If the system did not switch into NOHZ mode ts->inidle is not set when
tick_nohz_stop_sched_tick() is called from the idle routine. Therefor
all subsequent calls from irq_exit() to tick_nohz_stop_sched_tick()
fail to call tick_nohz_start_idle(). This results in bogus idle
accounting information which is passed to cpufreq governors.
Set the inidle flag unconditionally of the NOHZ active state to keep
the idle time accounting correct in any case.
[ tglx: Added comment and tweaked the changelog ]
Reported-by: Steven Noonan <steven@uplinklabs.net> Signed-off-by: Eero Nurkkala <ext-eero.nurkkala@nokia.com> Cc: Rik van Riel <riel@redhat.com> Cc: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Cc: Steven Noonan <steven@uplinklabs.net>
LKML-Reference: <1254907901.30157.93.camel@eenurkka-desktop> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
It's caused by the displacement of the retry_private label in
futex_wake_op(). The code unlocks the hash bucket locks in the
error handling path and retries without locking them again which
makes the next unlock fail.
Move retry_private so we lock the hash bucket locks when we retry.
Reported-by: Rich Ercolany <rercola@acm.jhu.edu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Darren Hart <dvhltc@us.ibm.com>
LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
The robust list pointers of user space held futexes are kept intact
over an exec() call. When the exec'ed task exits exit_robust_list() is
called with the stale pointer. The risk of corruption is minimal, but
still it is incorrect to keep the pointers valid. Actually glibc
should uninstall the robust list before calling exec() but we have to
deal with it anyway.
Nullify the pointers after [compat_]exit_robust_list() has been
called.
Reported-by: Anirban Sinha <ani@anirban.org> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
If futex_wait_requeue_pi() wakes prior to requeue, we drop the
reference to the source futex_key twice, once in
handle_early_requeue_pi_wakeup() and once on our way out.
Remove the drop from the handle_early_requeue_pi_wakeup() and keep
the get/drops together in futex_wait_requeue_pi().
Reported-by: Helge Bahmann <hcb@chaoticmind.net> Signed-off-by: Darren Hart <dvhltc@us.ibm.com> Cc: Helge Bahmann <hcb@chaoticmind.net> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: Dinakar Guniguntala <dino@in.ibm.com> Cc: John Stultz <johnstul@us.ibm.com>
LKML-Reference: <4ACCE21E.5030805@us.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Due to legacy code from back when the dynamic tracer used a daemon,
only core kernel code was checking for failures. This is no longer
the case. We must check for failures any time we perform text modifications.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
When the module is about the unload we release its call records.
The ftrace_release function was given wrong values representing
the module core boundaries, thus not releasing its call records.
Plus making ftrace_release function module specific.
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
LKML-Reference: <1254934835-363-3-git-send-email-jolsa@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
A couple of people have hit the WARN_ON() in drivers/char/tty_io.c,
tty_open() that is unhappy about seeing the tty line discipline go away
during the tty hangup. See for example
http://bugzilla.kernel.org/show_bug.cgi?id=14255
and the reason is that we do the tty_ldisc_halt() outside the
ldisc_mutex in order to be able to flush the scheduled work without a
deadlock with vhangup_work.
However, it turns out that we can solve this particular case by
- using "cancel_delayed_work_sync()" in tty_ldisc_halt(), which waits
for just the particular work, rather than synchronizing with any
random outstanding pending work.
This won't deadlock, since the buf.work we synchronize with doesn't
care about the ldisc_mutex, it just flushes the tty ldisc buffers.
- realize that for this particular case, we don't need to wait for any
hangup work, because we are inside the hangup codepaths ourselves.
so as a result we can just drop the flush_scheduled_work() entirely, and
then move the tty_ldisc_halt() call to inside the mutex. That way we
never expose the partially torn down ldisc state to tty_open(), and hold
the ldisc_mutex over the whole sequence.
Just like ip_fast_csum, the assembly snippet in csum_ipv6_magic needs a
memory clobber, as it is only passed the address of the buffer, not a
memory reference to the buffer itself.
This caused failures in Hurd's pfinetv4 when we tried to compile it with
gcc-4.3 (bogus checksums).
Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Acked-by: "David S. Miller" <davem@davemloft.net> Cc: Andi Kleen <andi@firstfloor.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
For devices using OTP memory, EEPROM image can start from
any one of the OTP blocks. If shadow RAM is disabled, we need to
traverse link list to find the last valid block, then start the EEPROM
image reading.
If OTP is not full, the valid block is the block _before_ the last block
on the link list; the last block on the link list is the empty block
ready for next OTP refresh/update.
If OTP is full, then the last block is the valid block to be used for
configure the device.
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com> Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: John W. Linville <linville@tuxdriver.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
On 1000, there are two Switching Voltage Regulators (SVR). The first one
apply digital voltage level (1.32V) for PCIe block and core. We need to
use this regulator to solve a stability issue related to noisy DC2DC
line in the silicon.
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com> Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: John W. Linville <linville@tuxdriver.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Adding new API version to account for change to ucode file format. New
header includes the build number of the ucode. This build number is the
SVN revision thus allowing for exact correlation to the code that
generated it.
