We're currently passing the file handle for the root file system to
efi_file_read() and efi_file_close(), instead of the file handle for the
file we wish to read/close.

While this has worked up until now, it seems that it has only been by
pure luck. Olivier explains,

 "The issue is the UEFI Fat driver might return the same function for
  'fh->read()' and 'h->read()'. While in our case it does not work with
  a different implementation of EFI_SIMPLE_FILE_SYSTEM_PROTOCOL. In our
  case, we return a different pointer when reading a directory and
  reading a file."

Fixing this actually clears up the two functions because we can drop one
of the arguments, and instead only pass a file 'handle' argument.
Reported-by: NOlivier Martin <olivier.martin@arm.com>
Reviewed-by: NOlivier Martin <olivier.martin@arm.com>
Reviewed-by: NMark Rutland <mark.rutland@arm.com>
Cc: Leif Lindholm <leif.lindholm@linaro.org>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>

The ARM EFI boot stub doesn't need to care about the efi_early
infrastructure that x86 requires in order to do mixed mode thunking. So
wrap everything up in an efi_call_early() macro.

This allows x86 to do the necessary indirection jumps to call whatever
firmware interface is necessary (native or mixed mode), but also allows
the ARM folks to mask the fact that they don't support relocation in the
boot stub and need to pass 'sys_table_arg' to every function.

[ hpa: there are no object code changes from this patch ]
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>
Link: http://lkml.kernel.org/r/20140326091011.GB2958@console-pimps.org
Cc: Roy Franz <roy.franz@linaro.org>
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>

It's not possible to dereference the EFI System table directly when
booting a 64-bit kernel on a 32-bit EFI firmware because the size of
pointers don't match.

In preparation for supporting the above use case, build a list of
function pointers on boot so that callers don't have to worry about
converting pointer sizes through multiple levels of indirection.
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>

Fix following sparse warnings:

drivers/firmware/efi/efivars.c:230:66: warning:
 Using plain integer as NULL pointer
drivers/firmware/efi/efi.c:236:27: warning:
 Using plain integer as NULL pointer
Signed-off-by: NDaeseok Youn <daeseok.youn@gmail.com>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>

It makes more sense to set the feature flag in the success path of the
detection function than it does to rely on the caller doing it. Apart
from it being more logical to group the code and data together, it sets
a much better example for new EFI architectures.
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>

kexec kernel will need exactly same mapping for EFI runtime memory
ranges. Thus here export the runtime ranges mapping to sysfs,
kexec-tools will assemble them and pass to 2nd kernel via setup_data.

Introducing a new directory /sys/firmware/efi/runtime-map just like
/sys/firmware/memmap. Containing below attribute in each file of that
directory:

attribute  num_pages  phys_addr  type  virt_addr
Signed-off-by: NDave Young <dyoung@redhat.com>
Tested-by: NToshi Kani <toshi.kani@hp.com>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>

Export fw_vendor, runtime and config table physical addresses to
/sys/firmware/efi/{fw_vendor,runtime,config_table} because kexec kernels
need them.

From EFI spec these 3 variables will be updated to virtual address after
entering virtual mode. But kernel startup code will need the physical
address.
Signed-off-by: NDave Young <dyoung@redhat.com>
Tested-by: NToshi Kani <toshi.kani@hp.com>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>

Some pstore backing devices use on board flash as persistent
storage. These have limited numbers of write cycles so it
is a poor idea to use them from high frequency operations.
Signed-off-by: NTony Luck <tony.luck@intel.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Commit 7ea6c6c1 ("Move cper.c from drivers/acpi/apei to
drivers/firmware/efi") results in CONFIG_EFI being enabled even
when the user doesn't want this. Since ACPI APEI used to build
fine without UEFI (and as far as I know also has no functional
depency on it), at least in that case using a reverse dependency
is wrong (and a straight one isn't needed).

