[PATCH] usb: gadget: f_mass_storage: Disable eps during disconnect

[Mattijs Korpershoek]

When trying two ums commands in a row, the second one no longer
enumerates properly from the host.

This happens since commit
59310d1ecb9f ("usb: gadget: introduce 'enabled' flag in struct usb_ep")
causing usb_ep_enable() to return early when ep->enabled is already set.

Gadget function drivers (such as f_fastboot or f_mass_storage) implement
a disable() function which is called whenever we are done using the
gadget.

Because f_mass_storage driver does not disable the endpoints,
ep->enabled will never be set to false again.

This can be reproduced on the STM32MP157C-DK2 or the Khadas VIM3 boards.

Add calls to usb_ep_disable() as done in linux [1] to fix this.

[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=9fff139aeb11186fd8e75860c959c86cb43ab2f6

Fixes: 59310d1ecb9f ("usb: gadget: introduce 'enabled' flag in struct usb_ep")
Signed-off-by: Mattijs Korpershoek <mkorpershoek at kernel.org>
---
This was initially reported by Patrice Chotard at:
https://lore.kernel.org/all/20260616-ums_fix-v1-1-f1f6c903b3fc@foss.st.com/

That thread contains reproduction steps.
---
 drivers/usb/gadget/f_mass_storage.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/usb/gadget/f_mass_storage.c b/drivers/usb/gadget/f_mass_storage.c
index 71dc58da3f03..87ed25e8bb3a 100644
--- a/drivers/usb/gadget/f_mass_storage.c
+++ b/drivers/usb/gadget/f_mass_storage.c
@@ -2275,6 +2275,17 @@ static int fsg_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
 static void fsg_disable(struct usb_function *f)
 {
 	struct fsg_dev *fsg = fsg_from_func(f);
+
+	/* Disable the endpoints */
+	if (fsg->bulk_in_enabled) {
+		usb_ep_disable(fsg->bulk_in);
+		fsg->bulk_in_enabled = 0;
+	}
+	if (fsg->bulk_out_enabled) {
+		usb_ep_disable(fsg->bulk_out);
+		fsg->bulk_out_enabled = 0;
+	}
+
 	fsg->common->new_fsg = NULL;
 	raise_exception(fsg->common, FSG_STATE_CONFIG_CHANGE);
 }

---
base-commit: a7830e87555abfb81cc69275cecb2bc0fbde5b28
change-id: 20260617-ums-disconnect-d839bc17a47d

Best regards,
--  
Mattijs Korpershoek <mkorpershoek at kernel.org>