The header adds the build number so that older ucode images can also be
enhanced to include the build in the future.
some cleanup in iwl_read_ucode needed to ensure old header not used and
reduce unnecessary references through pointer with the data is already
in heap variable.
Signed-off-by: Jay Sternberg <jay.e.sternberg@intel.com> Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: John W. Linville <linville@tuxdriver.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Fix MAP_PRIVATE mmap() of files and devices where the data in the backing store
might be mapped directly. Use the BDI_CAP_MAP_DIRECT capability flag to govern
whether or not we should be trying to map a file directly. This can be used to
determine whether or not a region has been filled in at the point where we call
do_mmap_shared() or do_mmap_private().
The BDI_CAP_MAP_DIRECT capability flag is cleared by validate_mmap_request() if
there's any reason we can't use it. It's also cleared in do_mmap_pgoff() if
f_op->get_unmapped_area() fails.
Without this fix, attempting to run a program from a RomFS image on a
non-mappable MTD partition results in a BUG as the kernel attempts XIP, and
this can be caught in gdb:
Program received signal SIGABRT, Aborted.
0xc005dce8 in add_nommu_region (region=<value optimized out>) at mm/nommu.c:547
(gdb) bt
#0 0xc005dce8 in add_nommu_region (region=<value optimized out>) at mm/nommu.c:547
#1 0xc005f168 in do_mmap_pgoff (file=0xc31a6620, addr=<value optimized out>, len=3808, prot=3, flags=6146, pgoff=0) at mm/nommu.c:1373
#2 0xc00a96b8 in elf_fdpic_map_file (params=0xc33fbbec, file=0xc31a6620, mm=0xc31bef60, what=0xc0213144 "executable") at mm.h:1145
#3 0xc00aa8b4 in load_elf_fdpic_binary (bprm=0xc316cb00, regs=<value optimized out>) at fs/binfmt_elf_fdpic.c:343
#4 0xc006b588 in search_binary_handler (bprm=0x6, regs=0xc33fbce0) at fs/exec.c:1234
#5 0xc006c648 in do_execve (filename=<value optimized out>, argv=0xc3ad14cc, envp=0xc3ad1460, regs=0xc33fbce0) at fs/exec.c:1356
#6 0xc0008cf0 in sys_execve (name=<value optimized out>, argv=0xc3ad14cc, envp=0xc3ad1460) at arch/frv/kernel/process.c:263
#7 0xc00075dc in __syscall_call () at arch/frv/kernel/entry.S:897
Note that this fix does the following commit differently:
commit a190887b58c32d19c2eee007c5eb8faa970a69ba
Author: David Howells <dhowells@redhat.com>
Date: Sat Sep 5 11:17:07 2009 -0700
nommu: fix error handling in do_mmap_pgoff()
Reported-by: Graff Yang <graff.yang@gmail.com> Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Pekka Enberg <penberg@cs.helsinki.fi> Cc: Paul Mundt <lethal@linux-sh.org> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Greg Ungerer <gerg@snapgear.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch is solving problem for PAE kernel DMA operation.
On PAE system dma_addr and unsigned long will have different
values.
Now dma_addr is not type casted using unsigned long.
Signed-off-by: Kashyap Desai <kashyap.desai@lsi.com> Signed-off-by: James Bottomley <James.Bottomley@suse.de> Cc: Jan Beulich <JBeulich@novell.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Commit fa047e4f6fa63a6e9d0ae4d7749538830d14a343 "HID: fix inverted
wheel for bluetooth version of apple mighty mouse" is incomplete. If
we remove Apple MightyMouse (bluetooth version) from the list of
apple_devices in drivers/hid/hid-apple.c we have to remove it from
hid_blacklist in drivers/hid/hid-core.c as well.
powerpc: Fix incorrect setting of __HAVE_ARCH_PTE_SPECIAL
[I'm going to fix upstream differently, by having all CPU types
actually support _PAGE_SPECIAL, but I prefer the simple and obvious
fix for -stable. -- Ben]
The test that decides whether to define __HAVE_ARCH_PTE_SPECIAL on
powerpc is bogus and will end up always defining it, even when
_PAGE_SPECIAL is not supported (in which case it's 0) such as on
8xx or 40x processors.
Signed-off-by: Bernhard Weirich <bernhard.weirich@riedel.net> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
After upgrading to the latest kernel on my mpc875 userspace started
running incredibly slow (hours to get to a shell, even!).
I tracked it down to commit 8d30c14cab30d405a05f2aaceda1e9ad57800f36,
that patch removed a work-around for the 8xx. Adding it
back makes my problem go away.
Signed-off-by: Rex Feany <rfeany@mrv.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
ir-kbd-i2c's ir_probe() function can be called much later (i.e. at
ir-kbd-i2c module load), than the lifetime of a struct IR_i2c_init_data
allocated off of the stack in cx18_i2c_new_ir() at registration time.
Make sure we pass a pointer to a persistent IR_i2c_init_data object at
i2c registration time.
Thanks to Brian Rogers, Dustin Mitchell, Andy Walls and Jean Delvare to
rise this question.
