No functional change; just rename "data" to something more
descriptive.
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Rene Herman <rene.herman@gmail.com>
Signed-off-by: Len Brown <len.brown@intel.com>
ACPI Extended Interrupt Descriptors can encode 32-bit interrupt
numbers, so an interrupt number may exceed the size of the bitmap
we use to track possible IRQ settings.
To avoid corrupting memory, complain and ignore too-large interrupt
numbers.
There's similar code in pnpacpi_parse_irq_option(), but I didn't
change that because the small IRQ descriptor can only encode
IRQs 0-15, which do not exceed bitmap size.
In the future, we could handle IRQ numbers greater than PNP_IRQ_NR
by replacing the bitmap with a table or list.
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Rene Herman <rene.herman@gmail.com>
Signed-off-by: Len Brown <len.brown@intel.com>
This patch moves all the option allocations (pnp_mem, pnp_port, etc)
into the pnp_register_{mem,port,irq,dma}_resource() functions. This
will make it easier to rework the option data structures.
The non-trivial part of this patch is the IRQ handling. The backends
have to allocate a local pnp_irq_mask_t bitmap, populate it, and pass
a pointer to pnp_register_irq_resource().
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Rene Herman <rene.herman@gmail.com>
Signed-off-by: Len Brown <len.brown@intel.com>
pnp_assign_resources() is static and the only caller checks
pnp_can_configure() before calling it, so no need to do it
again.
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Rene Herman <rene.herman@gmail.com>
Signed-off-by: Len Brown <len.brown@intel.com>
This patch doesn't change any behavior; it just makes the return
values more conventional.
This changes pnp_assign_dma() from a void function to one that
returns an int, just like the other assignment functions. For
now, at least, pnp_assign_dma() always returns 0 (success), so
it appears to never fail, just like before.
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Rene Herman <rene.herman@gmail.com>
Signed-off-by: Len Brown <len.brown@intel.com>
If the resource list is empty, say that explicitly. Previously,
it was confusing because often the heading was followed by zero
resource lines, then some "add resource" lines from auto-assignment,
so the "add" lines looked like current resources.
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Rene Herman <rene.herman@gmail.com>
Signed-off-by: Len Brown <len.brown@intel.com>
When we fail to assign an I/O or MEM resource, include the min/max
in the debug output to help match it with the options.
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Rene Herman <rene.herman@gmail.com>
Signed-off-by: Len Brown <len.brown@intel.com>
ACPI Address Space Descriptors can be up to 64 bits wide.
We should keep track of the whole thing when parsing resource
options, so this patch changes PNP port and mem option
fields from "unsigned short" and "unsigned int" to
"resource_size_t".
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Rene Herman <rene.herman@gmail.com>
Signed-off-by: Len Brown <len.brown@intel.com>
This adds a typedef for the IRQ bitmap, which should cause
no functional change, but will make it easier to pass a
pointer to a bitmap to pnp_register_irq_resource().
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Rene Herman <rene.herman@gmail.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Nothing outside the PNP subsystem should need access to a
device's resource options, so this patch moves the option
structure declarations to a private header file.
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Rene Herman <rene.herman@gmail.com>
Signed-off-by: Len Brown <len.brown@intel.com>
PNP previously defined PNP_PORT_FLAG_16BITADDR and PNP_PORT_FLAG_FIXED
in a private header file, but put those flags in struct resource.flags
fields. Better to make them IORESOURCE_IO_* flags like the existing
IRQ, DMA, and MEM flags.
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Rene Herman <rene.herman@gmail.com>
Signed-off-by: Len Brown <len.brown@intel.com>
No functional change; just make a couple declarations
consistent with the rest of the file.
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Rene Herman <rene.herman@gmail.com>
Signed-off-by: Len Brown <len.brown@intel.com>
As part of a heuristic to identify modem devices, 8250_pnp.c
checks to see whether a device can be configured at any of the
legacy COM port addresses.
This patch moves the code that traverses the PNP "possible resource
options" from 8250_pnp.c to the PNP subsystem. This encapsulation
is important because a future patch will change the implementation
of those resource options.
