[PATCH v2 2/2] block: set S_IFBLK for block devices instead of S_IFCHR

[Ahmad Fatoum]

From: Ahmad Fatoum <ahmad at a3f.at>

In barebox, block devices are a special case of character devices.
Nevertheless, differentiation can be useful to allow scripts iterating
over all block devices without accounting for naming, e.g.

  for dev in /dev/*; do
	test -b $dev && echo $dev: blockdevice
  done

Add the necessary support. This will break scripts that assume
test -c blockdevice to be true, but that's a quite improbable check.

Tested-by: Jules Maselbas <jmaselbas at kalray.eu>
Signed-off-by: Ahmad Fatoum <ahmad at a3f.at>
---
v1 -> v2:
  - Collected Jules Tested-by
  - added !CONFIG_BLOCK stub for cdev_get_block_device (Sascha)
  - added !cdev check to cdev_get_block_device
---
 commands/memtester/memtester.c | 2 +-
 common/block.c                 | 8 ++++++++
 fs/devfs.c                     | 7 ++++++-
 fs/legacy.c                    | 1 +
 include/block.h                | 9 +++++++++
 5 files changed, 25 insertions(+), 2 deletions(-)

diff --git a/commands/memtester/memtester.c b/commands/memtester/memtester.c
index 130dc97c8334..f4adbfc855cb 100644
--- a/commands/memtester/memtester.c
+++ b/commands/memtester/memtester.c
@@ -113,7 +113,7 @@ static int do_memtester(int argc, char **argv) {
                             strerror(errno));
                     return COMMAND_ERROR_USAGE;
                 } else {
-                    if (!S_ISCHR(statbuf.st_mode)) {
+                    if (!S_ISCHR(statbuf.st_mode) && !S_ISBLK(statbuf.st_mode)) {
                         printf("can not mmap non-char device %s\n",
                                 optarg);
                         return COMMAND_ERROR_USAGE;
diff --git a/common/block.c b/common/block.c
index 1d386edcfd49..19bb81df2c3d 100644
--- a/common/block.c
+++ b/common/block.c
@@ -361,6 +361,14 @@ static struct cdev_operations block_ops = {
 	.discard_range = block_op_discard_range,
 };
 
+struct block_device *cdev_get_block_device(struct cdev *cdev)
+{
+	if (!cdev || cdev->ops != &block_ops)
+		return NULL;
+
+	return container_of(cdev, struct block_device, cdev);
+}
+
 int blockdevice_register(struct block_device *blk)
 {
 	loff_t size = (loff_t)blk->num_blocks * BLOCKSIZE(blk);
diff --git a/fs/devfs.c b/fs/devfs.c
index deb244feeab6..49cd48f6d84e 100644
--- a/fs/devfs.c
+++ b/fs/devfs.c
@@ -29,6 +29,7 @@
 #include <linux/mtd/mtd.h>
 #include <linux/mtd/mtd-abi.h>
 #include <partition.h>
+#include <block.h>
 
 struct devfs_inode {
 	struct inode inode;
@@ -231,6 +232,7 @@ static struct inode *devfs_get_inode(struct super_block *sb, const struct inode
 	default:
 		return NULL;
 	case S_IFCHR:
+	case S_IFBLK:
 		inode->i_op = &devfs_file_inode_operations;
 		inode->i_fop = &devfs_file_operations;
 		break;
@@ -250,12 +252,15 @@ static struct dentry *devfs_lookup(struct inode *dir, struct dentry *dentry,
 	struct devfs_inode *dinode;
 	struct inode *inode;
 	struct cdev *cdev;
+	umode_t mode;
 
 	cdev = cdev_by_name(dentry->name);
 	if (!cdev)
 		return ERR_PTR(-ENOENT);
 
-	inode = devfs_get_inode(dir->i_sb, dir, S_IFCHR);
+	mode = cdev_get_block_device(cdev) ? S_IFBLK : S_IFCHR;
+
+	inode = devfs_get_inode(dir->i_sb, dir, mode);
 	if (!inode)
 		return ERR_PTR(-ENOMEM);
 
diff --git a/fs/legacy.c b/fs/legacy.c
index fc6a18f408ed..779f54629440 100644
--- a/fs/legacy.c
+++ b/fs/legacy.c
@@ -288,6 +288,7 @@ static struct inode *legacy_get_inode(struct super_block *sb, const struct inode
 		return NULL;
 	case S_IFREG:
 	case S_IFCHR:
+	case S_IFBLK:
 		inode->i_op = &legacy_file_inode_operations;
 		break;
 	case S_IFDIR:
diff --git a/include/block.h b/include/block.h
index d3a154bf73c0..1fb40e942f9f 100644
--- a/include/block.h
+++ b/include/block.h
@@ -49,4 +49,13 @@ static inline int block_flush(struct block_device *blk)
 	return cdev_flush(&blk->cdev);
 }
 
+#ifdef CONFIG_BLOCK
+struct block_device *cdev_get_block_device(struct cdev *cdev);
+#else
+static inline struct block_device *cdev_get_block_device(struct cdev *cdev)
+{
+	return NULL;
+}
+#endif
+
 #endif /* __BLOCK_H */
-- 
2.30.2