Before this patch, if ir-kbd-i2c were probed after SAA7134, trash data
were used.
Compile tested only, but the patch is identical to em28xx one. So, it
should work properly.
ir-kbd-i2c's ir_probe() function can be called much later (i.e. at
ir-kbd-i2c module load), than the lifetime of a struct IR_i2c_init_data
allocated off of the stack in cx18_i2c_new_ir() at registration time.
Make sure we pass a pointer to a persistent IR_i2c_init_data object at
i2c registration time.
Thanks to Brian Rogers, Dustin Mitchell, Andy Walls and Jean Delvare to
rise this question.
Before this patch, if ir-kbd-i2c were probed after em28xx, trash data
were used. After the patch, no matter what order, it is properly
reported as tested by me:
input: i2c IR (i2c IR (EM2840 Hauppaug as /class/input/input10
ir-kbd-i2c: i2c IR (i2c IR (EM2840 Hauppaug detected at i2c-4/4-0030/ir0 [em28xx #0]
During a page fault and rebinding the buffer there exists a window for a
signal to arrive during the i915_wait_request() and trigger a
ERESTARTSYS. This used to be handled by returning SIGBUS and thereby
killing the application. Try 'cairo-perf-trace & cairo-test-suite' and
watch X go boom!
The solution as suggested by H. Peter Anvin is to simply return NOPAGE and
leave the higher layers to spot we did not fill the page and resubmit
the page fault.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
[anholt: Mostly squash it with another commit] Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Git commit 79741dd changes idle cputime accounting, but unfortunately
the /proc/uptime file hasn't caught up. Here the idle time calculation
from /proc/stat is copied over.
Signed-off-by: Michael Abbott <michael.abbott@diamond.ac.uk> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
We noticed very erratic behavior [throughput] with the AIM7 shared
workload running on recent distro [SLES11] and mainline kernels on an
8-socket, 32-core, 256GB x86_64 platform. On the SLES11 kernel
[2.6.27.19+] with Barcelona processors, as we increased the load [10s of
thousands of tasks], the throughput would vary between two "plateaus"--one
at ~65K jobs per minute and one at ~130K jpm. The simple patch below
causes the results to smooth out at the ~130k plateau.
But wait, there's more:
We do not see this behavior on smaller platforms--e.g., 4 socket/8 core.
This could be the result of the larger number of cpus on the larger
platform--a scalability issue--or it could be the result of the larger
number of interconnect "hops" between some nodes in this platform and how
the tasks for a given load end up distributed over the nodes' cpus and
memories--a stochastic NUMA effect.
The variability in the results are less pronounced [on the same platform]
with Shanghai processors and with mainline kernels. With 31-rc6 on
Shanghai processors and 288 file systems on 288 fibre attached storage
volumes, the curves [jpm vs load] are both quite flat with the patched
kernel consistently producing ~3.9% better throughput [~80K jpm vs ~77K
jpm] than the unpatched kernel.
Profiling indicated that the "slow" runs were incurring high[er]
contention on an anon_vma lock in vma_adjust(), apparently called from the
sbrk() system call.
The patch:
A comment in mm/mmap.c:vma_adjust() suggests that we don't really need the
anon_vma lock when we're only adjusting the end of a vma, as is the case
for brk(). The comment questions whether it's worth while to optimize for
this case. Apparently, on the newer, larger x86_64 platforms, with
interesting NUMA topologies, it is worth while--especially considering
that the patch [if correct!] is quite simple.
We can detect this condition--no overlap with next vma--by noting a NULL
"importer". The anon_vma pointer will also be NULL in this case, so
simply avoid loading vma->anon_vma to avoid the lock.
However, we DO need to take the anon_vma lock when we're inserting a vma
['insert' non-NULL] even when we have no overlap [NULL "importer"], so we
need to check for 'insert', as well. And Hugh points out that we should
also take it when adjusting vm_start (so that rmap.c can rely upon
vma_address() while it holds the anon_vma lock).
akpm: Zhang Yanmin reprts a 150% throughput improvement with aim7, so it
might be -stable material even though thiss isn't a regression: "this
issue is not clear on dual socket Nehalem machine (2*4*2 cpu), but is
severe on large machine (4*8*2 cpu)"
[hugh.dickins@tiscali.co.uk: test vma start too] Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk> Cc: Nick Piggin <npiggin@suse.de> Cc: Eric Whitney <eric.whitney@hp.com> Tested-by: "Zhang, Yanmin" <yanmin_zhang@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
do_anonymous_page() has been wrong to dirty the pte regardless.
If it's not going to mark the pte writable, then it won't help
to mark it dirty here, and clogs up memory with pages which will
need swap instead of being thrown away. Especially wrong if no
overcommit is chosen, and this vma is not yet VM_ACCOUNTed -
we could exceed the limit and OOM despite no overcommit.
Hiroaki Wakabayashi points out that when mlock() has been interrupted
by SIGKILL, the subsequent munlock() takes unnecessarily long because
its use of __get_user_pages() insists on faulting in all the pages
which mlock() never reached.
