diff options
| author | UCHINO Satoshi <satoshi.uchino@toshiba.co.jp> | 2013-05-23 11:10:11 +0900 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-07-21 18:21:24 -0700 |
| commit | f8da12fa870df0d4304a3661352d721d90bd0929 (patch) | |
| tree | 02aba6ed04f53f1a1e6f47a3fe69ff3c3c22d6f7 | |
| parent | 859cfbcdc4374da93fc1258f18f95849c02e52c4 (diff) | |
usb: gadget: f_mass_storage: add missing memory barrier for thread_wakeup_needed
commit d68c277b501889b3a50c179d1c3d704db7947b83 upstream.
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;
}
Signed-off-by: UCHINO Satoshi <satoshi.uchino@toshiba.co.jp>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/usb/gadget/f_mass_storage.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/usb/gadget/f_mass_storage.c b/drivers/usb/gadget/f_mass_storage.c index 97666e8b1b9..c35a9ecc576 100644 --- a/drivers/usb/gadget/f_mass_storage.c +++ b/drivers/usb/gadget/f_mass_storage.c @@ -413,6 +413,7 @@ static int fsg_set_halt(struct fsg_dev *fsg, struct usb_ep *ep) /* Caller must hold fsg->lock */ 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 */ common->thread_wakeup_needed = 1; if (common->thread_task) @@ -632,6 +633,7 @@ static int sleep_thread(struct fsg_common *common) } __set_current_state(TASK_RUNNING); common->thread_wakeup_needed = 0; + smp_rmb(); /* ensure the latest bh->state is visible */ return rc; } |