Signed-off-by: Tzung-Bi Shih <[email protected]> --- PoC patch. v5: - No primary changes but modify the API usage accordingly to support multiple revocable providers.
v4: https://lore.kernel.org/chrome-platform/[email protected] - New in the series. drivers/char/misc.c | 8 ++++++++ include/linux/miscdevice.h | 4 ++++ 2 files changed, 12 insertions(+) diff --git a/drivers/char/misc.c b/drivers/char/misc.c index 726516fb0a3b..5b412e18b8a6 100644 --- a/drivers/char/misc.c +++ b/drivers/char/misc.c @@ -50,6 +50,7 @@ #include <linux/tty.h> #include <linux/kmod.h> #include <linux/gfp.h> +#include <linux/fs_revocable.h> /* * Head entry for the doubly linked miscdevice list @@ -159,6 +160,13 @@ static int misc_open(struct inode *inode, struct file *file) err = 0; replace_fops(file, new_fops); + + if (c->frops && c->rps) { + err = fs_revocable_replace(file, c->frops, c->rps, c->num_rps); + 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..b7024a0cebb9 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 [email protected]. If you need @@ -92,6 +93,9 @@ struct miscdevice { const struct attribute_group **groups; const char *nodename; umode_t mode; + struct revocable_provider **rps; + size_t num_rps; + const struct fs_revocable_operations *frops; }; extern int misc_register(struct miscdevice *misc); -- 2.51.0.788.g6d19910ace-goog