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Rene Herman <rene.herman@gmail.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Rather than stepping through all IO resources, then stepping through
all MMIO resources, etc., we can just iterate over the resource list
once directly.
This can change the order in /sys, e.g.,
# cat /sys/devices/pnp0/00:07/resources # OLD
state = active
io 0x3f8-0x3ff
irq 4
# cat /sys/devices/pnp0/00:07/resources # NEW
state = active
irq 4
io 0x3f8-0x3ff
The old code artificially sorted resources by type; the new code
just lists them in the order we read them from the ISAPNP hardware
or the BIOS.
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
We used to have a fixed-size resource table. If a device had
twenty resources when the table only had space for ten, we didn't
need ten warnings, so we added the ratelimit.
Now that we can dynamically allocate new resources, we should
only get failures if the allocation fails. That should be
rare enough that we don't need to ratelimit the messages.
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
When we parse a device's _CRS data (the current resource settings),
we should keep track of everything we find, even if it's currently
disabled or invalid.
This is what we already do for ISAPNP and PNPBIOS, and it helps
keep things matched up when we subsequently re-encode resources.
For example, consider a device with (mem, irq0, irq1, io), where
irq0 is disabled. If we drop irq0 when parsing the _CRS, we will
mistakenly put irq1 in the irq0 slot when we encode resources
for an _SRS call.
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
PNP used to have a fixed-size pnp_resource_table for tracking the
resources used by a device. This table often overflowed, so we've
had to increase the table size, which wastes memory because most
devices have very few resources.
This patch replaces the table with a linked list of resources where
the entries are allocated on demand.
This removes messages like these:
pnpacpi: exceeded the max number of IO resources
00:01: too many I/O port resources
References:
http://bugzilla.kernel.org/show_bug.cgi?id=9535http://bugzilla.kernel.org/show_bug.cgi?id=9740http://lkml.org/lkml/2007/11/30/110
This patch also changes the way PNP uses the IORESOURCE_UNSET,
IORESOURCE_AUTO, and IORESOURCE_DISABLED flags.
Prior to this patch, the pnp_resource_table entries used the flags
like this:
IORESOURCE_UNSET
This table entry is unused and available for use. When this flag
is set, we shouldn't look at anything else in the resource structure.
This flag is set when a resource table entry is initialized.
IORESOURCE_AUTO
This resource was assigned automatically by pnp_assign_{io,mem,etc}().
This flag is set when a resource table entry is initialized and
cleared whenever we discover a resource setting by reading an ISAPNP
config register, parsing a PNPBIOS resource data stream, parsing an
ACPI _CRS list, or interpreting a sysfs "set" command.
Resources marked IORESOURCE_AUTO are reinitialized and marked as
IORESOURCE_UNSET by pnp_clean_resource_table() in these cases:
- before we attempt to assign resources automatically,
- if we fail to assign resources automatically,
- after disabling a device
IORESOURCE_DISABLED
Set by pnp_assign_{io,mem,etc}() when automatic assignment fails.
Also set by PNPBIOS and PNPACPI for:
- invalid IRQs or GSI registration failures
- invalid DMA channels
- I/O ports above 0x10000
- mem ranges with negative length
After this patch, there is no pnp_resource_table, and the resource list
entries use the flags like this:
IORESOURCE_UNSET
This flag is no longer used in PNP. Instead of keeping
IORESOURCE_UNSET entries in the resource list, we remove
entries from the list and free them.
IORESOURCE_AUTO
No change in meaning: it still means the resource was assigned
automatically by pnp_assign_{port,mem,etc}(), but these functions
now set the bit explicitly.
We still "clean" a device's resource list in the same places,
but rather than reinitializing IORESOURCE_AUTO entries, we
just remove them from the list.
Note that IORESOURCE_AUTO entries are always at the end of the
list, so removing them doesn't reorder other list entries.
This is because non-IORESOURCE_AUTO entries are added by the
ISAPNP, PNPBIOS, or PNPACPI "get resources" methods and by the
sysfs "set" command. In each of these cases, we completely free
the resource list first.