Whether the same is true for ACPI_EXTLOG I don't know - if there
is a functional dependency, it should depend on EFI rather than
selecting it. It certainly has (currently) no build dependency.

Adjust Kconfig and build logic so that the bad dependency gets
avoided.
Signed-off-by: NJan Beulich <jbeulich@suse.com>
Acked-by: NTony Luck <tony.luck@intel.com>
Cc: Matt Fleming <matt.fleming@intel.com>
Link: http://lkml.kernel.org/r/52AF1EBC020000780010DBF9@nat28.tlf.novell.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Pstore fs expects that backends provide a unique id which could avoid
pstore making entries as duplication or denominating entries the same
name. So I combine the timestamp, part and count into id.
Signed-off-by: NMadper Xie <cxie@redhat.com>
Cc: Seiji Aguchi <seiji.aguchi@hds.com>
Cc: stable@vger.kernel.org
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>

Currently, when mounting pstore file system, a read callback of
efi_pstore driver runs mutiple times as below.

- In the first read callback, scan efivar_sysfs_list from head and pass
  a kmsg buffer of a entry to an upper pstore layer.
- In the second read callback, rescan efivar_sysfs_list from the entry
  and pass another kmsg buffer to it.
- Repeat the scan and pass until the end of efivar_sysfs_list.

In this process, an entry is read across the multiple read function
calls. To avoid race between the read and erasion, the whole process
above is protected by a spinlock, holding in open() and releasing in
close().

At the same time, kmemdup() is called to pass the buffer to pstore
filesystem during it. And then, it causes a following lockdep warning.

To make the dynamic memory allocation runnable without taking spinlock,
holding off a deletion of sysfs entry if it happens while scanning it
via efi_pstore, and deleting it after the scan is completed.

To implement it, this patch introduces two flags, scanning and deleting,
to efivar_entry.

On the code basis, it seems that all the scanning and deleting logic is
not needed because __efivars->lock are not dropped when reading from the
EFI variable store.

But, the scanning and deleting logic is still needed because an
efi-pstore and a pstore filesystem works as follows.

In case an entry(A) is found, the pointer is saved to psi->data.  And
efi_pstore_read() passes the entry(A) to a pstore filesystem by
releasing  __efivars->lock.

And then, the pstore filesystem calls efi_pstore_read() again and the
same entry(A), which is saved to psi->data, is used for resuming to scan
a sysfs-list.

So, to protect the entry(A), the logic is needed.