It's worse than slowness if mlock() is terminated by Out Of Memory kill:
the munlock_vma_pages_all() in exit_mmap() insists on faulting in all the
pages which mlock() could not find memory for; so innocent bystanders are
killed too, and perhaps the system hangs.
__get_user_pages() does a lot that's silly for munlock(): so remove the
munlock option from __mlock_vma_pages_range(), and use a simple loop of
follow_page()s in munlock_vma_pages_range() instead; ignoring absent
pages, and not marking present pages as accessed or dirty.
(Change munlock() to only go so far as mlock() reached? That does not
work out, given the convention that mlock() claims complete success even
when it has to give up early - in part so that an underlying file can be
extended later, and those pages locked which earlier would give SIGBUS.)
After anti-fragmentation was merged, a bug was reported whereby devices
that depended on high-order atomic allocations were failing. The solution
was to preserve a property in the buddy allocator which tended to keep the
minimum number of free pages in the zone at the lower physical addresses
and contiguous. To preserve this property, MIGRATE_RESERVE was introduced
and a number of pageblocks at the start of a zone would be marked
"reserve", the number of which depended on min_free_kbytes.
Anti-fragmentation works by avoiding the mixing of page migratetypes
within the same pageblock. One way of helping this is to increase
min_free_kbytes because it becomes less like that it will be necessary to
place pages of of MIGRATE_RESERVE is unbounded, the free memory is kept
there in large contiguous blocks instead of helping anti-fragmentation as
much as it should. With the page-allocator tracepoint patches applied, it
was found during anti-fragmentation tests that the number of
fragmentation-related events were far higher than expected even with
min_free_kbytes at higher values.
This patch limits the number of MIGRATE_RESERVE blocks that exist per zone
to two. For example, with a sufficient min_free_kbytes, 4MB of memory
will be kept aside on an x86-64 and remain more or less free and
contiguous for the systems uptime. This should be sufficient for devices
depending on high-order atomic allocations while helping fragmentation
control when min_free_kbytes is tuned appropriately. As side-effect of
this patch is that the reserve variable is converted to int as unsigned
long was the wrong type to use when ensuring that only the required number
of reserve blocks are created.
With the patches applied, fragmentation-related events as measured by the
page allocator tracepoints were significantly reduced when running some
fragmentation stress-tests on systems with min_free_kbytes tuned to a
value appropriate for hugepage allocations at runtime. On x86, the events
recorded were reduced by 99.8%, on x86-64 by 99.72% and on ppc64 by
99.83%.
Lee Schermerhorn [Tue, 22 Sep 2009 00:01:04 +0000 (17:01 -0700)]
hugetlb: restore interleaving of bootmem huge pages (2.6.31)
Not upstream as it is fixed differently in .32
I noticed that alloc_bootmem_huge_page() will only advance to the next
node on failure to allocate a huge page. I asked about this on linux-mm
and linux-numa, cc'ing the usual huge page suspects. Mel Gorman
responded:
I strongly suspect that the same node being used until allocation
failure instead of round-robin is an oversight and not deliberate
at all. It appears to be a side-effect of a fix made way back in
commit 63b4613c3f0d4b724ba259dc6c201bb68b884e1a ["hugetlb: fix
hugepage allocation with memoryless nodes"]. Prior to that patch
it looked like allocations would always round-robin even when
allocation was successful.
Andy Whitcroft countered that the existing behavior looked like Andi
Kleen's original implementation and suggested that we ask him. We did and
Andy replied that his intention was to interleave the allocations. So,
...
This patch moves the advance of the hstate next node from which to
allocate up before the test for success of the attempted allocation. This
will unconditionally advance the next node from which to alloc,
interleaving successful allocations over the nodes with sufficient
contiguous memory, and skipping over nodes that fail the huge page
allocation attempt.
Note that alloc_bootmem_huge_page() will only be called for huge pages of
order > MAX_ORDER.
Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Reviewed-by: Andi Kleen <ak@linux.intel.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: David Rientjes <rientjes@google.com> Cc: Adam Litke <agl@us.ibm.com> Cc: Andy Whitcroft <apw@canonical.com> Cc: Eric Whitney <eric.whitney@hp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
When there's a descriptor after the SuperSpeed endpoint companion
descriptor, the previous code would have skipped over twice the length it
was supposed to. This code fixes crashes seen with UASP devices (which
have a UASP descriptor after the SS endpoint companion descriptor).
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Interrupt transfers are submitted to the xHCI hardware using the same TRB
type as bulk transfers. Re-use the bulk transfer enqueueing code to
enqueue interrupt transfers.
Interrupt transfers are a bit different than bulk transfers. When the
interrupt endpoint is to be serviced, the xHC will consume (at most) one
TD. A TD (comprised of sg list entries) can take several service
intervals to transmit. The important thing for device drivers to note is
that if they use the scatter gather interface to submit interrupt
requests, they will not get data sent from two different scatter gather
lists in the same service interval.
For now, the xHCI driver will use the service interval from the endpoint's
descriptor (bInterval). Drivers will need a hook to poll at a more
frequent interval. Set urb->interval to the interval that the xHCI
hardware will use.
