[MTD] return error code from get_mtd_device()

get_mtd_device() returns NULL in case of any failure. Teach it to return an
error code instead. Fix all users as well.

Signed-off-by: Artem Bityutskiy <dedekind@infradead.org>

5 files changed, 24 insertions, 18 deletions

diff --git a/drivers/mtd/maps/nettel.c b/drivers/mtd/maps/nettel.c
index f9e8e5bcbc33..528e523245c2 100644
--- a/drivers/mtd/maps/nettel.c
+++ b/drivers/mtd/maps/nettel.c
@@ -20,6 +20,7 @@
 #include <linux/mtd/partitions.h>
 #include <linux/mtd/cfi.h>
 #include <linux/reboot.h>
+#include <linux/err.h>
 #include <linux/kdev_t.h>
 #include <linux/root_dev.h>
 #include <asm/io.h>
@@ -178,7 +179,7 @@ int nettel_eraseconfig(void)
 
         init_waitqueue_head(&wait_q);
         mtd = get_mtd_device(NULL, 2);
-        if (mtd) {
+        if (!IS_ERR(mtd)) {
                 nettel_erase.mtd = mtd;
                 nettel_erase.callback = nettel_erasecallback;
                 nettel_erase.callback = NULL;
diff --git a/drivers/mtd/mtdchar.c b/drivers/mtd/mtdchar.c
index 7c4adc641328..3013d0883b97 100644
--- a/drivers/mtd/mtdchar.c
+++ b/drivers/mtd/mtdchar.c
@@ -7,6 +7,7 @@
 
 #include <linux/device.h>
 #include <linux/fs.h>
+#include <linux/err.h>
 #include <linux/init.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
@@ -100,8 +101,8 @@ static int mtd_open(struct inode *inode, struct file *file)
 
         mtd = get_mtd_device(NULL, devnum);
 
-        if (!mtd)
-                return -ENODEV;
+        if (IS_ERR(mtd))
+                return PTR_ERR(mtd);
 
         if (MTD_ABSENT == mtd->type) {
                 put_mtd_device(mtd);
diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c
index f11f55f02413..60f237f91bb2 100644
--- a/drivers/mtd/mtdcore.c
+++ b/drivers/mtd/mtdcore.c
@@ -193,14 +193,14 @@ int unregister_mtd_user (struct mtd_notifier *old)
  *      Given a number and NULL address, return the num'th entry in the device
  *      table, if any.  Given an address and num == -1, search the device table
  *      for a device with that address and return if it's still present. Given
- *      both, return the num'th driver only if its address matches. Return NULL
- *      if not.
+ *      both, return the num'th driver only if its address matches. Return
+ *      error code if not.
  */
 
 struct mtd_info *get_mtd_device(struct mtd_info *mtd, int num)
 {
         struct mtd_info *ret = NULL;
-        int i;
+        int i, err = -ENODEV;
 
         mutex_lock(&mtd_table_mutex);
 
@@ -217,22 +217,24 @@ struct mtd_info *get_mtd_device(struct mtd_info *mtd, int num)
         if (!ret)
                 goto out_unlock;
 
-        if (!try_module_get(ret->owner)) {
-                ret = NULL;
+        if (!try_module_get(ret->owner))
                 goto out_unlock;
-        }
 
-        if (ret->get_device && ret->get_device(ret)) {
-                module_put(ret->owner);
-                ret = NULL;
-                goto out_unlock;
+        if (ret->get_device) {
+                err = ret->get_device(ret);
+                if (err)
+                        goto out_put;
         }
 
         ret->usecount++;
+        mutex_unlock(&mtd_table_mutex);
+        return ret;
 
+out_put:
+        module_put(ret->owner);
 out_unlock:
         mutex_unlock(&mtd_table_mutex);
-        return ret;
+        return ERR_PTR(err);
 }
 
 /**
diff --git a/fs/jffs/jffs_fm.c b/fs/jffs/jffs_fm.c
index 29b68d939bd9..6aab317f56e0 100644
--- a/fs/jffs/jffs_fm.c
+++ b/fs/jffs/jffs_fm.c
@@ -17,6 +17,7 @@
  *
  */
 #include <linux/slab.h>
+#include <linux/err.h>
 #include <linux/blkdev.h>
 #include <linux/jffs.h>
 #include "jffs_fm.h"
@@ -104,7 +105,7 @@ jffs_build_begin(struct jffs_control *c, int unit)
 
         mtd = get_mtd_device(NULL, unit);
 
-        if (!mtd) {
+        if (IS_ERR(mtd)) {
                 kfree(fmc);
                 DJM(no_jffs_fmcontrol--);
                 return NULL;
diff --git a/fs/jffs2/super.c b/fs/jffs2/super.c
index bc4b8106a490..590f60a897c1 100644
--- a/fs/jffs2/super.c
+++ b/fs/jffs2/super.c
@@ -17,6 +17,7 @@
 #include <linux/init.h>
 #include <linux/list.h>
 #include <linux/fs.h>
+#include <linux/err.h>
 #include <linux/mount.h>
 #include <linux/jffs2.h>
 #include <linux/pagemap.h>
@@ -184,9 +185,9 @@ static int jffs2_get_sb_mtdnr(struct file_system_type *fs_type,
         struct mtd_info *mtd;
 
         mtd = get_mtd_device(NULL, mtdnr);
-        if (!mtd) {
+        if (IS_ERR(mtd)) {
                 D1(printk(KERN_DEBUG "jffs2: MTD device #%u doesn't appear to exist\n", mtdnr));
-                return -EINVAL;
+                return PTR_ERR(mtd);
         }
 
         return jffs2_get_sb_mtd(fs_type, flags, dev_name, data, mtd, mnt);
@@ -221,7 +222,7 @@ static int jffs2_get_sb(struct file_system_type *fs_type,
                         D1(printk(KERN_DEBUG "jffs2_get_sb(): mtd:%%s, name \"%s\"\n", dev_name+4));
                         for (mtdnr = 0; mtdnr < MAX_MTD_DEVICES; mtdnr++) {
                                 mtd = get_mtd_device(NULL, mtdnr);
-                                if (mtd) {
+                                if (!IS_ERR(mtd)) {
                                         if (!strcmp(mtd->name, dev_name+4))
                                                 return jffs2_get_sb_mtd(fs_type, flags, dev_name, data, mtd, mnt);
                                         put_mtd_device(mtd);