mtd: prepare partition add and del functions for ioctl requests

mtd_is_master, mtd_add_partition and mtd_del_partition functions
are added to give the possibility of partition manipulation
by ioctl request.

The old partition add function is modified to fit the dynamic
allocation.

Signed-off-by: Roman Tereshonkov <roman.tereshonkov@nokia.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

1 files changed, 136 insertions, 18 deletions

diff --git a/drivers/mtd/mtdpart.c b/drivers/mtd/mtdpart.c
index dc6558568876..79e3689f1e16 100644
--- a/drivers/mtd/mtdpart.c
+++ b/drivers/mtd/mtdpart.c
@@ -29,9 +29,11 @@
 #include <linux/kmod.h>
 #include <linux/mtd/mtd.h>
 #include <linux/mtd/partitions.h>
+#include <linux/err.h>
 
 /* Our partition linked list */
 static LIST_HEAD(mtd_partitions);
+static DEFINE_MUTEX(mtd_partitions_mutex);
 
 /* Our partition node structure */
 struct mtd_part {
@@ -326,6 +328,12 @@ static int part_block_markbad(struct mtd_info *mtd, loff_t ofs)
         return res;
 }
 
+static inline void free_partition(struct mtd_part *p)
+{
+        kfree(p->mtd.name);
+        kfree(p);
+}
+
 /*
  * This function unregisters and destroy all slave MTD objects which are
  * attached to the given master MTD object.
@@ -334,33 +342,42 @@ static int part_block_markbad(struct mtd_info *mtd, loff_t ofs)
 int del_mtd_partitions(struct mtd_info *master)
 {
         struct mtd_part *slave, *next;
+        int ret, err = 0;
 
+        mutex_lock(&mtd_partitions_mutex);
         list_for_each_entry_safe(slave, next, &mtd_partitions, list)
                 if (slave->master == master) {
+                        ret = del_mtd_device(&slave->mtd);
+                        if (ret < 0) {
+                                err = ret;
+                                continue;
+                        }
                         list_del(&slave->list);
-                        del_mtd_device(&slave->mtd);
-                        kfree(slave);
+                        free_partition(slave);
                 }
+        mutex_unlock(&mtd_partitions_mutex);
 
-        return 0;
+        return err;
 }
 EXPORT_SYMBOL(del_mtd_partitions);
 
-static struct mtd_part *add_one_partition(struct mtd_info *master,
-                const struct mtd_partition *part, int partno,
-                uint64_t cur_offset)
+static struct mtd_part *allocate_partition(struct mtd_info *master,
+                        const struct mtd_partition *part, int partno,
+                        uint64_t cur_offset)
 {
         struct mtd_part *slave;
+        char *name;
 
         /* allocate the partition structure */
         slave = kzalloc(sizeof(*slave), GFP_KERNEL);
-        if (!slave) {
+        name = kstrdup(part->name, GFP_KERNEL);
+        if (!name || !slave) {
                 printk(KERN_ERR"memory allocation error while creating partitions for \"%s\"\n",
-                        master->name);
-                del_mtd_partitions(master);
-                return NULL;
+                       master->name);
+                kfree(name);
+                kfree(slave);
+                return ERR_PTR(-ENOMEM);
         }
-        list_add(&slave->list, &mtd_partitions);
 
         /* set up the MTD object for this partition */
         slave->mtd.type = master->type;
@@ -371,7 +388,7 @@ static struct mtd_part *add_one_partition(struct mtd_info *master,
         slave->mtd.oobavail = master->oobavail;
         slave->mtd.subpage_sft = master->subpage_sft;
 
-        slave->mtd.name = part->name;
+        slave->mtd.name = name;
         slave->mtd.owner = master->owner;
         slave->mtd.backing_dev_info = master->backing_dev_info;
 
@@ -518,12 +535,89 @@ static struct mtd_part *add_one_partition(struct mtd_info *master,
         }
 
 out_register:
-        /* register our partition */
-        add_mtd_device(&slave->mtd);
-
         return slave;
 }
 
