!av)
-                goto out;
-
-        av->highest_lnum = av->leb_count = av->used_ebs = 0;
-        av->vol_id = vol_id;
         av->data_pad = data_pad;
         av->last_data_size = last_eb_bytes;
         av->compat = 0;
         av->vol_type = vol_type;
-        av->root = RB_ROOT;
         if (av->vol_type == UBI_STATIC_VOLUME)
                 av->used_ebs = used_ebs;
 
         dbg_bld("found volume (ID %i)", vol_id);
-
-        rb_link_node(&av->rb, parent, p);
-        rb_insert_color(&av->rb, &ai->volumes);
-
-out:
         return av;
 }
 
diff --git a/drivers/mtd/ubi/ubi.h b/drivers/mtd/ubi/ubi.h
index b616a115c9d3..fce142666bf3 100644
--- a/drivers/mtd/ubi/ubi.h
+++ b/drivers/mtd/ubi/ubi.h
@@ -794,6 +794,7 @@ extern struct blocking_notifier_head ubi_notifiers;
 /* attach.c */
 int ubi_add_to_av(struct ubi_device *ubi, struct ubi_attach_info *ai, int pnum,
                   int ec, const struct ubi_vid_hdr *vid_hdr, int bitflips);
+struct ubi_ainf_volume *ubi_add_av(struct ubi_attach_info *ai, int vol_id);
 struct ubi_ainf_volume *ubi_find_av(const struct ubi_attach_info *ai,
                                     int vol_id);
 void ubi_remove_av(struct ubi_attach_info *ai, struct ubi_ainf_volume *av);