IORESOURCE_DISABLED
In addition to the cases where we used to set this flag, ISAPNP now
adds an IORESOURCE_DISABLED resource when it reads a configuration
register with a "disabled" value.
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Some callers use pnp_port_start() and similar functions without
making sure the resource is valid. This patch makes us fall
back to returning the initial values if the resource is not
valid or not even present.
This mostly preserves the previous behavior, where we would just
return the initial values set by pnp_init_resource_table(). The
original 2.6.25 code didn't range-check the "bar", so it would
return garbage if the bar exceeded the table size. This code
returns sensible values instead.
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
This patch adds a "pnp_resource_type_name(struct resource *)" that
returns the string resource type. This will be used by the sysfs
"show resources" function and the debug resource dump function.
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Given a struct resource, this returns the type (IO, MEM, IRQ, DMA).
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
We used pnp_resource.index to keep track of which ISAPNP configuration
register a resource should be written to. We needed this only to
handle the case where a register is disabled but a subsequent register
in the same set is enabled.
Rather than explicitly maintaining the pnp_resource.index, this patch
adds a resource every time we read an ISAPNP configuration register
and marks the resource as IORESOURCE_DISABLED when appropriate. This
makes the position in the pnp_resource_table always correspond to the
config register index.
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
In the debug resource dump, decode the flags and indicate when
a resource is disabled or has been automatically assigned.
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Fix use of uninitialized device->brightness.
Signed-off-by: Julia Jomantaite <julia.jomantaite@gmail.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Reflect that Zhang-Rui has been the sub-maintainer for
ACPI THERMAL and FAN for some time now.
Also, the Chinese custom is to speak family name first,
so rather than "Rui Zhang", write "Zhang Rui",
as he does on e-mail.
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
If a system matches in this DMI table,
Linux will disable MWAIT support for idle.
ie. "idle=nomwait" is automatically invoked
and C1_FFH and C2C3_FFH access mode are disabled.
http://bugzilla.kernel.org/show_bug.cgi?id=10807http://bugzilla.kernel.org/show_bug.cgi?id=10914
Signed-off-by: Zhao Yakui <yakui.zhao@intel.com>
Signed-off-by: Li Shaohua <shaohua.li@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
"idle=nomwait" disables the use of the MWAIT
instruction from both C1 (C1_FFH) and deeper (C2C3_FFH)
C-states.
When MWAIT is unavailable, the BIOS and OS generally
negotiate to use the HALT instruction for C1,
and use IO accesses for deeper C-states.
This option is useful for power and performance
comparisons, and also to work around BIOS bugs
where broken MWAIT support is advertised.
http://bugzilla.kernel.org/show_bug.cgi?id=10807http://bugzilla.kernel.org/show_bug.cgi?id=10914
Signed-off-by: Zhao Yakui <yakui.zhao@intel.com>
Signed-off-by: Li Shaohua <shaohua.li@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
"idle=halt" limits the idle loop to using
the halt instruction. No MWAIT, no IO accesses,
no C-states deeper than C1.
If something is broken in the idle code,
"idle=halt" is a less severe workaround
than "idle=poll" which disables all power savings.
Signed-off-by: Zhao Yakui <yakui.zhao@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
991528d734
(ACPI: Processor native C-states using MWAIT)
started passing C2C3_FFH to _PDC to tell the BIOS
that Linux supports MWAIT for deep C-states.
However, we should first double check with the hardware
that it actually supports MWAIT before potentially exposing
a BIOS bug of an MWAIT _CST on HW that doesn't support MWAIT.
Signed-off-by: Zhao Yakui <yakui.zhao@intel.com>
Signed-off-by: Li Shaohua <shaohua.li@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Allow users to enable/disable/clear a specific & valid GPE/Fixed Event
in user space.
This is useful for debugging, especially for some
interrupt storm issues.
All wakeup GPEs are disabled and they can not be enabled at runtime,
and we mark them as invalid.
All GPEs that don't have a _Lxx/_Exx method are marked as invalid.