[    1.143710] ------------[ cut here ]------------
[    1.144058] WARNING: CPU: 1 PID: 1 at kernel/lockdep.c:2740 lockdep_trace_alloc+0x104/0x110()
[    1.144058] DEBUG_LOCKS_WARN_ON(irqs_disabled_flags(flags))
[    1.144058] Modules linked in:
[    1.144058] CPU: 1 PID: 1 Comm: systemd Not tainted 3.11.0-rc5 #2
[    1.144058]  0000000000000009 ffff8800797e9ae0 ffffffff816614a5 ffff8800797e9b28
[    1.144058]  ffff8800797e9b18 ffffffff8105510d 0000000000000080 0000000000000046
[    1.144058]  00000000000000d0 00000000000003af ffffffff81ccd0c0 ffff8800797e9b78
[    1.144058] Call Trace:
[    1.144058]  [<ffffffff816614a5>] dump_stack+0x54/0x74
[    1.144058]  [<ffffffff8105510d>] warn_slowpath_common+0x7d/0xa0
[    1.144058]  [<ffffffff8105517c>] warn_slowpath_fmt+0x4c/0x50
[    1.144058]  [<ffffffff8131290f>] ? vsscanf+0x57f/0x7b0
[    1.144058]  [<ffffffff810bbd74>] lockdep_trace_alloc+0x104/0x110
[    1.144058]  [<ffffffff81192da0>] __kmalloc_track_caller+0x50/0x280
[    1.144058]  [<ffffffff815147bb>] ? efi_pstore_read_func.part.1+0x12b/0x170
[    1.144058]  [<ffffffff8115b260>] kmemdup+0x20/0x50
[    1.144058]  [<ffffffff815147bb>] efi_pstore_read_func.part.1+0x12b/0x170
[    1.144058]  [<ffffffff81514800>] ? efi_pstore_read_func.part.1+0x170/0x170
[    1.144058]  [<ffffffff815148b4>] efi_pstore_read_func+0xb4/0xe0
[    1.144058]  [<ffffffff81512b7b>] __efivar_entry_iter+0xfb/0x120
[    1.144058]  [<ffffffff8151428f>] efi_pstore_read+0x3f/0x50
[    1.144058]  [<ffffffff8128d7ba>] pstore_get_records+0x9a/0x150
[    1.158207]  [<ffffffff812af25c>] ? selinux_d_instantiate+0x1c/0x20
[    1.158207]  [<ffffffff8128ce30>] ? parse_options+0x80/0x80
[    1.158207]  [<ffffffff8128ced5>] pstore_fill_super+0xa5/0xc0
[    1.158207]  [<ffffffff811ae7d2>] mount_single+0xa2/0xd0
[    1.158207]  [<ffffffff8128ccf8>] pstore_mount+0x18/0x20
[    1.158207]  [<ffffffff811ae8b9>] mount_fs+0x39/0x1b0
[    1.158207]  [<ffffffff81160550>] ? __alloc_percpu+0x10/0x20
[    1.158207]  [<ffffffff811c9493>] vfs_kern_mount+0x63/0xf0
[    1.158207]  [<ffffffff811cbb0e>] do_mount+0x23e/0xa20
[    1.158207]  [<ffffffff8115b51b>] ? strndup_user+0x4b/0xf0
[    1.158207]  [<ffffffff811cc373>] SyS_mount+0x83/0xc0
[    1.158207]  [<ffffffff81673cc2>] system_call_fastpath+0x16/0x1b
[    1.158207] ---[ end trace 61981bc62de9f6f4 ]---
Signed-off-by: NSeiji Aguchi <seiji.aguchi@hds.com>
Tested-by: NMadper Xie <cxie@redhat.com>
Cc: stable@kernel.org
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>

cper.c contains code to decode and print "Common Platform Error Records".
Originally added under drivers/acpi/apei because the only user was in that
same directory - but now we have another consumer, and we shouldn't have
to force CONFIG_ACPI_APEI get access to this code.

Since CPER is defined in the UEFI specification - the logical home for
this code is under drivers/firmware/efi/
Acked-by: NMatt Fleming <matt.fleming@intel.com>
Acked-by: NIngo Molnar <mingo@kernel.org>
Signed-off-by: NTony Luck <tony.luck@intel.com>

Remove a redundant memset() call from efi_relocate_kernel() that
was clearing memory that would be used by BSS in non-compressed
images loaded with this function.  This clear was redundant with
the clearing done in the image itself, and also implemented incorrectly
with a 0 length.
Signed-off-by: NRoy Franz <roy.franz@linaro.org>
Acked-by: NMark Salter <msalter@redhat.com>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>

warnings from gcc:
warning: label 'free_pool' defined but not used [-Wunused-label]
warning: value computed is not used [-Wunused-value]
Signed-off-by: NRoy Franz <roy.franz@linaro.org>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>

EFI calls can made directly on ARM, so the function pointers
are directly invoked.  This allows types to be checked at
compile time, so here we ensure that the parameters match
the function signature. The wrappers used by x86 prevent
any type checking.
Correct the type of chunksize to be based on native
width as specified by the EFI_FILE_PROTOCOL read()
function.
Signed-off-by: NRoy Franz <roy.franz@linaro.org>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>

Rename variables to be not initrd specific, as now the function
loads arbitrary files.  This change is exclusively renames
and comment changes to reflect the generalization.
Signed-off-by: NRoy Franz <roy.franz@linaro.org>
Acked-by: NMark Salter <msalter@redhat.com>
Reviewed-by: NGrant Likely <grant.likely@linaro.org>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>

The handle_cmdline_files now takes the option to handle as a string,
and returns the loaded data through parameters, rather than taking
an x86 specific setup_header structure.  For ARM, this will be used
to load a device tree blob in addition to initrd images.
Signed-off-by: NRoy Franz <roy.franz@linaro.org>
Acked-by: NMark Salter <msalter@redhat.com>
Reviewed-by: NGrant Likely <grant.likely@linaro.org>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>

Make efi_free() safely callable with size of 0, similar to free() being
callable with NULL pointers, and do nothing in that case.
Remove size checks that this makes redundant.  This also avoids some
size checks in the ARM EFI stub code that will be added as well.
Signed-off-by: NRoy Franz <roy.franz@linaro.org>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>

Add arguments for returning the descriptor version and also
the memory map key.  The key is required for calling
exit_boot_services().
Signed-off-by: NRoy Franz <roy.franz@linaro.org>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>

Rename function in preparation for making it more flexible
and sharing it.
Signed-off-by: NRoy Franz <roy.franz@linaro.org>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>

Move the open-coded conversion to a shared function for
use by all architectures.  Change the allocation to prefer
a high address for ARM, as this is required to avoid conflicts
with reserved regions in low memory.  We don't know the specifics
of these regions until after we process the command line and
device tree.
Signed-off-by: NRoy Franz <roy.franz@linaro.org>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>

Rename relocate_kernel() to efi_relocate_kernel(), and take
parameters rather than x86 specific structure.  Add max_addr
argument as for ARM we have some address constraints that we
need to enforce when relocating the kernel.  Add alloc_size
parameter for use by ARM64 which uses an uncompressed kernel,
and needs to allocate space for BSS.
Signed-off-by: NRoy Franz <roy.franz@linaro.org>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>

The relocate_kernel() function will be generalized and used
by all architectures, as they all have similar requirements.
Signed-off-by: NRoy Franz <roy.franz@linaro.org>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>

The efi_high_alloc() and efi_low_alloc() functions
use the EFI_ALLOCATE_ADDRESS option to the EFI
function allocate_pages(), which requires a minimum
of page alignment, and rejects all other requests.
The existing code could fail to allocate depending
on allocation size, as although repeated allocation
attempts were made, none were guaranteed to be page
aligned.
Signed-off-by: NRoy Franz <roy.franz@linaro.org>
Acked-by: NMark Salter <msalter@redhat.com>
Reviewed-by: NGrant Likely <grant.likely@linaro.org>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>

Rename them to be more similar, as low_free() could be used to free
memory allocated by both high_alloc() and low_alloc().
high_alloc() -> efi_high_alloc()
low_alloc()  -> efi_low_alloc()
low_free()   -> efi_free()
Signed-off-by: NRoy Franz <roy.franz@linaro.org>
Acked-by: NMark Salter <msalter@redhat.com>
Reviewed-by: NGrant Likely <grant.likely@linaro.org>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>

Add system table pointer argument to shared EFI stub related functions
so they no longer use a global system table pointer as they did when part
of eboot.c.  For the ARM EFI stub this allows us to avoid global
variables completely and thereby not have to deal with GOT fixups.
Not having the EFI stub fixup its GOT, which is shared with the
decompressor, simplifies the relocating of the zImage to a
bootable address.
Signed-off-by: NRoy Franz <roy.franz@linaro.org>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>

No code changes made, just moving functions and #define from x86 arch
directory to common location.  Code is shared using #include, similar
to how decompression code is shared among architectures.
Signed-off-by: NRoy Franz <roy.franz@linaro.org>
Acked-by: NMark Salter <msalter@redhat.com>
Reviewed-by: NGrant Likely <grant.likely@linaro.org>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>

efi_lookup_mapped_addr() is a handy utility for other platforms than
x86. Move it from arch/x86 to drivers/firmware. Add memmap pointer
to global efi structure, and initialise it on x86.
Signed-off-by: NLeif Lindholm <leif.lindholm@linaro.org>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>

Common to (U)EFI support on all platforms is the global "efi" data
structure, and the code that parses the System Table to locate
addresses to populate that structure with.

This patch adds both of these to the global EFI driver code and
removes the local definition of the global "efi" data structure from
the x86 and ia64 code.

Squashed into one big patch to avoid breaking bisection.
Signed-off-by: NLeif Lindholm <leif.lindholm@linaro.org>
Acked-by: NTony Luck <tony.luck@intel.com>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>

This fixes the following sparse warning
drivers/firmware/efi/efivars.c:567:6: warning: symbol 'efivars_sysfs_exit' was not declared. Should it be static?
Signed-off-by: NBojan Prtvar <prtvar.b@gmail.com>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>

In pstore write, Efi will add a character 'C'(compressed) or
D'(decompressed) in its header while writing to persistent store.
In pstore read, read the header and update the 'compressed' flag
accordingly.
Signed-off-by: NAruna Balakrishnaiah <aruna@linux.vnet.ibm.com>
Reviewed-by: NKees Cook <keescook@chromium.org>
Signed-off-by: NTony Luck <tony.luck@intel.com>

Backends will set the flag 'compressed' after reading the log from
persistent store to indicate the data being returned to pstore is
compressed or not.
Signed-off-by: NAruna Balakrishnaiah <aruna@linux.vnet.ibm.com>
Reviewed-by: NKees Cook <keescook@chromium.org>
Signed-off-by: NTony Luck <tony.luck@intel.com>

Addition of new argument 'compressed' in the write call back will
help the backend to know if the data passed from pstore is compressed
or not (In case where compression fails.). If compressed, the backend
can add a tag indicating the data is compressed while writing to
persistent store.
Signed-off-by: NAruna Balakrishnaiah <aruna@linux.vnet.ibm.com>
Reviewed-by: NKees Cook <keescook@chromium.org>
Signed-off-by: NTony Luck <tony.luck@intel.com>

The efivars code requires EFI runtime services to function, so check
that they are enabled.

This fixes a crash when booting with the "noefi" kernel parameter, and
also when mixing kernel and firmware "bitness", e.g. 32-bit kernel with
64-bit firmware.
Tested-by: NDave Young <dyoung@redhat.com>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>

Header size is needed to distinguish between header and the dump data.
Incorporate the addition of new argument (hsize) in the pstore write
callback.
Signed-off-by: NAruna Balakrishnaiah <aruna@linux.vnet.ibm.com>
Acked-by: NKees Cook <keescook@chromium.org>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

This is patch 3/3 of a patch set that cleans up pstore_register failure paths.

If efivars fails to register with pstore, there is no point to keeping
the 4 KB buffer around. It's only used by the pstore read/write routines.
Signed-off-by: NLenny Szubowicz <lszubowi@redhat.com>
Reported-by: NNaotaka Hamaguchi <n.hamaguchi@jp.fujitsu.com>
Signed-off-by: NTony Luck <tony.luck@intel.com>

Change a kmalloc() + memcpy() pair for a single kmemdup() call.
Signed-off-by: NThomas Meyer <thomas@m3y3r.de>
Acked-by: NKees Cook <keescook@chromium.org>
Signed-off-by: NTony Luck <tony.luck@intel.com>

The loop in efivar_update_sysfs_entries() reuses the same allocation for
entries each time it calls efivar_create_sysfs_entry(entry).  This is
wrong because efivar_create_sysfs_entry() expects to keep the memory it
was passed, so the caller may not free it (and may not pass the same
memory in multiple times).  This leads to the oops below.  Fix by
getting a new allocation each time we go around the loop.

