Commit d68c277b authored by UCHINO Satoshi's avatar UCHINO Satoshi Committed by Felipe Balbi

usb: gadget: f_mass_storage: add missing memory barrier for thread_wakeup_needed

Without this memory barrier, the file-storage thread may fail to
escape from the following while loop, because it may observe new
common->thread_wakeup_needed and old bh->state which are updated by
the callback functions.

	/* Wait for the CBW to arrive */
	while (bh->state != BUF_STATE_FULL) {
		rc = sleep_thread(common);
		if (rc)
			return rc;
	}

Cc: stable@vger.kernel.org
Signed-off-by: default avatarUCHINO Satoshi <satoshi.uchino@toshiba.co.jp>
Acked-by: default avatarMichal Nazarewicz <mina86@mina86.com>
Signed-off-by: default avatarFelipe Balbi <balbi@ti.com>
parent eb127cb5
...@@ -413,6 +413,7 @@ static int fsg_set_halt(struct fsg_dev *fsg, struct usb_ep *ep) ...@@ -413,6 +413,7 @@ static int fsg_set_halt(struct fsg_dev *fsg, struct usb_ep *ep)
/* Caller must hold fsg->lock */ /* Caller must hold fsg->lock */
static void wakeup_thread(struct fsg_common *common) static void wakeup_thread(struct fsg_common *common)
{ {
smp_wmb(); /* ensure the write of bh->state is complete */
/* Tell the main thread that something has happened */ /* Tell the main thread that something has happened */
common->thread_wakeup_needed = 1; common->thread_wakeup_needed = 1;
if (common->thread_task) if (common->thread_task)
...@@ -632,6 +633,7 @@ static int sleep_thread(struct fsg_common *common) ...@@ -632,6 +633,7 @@ static int sleep_thread(struct fsg_common *common)
} }
__set_current_state(TASK_RUNNING); __set_current_state(TASK_RUNNING);
common->thread_wakeup_needed = 0; common->thread_wakeup_needed = 0;
smp_rmb(); /* ensure the latest bh->state is visible */
return rc; return rc;
} }
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment