Use irq_get_msi_desc() to get MSI IRQ related msi_desc directly instead of
searching the dev->msi_list.
Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
In __pci_restore_msix_state(), we get the first element from msi_list, but
we never use it. Remove this useless code.
Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Retrieve the first MSI IRQ to compute the MSI index from struct msi_desc
rather than the struct pci_dev to avoid an additional memory access.
Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
msi_remove_pci_irq_vectors() is unused, so remove it.
Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Move MSI entry stuff to a new function, msi_setup_entry(), to simplify
msi_capability_init() as MSI-X does.
Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
The Multiple Message Capable field in the MSI Message Control register
indicates how many vectors the device supports. This field is read-only,
so cache it in msi_desc to avoid reading it repeatedly.
Since we cache the extracted field (not the entire Message Control
register), we can use msi_mask() instead of msi_capable_mask(), which is
then unused, so remove it.
[bhelgaas: fix whitespace, changelog]
Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
No one uses msi_enabled_mask(); remove the dead code. No functional
change.
Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
free_msi_irqs() is leaking memory, since list_for_each_entry(entry,
&dev->msi_list, list) {...} is never executed, because dev->msi_list is
made empty by the loop just above this one.
Fix it by relying on zero termination of attribute array like
populate_msi_sysfs() does.
Fixes: 1c51b50c29 ("PCI/MSI: Export MSI mode using attributes, not kobjects")
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
CC: stable@vger.kernel.org # v3.14+
Merge quoted strings that are broken across lines into a single entity.
The compiler merges them anyway, but checkpatch complains about it, and
merging them makes it easier to grep for strings.
No functional change.
[bhelgaas: changelog, do the same for everything under drivers/pci]
Signed-off-by: Ryan Desfosses <ryan@desfo.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
* dma-api:
iommu/exynos: Remove unnecessary "&" from function pointers
DMA-API: Update dma_pool_create ()and dma_pool_alloc() descriptions
DMA-API: Fix duplicated word in DMA-API-HOWTO.txt
DMA-API: Capitalize "CPU" consistently
sh/PCI: Pass GAPSPCI_DMA_BASE CPU & bus address to dma_declare_coherent_memory()
DMA-API: Change dma_declare_coherent_memory() CPU address to phys_addr_t
DMA-API: Clarify physical/bus address distinction
* pci/virtualization:
PCI: Mark RTL8110SC INTx masking as broken
* pci/msi:
PCI/MSI: Remove pci_enable_msi_block()
* pci/misc:
PCI: Remove pcibios_add_platform_entries()
s390/pci: use pdev->dev.groups for attribute creation
PCI: Move Open Firmware devspec attribute to PCI common code
* pci/resource:
PCI: Add resource allocation comments
PCI: Simplify __pci_assign_resource() coding style
PCI: Change pbus_size_mem() return values to be more conventional
PCI: Restrict 64-bit prefetchable bridge windows to 64-bit resources
PCI: Support BAR sizes up to 8GB
resources: Clarify sanity check message
PCI: Don't add disabled subtractive decode bus resources
PCI: Don't print anything while decoding is disabled
PCI: Don't set BAR to zero if dma_addr_t is too small
PCI: Don't convert BAR address to resource if dma_addr_t is too small
PCI: Reject BAR above 4GB if dma_addr_t is too small
PCI: Fail safely if we can't handle BARs larger than 4GB
x86/gart: Tidy messages and add bridge device info
x86/gart: Replace printk() with pr_info()
x86/PCI: Move pcibios_assign_resources() annotation to definition
x86/PCI: Mark ATI SBx00 HPET BAR as IORESOURCE_PCI_FIXED
x86/PCI: Don't try to move IORESOURCE_PCI_FIXED resources
x86/PCI: Fix Broadcom CNB20LE unintended sign extension
There are no users of pci_enable_msi_block() function left. Obsolete it in
favor of pci_enable_msi_range() and pci_enable_msi_exact() functions.
Previously, we called arch_setup_msi_irqs() once, requesting the same
vector count we passed to arch_msi_check_device(). Now we may call it
several times: if it returns failure, we may retry and request fewer
vectors.
We don't keep track of the vector count we initially passed to
arch_msi_check_device(). We only keep track of the number of vectors
successfully set up by arch_setup_msi_irqs(), and this is what we use to
clean things up when disabling MSI. Therefore, we assume that
arch_msi_check_device() does nothing that will have to be cleaned up later.