All Fixed Events that don't have an event handler are marked as invalid
and they can't be enabled until an event handler is registered.
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Ling Ming <ming.m.lin@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Loop was terminating one iteration early, missing one of the
debugger handshake mutexes. Linn Crosetto.
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Removed extraneous else clauses, other general cleanup.
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Eliminated unnecessary operands; eliminated use of negative index
in loop. Operands now displayed in correct order, not backwards.
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
This problem was introduced in 20080514 as a result of the
elimination of the acpi_native_uint type. Code uses a negative
array index, which should be eliminated.
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Now supports the 2007 intel Virtualization Technology for Directed
I/O specification.
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Synchronized tables with current specifications.
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Some BIOSs erroneously reverse the _PRT SourceName and the
SourceIndex. Detect and repair this problem. MS ACPI also allows
and repairs this problem, thus ACPICA must also.
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Update version to 20080514
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Mostly MODULE_NAME and printf format strings.
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Remove pointer cast warnings and fix for a debug printf.
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
From lint.
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
No longer needed; replaced mostly with u32, but also acpi_size
where a type that changes 32/64 bit on 32/64-bit platforms is
required.
v2: Fix a cast of a 32-bit int to a pointer in ACPI to avoid a compiler warning.
from David Howells
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Added NULL fields to the exception string arrays to eliminate
the -1 subtraction on the SubStatus field.
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Changed ACPI_MODULE_NAME and ACPI_FUNCTION_NAME to use arrays of
strings instead of pointers to static strings. Jan Beulich and
Bob Moore.
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Fixes problem where the new method argument count validation mechanism
will enter an infinite loop when a GPE method is dispatched.
Problem fixed be removing the obsolete code that passes GPE block
information to the notify handler via the control method parameter pointer.
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Error if too few arguments, warning if too many. This applies
only to external programmatic control method execution, not
method-to-method calls within the AML.
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
fujitsu-laptop uses input_* functions, so it should depend on INPUT.
drivers/built-in.o: In function `acpi_fujitsu_add':
fujitsu-laptop.c:(.text+0xaaec7): undefined reference to `input_allocate_device'
fujitsu-laptop.c:(.text+0xaaf39): undefined reference to `input_register_device'
fujitsu-laptop.c:(.text+0xab025): undefined reference to `input_free_device'
drivers/built-in.o: In function `acpi_fujitsu_notify':
fujitsu-laptop.c:(.text+0xab0d8): undefined reference to `input_event'
fujitsu-laptop.c:(.text+0xab0e5): undefined reference to `input_event'
fujitsu-laptop.c:(.text+0xab0f5): undefined reference to `input_event'
fujitsu-laptop.c:(.text+0xab102): undefined reference to `input_event'
drivers/built-in.o: In function `acpi_fujitsu_hotkey_notify':
fujitsu-laptop.c:(.text+0xab261): undefined reference to `input_event'
drivers/built-in.o:fujitsu-laptop.c:(.text+0xab26e): more undefined references to `input_event' follow
drivers/built-in.o: In function `acpi_fujitsu_hotkey_add':
fujitsu-laptop.c:(.text+0xab49c): undefined reference to `input_allocate_device'
fujitsu-laptop.c:(.text+0xab51a): undefined reference to `input_register_device'
fujitsu-laptop.c:(.text+0xab5e4): undefined reference to `input_free_device'
make[1]: *** [.tmp_vmlinux1] Error 1
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Jonathan Woithe <jwoithe@physics.adelaide.edu.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Len Brown <len.brown@intel.com>
We can avoid taking the BKL in snapshot_ioctl() if pm_mutex is used to prevent
the ioctls from being executed concurrently.
In addition, although it is only possible to open /dev/snapshot once, the task
which has done that may spawn a child that will inherit the open descriptor,
so in theory they can call snapshot_write(), snapshot_read() and
snapshot_release() concurrently. pm_mutex can also be used for mutual
exclusion in such cases.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Pavel Machek <pavel@suse.cz>
Signed-off-by: Len Brown <len.brown@intel.com>
Push BKL down into ioctl handlers - snapshot device.
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
