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Fix a reference counting error in the USB host mass storage class

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This commit is contained in:
Gregory Nutt 2013-09-10 11:38:40 -06:00
parent 89c829d1ae
commit 349677aaf9
3 changed files with 120 additions and 41 deletions
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4
ChangeLog
View File

@ -5526,4 +5526,8 @@
transfer errors while attempt to initialize, don't bother with
the startup retries; abort immediately so that the device will
be reset and we can try again (2013-9-9).
* drivers/usbhost/usbhost_storagge: Correct a reference counting
error: When an MSC device transfer fails while waiting for
UnitTestReady (see 2013-9-9), the reference count was not being
decremented. The end result is a memory leak (2013-9-10).

97
configs/sama5d3x-ek/README.txt
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@ -1039,6 +1039,7 @@ Configurations
7. The USB high-speed EHCI and the low-/full- OHCI host drivers are supported
in this configuration.
Here are the relevant configuration options that enable EHCI support:
System Type -> ATSAMA5 Peripheral Support
@ -1064,24 +1065,64 @@ Configurations
Application Configuration -> NSH Library
CONFIG_NSH_ARCHINIT=y : NSH board-initialization
Example Usage:
NuttShell (NSH) NuttX-6.29
nsh> ls /dev
/dev:
console
mtdblock0
null
ttyS0
Here a USB FLASH stick is inserted. Nothing visible happens in the
the shell. But a new device will appear:
nsh> ls /dev
/dev:
console
mtdblock0
null
sda
ttyS0
nsh> mount -t vfat /dev/sda /mnt/sda
nsh> ls -l /mnt/sda
/mnt/sda:
-rw-rw-rw- 8788 viminfo
drw-rw-rw- 0 .Trash-1000/
-rw-rw-rw- 3378 zmodem.patch
-rw-rw-rw- 1503 sz-1.log
-rw-rw-rw- 613 .bashrc
The following features are *not* enabled in the demo configuration but
might be of some use to you:
8. Debugging USB Device. There is normal console debug output available
that can be enabled with CONFIG_DEBUG + CONFIG_DEBUG_USB. However,
USB device operation is very time critical and enabling this debug
output WILL interfere with the operation of the UDPHS. USB device
tracing is a less invasive way to get debug information: If tracing
is enabled, the USB device will save encoded trace output in in-memory
buffer; if the USB monitor is also enabled, that trace buffer will be
periodically emptied and dumped to the system logging device (the
serial console in this configuration):
8. Debugging USB. There is normal console debug output available that
can be enabled with CONFIG_DEBUG + CONFIG_DEBUG_USB. However, USB
operation is very time critical and enabling this debug output WILL
interfere with some operation. USB tracing is a less invasive way
to get debug information: If tracing is enabled, the USB driver(s)
will save encoded trace output in in-memory buffers; if the USB
monitor is also enabled, those trace buffers will be periodically
emptied and dumped to the system logging device (the serial console
in this configuration):
Either or both USB device or host controller driver tracing can
be enabled:
Device Drivers -> "USB Device Driver Support:
CONFIG_USBDEV_TRACE=y : Enable USB trace feature
CONFIG_USBDEV_TRACE=y : Enable USB device trace feature
CONFIG_USBDEV_TRACE_NRECORDS=256 : Buffer 256 records in memory
CONFIG_USBDEV_TRACE_STRINGS=y : (optional)
Device Drivers -> "USB Host Driver Support:
CONFIG_USBHOST_TRACE=y : Enable USB host trace feature
CONFIG_USBHOST_TRACE_NRECORDS=256 : Buffer 256 records in memory
CONFIG_USBHOST_TRACE_VERBOSE=y : Buffer everything
These settings will configure the USB monitor thread which will dump the
buffered USB debug data once every second:
Application Configuration -> NSH LIbrary:
CONFIG_NSH_USBDEV_TRACE=n : No builtin tracing from NSH
CONFIG_NSH_ARCHINIT=y : Automatically start the USB monitor
@ -1459,6 +1500,41 @@ Configurations
Application Configuration -> NSH Library
CONFIG_NSH_ARCHINIT=y : NSH board-initialization
Debugging USB Host. There is normal console debug output available
that can be enabled with CONFIG_DEBUG + CONFIG_DEBUG_USB. However,
USB host operation is very time critical and enabling this debug
output might interfere with the operation of the UDPHS. USB host
tracing is a less invasive way to get debug information: If tracing
is enabled, the USB host will save encoded trace output in in-memory
buffer; if the USB monitor is also enabled, that trace buffer will be
periodically emptied and dumped to the system logging device (the
serial console in this configuration):
Device Drivers -> "USB Host Driver Support:
CONFIG_USBHOST_TRACE=y : Enable USB host trace feature
CONFIG_USBHOST_TRACE_NRECORDS=256 : Buffer 256 records in memory
CONFIG_USBHOST_TRACE_VERBOSE=y : Buffer everything
Application Configuration -> NSH LIbrary:
CONFIG_NSH_USBDEV_TRACE=n : No builtin tracing from NSH
CONFIG_NSH_ARCHINIT=y : Automatically start the USB monitor
Application Configuration -> System NSH Add-Ons:
CONFIG_SYSTEM_USBMONITOR=y : Enable the USB monitor daemon
CONFIG_SYSTEM_USBMONITOR_STACKSIZE=2048 : USB monitor daemon stack size
CONFIG_SYSTEM_USBMONITOR_PRIORITY=50 : USB monitor daemon priority
CONFIG_SYSTEM_USBMONITOR_INTERVAL=1 : Dump trace data every second
CONFIG_SYSTEM_USBMONITOR_TRACEINIT=y : Enable TRACE output
CONFIG_SYSTEM_USBMONITOR_TRACECLASS=y
CONFIG_SYSTEM_USBMONITOR_TRACETRANSFERS=y
CONFIG_SYSTEM_USBMONITOR_TRACECONTROLLER=y
CONFIG_SYSTEM_USBMONITOR_TRACEINTERRUPTS=y
NOTE: If USB debug output is also enabled, both outpus will appear
on the serial console. However, the debug output will be
asynchronous with the trace output and, hence, difficult to
interpret.
12. Support the USB high-speed USB device driver (UDPHS) can be enabled
by changing the NuttX configuration file as follows:
@ -1503,6 +1579,7 @@ Configurations
Device Drivers -> "USB Device Driver Support:
CONFIG_USBDEV_TRACE=y : Enable USB trace feature
CONFIG_USBDEV_TRACE_NRECORDS=256 : Buffer 256 records in memory
CONFIG_USBDEV_TRACE_STRINGS=y : (optional)
Application Configuration -> NSH LIbrary:
CONFIG_NSH_USBDEV_TRACE=n : No builtin tracing from NSH

