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| author | Maxim Devaev <mdevaev@gmail.com> | 2022-07-11 12:29:57 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-07-14 16:06:42 +0200 |
| commit | 421c8d9a20da92deed2dac227e7ebdee7eb3e88f (patch) | |
| tree | 9dd7b02019b4500836d798ac73042c36735cfe6f /Documentation/ABI | |
| parent | usb: gadget: udc: amd5536 depends on HAS_DMA (diff) | |
| download | linux-421c8d9a20da92deed2dac227e7ebdee7eb3e88f.tar.xz linux-421c8d9a20da92deed2dac227e7ebdee7eb3e88f.zip | |
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 <stern@rowland.harvard.edu>
Signed-off-by: Maxim Devaev <mdevaev@gmail.com>
Link: https://lore.kernel.org/r/20220711102956.19642-1-mdevaev@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'Documentation/ABI')
| -rw-r--r-- | Documentation/ABI/testing/configfs-usb-gadget-mass-storage | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/configfs-usb-gadget-mass-storage b/Documentation/ABI/testing/configfs-usb-gadget-mass-storage index c86b63a7bb43..d899adb57e81 100644 --- a/Documentation/ABI/testing/configfs-usb-gadget-mass-storage +++ b/Documentation/ABI/testing/configfs-usb-gadget-mass-storage @@ -32,4 +32,10 @@ Description: being a CD-ROM. nofua Flag specifying that FUA flag in SCSI WRITE(10,12) + forced_eject This write-only file is useful only when + the function is active. It causes the backing + file to be forcibly detached from the LUN, + regardless of whether the host has allowed it. + Any non-zero number of bytes written will + result in ejection. =========== ============================================== |