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
The xHCI hardware reports the number of bytes untransferred for a given
transfer buffer. If the hardware reports a bytes untransferred value
greater than the submitted buffer size, we want to play it safe and say no
data was transferred. If the driver considers a short packet to be an
error, remember to set -EREMOTEIO.
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Make sure that the amount of data the xHC says was transmitted is less
than or equal to the size of the requested transfer buffer. Before, if
the host controller erroneously reported that the number of bytes
untransferred was bigger than the buffer in the URB, urb->actual_length
could be set to a very large size.
Make sure urb->actual_length <= urb->transfer_buffer_length.
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
On a successful transfer, urb->td is freed before the URB is ready to be
given back to the driver. Don't touch urb->td after it's freed. This bug
would have only shown up when xHCI debugging was turned on, and the freed
memory was quickly reused for something else.
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
The 0.95 xHCI spec says that non-control endpoints will be halted if a
babble is detected on a transfer. The 0.96 xHCI spec says all types of
endpoints will be halted when a babble is detected. Some hardware that
claims to be 0.95 compliant halts the control endpoint anyway.
When a babble is detected on a control endpoint, check the hardware's
output endpoint context to see if the endpoint is marked as halted. If
the control endpoint is halted, a reset endpoint command must be issued
and the transfer ring dequeue pointer needs to be moved past the stopped
transfer. Basically, we treat it as if the control endpoint had stalled.
Handle bulk babbling endpoints as if we got a completion event with a
stall completion code.
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This Fresco Logic xHCI host controller chip revision puts bad data into
the output endpoint context after a Reset Endpoint command. It needs a
Configure Endpoint command (instead of a Set TR Dequeue Pointer command)
after the reset endpoint command.
Set up the input context before issuing the Reset Endpoint command so we
don't copy bad data from the output endpoint context. The HW also can't
handle two commands queued at once, so submit the TRB for the Configure
Endpoint command in the event handler for the Reset Endpoint command.
Devices that stall on control endpoints before a configuration is selected
will not work under this Fresco Logic xHCI host controller revision.
This patch is for prototype hardware that will be given to other companies
for evaluation purposes only, and should not reach consumer hands. Fresco
Logic's next chip rev should have this bug fixed.
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
When a control endpoint stalls, the next control transfer will clear the
stall. The USB core doesn't call down to the host controller driver's
endpoint_reset() method when control endpoints stall, so the xHCI driver
has to do all its stall handling for internal state in its interrupt handler.
When the host stalls on a control endpoint, it may stop on the data phase
or status phase of the control transfer. Like other stalled endpoints,
the xHCI driver needs to queue a Reset Endpoint command and move the
hardware's control endpoint ring dequeue pointer past the failed control
transfer (with a Set TR Dequeue Pointer or a Configure Endpoint command).
Since the USB core doesn't call usb_hcd_reset_endpoint() for control
endpoints, we need to do this in interrupt context when we get notified of
the stalled transfer. URBs may be queued to the hardware before these two
commands complete. The endpoint queue will be restarted once both
commands complete.
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Full speed devices have varying max packet sizes (8, 16, 32, or 64) for
endpoint 0. The xHCI hardware needs to know the real max packet size
that the USB core discovers after it fetches the first 8 bytes of the
device descriptor.
In order to fix this without adding a new hook to host controller drivers,
the xHCI driver looks for an updated max packet size for control
endpoints. If it finds an updated size, it issues an evaluate context
command and waits for that command to finish. This should only happen in
the initialization and device descriptor fetching steps in the khubd
thread, so blocking should be fine.
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Set the max packet size for the default control endpoint on high speed
devices to be 64 bytes. High speed devices always have a max packet size
of 64 bytes. There's no use setting it to eight for the initial 8 byte
descriptor fetch and then issuing (and waiting for) an evaluate context
command to update it to 64 bytes for the subsequent control transfers.
The USB core guesses that the max packet size on a full speed control
endpoint is 64 bytes, and then updates it after the first 8-byte
descriptor fetch. Change the initial setup for the xHCI internal
representation of the full speed device to have a 64 byte max packet size.
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Refactor out the code issue, wait for, and parse the event completion code
for a configure endpoint command. Modify it to support the evaluate
context command, which has a very similar submission process. Add
functions to copy parts of the output context into the input context
(which will be used in the evaluate context command).
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Different sections of the xHCI 0.95 specification had opposing
requirements for the chain bit in a link transaction request buffer (TRB).
The chain bit is used to designate that adjacent TRBs are all part of the
same scatter gather list that should be sent to the device. Link TRBs can
be in the middle, or at the beginning or end of these chained TRBs.
Sections 4.11.5.1 and 6.4.4.1 both stated the link TRB "shall have the
chain bit set to 1", meaning it is always chained to the next TRB.
However, section 4.6.9 on the stop endpoint command has specific cases for
what the hardware must do for a link TRB with the chain bit set to 0. The
0.96 specification errata later cleared up this issue by fixing the
4.11.5.1 and 6.4.4.1 sections to state that a link TRB can have the chain
bit set to 1 or 0.
The problem is that the xHCI cancellation code depends on the chain bit of
the link TRB being cleared when it's at the end of a TD, and some 0.95
xHCI hardware simply stops processing the ring when it encounters a link
TRB with the chain bit cleared.
Allow users who are testing 0.95 xHCI prototypes to set a module parameter
(link_quirk) to turn on this link TRB work around. Cancellation may not
work if the ring is stopped exactly on a link TRB with chain bit set, but
cancellation should be a relatively uncommon case.
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1292) modifies the USB serial console driver, to make it
compatible with the recent changes to the USB serial core. The most
important change is that serial->disc_mutex now has to be unlocked
following a successful call to usb_serial_get_by_index().
Other less notable changes include:
Use the requested port number instead of port 0 always.
Prevent the serial device from being autosuspended.
Use the ASYNCB_INITIALIZED flag bit to indicate when the
port hardware has been initialized.
In spite of these changes, there's no question that the USB serial
console code is still a big hack.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1291) removes a bunch of code from serial_open(), things
that were rendered unnecessary by earlier patches. A missing spinlock
is added to protect port->port.count, which needs to be incremented
even if the open fails but not if the tty has gotten a hangup. The
test for whether the hardware has been initialized, based on the use
count, is replaced by a more transparent test of the
ASYNCB_INITIALIZED bit in the port flags.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1290) adds some missing tests. serial_down() isn't
supposed to do anything if the hardware hasn't been initialized, and
serial_close() isn't supposed to do anything if the tty has gotten a
hangup (because serial_hangup() takes care of shutting down the
hardware).
The patch also updates and adds a few debugging lines.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1289) renames serial_do_down() to serial_down() and
serial_do_free() to serial_release(). It also adds a missing call to
tty_shutdown() in serial_release().
Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1288) fixes the initialization logic in
serial_install(). A new tty always needs to have a termios
initialized no matter what, not just in the case where the lower
driver will override the termios settings.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1287) makes serial_install() be reponsible for acquiring
references to the usb_serial structure and the driver module when a
tty is first used. This is more sensible than having serial_open() do
it, because a tty can be opened many times whereas it is installed
only once, when it is created. (Not to mention that these actions are
reversed when the tty is released, not when it is closed.) Finally,
it is at install time that the TTY core takes its own reference to the
usb_serial module, so it is only fitting that we should act the same
way in regard to the lower-level serial driver.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1286) changes usb_serial_get_by_index(). Now the
routine will check whether the serial device has been disconnected; if
it has then the return value will be NULL. If the device hasn't been
disconnected then the routine will return with serial->disc_mutex
held, so that the caller can use the structure without fear of racing
against driver unloads.
This permits the scope of table_mutex in destroy_serial() to be
reduced. Instead of protecting the entire function, it suffices to
protect the part that actually uses serial_table[], i.e., the call to
return_serial(). There's no longer any danger of the refcount being
incremented after it reaches 0 (which was the reason for having the
large scope previously), because it can't reach 0 until the serial
device has been disconnected.
Also, the patch makes serial_install() check that serial is non-NULL
before attempting to use it.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1285) rearranges the subroutines in usb-serial.c
concerned with tty lifetimes into a more logical order: install, open,
hangup, close, release. It also updates the formatting of the
kerneldoc comments.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1284) changes the referencing of the usb_serial and
usb_serial_port structures in usb-serial.c. It's not feasible to make
the port structures keep a reference to the serial structure, because
the ports need to remain in existence when serial is released -- quite
a few of the drivers expect this. Consequently taking a reference
to the port when the device file is open is insufficient; such a
reference would not pin serial.
To fix this, we now take a reference to serial when the device file is
opened. The final put_device() for the ports occurs in
destroy_serial(), so that the ports will last as long as they are
needed.
The patch initializes all the port devices, including those in the
unused "fake" ports. This makes the code more uniform because they
can all be released in the same way. The error handling code in
usb_serial_probe() is much simplified by this approach; instead of
freeing everything by hand we can use a single usb_serial_put() call.
Also simplified is the port-release mechanism. Instead of being two
separate routines, port_release() and port_free() can be combined into
one.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Various drivers have hacks to mangle termios structures. This stems from
the fact there is no nice setup hook for configuring the termios settings
when the port is created
Signed-off-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
The USB layer uses tty_hangup to deal with unplugs of the physical hardware
(analogous to loss of carrier) and then frees the resources. However the
tty_hangup is asynchronous. As the hangup can sleep we can use tty_vhangup
which is the non async version to avoid freeing resources too early.
Signed-off-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Now we are extracting out methods for shutdown and the like we can add a
proper tty_port_close method that knows all the innards of the tty closing
process and hides the lot from the caller.
At some point in the future this will be paired with a similar open()
helper and the drivers can stick to hardware management.
Signed-off-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1271) affects when new devices get linked into their
bus's list of devices. Currently this happens after probing, and it
doesn't happen at all if probing fails. Clearly this is wrong,
because at that point quite a few symbolic links have already been
created in sysfs. We are committed to adding the device, so it should
be linked into the bus's list regardless.
In addition, this needs to happen before the uevent announcing the new
device gets issued. Otherwise user programs might try to access the
device before it has been added to the bus.
