rcu: More on deadlock between CPU hotplug and expedited grace periods

Commit dd56af42bd82 (rcu: Eliminate deadlock between CPU hotplug and
expedited grace periods) was incomplete.  Although it did eliminate
deadlocks involving synchronize_sched_expedited()'s acquisition of
cpu_hotplug.lock via get_online_cpus(), it did nothing about the similar
deadlock involving acquisition of this same lock via put_online_cpus().
This deadlock became apparent with testing involving hibernation.

This commit therefore changes put_online_cpus() acquisition of this lock
to be conditional, and increments a new cpu_hotplug.puts_pending field
in case of acquisition failure.  Then cpu_hotplug_begin() checks for this
new field being non-zero, and applies any changes to cpu_hotplug.refcount.

Reported-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Jiri Kosina <jkosina@suse.cz>
Tested-by: Borislav Petkov <bp@suse.de>
usb: dwc3: ep0: fix Data Phase for transfer sizes aligned to wMaxPacketSize

According to Section 8.5.3.2 of the USB 2.0 specification,
a USB device must terminate a Data Phase with either a
short packet or a ZLP (if the previous transfer was
a multiple of wMaxPacketSize).

For reference, here's what the USB 2.0 specification, section
8.5.3.2 says:

"
8.5.3.2 Variable-length Data Stage

A control pipe may have a variable-length data phase
in which the host requests more data than is contained
in the specified data structure. When all of the data
structure is returned to the host, the function should
indicate that the Data stage is ended by returning a
packet that is shorter than the MaxPacketSize for the
pipe. If the data structure is an exact multiple of
wMaxPacketSize for the pipe, the function will return
a zero-length packet to indicate the end of the Data
stage.
"

Signed-off-by: Felipe Balbi <balbi@ti.com>
usb: musb: cppi41: restart hrtimer only if not yet done

commit c58d80f52 ("usb: musb: Ensure that cppi41 timer gets armed on
premature DMA TX irq") fixed hrtimer scheduling bug. There is one left
which does not trigger that often.
The following scenario is still possible:

    lock(&x->lock);
    hrtimer_start(&x->t);
    unlock(&x->lock);

expires:
    t->function();
                                lock(&x->lock);
    lock(&x->lock);             if (!hrtimer_queued(&x->t))
                                        hrtimer_start(&x->t);
                                unlock(&x->lock);

    if (!list_empty(x->early_tx_list))
           ret = HRTIMER_RESTART;
->         hrtimer_forward_now(...)
    } else
           ret = HRTIMER_NORESTART;

    unlock(&x->lock);

and the timer callback returns HRTIMER_RESTART for an armed timer. This
is wrong and we run into the BUG_ON() in __run_hrtimer().
This can happens on SMP or PREEMPT-RT.
The patch fixes the problem by only starting the timer if the timer is
not yet queued.

Cc: stable@vger.kernel.org
Reported-by: Torben Hohn <torbenh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
[bigeasy: collected information and created a patch + description based
          on it]
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Felipe Balbi <balbi@ti.com>
usb: gadget: composite: enable BESL support

According to USB 2.0 ECN Errata for Link Power
Management (USB2-LPM-Errata-final.pdf), BESL
must be enabled if LPM is enabled.

This helps with USB30CV TD 9.21 LPM L1
Suspend Resume Test.

Signed-off-by: Felipe Balbi <balbi@ti.com>
Revert "usb: dwc3: dwc3-omap: Disable/Enable only wrapper interrupts in prepare/complete"

This reverts commit 02dae36aa649a66c5c6181157ddd806e7b4913fc.

That commit is bogus in two ways:

1) There's no way dwc3-omap's ->suspend() can cause any effect
	on xhci's ->suspend(). Linux device driver model guarantees
	that a parent's ->suspend() will only be called after all
	children are suspended. dwc3-omap is the parent of the
	parent of xhci.

2) When implementing Deep Sleep states where context is lost,
	USBOTGSS_IRQ0 register, well, looses context so we
	_must_ rewrite it otherwise core IRQs will never be
	reenabled and USB will appear to be dead.

