[PATCH v4 6/7] char: misc: Leverage revocable fops replacement

[Tzung-Bi Shih]

Signed-off-by: Tzung-Bi Shih <tzun...@kernel.org>
---
PoC patch.

v4:
- New in the series.

 drivers/char/misc.c        | 7 +++++++
 include/linux/miscdevice.h | 3 +++
 2 files changed, 10 insertions(+)

diff --git a/drivers/char/misc.c b/drivers/char/misc.c
index 726516fb0a3b..fcbbb0b1af35 100644
--- a/drivers/char/misc.c
+++ b/drivers/char/misc.c
@@ -159,6 +159,13 @@ static int misc_open(struct inode *inode, struct file 
*file)
 
        err = 0;
        replace_fops(file, new_fops);
+
+       if (c->rp && c->rops) {
+               err = revocable_replace_fops(file, c->rp, c->rops);
+               if (err)
+                       goto fail;
+       }
+
        if (file->f_op->open)
                err = file->f_op->open(inode, file);
 fail:
diff --git a/include/linux/miscdevice.h b/include/linux/miscdevice.h
index 7d0aa718499c..00f5c878266a 100644
--- a/include/linux/miscdevice.h
+++ b/include/linux/miscdevice.h
@@ -5,6 +5,7 @@
 #include <linux/list.h>
 #include <linux/types.h>
 #include <linux/device.h>
+#include <linux/revocable.h>
 
 /*
  *     These allocations are managed by dev...@lanana.org. If you need
@@ -92,6 +93,8 @@ struct miscdevice {
        const struct attribute_group **groups;
        const char *nodename;
        umode_t mode;
+       struct revocable_provider *rp;
+       const struct revocable_operations *rops;
 };
 
 extern int misc_register(struct miscdevice *misc);
-- 
2.51.0.534.gc79095c0ca-goog