+int mtd_add_partition(struct mtd_info *master, char *name,
+                      long long offset, long long length)
+{
+        struct mtd_partition part;
+        struct mtd_part *p, *new;
+        uint64_t start, end;
+        int ret = 0;
+
+        /* the direct offset is expected */
+        if (offset == MTDPART_OFS_APPEND ||
+            offset == MTDPART_OFS_NXTBLK)
+                return -EINVAL;
+
+        if (length == MTDPART_SIZ_FULL)
+                length = master->size - offset;
+
+        if (length <= 0)
+                return -EINVAL;
+
+        part.name = name;
+        part.size = length;
+        part.offset = offset;
+        part.mask_flags = 0;
+        part.ecclayout = NULL;
+
+        new = allocate_partition(master, &part, -1, offset);
+        if (IS_ERR(new))
+                return PTR_ERR(new);
+
+        start = offset;
+        end = offset + length;
+
+        mutex_lock(&mtd_partitions_mutex);
+        list_for_each_entry(p, &mtd_partitions, list)
+                if (p->master == master) {
+                        if ((start >= p->offset) &&
+                            (start < (p->offset + p->mtd.size)))
+                                goto err_inv;
+
+                        if ((end >= p->offset) &&
+                            (end < (p->offset + p->mtd.size)))
+                                goto err_inv;
+                }
+
+        list_add(&new->list, &mtd_partitions);
+        mutex_unlock(&mtd_partitions_mutex);
+
+        add_mtd_device(&new->mtd);
+
+        return ret;
+err_inv:
+        mutex_unlock(&mtd_partitions_mutex);
+        free_partition(new);
+        return -EINVAL;
+}
+EXPORT_SYMBOL_GPL(mtd_add_partition);
+
+int mtd_del_partition(struct mtd_info *master, int partno)
+{
+        struct mtd_part *slave, *next;
+        int ret = -EINVAL;
+
+        mutex_lock(&mtd_partitions_mutex);
+        list_for_each_entry_safe(slave, next, &mtd_partitions, list)
+                if ((slave->master == master) &&
+                    (slave->mtd.index == partno)) {
+                        ret = del_mtd_device(&slave->mtd);
+                        if (ret < 0)
+                                break;
+
+                        list_del(&slave->list);
+                        free_partition(slave);
+                        break;
+                }
+        mutex_unlock(&mtd_partitions_mutex);
+
+        return ret;
+}
+EXPORT_SYMBOL_GPL(mtd_del_partition);
+
 /*
  * This function, given a master MTD object and a partition table, creates
  * and registers slave MTD objects which are bound to the master according to
@@ -544,9 +638,16 @@ int add_mtd_partitions(struct mtd_info *master,
         printk(KERN_NOTICE "Creating %d MTD partitions on \"%s\":\n", nbparts, master->name);
 
         for (i = 0; i < nbparts; i++) {
-                slave = add_one_partition(master, parts + i, i, cur_offset);
-                if (!slave)
-                        return -ENOMEM;
+                slave = allocate_partition(master, parts + i, i, cur_offset);
+                if (IS_ERR(slave))
+                        return PTR_ERR(slave);
+
+                mutex_lock(&mtd_partitions_mutex);
+                list_add(&slave->list, &mtd_partitions);
+                mutex_unlock(&mtd_partitions_mutex);
+
+                add_mtd_device(&slave->mtd);
+
                 cur_offset = slave->offset + slave->mtd.size;
         }
 
@@ -618,3 +719,20 @@ int parse_mtd_partitions(struct mtd_info *master, const char **types,
         return ret;
 }
 EXPORT_SYMBOL_GPL(parse_mtd_partitions);
+
+int mtd_is_master(struct mtd_info *mtd)
+{
+        struct mtd_part *part;
+        int nopart = 0;
+
+        mutex_lock(&mtd_partitions_mutex);
+        list_for_each_entry(part, &mtd_partitions, list)
+                if (&part->mtd == mtd) {
+                        nopart = 1;
+                        break;
+                }
+        mutex_unlock(&mtd_partitions_mutex);
+
+        return nopart;
+}
+EXPORT_SYMBOL_GPL(mtd_is_master);