To fix both these problems, the patch moves the call to
klist_add_tail() forward from bus_attach_device() to bus_add_device().
Since bus_attach_device() now does nothing but probe for drivers, it
has been renamed to bus_probe_device(). And lastly, the kerneldoc is
updated.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu> CC: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Paraphrasing Rafael J. Wysocki: "drivers should not release PCI IRQs
in suspend." Doing so causes a warning during suspend/resume on some
platforms.
Cc: Rafael J. Wysocki <rjw@sisk.pl> Reported-by: Alan Jenkins <alan-jenkins@tuffmail.co.uk> Signed-off-by: Bob Copeland <me@bobcopeland.com> Signed-off-by: John W. Linville <linville@tuxdriver.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* Don't put chip to full sleep because there are problems during
wakeup. Instead hold MAC/Baseband on warm reset state via a new
function ath5k_hw_on_hold.
* Minor cleanups
Signed-off-by: Nick Kossifidis <mickflemm@gmail.com> Tested-by: Ben Greear <greearb@candelatech.com> Tested-by: Johannes Stezenbach <js@sig21.net> Signed-off-by: John W. Linville <linville@tuxdriver.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Commit 19eda87 (netfilter: change return types of check functions for
Ebtables extensions) broke the ebtables ulog module by missing a return
value conversion.
Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Kernel 2.6.30 introduced a patch [1] for the persistent option in the
netfilter SNAT target. This is exactly what we need here so I had a quick look
at the code and noticed that the patch is wrong. The logic is simply inverted.
The patch below fixes this.
Also note that because of this the default behavior of the SNAT target has
changed since kernel 2.6.30 as it now ignores the destination IP in choosing
the source IP for nating (which should only be the case if the persistent
option is set).
This improves patch fa6963b24 so that perf.data stuff that has
been dumped as root can be read (annotate/report) by a user
without the use of the --force.
Rationale is that root has plenty of ways to screw us (usually)
that do not require twisted schemes involving specially
crafting a perf.data.
Signed-off-by: Pierre Habouzit <pierre.habouzit@intersec.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20090827075902.GF19653@laphroaig.corp> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
To my understanding, it became obsolete with the advent of the more
robust check in mmu_alloc_roots (89da4ff17f). Moreover, it prevents
the conceptually safe pattern
1. set sregs
2. register mem-slots
3. run vcpu
by setting a sticky triple fault during step 1.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com> Signed-off-by: Avi Kivity <avi@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
n_requested_mmu_pages/n_free_mmu_pages are used by
kvm_mmu_change_mmu_pages to calculate the number of pages to zap.
alloc_mmu_pages, called from the vcpu initialization path, modifies this
variables without proper locking, which can result in a negative value
in kvm_mmu_change_mmu_pages (say, with cpu hotplug).
Commit ac89a9174 ("pty: don't limit the writes to 'pty_space()' inside
'pty_write()'") removed the pty_space() checking, in order to let the
regular tty buffer code limit the buffering itself.
That was all good, but as a subtle side effect it meant that we'd be
doing a tty_wakeup() even in the case where the buffers were all filled
up, and didn't actually make any progress on the write.
Which sounds innocuous, but it interacts very badly with the ppp_async
code, which has an infinite loop in ppp_async_push() that tries to push
out data to the tty. When we call tty_wakeup(), that loop ends up
thinking that progress was made (see the subtle interactions between
XMIT_WAKEUP and 'tty_stuffed' for details). End result: one unhappy ppp
user.
Fixed by noticing when tty_insert_flip_string() didn't actually do
anything, and then not doing any more processing (including, very much
not calling tty_wakeup()).
The length of the to-copy data structure is currently stored in
a signed integer. However many comparisons are done with sizeof(..)
which is unsigned. It's more suitable for this variable to be unsigned
to make these comparisons more naturally right.
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Cc: David S. Miller <davem@davemloft.net> Cc: Ingo Molnar <mingo@elte.hu> Cc: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
as a security check against optlen being negative (or zero) in the
set socket option.
Unfortunately, "sizeof(int)" is an unsigned property, with the
result that the whole comparison is done in unsigned, letting
negative values slip through.
This patch changes this to
if (optlen < (int)sizeof(int))
return -EINVAL;
so that the comparison is done as signed, and negative values
get properly caught.
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Cc: David S. Miller <davem@davemloft.net> Cc: Ingo Molnar <mingo@elte.hu> Cc: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
sharpsl_pm.c code tries to read battery state very early during
resume, but those battery meters are connected on SPI and that's only
resumed way later.
Replace the check with simple checking of battery fatal signal, that
actually works at this stage.
Signed-off-by: Pavel Machek <pavel@ucw.cz> Tested-by: Stanislav Brabec <utx@penguin.cz> Signed-off-by: Eric Miao <eric.y.miao@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Commit a5bfc4714b3f01365aef89a92673f2ceb1ccf246 dropped explicit
pci_intx() manipulation from ahci because it seemed unnecessary and
ahci doesn't seem to be the right place to be tweaking it if it were.