[bhelgaas: changelog]
Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
* pci/hotplug:
PCI: rphahp: Fix endianess issues
PCI: Allow hotplug service drivers to operate in polling mode
PCI: pciehp: Acknowledge spurious "cmd completed" event
PCI: pciehp: Use PCI_EXP_SLTCAP_PSN define
PCI: hotplug: Remove unnecessary "dev->bus" test
* pci/msi:
GenWQE: Use pci_enable_msi_exact() instead of pci_enable_msi_block()
PCI/MSI: Simplify populate_msi_sysfs()
PCI/portdrv: Use pci_enable_msix_exact() instead of pci_enable_msix()
* pci/virtualization:
PCI: Add Patsburg (X79) to Intel PCH root port ACS quirk
* pci/misc:
PCI: Fix use of uninitialized MPS value
PCI: Remove dead code
MAINTAINERS: Add arch/x86/kernel/quirks.c to PCI file patterns
PCI: Remove unnecessary __ref annotations
PCI: Fail new_id for vendor/device values already built into driver
PCI: Add new ID for Intel GPU "spurious interrupt" quirk
PCI: Update my email address
PCI: Fix incorrect vgaarb conditional in WARN_ON()
PCI: Use designated initialization in PCI_VDEVICE
PCI: Remove old serial device IDs
PCI: Remove unnecessary includes of <linux/init.h>
powerpc/PCI: Fix NULL dereference in sys_pciconfig_iobase() list traversal
None of these files are actually using any __init type directives and hence
don't need to include <linux/init.h>. Most are just a left over from
__devinit and __cpuinit removal, or simply due to code getting copied from
one driver to the next.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Simplify populate_msi_sysfs() by
- Swapping the order of the two allocations and storing the
msi_dev_attr-derived pointer right after allocation, allowing the
cleanup code to pick things up without extra effort.
- Using kasprintf() instead of the kmalloc()/sprintf() pair.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Coverity reported that I forgot to clean up some allocated memory on the
error path in populate_msi_sysfs(), so this patch fixes that.
Thanks to Dave Jones for pointing out where the error was, I obviously
can't read code this morning...
Found by Coverity (CID 1163317).
Fixes: 1c51b50c29 ("PCI/MSI: Export MSI mode using attributes, not kobjects")
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Dave Jones <davej@redhat.com>
Coverity reported that I forgot to check the return value of kmalloc() when
creating the MSI attribute name, so fix that up and properly free it if
there is an error when allocating the msi_dev_attr variable.
Found by Coverity (CID 1163315 and 1163316).
Fixes: 1c51b50c29 ("PCI/MSI: Export MSI mode using attributes, not kobjects")
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
This adds pci_enable_msi_range(), which supersedes the pci_enable_msi()
and pci_enable_msi_block() MSI interfaces.
It also adds pci_enable_msix_range(), which supersedes the
pci_enable_msix() MSI-X interface.
The old interfaces have three categories of return values:
negative: failure; caller should not retry
positive: failure; value indicates number of interrupts that *could*
have been allocated, and caller may retry with a smaller request
zero: success; at least as many interrupts allocated as requested
It is error-prone to handle these three cases correctly in drivers.
The new functions return either a negative error code or a number of
successfully allocated MSI/MSI-X interrupts, which is expected to lead to
clearer device driver code.
pci_enable_msi(), pci_enable_msi_block() and pci_enable_msix() still exist
unchanged, but are deprecated and may be removed after callers are updated.
[bhelgaas: tweak changelog]
Suggested-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Tejun Heo <tj@kernel.org>
This creates an MSI-X counterpart for pci_msi_vec_count(). Device drivers
can use this function to obtain maximum number of MSI-X interrupts the
device supports and use that number in a subsequent call to
pci_enable_msix().
pci_msix_vec_count() supersedes pci_msix_table_size() and returns a
negative errno if device does not support MSI-X interrupts. After this
update, callers must always check the returned value.
The only user of pci_msix_table_size() was the PCI-Express port driver,
which is also updated by this change.
Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Tejun Heo <tj@kernel.org>
The new pci_msi_vec_count() interface makes pci_enable_msi_block_auto()
superfluous.
Drivers can use pci_msi_vec_count() to learn the maximum number of MSIs
supported by the device, and then call pci_enable_msi_block().
pci_enable_msi_block_auto() was introduced recently, and its only user is
the AHCI driver, which is also updated by this change.
Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Tejun Heo <tj@kernel.org>
Device drivers can use this interface to obtain the maximum number of MSI
interrupts the device supports and use that number, e.g., in a subsequent
call to pci_enable_msi_block().
Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Tejun Heo <tj@kernel.org>
* pci/msi:
PCI/MSI: Make pci_enable_msi/msix() 'nvec' argument type as int
PCI/MSI: Return -ENOSYS for unimplemented interfaces, not -1
PCI/MSI: Return msix_capability_init() failure if populate_msi_sysfs() fails
s390/PCI: Remove superfluous check of MSI type
s390/PCI: Fix single MSI only check
PCI/MSI: Export MSI mode using attributes, not kobjects
Make pci_enable_msi_block(), pci_enable_msi_block_auto() and
pci_enable_msix() consistent with regard to the type of 'nvec' argument.
Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Tejun Heo <tj@kernel.org>
If populate_msi_sysfs() function failed msix_capability_init() must return
the error code, but it returns the success instead. This update fixes the
described misbehaviour.
Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Tejun Heo <tj@kernel.org>
The PCI MSI sysfs code is a mess with kobjects for things that don't really
need to be kobjects. This patch creates attributes dynamically for the MSI
interrupts instead of using kobjects.
Note, this removes a directory from sysfs. Old MSI kobjects:
pci_device
└── msi_irqs
└── 40
└── mode
New MSI attributes:
pci_device
└── msi_irqs
└── 40
As there was only one file "mode" with the kobject model, the interrupt
number is now a file that returns the "mode" of the interrupt (msi vs.
msix).
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Change x86_msi.restore_msi_irqs(struct pci_dev *dev, int irq) to
x86_msi.restore_msi_irqs(struct pci_dev *dev).
restore_msi_irqs() restores multiple MSI-X IRQs, so param 'int irq' is
unneeded. This makes code more consistent between vm and bare metal.
Dom0 MSI-X restore code can also be optimized as XEN only has a hypercall
to restore all MSI-X vectors at one time.
Tested-by: Sucheta Chakraborty <sucheta.chakraborty@qlogic.com>
Signed-off-by: Zhenzhong Duan <zhenzhong.duan@oracle.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Fix whitespace, capitalization, and spelling errors. No functional change.
I know "busses" is not an error, but "buses" was more common, so I used it
consistently.
Signed-off-by: Marta Rybczynska <rybczynska@gmail.com> (pci_reset_bridge_secondary_bus())
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Certain platforms do not allow writes in the MSI-X BARs to setup or tear
down vector values. To combat against the generic code trying to write to
that and either silently being ignored or crashing due to the pagetables
being marked R/O this patch introduces a platform override.
Note that we keep two separate, non-weak, functions default_mask_msi_irqs()
and default_mask_msix_irqs() for the behavior of the arch_mask_msi_irqs()
and arch_mask_msix_irqs(), as the default behavior is needed by x86 PCI
code.
For Xen, which does not allow the guest to write to MSI-X tables - as the
hypervisor is solely responsible for setting the vector values - we
implement two nops.
This fixes a Xen guest crash when passing a PCI device with MSI-X to the
guest. See the bugzilla for more details.
[bhelgaas: add bugzilla info]
Reference: https://bugzilla.kernel.org/show_bug.cgi?id=64581
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
CC: Sucheta Chakraborty <sucheta.chakraborty@qlogic.com>
CC: Zhenzhong Duan <zhenzhong.duan@oracle.com>
Currently, pci_enable_msi() and pci_enable_msix() return success even if
the device power state is not D0. However, we don't write the MSI message
to the device registers, and the registers will never be updated later.
This patch makes pci_enable_msi() and pci_enable_msix() return an error
instead.
[bhelgaas: changelog]
Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Acked-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
After the last architecture switched to generic hard irqs the config
options HAVE_GENERIC_HARDIRQS & GENERIC_HARDIRQS and the related code
for !CONFIG_GENERIC_HARDIRQS can be removed.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Some platforms (e.g S390) don't use the generic hardirqs code and
therefore do not defined HAVE_GENERIC_HARDIRQS. This prevents using
the irq_set_chip_data() and irq_get_chip_data() functions that are
used for the default implementations of the MSI operations.
So, when CONFIG_GENERIC_HARDIRQS is not enabled, provide another
default implementation of the MSI operations, that simply errors
out. The architecture is responsible for implementing those operations
(which is the case on S390), and cannot use the msi_chip infrastructure.
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Jason Cooper <jason@lakedaemon.net>
The new struct msi_chip is used to associated an MSI controller with a
PCI bus. It is automatically handed down from the root to its children
during bus enumeration.
This patch provides default (weak) implementations for the architecture-
specific MSI functions (arch_setup_msi_irq(), arch_teardown_msi_irq()
and arch_msi_check_device()) which check if a PCI device's bus has an
attached MSI chip and forward the call appropriately.
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Tested-by: Daniel Price <daniel.price@gmail.com>
Tested-by: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Jason Cooper <jason@lakedaemon.net>
Until now, the MSI architecture-specific functions could be overloaded
using a fairly complex set of #define and compile-time
conditionals. In order to prepare for the introduction of the msi_chip
infrastructure, it is desirable to switch all those functions to use
the 'weak' mechanism. This commit converts all the architectures that
were overidding those MSI functions to use the new strategy.
Note that we keep two separate, non-weak, functions
default_teardown_msi_irqs() and default_restore_msi_irqs() for the
default behavior of the arch_teardown_msi_irqs() and
arch_restore_msi_irqs(), as the default behavior is needed by x86 PCI
code.
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Tested-by: Daniel Price <daniel.price@gmail.com>
Tested-by: Thierry Reding <thierry.reding@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: linuxppc-dev@lists.ozlabs.org
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: linux390@de.ibm.com
Cc: linux-s390@vger.kernel.org
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: x86@kernel.org
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: linux-ia64@vger.kernel.org
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: David S. Miller <davem@davemloft.net>
Cc: sparclinux@vger.kernel.org
Cc: Chris Metcalf <cmetcalf@tilera.com>
Signed-off-by: Jason Cooper <jason@lakedaemon.net>
Because of the encoding of the "Multiple Message Capable" and "Multiple
Message Enable" fields, a device can only advertise that it's capable of a
power-of-two number of vectors, and the OS can only enable a power-of-two
number.
For example, a device that's limited internally to using 18 vectors would
have to advertise that it's capable of 32. The 14 extra vectors consume
vector numbers and IRQ descriptors even though the device can't actually
use them.
This fix introduces a 'msi_desc::nvec_used' field to address this issue.
When non-zero, it is the actual number of MSIs the device will send, as
requested by the device driver. This value should be used by architectures
to set up and tear down only as many interrupt resources as the device will
actually use.
Note, although the existing 'msi_desc::multiple' field might seem
redundant, in fact it is not. The number of MSIs advertised need not be
the smallest power-of-two larger than the number of MSIs the device will
send. Thus, it is not always possible to derive the former from the
latter, so we need to keep them both to handle this case.
[bhelgaas: changelog, rename to "nvec_used"]
Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
The "+" operation has higher precedence than "?:" and ->msi_cap is
always non-zero here so the original statement is equivalent to:
entry->mask_pos = PCI_MSI_MASK_64;
Which wasn't the intent.
[bhelgaas: my fault from 78b5a310ce]
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
* pci/gavin-msi-cleanup:
vfio-pci: Use cached MSI/MSI-X capabilities
vfio-pci: Use PCI_MSIX_TABLE_BIR, not PCI_MSIX_FLAGS_BIRMASK
PCI: Remove "extern" from function declarations
PCI: Use PCI_MSIX_TABLE_BIR, not PCI_MSIX_FLAGS_BIRMASK
PCI: Drop msi_mask_reg() and remove drivers/pci/msi.h
PCI: Use msix_table_size() directly, drop multi_msix_capable()
PCI: Drop msix_table_offset_reg() and msix_pba_offset_reg() macros
PCI: Drop is_64bit_address() and is_mask_bit_support() macros
PCI: Drop msi_data_reg() macro
PCI: Drop msi_lower_address_reg() and msi_upper_address_reg() macros
PCI: Drop msi_control_reg() macro and use PCI_MSI_FLAGS directly
PCI: Use cached MSI/MSI-X offsets from dev, not from msi_desc
PCI: Clean up MSI/MSI-X capability #defines
PCI: Use cached MSI-X cap while enabling MSI-X
PCI: Use cached MSI cap while enabling MSI interrupts
PCI: Remove MSI/MSI-X cap check in pci_msi_check_device()
PCI: Cache MSI/MSI-X capability offsets in struct pci_dev
PCI: Use u8, not int, for PM capability offset
[SCSI] megaraid_sas: Use correct #define for MSI-X capability
PCI_MSIX_FLAGS_BIRMASK is mis-named because the BIR mask is in the
Table Offset register, not the flags ("Message Control" per spec)
register.
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
msi_mask_reg() doesn't provide any useful abstraction, do drop it.
Remove the now-empty drivers/pci/msi.h.
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
The users of multi_msix_capable() are really interested in the table
size, so just say what we mean.
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
msix_table_offset_reg() is used only once and adds a useless indirection,
so just use the table offset directly.
msix_pba_offset_reg() is unused, so just delete it.
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
msi_lower_address_reg() and msi_upper_address_reg() don't provide any
useful abstraction, so drop them.
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Note the error in pci_msix_table_size() -- we used PCI_MSI_FLAGS to
locate the PCI_MSIX_FLAGS word. No actual breakage because PCI_MSI_FLAGS
and PCI_MSIX_FLAGS happen to be the same.
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
We always know the type (MSI vs MSI-X), so we can use the correct
cached capability offset rather than relying on the copy in the
msi_attrib.
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
The patch uses the cached MSI-X capability offset in
pci_dev instead of reading it from config space when enabling
MSI-X interrupts.
Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
The patch uses the cached MSI capability offset in pci_dev instead
of reading it from config space when enabling MSI interrupts.
[bhelgaas: removed unrelated msi_control_reg() changes]
Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