Fixes: 02dae36 (usb: dwc3: dwc3-omap: Disable/Enable only
	wrapper interrupts in prepare/complete)
Cc: <stable@vger.kernel.org> # v3.17
Cc: George Cherian <george.cherian@ti.com>
Signed-off-by: Roger Quadros <rogerq@ti.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
usb: gadget: udc: USB_GADGET_XILINX should depend on HAS_DMA

If NO_DMA=y:

drivers/built-in.o: In function `xudc_done':
udc-xilinx.c:(.text+0x54f4d2): undefined reference to `usb_gadget_unmap_request'
drivers/built-in.o: In function `xudc_dma_send':
udc-xilinx.c:(.text+0x54f9f8): undefined reference to `dma_sync_single_for_cpu'
drivers/built-in.o: In function `xudc_read_fifo':
udc-xilinx.c:(.text+0x54ff4a): undefined reference to `dma_sync_single_for_cpu'
drivers/built-in.o: In function `xudc_ep_queue':
udc-xilinx.c:(.text+0x550e7c): undefined reference to `usb_gadget_map_request'

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Felipe Balbi <balbi@ti.com>
usb: gadget: f_fs: remove redundant ffs_data_get()

During FunctionFS bind, ffs_data_get() function was called twice
(in functionfs_bind() and in ffs_do_functionfs_bind()), while on unbind
ffs_data_put() was called once (in functionfs_unbind() function).
In result refcount never reached value 0, and ffs memory resources has
been never released.

Since ffs_data_get() call in ffs_do_functionfs_bind() is redundant
and not neccessary, we remove it to have equal number of gets ans puts,
and free allocated memory after refcount reach 0.

Fixes: 5920cda (usb: gadget: FunctionFS: convert to new function
	interface with backward compatibility)
Cc: <stable@vger.kernel.org> # v3.14+
Signed-off-by: Robert Baldyga <r.baldyga@samsung.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
usb: ffs: fix regression when quirk_ep_out_aligned_size flag is set

The commit '2e4c7553cd usb: gadget: f_fs: add aio support' broke the
quirk implemented to align buffer size to maxpacketsize on out endpoint.
As result, functionfs does not work on Intel platforms using dwc3 driver
(i.e. Bay Trail and Merrifield). This patch fixes the issue.

This code is based on a previous Qiuxu's patch.

Fixes: 2e4c7553cd (usb: gadget: f_fs: add aio support)
Cc: <stable@vger.kernel.org> # v3.16+
Signed-off-by: David Cohen <david.a.cohen@linux.intel.com>
Signed-off-by: Qiuxu Zhuo <qiuxu.zhuo@intel.com>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
usb: gadget: loopback: don't queue requests to bogus endpoints

A request allocated from e.g. ep1out cannot
be queued to any other endpoint. This bug has
been in f_loopback at least since mid-2011 and
since nobody has really screamed about it, we're
not backporting to any stable kernels.

Debugged with MUSB since that's the only controller
which complains about this case.

Signed-off-by: Felipe Balbi <balbi@ti.com>
usb: musb: dsps: start OTG timer on resume again

Commit 468bcc2a2ca ("usb: musb: dsps: kill OTG timer on suspend") stopped
the timer in suspend path but forgot the re-enable it in the resume
path. This patch fixes the behaviour.

Cc: <stable@vger.kernel.org> # v3.14+
Fixes 468bcc2a2ca "usb: musb: dsps: kill OTG timer on suspend"
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Felipe Balbi <balbi@ti.com>
usb: musb: musb_dsps: fix NULL pointer in suspend

So testing managed to configure musb in DMA mode but not load the
matching cppi41 driver for DMA. This results in

|musb-hdrc musb-hdrc.0.auto: Failed to request rx1.
|musb-hdrc musb-hdrc.0.auto: musb_init_controller failed with status -517
|platform musb-hdrc.0.auto: Driver musb-hdrc requests probe deferral

which is "okay". Once the driver is loaded we re-try probing and
everyone is happy. Until then if you try suspend say
    echo mem > /sys/power/state
then you go boom

|Unable to handle kernel NULL pointer dereference at virtual address 000003a4
|pgd = cf50c000
|[000003a4] *pgd=8f6a3831, *pte=00000000, *ppte=00000000
|Internal error: Oops: 17 [#1] ARM
|PC is at dsps_suspend+0x18/0x9c [musb_dsps]
|LR is at dsps_suspend+0x18/0x9c [musb_dsps]
|pc : [<bf08e268>] lr : [<bf08e268>] psr: a0000013
|sp : cbd97e00 ip : c0af4394 fp : 00000000
|r10: c0831d90 r9 : 00000002 r8 : cf6da410
|r7 : c03ba4dc r6 : bf08f224 r5 : 00000000 r4 : cbc5fcd0
|r3 : bf08e250 r2 : bf08f264 r1 : cf6da410 r0 : 00000000
|[<bf08e268>] (dsps_suspend [musb_dsps]) from [<c03ba508>] (platform_pm_suspend+0x2c/0x54)
|Code: e1a04000 e9900041 e2800010 eb4caa8e (e59053a4)

because platform_get_drvdata(glue->musb) returns a NULL pointer as long as the
device is not fully probed.

