OK, the USB gadget serial driver actually has a couple of problems. On
gs_open(), it always allocates and queues an additional QUEUE_SIZE (16)
worth of requests, so with a loop like this:
i=1 ; while echo $i > /dev/ttyGS0 ; do let i++ ; done
eventually we run into OOM (Out of Memory).
Technically, it is not a leak as everything gets freed up when the USB
connection is broken, but not on gs_close().
With a USB device/gadget controller driver that has limited resources
(e.g., Marvell has a this MAX_XDS_FOR_TR_CALLS of 64 for transmit and
receive), so even after 4
stty -F /dev/ttyGS0
we cannot transmit anymore. We can still receive (not necessarily
reliably) as now we have 16 * 4 = 64 descriptors/buffers ready, but the
device is otherwise not usable.
Signed-off-by: Jim Sung <jsung@syncadence.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Here is the patch for the following issue:
drivers/usb/gadget/u_serial.c: In function ‘gs_start_tx’:
drivers/usb/gadget/u_serial.c:369: error: ‘TASK_INTERRUPTIBLE’ undeclared (first use in this function)
drivers/usb/gadget/u_serial.c:369: error: (Each undeclared identifier is reported only once
drivers/usb/gadget/u_serial.c:369: error: for each function it appears in.)
drivers/usb/gadget/u_serial.c: In function ‘gs_rx_push’:
drivers/usb/gadget/u_serial.c:546: error: ‘TASK_INTERRUPTIBLE’ undeclared (first use in this function)
drivers/usb/gadget/u_serial.c: In function ‘gs_close’:
drivers/usb/gadget/u_serial.c:857: error: ‘TASK_INTERRUPTIBLE’ undeclared (first use in this function)
drivers/usb/gadget/u_serial.c:857: error: implicit declaration of function ‘signal_pending’
drivers/usb/gadget/u_serial.c:857: error: implicit declaration of function ‘schedule_timeout’
drivers/usb/gadget/u_serial.c: In function ‘gserial_cleanup’:
drivers/usb/gadget/u_serial.c:1190: error: ‘TASK_UNINTERRUPTIBLE’ undeclared (first use in this function)
drivers/usb/gadget/u_serial.c:1190: error: implicit declaration of function ‘schedule’
drivers/usb/gadget/u_serial.c: In function ‘gserial_disconnect’:
drivers/usb/gadget/u_serial.c:1311: error: ‘TASK_INTERRUPTIBLE’ undeclared (first use in this function)
Signed-off-by: Stephane Duverger <stephane.duverger@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Call put_tty_driver() in cleanup function, to fix Oops when trying to open
gadget serial char device after module unload.
Signed-off-by: Jon Povey <jon.povey@racelogic.co.uk>
Acked-by: David Brownell <dbrownell@users.sourceforge.net>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
No longer set low_latency flag as it causes this warning backtrace:
WARNING: at kernel/mutex.c:207 __mutex_lock_slowpath+0x6c/0x288()
Fix associated locking and wakeups.
Signed-off-by: Jon Povey <jon.povey@racelogic.co.uk>
Cc: Maulik Mankad <x0082077@ti.com>
Cc: stable <stable@kernel.org>
Acked-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files. percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.
percpu.h -> slab.h dependency is about to be removed. Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability. As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.
http://userweb.kernel.org/~tj/misc/slabh-sweep.py
The script does the followings.
* Scan files for gfp and slab usages and update includes such that
only the necessary includes are there. ie. if only gfp is used,
gfp.h, if slab is used, slab.h.
* When the script inserts a new include, it looks at the include
blocks and try to put the new include such that its order conforms
to its surrounding. It's put in the include block which contains
core kernel includes, in the same order that the rest are ordered -
alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
doesn't seem to be any matching order.
* If the script can't find a place to put a new include (mostly
because the file doesn't have fitting include block), it prints out
an error message indicating which .h file needs to be added to the
file.
The conversion was done in the following steps.
1. The initial automatic conversion of all .c files updated slightly
over 4000 files, deleting around 700 includes and adding ~480 gfp.h
and ~3000 slab.h inclusions. The script emitted errors for ~400
files.
2. Each error was manually checked. Some didn't need the inclusion,
some needed manual addition while adding it to implementation .h or
embedding .c file was more appropriate for others. This step added
inclusions to around 150 files.
3. The script was run again and the output was compared to the edits
from #2 to make sure no file was left behind.
4. Several build tests were done and a couple of problems were fixed.
e.g. lib/decompress_*.c used malloc/free() wrappers around slab
APIs requiring slab.h to be added manually.
