From 421c8d9a20da92deed2dac227e7ebdee7eb3e88f Mon Sep 17 00:00:00 2001 From: Maxim Devaev Date: Mon, 11 Jul 2022 13:29:57 +0300 Subject: usb: gadget: f_mass_storage: forced_eject attribute It allows to reset prevent_medium_removal flag and "eject" the image. This can be useful to free the drive from a hunging host or if the host continues to use the drive even after unmounting (Linux does this). It's also a bit like using an unfolded paperclip on an optical drive. Previously, the undocumented method of sending SIGUSR1 to a special "file-storage" kernel thread could be used for these purposes, but when using multiple storages there was no way to distinguish one from the other, so we had to send a signal to everyone. Reviewed-by: Alan Stern Signed-off-by: Maxim Devaev Link: https://lore.kernel.org/r/20220711102956.19642-1-mdevaev@gmail.com Signed-off-by: Greg Kroah-Hartman --- drivers/usb/gadget/function/storage_common.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'drivers/usb/gadget/function/storage_common.h') diff --git a/drivers/usb/gadget/function/storage_common.h b/drivers/usb/gadget/function/storage_common.h index bdeb1e233fc9..0a544a82cbf8 100644 --- a/drivers/usb/gadget/function/storage_common.h +++ b/drivers/usb/gadget/function/storage_common.h @@ -219,5 +219,7 @@ ssize_t fsg_store_removable(struct fsg_lun *curlun, const char *buf, size_t count); ssize_t fsg_store_inquiry_string(struct fsg_lun *curlun, const char *buf, size_t count); +ssize_t fsg_store_forced_eject(struct fsg_lun *curlun, struct rw_semaphore *filesem, + const char *buf, size_t count); #endif /* USB_STORAGE_COMMON_H */ -- cgit v1.2.3