Tested-by: George Cherian <george.cherian@ti.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Felipe Balbi <balbi@ti.com>
usb: gadget: udc: core: fix kernel oops with soft-connect

Currently, there's no guarantee that udc->driver
will be valid when using soft_connect sysfs
interface. In fact, we can very easily trigger
a NULL pointer dereference by trying to disconnect
when a gadget driver isn't loaded.

Fix this bug:

~# echo disconnect > soft_connect
[   33.685743] Unable to handle kernel NULL pointer dereference at virtual address 00000014
[   33.694221] pgd = ed0cc000
[   33.697174] [00000014] *pgd=ae351831, *pte=00000000, *ppte=00000000
[   33.703766] Internal error: Oops: 17 [#1] SMP ARM
[   33.708697] Modules linked in: xhci_plat_hcd xhci_hcd snd_soc_davinci_mcasp snd_soc_tlv320aic3x snd_soc_edma snd_soc_omap snd_soc_evm snd_soc_core dwc3 snd_compress snd_pcm_dmaengine snd_pcm snd_timer snd lis3lv02d_i2c matrix_keypad lis3lv02d dwc3_omap input_polldev soundcore
[   33.734372] CPU: 0 PID: 1457 Comm: bash Not tainted 3.17.0-09740-ga93416e-dirty #345
[   33.742457] task: ee71ce00 ti: ee68a000 task.ti: ee68a000
[   33.748116] PC is at usb_udc_softconn_store+0xa4/0xec
[   33.753416] LR is at mark_held_locks+0x78/0x90
[   33.758057] pc : [<c04df128>]    lr : [<c00896a4>]    psr: 20000013
[   33.758057] sp : ee68bec8  ip : c0c00008  fp : ee68bee4
[   33.770050] r10: ee6b394c  r9 : ee68bf80  r8 : ee6062c0
[   33.775508] r7 : 00000000  r6 : ee6062c0  r5 : 0000000b  r4 : ee739408
[   33.782346] r3 : 00000000  r2 : 00000000  r1 : ee71d390  r0 : ee664170
[   33.789168] Flags: nzCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment user
[   33.796636] Control: 10c5387d  Table: ad0cc059  DAC: 00000015
[   33.802638] Process bash (pid: 1457, stack limit = 0xee68a248)
[   33.808740] Stack: (0xee68bec8 to 0xee68c000)
[   33.813299] bec0:                   0000000b c0411284 ee6062c0 00000000 ee68bef4 ee68bee8
[   33.821862] bee0: c04112ac c04df090 ee68bf14 ee68bef8 c01c2868 c0411290 0000000b ee6b3940
[   33.830419] bf00: 00000000 00000000 ee68bf4c ee68bf18 c01c1a24 c01c2818 00000000 00000000
[   33.838990] bf20: ee61b940 ee2f47c0 0000000b 000ce408 ee68bf80 c000f304 ee68a000 00000000
[   33.847544] bf40: ee68bf7c ee68bf50 c0152dd8 c01c1960 ee68bf7c c0170af8 ee68bf7c ee2f47c0
[   33.856099] bf60: ee2f47c0 000ce408 0000000b c000f304 ee68bfa4 ee68bf80 c0153330 c0152d34
[   33.864653] bf80: 00000000 00000000 0000000b 000ce408 b6e7fb50 00000004 00000000 ee68bfa8
[   33.873204] bfa0: c000f080 c01532e8 0000000b 000ce408 00000001 000ce408 0000000b 00000000
[   33.881763] bfc0: 0000000b 000ce408 b6e7fb50 00000004 0000000b 00000000 000c5758 00000000
[   33.890319] bfe0: 00000000 bec2c924 b6de422d b6e1d226 40000030 00000001 75716d2f 00657565
[   33.898890] [<c04df128>] (usb_udc_softconn_store) from [<c04112ac>] (dev_attr_store+0x28/0x34)
[   33.907920] [<c04112ac>] (dev_attr_store) from [<c01c2868>] (sysfs_kf_write+0x5c/0x60)
[   33.916200] [<c01c2868>] (sysfs_kf_write) from [<c01c1a24>] (kernfs_fop_write+0xd0/0x194)
[   33.924773] [<c01c1a24>] (kernfs_fop_write) from [<c0152dd8>] (vfs_write+0xb0/0x1bc)
[   33.932874] [<c0152dd8>] (vfs_write) from [<c0153330>] (SyS_write+0x54/0xb0)
[   33.940247] [<c0153330>] (SyS_write) from [<c000f080>] (ret_fast_syscall+0x0/0x48)
[   33.948160] Code: e1a01007 e12fff33 e5140004 e5143008 (e5933014)
[   33.954625] ---[ end trace f849bead94eab7ea ]---

