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USB: gadget: f_mass_storage: Defer handling interface changes until it is safe.

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Pulling in some code from file_storage.c, we now handle interface changes
in do_set_config(), which is now not called until any pending requests have
been successfully completed or cancelled.

This fixes a race condition that resulted in usb_ep_free_request() being called
while the request is still busy.

Signed-off-by: Mike Lockwood <lockwood@android.com>
This commit is contained in:
Mike Lockwood
2010-04-15 15:04:07 -04:00
committed by Colin Cross
parent 0274cdc300
commit e2dd99e8e2
1 changed files with 28 additions and 11 deletions
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39
drivers/usb/gadget/f_mass_storage_tmp.c
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@@ -2261,18 +2261,19 @@ static int do_set_config(struct fsg_dev *fsg, u8 new_config)
{
int rc = 0;
if (new_config == fsg->config)
return rc;
/* Disable the single interface */
if (fsg->config != 0) {
DBG(fsg, "reset config\n");
fsg->config = 0;
rc = do_set_interface(fsg, -1);
}
/* Enable the interface */
if (new_config != 0)
if (new_config != 0) {
fsg->config = new_config;
if ((rc = do_set_interface(fsg, 0)) != 0)
fsg->config = 0; // Reset on errors
}
switch_set_state(&fsg->sdev, new_config);
adjust_wake_lock(fsg);
@@ -2287,6 +2288,7 @@ static void handle_exception(struct fsg_dev *fsg)
siginfo_t info;
int sig;
int i;
int num_active;
struct fsg_buffhd *bh;
enum fsg_state old_state;
u8 new_config;
@@ -2308,6 +2310,28 @@ static void handle_exception(struct fsg_dev *fsg)
}
}
/* Cancel all the pending transfers */
for (i = 0; i < NUM_BUFFERS; ++i) {
bh = &fsg->buffhds[i];
if (bh->inreq_busy)
usb_ep_dequeue(fsg->bulk_in, bh->inreq);
if (bh->outreq_busy)
usb_ep_dequeue(fsg->bulk_out, bh->outreq);
}
/* Wait until everything is idle */
for (;;) {
num_active = 0;
for (i = 0; i < NUM_BUFFERS; ++i) {
bh = &fsg->buffhds[i];
num_active += bh->outreq_busy;
}
if (num_active == 0)
break;
if (sleep_thread(fsg))
return;
}
/*
* Do NOT flush the fifo after set_interface()
* Otherwise, it results in some data being lost
@@ -2378,10 +2402,6 @@ static void handle_exception(struct fsg_dev *fsg)
case FSG_STATE_EXIT:
case FSG_STATE_TERMINATED:
if (new_config) {
fsg->new_config = 0;
do_set_interface(fsg, -1);
}
do_set_config(fsg, 0); /* Free resources */
spin_lock_irqsave(&fsg->lock, flags);
fsg->state = FSG_STATE_TERMINATED; /* Stop the thread */
@@ -2885,7 +2905,6 @@ static int fsg_function_set_alt(struct usb_function *f,
struct fsg_dev *fsg = func_to_dev(f);
DBG(fsg, "fsg_function_set_alt intf: %d alt: %d\n", intf, alt);
fsg->new_config = 1;
do_set_interface(fsg, 0);
raise_exception(fsg, FSG_STATE_CONFIG_CHANGE);
return 0;
}
@@ -2894,8 +2913,6 @@ static void fsg_function_disable(struct usb_function *f)
{
struct fsg_dev *fsg = func_to_dev(f);
DBG(fsg, "fsg_function_disable\n");
if (fsg->new_config)
do_set_interface(fsg, -1);
fsg->new_config = 0;
raise_exception(fsg, FSG_STATE_CONFIG_CHANGE);
}