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libpayload: usbmsc: Remove DETACHED state from MSC device structure 

The USB MSC device structure contains a "ready" state that can be either
"ready", "not ready" or "detached". The last one can only be assigned
when the device is completely unresponsive and gets forcefully logically
detached via usb_detach_device(). This call (at least in the current
version) also calls all destructors and frees the complete usbdev_t
structure (including the MSC specific part), which unfortunately makes
storing the "detached" state in that very structure a little pointless.

This patch reduces the "ready" value to a simple boolean and makes sure
that all detachment cases immediately return from the MSC driver,
carefully avoiding any use-after-free opportunities.

Change-Id: Iff1c0849f9ce7c95d399bb9a1a0a94469951194d
Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/170667
(cherry picked from commit fd4529f37fdd1c93a8b902488ffeef7001b1a05a)
Signed-off-by: Isaac Christensen <isaac.christensen@se-eng.com>
Reviewed-on: http://review.coreboot.org/6654
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>
Tested-by: build bot (Jenkins)
This commit is contained in:
Julius Werner 2013-09-25 13:54:57 -07:00 committed by Isaac Christensen
parent f0cd03c142
commit b59e8505d8
1 changed files with 22 additions and 61 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

83
payloads/libpayload/drivers/usb/usbmsc.c
View File

@ -67,36 +67,6 @@ static const char *msc_protocol_strings[0x51] = {
"Bulk-Only Transport"
};
static inline void
usb_msc_mark_ready (usbdev_t *dev)
{
MSC_INST (dev)->ready = USB_MSC_READY;
}
static inline void
usb_msc_mark_not_ready (usbdev_t *dev)
{
MSC_INST (dev)->ready = USB_MSC_NOT_READY;
}
static inline void
usb_msc_mark_detached (usbdev_t *dev)
{
MSC_INST (dev)->ready = USB_MSC_DETACHED;
}
static inline int
usb_msc_is_detached (usbdev_t *dev)
{
return MSC_INST (dev)->ready == USB_MSC_DETACHED;
}
static inline int
usb_msc_is_ready (usbdev_t *dev)
{
return MSC_INST (dev)->ready == USB_MSC_READY;
}
static void
usb_msc_create_disk (usbdev_t *dev)
{
@ -156,7 +126,8 @@ enum {
* MSC commands can be
* successful,
* fail with proper response or
* fail totally, which results in detaching of the usb device.
* fail totally, which results in detaching of the usb device
* and immediate cleanup of the usbdev_t structure.
* In the latter case the caller has to make sure, that he won't
* use the device any more.
*/
@ -468,7 +439,7 @@ static int request_sense_no_media (usbdev_t *dev)
/* No media is present. Return MSC_COMMAND_OK while marking the disk
* not ready. */
usb_debug ("Empty media found.\n");
usb_msc_mark_not_ready (dev);
MSC_INST (dev)->ready = USB_MSC_NOT_READY;
return MSC_COMMAND_OK;
}
@ -533,7 +504,7 @@ read_capacity (usbdev_t *dev)
return MSC_COMMAND_OK;
}
static void
static int
usb_msc_test_unit_ready (usbdev_t *dev)
{
int i;
@ -547,7 +518,7 @@ usb_msc_test_unit_ready (usbdev_t *dev)
usb_debug (" Waiting for device to become ready...");
/* Initially mark the device ready. */
usb_msc_mark_ready (dev);
MSC_INST (dev)->ready = USB_MSC_READY;
gettimeofday (&tv, NULL);
start_time_secs = tv.tv_sec;
@ -561,22 +532,21 @@ usb_msc_test_unit_ready (usbdev_t *dev)
gettimeofday (&tv, NULL);
continue;
default:
usb_debug ("detached. Device not ready.\n");
usb_msc_mark_detached (dev);
return;
/* Device detached, return immediately */
return USB_MSC_DETACHED;
}
break;
}
if (!(tv.tv_sec - start_time_secs < timeout_secs)) {
usb_debug ("timeout. Device not ready.\n");
usb_msc_mark_not_ready (dev);
MSC_INST (dev)->ready = USB_MSC_NOT_READY;
}
/* Don't bother spinning up the stroage device if the device is not
* ready. This can happen when empty card readers are present.
* Polling will pick it back up if readiness changes. */
if (!usb_msc_is_ready (dev))
return;
if (!MSC_INST (dev)->ready)
return MSC_INST (dev)->ready;
usb_debug ("ok.\n");
@ -591,16 +561,17 @@ usb_msc_test_unit_ready (usbdev_t *dev)
mdelay (100);
continue;
default:
/* Device is no longer ready. */
usb_msc_mark_detached (dev);
return;
/* Device detached, return immediately */
return USB_MSC_DETACHED;
}
break;
}
usb_debug ("\n");
if (read_capacity (dev) != MSC_COMMAND_OK)
usb_msc_mark_not_ready (dev);
if (read_capacity (dev) == MSC_COMMAND_DETACHED)
return USB_MSC_DETACHED;
return MSC_INST (dev)->ready;
}
void
@ -646,7 +617,6 @@ usb_msc_init (usbdev_t *dev)
MSC_INST (dev)->bulk_in = 0;
MSC_INST (dev)->bulk_out = 0;
MSC_INST (dev)->usbdisk_created = 0;
usb_msc_mark_ready (dev);
for (i = 1; i <= dev->num_endp; i++) {
if (dev->endpoints[i].endpoint == 0)
@ -675,11 +645,8 @@ usb_msc_init (usbdev_t *dev)
usb_debug (" has %d luns\n", get_max_luns (dev) + 1);
/* Test if unit is ready. */
usb_msc_test_unit_ready (dev);
/* Nothing to do if device is not ready. */
if (!usb_msc_is_ready (dev))
/* Test if unit is ready (nothing to do if it isn't). */
if (usb_msc_test_unit_ready (dev) != USB_MSC_READY)
return;
/* Create the disk. */
@ -689,21 +656,15 @@ usb_msc_init (usbdev_t *dev)
static void
usb_msc_poll (usbdev_t *dev)
{
int prev_ready;
int prev_ready = MSC_INST (dev)->ready;
/* Nothing to do if device is detached. */
if (usb_msc_is_detached (dev))
if (usb_msc_test_unit_ready (dev) == USB_MSC_DETACHED)
return;
/* Handle ready transitions by keeping track of previous state . */
prev_ready = usb_msc_is_ready (dev);
usb_msc_test_unit_ready (dev);
if (!prev_ready && usb_msc_is_ready (dev)) {
if (!prev_ready && MSC_INST (dev)->ready) {
usb_debug ("usb msc: not ready -> ready\n");
usb_msc_create_disk (dev);
} else if (prev_ready && !usb_msc_is_ready (dev)) {
} else if (prev_ready && !MSC_INST (dev)->ready) {
usb_debug ("usb msc: ready -> not ready\n");
usb_msc_remove_disk (dev);
}