Fixes: 2ccea03 (usb: gadget: introduce UDC Class)
Cc: <stable@vger.kernel.org> # v3.1+
Signed-off-by: Felipe Balbi <balbi@ti.com>
usb: dwc2: gadget: sparse warning of context imbalance

sparse was giving the following warning:
        warning: context imbalance in 's3c_hsotg_ep_enable'
	                - different lock contexts for basic block

we were returning ENOMEM while still holding the spinlock.
The sparse warning was fixed by releasing the spinlock before return.

Cc: <stable@vger.kernel.org> # v3.17
Acked-by: Paul Zimmerman <paulz@synopsys.com>
Signed-off-by: Sudip Mukherjee <sudip@vectorindia.org>
Signed-off-by: Felipe Balbi <balbi@ti.com>
usb: dwc2: Bits in bitfield should add up to 32

The unioned u32 is used for clearing etc. Having the number of
bitfield bits add up to more than 32 is broken, even if benign.

Acked-by: Paul Zimmerman <paulz@synopsys.com>
Signed-off-by: Charles Manning <cdhmanning@gmail.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
xen/balloon: Don't continue ballooning when BP_ECANCELED is encountered

Commit 3dcf63677d4e ("xen/balloon: cancel ballooning if adding new
memory failed") makes reserve_additional_memory() return BP_ECANCELED
when an error is encountered. This error, however, is ignored by the
caller (balloon_process()) since it is overwritten by subsequent call
to update_schedule(). This results in continuous attempts to add more
memory, all of which are likely to fail again.

We should stop trying to schedule next iteration of ballooning when
the current one has failed.

Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
x86/xen: avoid writing to freed memory after race in p2m handling

In case a race was detected during allocation of a new p2m tree
element in alloc_p2m() the new allocated mid_mfn page is freed without
updating the pointer to the found value in the tree. This will result
in overwriting the just freed page with the mfn of the p2m leaf.

Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
x86/xen: delay construction of mfn_list_list

The 3 level p2m tree for the Xen tools is constructed very early at
boot by calling xen_build_mfn_list_list(). Memory needed for this tree
is allocated via extend_brk().

As this tree (other than the kernel internal p2m tree) is only needed
for domain save/restore, live migration and crash dump analysis it
doesn't matter whether it is constructed very early or just some
milliseconds later when memory allocation is possible by other means.

This patch moves the call of xen_build_mfn_list_list() just after
calling xen_pagetable_p2m_copy() simplifying this function, too, as it
doesn't have to bother with two parallel trees now. The same applies
for some other internal functions.

While simplifying code, make early_can_reuse_p2m_middle() static and
drop the unused second parameter. p2m_mid_identity_mfn can be removed
as well, it isn't used either.

Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
x86/xen: avoid race in p2m handling

When a new p2m leaf is allocated this leaf is linked into the p2m tree
via cmpxchg. Unfortunately the compare value for checking the success
of the update is read after checking for the need of a new leaf. It is
possible that a new leaf has been linked into the tree concurrently
in between. This could lead to a leaked memory page and to the loss of
some p2m entries.

Avoid the race by using the read compare value for checking the need
of a new p2m leaf and use ACCESS_ONCE() to get it.

There are other places which seem to need ACCESS_ONCE() to ensure
proper operation. Change them accordingly.

Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
x86/xen: Fix incorrect per_cpu accessor in xen_clocksource_read()

Commit 89cbc76768c2 ("x86: Replace __get_cpu_var uses") replaced
__get_cpu_var() with this_cpu_ptr() in xen_clocksource_read() in such a
way that instead of accessing a structure pointed to by a per-cpu pointer
we are trying to get to a per-cpu structure.

__this_cpu_read() of the pointer is the more appropriate accessor.

Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
x86/xen: panic on bad Xen-provided memory map

Panic if Xen provides a memory map with 0 entries. Although this is
unlikely, it is better to catch the error at the point of seeing the map
than later on as a symptom of some other crash.

Signed-off-by: Martin Kelly <martkell@amazon.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>