This was largely okay but there are exceptions. There was one on an
embedded platform which was fixed via firmware and now bko#14124
reports it on a HP DL320.
http://bugzilla.kernel.org/show_bug.cgi?id=14124
I still think this isn't something libata drivers should be caring
about (the only ones which are calling pci_intx() explicitly are
libata ones and one other driver) but for now reverting the change
seems to be the right thing to do.
Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Thomas Jarosch <thomas.jarosch@intra2net.com> Signed-off-by: Jeff Garzik <jgarzik@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
When using nanosleep() in an userspace application we get a ratelimit warning
NOHZ: local_softirq_pending 08
for 10 times.
The echo of CAN frames is done from process context and softirq context only.
Therefore the usage of netif_rx() was wrong (for years).
This patch replaces netif_rx() with netif_rx_ni() which has to be used from
process/softirq context. It also adds a missing comment that can_send() must
no be used from hardirq context.
Signed-off-by: Oliver Hartkopp <oliver@hartkopp.net> Signed-off-by: Urs Thuermann <urs@isnogud.escape.de> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
On setting up the callback to the client, we attempt to use the same
authentication flavor the client did. We find an rpc cred to use by
calling rpcauth_lookup_credcache(), which assumes that the given
authentication flavor has a credentials cache. However, this is not
required to be true--in particular, auth_null does not use one.
Instead, we should call the auth's lookup_cred() method.
Without this, a client attempting to mount using nfsv4 and auth_null
triggers a null dereference.
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Ever since we enabled GEM, the pre-9xx chipsets (particularly 865) have had
serious stability issues. Back in May a wbinvd was added to the DRM to
work around much of the problem. Some failure remained -- easily visible
by dragging a window around on an X -retro desktop, or by looking at bugzilla.
The chipset flush was on the right track -- hitting the right amount of
memory, and it appears to be the only way to flush on these chipsets, but the
flush page was mapped uncached. As a result, the writes trying to clear the
writeback cache ended up bypassing the cache, and not flushing anything! The
wbinvd would flush out other writeback data and often cause the data we wanted
to get flushed, but not always. By removing the setting of the page to UC
and instead just clflushing the data we write to try to flush it, we get the
desired behavior with no wbinvd.
This exports clflush_cache_range(), which was laying around and happened to
basically match the code I was otherwise going to copy from the DRM.
mac Mini's have a single DDC line on the DVI connector, shared between the
analog link and the digital link. So, if DDC isn't detected on GPIOE (the
usual SDVO DDC link), try GPIOA (the usual VGA DDC link) when there isn't a
VGA monitor connected.
Signed-off-by: Keith Packard <keithp@keithp.com> Signed-off-by: Zhao Yakui <yakui.zhao@intel.com> Signed-off-by: Eric Anholt <eric@anholt.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Arrandale has new window based method for panel fitting.
This one enables full screen aspect scaling on LVDS. It fixes
standard mode display failure on LVDS for Arrandale.
Eric noted a potential concern with the low bits not being strictly used
as part of the absolute offset (instead part of the command stream to the
GPU), but in practice that should not be an issue.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Tested-by: Andy Whitcroft <apw@canonical.com> Cc: Eric Anholt <eric@anholt.net> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
A very high dotclock (e.g. 229500kHz as reported by Anton) can cause
the entries_required variable to overflow, potentially leading to a
FIFO watermark value that's too low to support the given mode. Split
the division across the calculation to avoid this.
Reported-by: Anton Khirnov <wyskas@gmail.com> Tested-by: Anton Khirnov <wyskas@gmail.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
drm_ht_remove_item() does not handle removing an absent item and the hlist
in particular is incorrectly initialised. The easy remedy is simply skip
calling i915_gem_free_mmap_offset() unless we have actually created the
offset and associated ht entry.
This also fixes the mishandling of a partially constructed offset which
leaves pointers initialized after freeing them along the
i915_gem_create_mmap_offset() error paths.
In particular this should fix the oops found here:
https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-intel/+bug/415357/comments/8
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Signed-off-by: Eric Anholt <eric@anholt.net>
SL811 Device detected after removal used to be working in linux-2.6.22
but then broke somewhere between 2.6.22 and 2.6.28. Current
hub_port_connect_change() in drivers/usb/core/hub.c won't call
usb_disconnect() in case the SL811 driver sets portstatus
USB_PORT_FEAT_CONNECTION upon removal.
AFAIK the SL811 has only a combined Device Insert/Remove
detection bit, therefore use a count to distinguish insert or remove.
Signed-Off-By: Michael Hennerich <hennerich@blackfin.uclinux.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
According to the specifications, an instrument should not return more data in a
DEV_DEP_MSG_IN urb than requested. However, some instruments can send more
than requested. This could cause the kernel to write the extra data past the
end of the buffer provided by read().
Fix this by checking that the value of the TranserSize field is not larger than
the urb itself and not larger than the size of the userspace buffer. Also
correctly decrement the remaining size of the buffer when userspace read()s
more than USBTMC_SIZE_IOBUFFER.
In this patch, we always make the return value of function
usb_stor_huawei_e220_init to be zero. Then it will not prevent usb-storage
driver from attaching to the CDROM device of Huawei Datacard.