60
drivers/usbhost/usbhost_storage.c
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@ -1322,45 +1322,43 @@ static inline int usbhost_initvolume(FAR struct usbhost_state_s *priv)
ret = register_blockdriver(devname, &g_bops, 0, priv);
}
/* Check if we successfully initialized. We now have to be concerned
* about asynchronous modification of crefs because the block
/* Decrement the reference count. We incremented the reference count
* above so that usbhost_destroy() could not be called. We now have to
* be concerned about asynchronous modification of crefs because the block
* driver has been registerd.
*/
if (ret == OK)
usbhost_takesem(&priv->exclsem);
DEBUGASSERT(priv->crefs >= 2);
/* Decrement the reference count */
priv->crefs--;
/* Check if we successfully initialized. If so, handle a corner case
* where (1) open() has been called so the reference count was > 2, but
* the device has been disconnected. In this case, the class instance
* needs to persist until close()
* is called.
*/
if (ret == OK && priv->crefs <= 1 && priv->disconnected)
{
usbhost_takesem(&priv->exclsem);
DEBUGASSERT(priv->crefs >= 2);
/* Decrement the reference count */
priv->crefs--;
/* Handle a corner case where (1) open() has been called so the
* reference count was > 2, but the device has been disconnected.
* In this case, the class instance needs to persist until close()
* is called.
/* The will cause the enumeration logic to disconnect the class
* driver.
*/
if (priv->crefs <= 1 && priv->disconnected)
{
/* The will cause the enumeration logic to disconnect
* the class driver.
*/
ret = -ENODEV;
}
/* Release the semaphore... there is a race condition here.
* Decrementing the reference count and releasing the semaphore
* allows usbhost_destroy() to execute (on the worker thread);
* the class driver instance could get destoryed before we are
* ready to handle it!
*/
usbhost_givesem(&priv->exclsem);
ret = -ENODEV;
}
/* Release the semaphore... there is a race condition here.
* Decrementing the reference count and releasing the semaphore
* allows usbhost_destroy() to execute (on the worker thread);
* the class driver instance could get destroyed before we are
* ready to handle it!
*/
usbhost_givesem(&priv->exclsem);
return ret;
}