---[ end trace ba4907d5c519d111 ]---
BUG: unable to handle kernel NULL pointer dereference at           (null)
IP: [<ffffffff8142f81f>] efivar_entry_find+0x14f/0x2d0
PGD 0
Oops: 0000 [#2] SMP
Modules linked in: oops(OF+) ebtable_nat ebtables xt_CHECKSUM [...]
CPU: 0 PID: 301 Comm: kworker/0:2 Tainted: GF     D    O 3.9.0+ #1
Hardware name: LENOVO 4291EV7/4291EV7, BIOS 8DET52WW (1.22 ) 09/15/2011
Workqueue: events efivar_update_sysfs_entries
task: ffff8801955920c0 ti: ffff88019413e000 task.ti: ffff88019413e000
RIP: 0010:[<ffffffff8142f81f>]  [<ffffffff8142f81f>] efivar_entry_find+0x14f/0x2d0
RSP: 0018:ffff88019413fa48  EFLAGS: 00010006
RAX: 0000000000000000 RBX: ffff880195d87c00 RCX: ffffffff81ab6f60
RDX: ffff88019413fb88 RSI: 0000000000000400 RDI: ffff880196254000
RBP: ffff88019413fbd8 R08: 0000000000000000 R09: ffff8800dad99037
R10: ffff880195d87c00 R11: 0000000000000430 R12: ffffffff81ab6f60
R13: fffffffffffff7d8 R14: ffff880196254000 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff88019e200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 0000000001a0b000 CR4: 00000000000407f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Stack:
 ffff88019413fb78 ffff88019413fb88 ffffffff81e85d60 03000000972b5c00
 ffff88019413fa29 ffffffff81e85d60 ffff88019413fbfb 0000000197087280
 00000000000000fe 0000000000000001 ffffffff81e85dd9 ffff880197087280
Call Trace:
 [<ffffffff81254371>] ? idr_get_empty_slot+0x131/0x240
 [<ffffffff8125b6d2>] ? put_dec+0x72/0x90
 [<ffffffff81158e40>] ? cache_alloc_refill+0x170/0x2f0
 [<ffffffff81430420>] efivar_update_sysfs_entry+0x150/0x220
 [<ffffffff8103dd29>] ? efi_call2+0x9/0x70
 [<ffffffff8103d787>] ? virt_efi_get_next_variable+0x47/0x1b0
 [<ffffffff8115a8df>] ? kmem_cache_alloc_trace+0x1af/0x1c0
 [<ffffffff81430033>] efivar_init+0x2c3/0x380
 [<ffffffff814302d0>] ? efivar_delete+0xd0/0xd0
 [<ffffffff8143111f>] efivar_update_sysfs_entries+0x6f/0x90
 [<ffffffff810605f3>] process_one_work+0x183/0x490
 [<ffffffff81061780>] worker_thread+0x120/0x3a0
 [<ffffffff81061660>] ? manage_workers+0x160/0x160
 [<ffffffff8106752e>] kthread+0xce/0xe0
 [<ffffffff81067460>] ? kthread_freezable_should_stop+0x70/0x70
 [<ffffffff81543c5c>] ret_from_fork+0x7c/0xb0
 [<ffffffff81067460>] ? kthread_freezable_should_stop+0x70/0x70
Code: 8d 55 b0 48 8d 45 a0 49 81 ed 28 08 00 00 48 89 95 78 fe [...]
RIP  [<ffffffff8142f81f>] efivar_entry_find+0x14f/0x2d0
 RSP <ffff88019413fa48>
CR2: 0000000000000000
---[ end trace ba4907d5c519d112 ]---

Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Tomoki Sekiyama <tomoki.sekiyama@hds.com>
Signed-off-by: NSeiji Aguchi <seiji.aguchi@hds.com>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>

No need to free a NULL pointer.
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>

The intent is that if we aren't allowed to block because we're in an
NMI or an emergency then we only take the lock if it is uncontended.

Part of the problem is the test is reversed so we return -EBUSY if we
acquire the lock.
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>