5. The script was run on all .h files but without automatically
editing them as sprinkling gfp.h and slab.h inclusions around .h
files could easily lead to inclusion dependency hell. Most gfp.h
inclusion directives were ignored as stuff from gfp.h was usually
wildly available and often used in preprocessor macros. Each
slab.h inclusion directive was examined and added manually as
necessary.
6. percpu.h was updated not to include slab.h.
7. Build test were done on the following configurations and failures
were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
distributed build env didn't work with gcov compiles) and a few
more options had to be turned off depending on archs to make things
build (like ipr on powerpc/64 which failed due to missing writeq).
* x86 and x86_64 UP and SMP allmodconfig and a custom test config.
* powerpc and powerpc64 SMP allmodconfig
* sparc and sparc64 SMP allmodconfig
* ia64 SMP allmodconfig
* s390 SMP allmodconfig
* alpha SMP allmodconfig
* um on x86_64 SMP allmodconfig
8. percpu.h modifications were reverted so that it could be applied as
a separate patch and serve as bisection point.
Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.
Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
If the driver cannot be registered, put_tty_driver(gs_tty_driver)
occurred here as well as at label fail.
put_tty_driver() already occurs at label fail
Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Some usb serial host drivers expect a short packet before they forward
the data to the application. This is caused by them trying to read more
than one packet at a time. So when the gadget sends an exact multiple
of the maximum packet size, it should append a zero-length packet.
Signed-off-by: Daniel Glöckner <dg@emlix.com>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
The base versions handle constant folding now.
Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Update the CDC-ACM gadget code to support the peripheral-to-host
notifications when the tty is opened or closed, or issues a BREAK.
The serial framework code calls new generic hooks; right now only
CDC-ACM uses those hooks. This resolves several REVISIT comments
in the code. (Based on a patch from Felipe Balbi.)
Note that this doesn't expose USB_CDC_CAP_BRK to the host, since
this code still rejects USB_CDC_REQ_SEND_BREAK control requests
for host-to-peripheral BREAK signaling (received via /dev/ttyGS*).
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Cc: Felipe Balbi <felipe.balbi@nokia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Update RX path handling in new serial gadget code to cope better with
RX blockage: queue every RX packet until its contents can safely be
passed up to the ldisc. Most of the RX path work is now done in the
RX tasklet, instead of just the final "push to ldisc" step. This
addresses some cases of data loss:
- A longstanding serial gadget bug: when tty_insert_flip_string()
didn't copy the entire buffer, the rest of the characters were
dropped! Now that packet stays queued until the rest of its data
is pushed to the ldisc.
- Another longstanding issue: in the unlikely case that an RX
transfer returns data and also reports a fault, that data is
no longer discarded.
- In the recently added RX throttling logic: it needs to stop
pushing data into the TTY layer, instead of just not submitting
new USB read requests. When the TTY is throttled long enough,
backpressure will eventually make the OUT endpoint NAK.
Also: an #ifdef is removed (no longer necessary); and start switching
to a better convention for debug messages (prefix them with tty name).
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
These two fixes ensure the new "CDC Composite Device" gadget
fails cleanly when it's loaded on hardware that can't support
this particular gadget driver.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This abstracts the "gadget serial" driver TTY glue into a separate
component, cleaning it up and disentangling it from connection state.
It also changed some behaviors for the better:
- Stops using "experimental" major #127, and switches over to
having the TTY layer allocate the dev_t numbers.
- Provides /sys/class/tty/ttyGS* nodes, thus mdev/udev support.
(Note "mdev" hotplug bug in Busybox v1.7.2: /dev/ttyGS0 will
be a *block* device without CONFIG_SYSFS_DEPRECATED_V2.)
- The tty nodes no longer reject opens when there's no host.
Now they can support normal getty configs in /etc/inttab...
- Now implements RX throttling. When the line discipline says
it doesn't want any more data, only packets in flight will be
delivered (currently, max 1K/8K at full/high speeds) until it
unthrottles the data.
- Supports low_latency. This is a good policy for all USB serial
adapters, since it eliminates scheduler overhead on RX paths.
This also includes much cleanup including better comments, fixing
memory leaks and other bugs (including some locking fixes), messaging
cleanup, and an interface audit and tightening. This added up to a
significant object code shrinkage, on the order of 20% (!) depending
on CPU and compiler.
A separate patch actually kicks in this new code, using the functions
declared in this new header, and removes the previous glue.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
