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path: root/drivers/mtd/mtdpart.c
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Diffstat (limited to 'drivers/mtd/mtdpart.c')
-rw-r--r--drivers/mtd/mtdpart.c68
1 files changed, 43 insertions, 25 deletions
diff --git a/drivers/mtd/mtdpart.c b/drivers/mtd/mtdpart.c
index e779de315ade..cafdb8855a79 100644
--- a/drivers/mtd/mtdpart.c
+++ b/drivers/mtd/mtdpart.c
@@ -30,6 +30,7 @@
#include <linux/mtd/mtd.h>
#include <linux/mtd/partitions.h>
#include <linux/err.h>
+#include <linux/kconfig.h>
#include "mtdcore.h"
@@ -379,10 +380,17 @@ static struct mtd_part *allocate_partition(struct mtd_info *master,
slave->mtd.name = name;
slave->mtd.owner = master->owner;
- /* NOTE: we don't arrange MTDs as a tree; it'd be error-prone
- * to have the same data be in two different partitions.
+ /* NOTE: Historically, we didn't arrange MTDs as a tree out of
+ * concern for showing the same data in multiple partitions.
+ * However, it is very useful to have the master node present,
+ * so the MTD_PARTITIONED_MASTER option allows that. The master
+ * will have device nodes etc only if this is set, so make the
+ * parent conditional on that option. Note, this is a way to
+ * distinguish between the master and the partition in sysfs.
*/
- slave->mtd.dev.parent = master->dev.parent;
+ slave->mtd.dev.parent = IS_ENABLED(CONFIG_MTD_PARTITIONED_MASTER) ?
+ &master->dev :
+ master->dev.parent;
slave->mtd._read = part_read;
slave->mtd._write = part_write;
@@ -546,12 +554,35 @@ out_register:
return slave;
}
+static ssize_t mtd_partition_offset_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct mtd_info *mtd = dev_get_drvdata(dev);
+ struct mtd_part *part = PART(mtd);
+ return snprintf(buf, PAGE_SIZE, "%lld\n", part->offset);
+}
+
+static DEVICE_ATTR(offset, S_IRUGO, mtd_partition_offset_show, NULL);
+
+static const struct attribute *mtd_partition_attrs[] = {
+ &dev_attr_offset.attr,
+ NULL
+};
+
+static int mtd_add_partition_attrs(struct mtd_part *new)
+{
+ int ret = sysfs_create_files(&new->mtd.dev.kobj, mtd_partition_attrs);
+ if (ret)
+ printk(KERN_WARNING
+ "mtd: failed to create partition attrs, err=%d\n", ret);
+ return ret;
+}
+
int mtd_add_partition(struct mtd_info *master, const char *name,
long long offset, long long length)
{
struct mtd_partition part;
- struct mtd_part *p, *new;
- uint64_t start, end;
+ struct mtd_part *new;
int ret = 0;
/* the direct offset is expected */
@@ -575,31 +606,15 @@ int mtd_add_partition(struct mtd_info *master, const char *name,
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);
+ mtd_add_partition_attrs(new);
+
return ret;
-err_inv:
- mutex_unlock(&mtd_partitions_mutex);
- free_partition(new);
- return -EINVAL;
}
EXPORT_SYMBOL_GPL(mtd_add_partition);
@@ -612,6 +627,8 @@ int mtd_del_partition(struct mtd_info *master, int partno)
list_for_each_entry_safe(slave, next, &mtd_partitions, list)
if ((slave->master == master) &&
(slave->mtd.index == partno)) {
+ sysfs_remove_files(&slave->mtd.dev.kobj,
+ mtd_partition_attrs);
ret = del_mtd_device(&slave->mtd);
if (ret < 0)
break;
@@ -631,8 +648,8 @@ EXPORT_SYMBOL_GPL(mtd_del_partition);
* and registers slave MTD objects which are bound to the master according to
* the partition definitions.
*
- * We don't register the master, or expect the caller to have done so,
- * for reasons of data integrity.
+ * For historical reasons, this function's caller only registers the master
+ * if the MTD_PARTITIONED_MASTER config option is set.
*/
int add_mtd_partitions(struct mtd_info *master,
@@ -655,6 +672,7 @@ int add_mtd_partitions(struct mtd_info *master,
mutex_unlock(&mtd_partitions_mutex);
add_mtd_device(&slave->mtd);
+ mtd_add_partition_attrs(slave);
cur_offset = slave->offset + slave->mtd.size;
}