If we enable MSI, then kexec a new kernel, the new kernel may receive MSIs
it is not prepared for. Commit d5dea7d95c ("PCI: msi: Disable msi
interrupts when we initialize a pci device") prevents this, but only if the
new kernel is built with CONFIG_PCI_MSI=y.
Move the "disable MSI" functionality from drivers/pci/msi.c to a new
pci_msi_setup_pci_dev() in drivers/pci/probe.c so we can disable MSIs when
we enumerate devices even if the kernel doesn't include full MSI support.
[bhelgaas: changelog, disable MSIs in pci_setup_device(), put
pci_msi_setup_pci_dev() at its final destination]
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Move pci_msi_set_enable() and pci_msix_clear_and_set_ctrl() to
drivers/pci/pci.h so they're available even when MSI isn't configured
into the kernel.
No functional change.
[bhelgaas: changelog, split into separate patch]
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Rename msi_set_enable() to pci_msi_set_enable() and
msix_clear_and_set_ctrl() to pci_msix_clear_and_set_ctrl().
No functional change.
[bhelgaas: changelog, split into separate patch]
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Unlike MSI, which is configured via registers in the MSI capability in
Configuration Space, MSI-X is configured via tables in Memory Space.
These MSI-X tables are mapped by a device BAR, and if no Memory Space
has been assigned to the BAR, MSI-X cannot be used.
Fail MSI-X setup if no space has been assigned for the BAR.
Previously, we ioremapped the MSI-X table even if the resource hadn't been
assigned. In this case, the resource address is undefined (and is often
zero), which may lead to warnings or oopses in this path:
pci_enable_msix
msix_capability_init
msix_map_region
ioremap_nocache
The PCI core sets resource flags to zero when it can't assign space for the
resource (see reset_resource()). There are also some cases where it sets
the IORESOURCE_UNSET flag, e.g., pci_reassigndev_resource_alignment(),
pci_assign_resource(), etc. So we must check for both cases.
[bhelgaas: changelog]
Reported-by: Zhang Jukuo <zhangjukuo@huawei.com>
Tested-by: Zhang Jukuo <zhangjukuo@huawei.com>
Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
This can be set by quirks/drivers to be used by the architecture code
that assigns the MSI addresses.
We additionally add verification in the core MSI code that the values
assigned by the architecture do satisfy the limitation in order to fail
gracefully if they don't (ie. the arch hasn't been updated to deal with
that quirk yet).
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CC: <stable@vger.kernel.org>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
With the new stacked irq domains, it becomes pretty tempting to
allocate an MSI domain per PCI bus, which would remove the requirement
of either relying on arch-specific code, or a default PCI MSI domain.
By allowing the msi_controller structure to carry a pointer to an
irq_domain, we can easily use this in pci_msi_setup_msi_irqs. The
existing code can still be used as a fallback if the MSI driver does
not populate the domain field.
Tested on arm64 with the GICv3 ITS driver.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: Yingjoe Chen <yingjoe.chen@mediatek.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Link: http://lkml.kernel.org/r/1416048553-29289-2-git-send-email-marc.zyngier@arm.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Provide mechanism to directly alloc/free MSI/MSIX interrupt from
irqdomain, which will be used to replace arch_setup_msi_irq()/
arch_setup_msi_irqs()/arch_teardown_msi_irq()/arch_teardown_msi_irqs().
To kill weak functions, this patch introduce a new weak function
arch_get_pci_msi_domain(), which is to retrieve the MSI irqdomain
for a PCI device. This weak function could be killed once we get
a common way to associate MSI domain with PCI device.
Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Yijing Wang <wangyijing@huawei.com>
Cc: Yingjoe Chen <yingjoe.chen@mediatek.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Matthias Brugger <matthias.bgg@gmail.com>
Cc: Alexander Gordeev <agordeev@redhat.com>
Link: http://lkml.kernel.org/r/1416061447-9472-10-git-send-email-jiang.liu@linux.intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Enhance PCI MSI core to support hierarchy irqdomain, so the common
code can be shared across architectures.
[ tglx: Extracted and combined from several patches ]
Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Yingjoe Chen <yingjoe.chen@mediatek.com>
Cc: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Required to support non PCI based MSI.
[ tglx: Extracted from Jiangs patch series ]
Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
mask/unmask_msi_irq and __mask_msi/msix_irq are PCI/MSI specific
functions and should be named accordingly. This is a preparatory patch
to support MSI on non PCI devices.
Rename mask/unmask_msi_irq to pci_msi_mask/unmask_irq and document the
functions. Provide conversion helpers.
Rename __mask_msi/msix_irq to __pci_msi/msix_desc_mask so its clear
that they operated on msi_desc. Fixup the only user outside of
pci/msi.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Yijing Wang <wangyijing@huawei.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Rename write_msi_msg() to pci_write_msi_msg() to mark it as PCI
specific.
Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Yingjoe Chen <yingjoe.chen@mediatek.com>
Cc: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Rename __read_msi_msg() to __pci_read_msi_msg() and kill unused
read_msi_msg(). It's a preparation to separate generic MSI code from
PCI core.
Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Yingjoe Chen <yingjoe.chen@mediatek.com>
Cc: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
It is the repsonsibility of arch_setup_msi_irq()/arch_setup_msi_irqs()
to call irq_set_msi_desc() to associate IRQ descriptors and MSI
descriptors. Kill the redundant call of irq_set_msi_desc() for MSI-X
interrupts in the PCI MSI core.
Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Yingjoe Chen <yingjoe.chen@mediatek.com>
Cc: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Per Documentation/CodingStyle, don't use braces around single statements.
Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Yingjoe Chen <yingjoe.chen@mediatek.com>
Cc: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Add pcibios_msi_controller() to get the msi_controller associated with a
PCI device. This is to allow arches to store the msi_controller in the
arch-specific PCI sysdata.
[bhelgaas: changelog, take pci_dev instead of pci_bus]
Suggested-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
"msi_chip" isn't very descriptive, so rename it to "msi_controller". That
tells a little more about what it does and is already used in device tree
bindings.
No functional change.
[bhelgaas: changelog, change *only* the struct name so it's reviewable]
Suggested-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
The problem fixed by 0e4ccb1505 ("PCI: Add x86_msi.msi_mask_irq() and
msix_mask_irq()") has been fixed in a simpler way by a previous commit
("PCI/MSI: Add pci_msi_ignore_mask to prevent writes to MSI/MSI-X Mask
Bits").
The msi_mask_irq() and msix_mask_irq() x86_msi_ops added by 0e4ccb1505
are no longer needed, so revert the commit.
default_msi_mask_irq() and default_msix_mask_irq() were added by
0e4ccb1505 and are still used by s390, so keep them for now.
[bhelgaas: changelog]
Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: David Vrabel <david.vrabel@citrix.com>
CC: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
CC: xen-devel@lists.xenproject.org
MSI-X vector Mask Bits are in MSI-X Tables in PCI memory space. Xen PV
guests can't write to those tables. MSI vector Mask Bits are in PCI
configuration space. Xen PV guests can write to config space, but those
writes are ignored.
Commit 0e4ccb1505 ("PCI: Add x86_msi.msi_mask_irq() and
msix_mask_irq()") added a way to override default_mask_msi_irqs() and
default_mask_msix_irqs() so they can be no-ops in Xen guests, but this is
more complicated than necessary.
Add "pci_msi_ignore_mask" in the core PCI MSI code. If set,
default_mask_msi_irqs() and default_mask_msix_irqs() return without doing
anything. This is less flexible, but much simpler.
[bhelgaas: changelog]
Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: David Vrabel <david.vrabel@citrix.com>
CC: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
CC: xen-devel@lists.xenproject.org
The only use of "status" is to hold a value which is immediately returned,
so just return and remove the variable directly.
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
default_restore_msi_irq() already has the struct msi_desc pointer required
by __write_msi_msg(), so call it directly instead of having write_msi_msg()
look it up from the IRQ.
No functional change.
[bhelgaas: split into separate patch]
Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
"msi_attrib.pos" is only used for MSI (not MSI-X), and we already cache the
MSI capability offset in "dev->msi_cap".
Remove "pos" from the struct msi_attrib and use "dev->msi_cap" directly.
[bhelgaas: changelog, fix whitespace]
Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
After commit 1c51b50c29 ("PCI/MSI: Export MSI mode using attributes, not
kobjects"), the kobject in struct msi_desc is unused.
Remove the unused struct kobject from struct msi_desc.
[bhelgaas: changelog]
Fixes: 1c51b50c29 ("PCI/MSI: Export MSI mode using attributes, not kobjects")
Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Rename pci_msi_check_device() to pci_msi_supported() for clarity. Note
that pci_msi_supported() returns true if MSI/MSI-X is supported, so code
like:
if (pci_msi_supported(...))
reads naturally.
[bhelgaas: changelog, split to separate patch, reverse sense]
Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Both callers of pci_msi_check_device() check that the device is in D0
state, so move the check from the callers into pci_msi_check_device()
itself.
In pci_enable_msi_range(), note that pci_msi_check_device() never returns a
positive value any more, so the loop that called it until it returns zero
or negative is no longer necessary.
[bhelgaas: changelog, split to separate patch]
Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
No architectures implement arch_msi_check_device() or the struct msi_chip
.check_device() method, so remove them.
Remove the "type" parameter to pci_msi_check_device() because it was only
used to call arch_msi_check_device() and is no longer needed.
[bhelgaas: changelog, split to separate patch]
Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
The patch exports 2 MSI message relevant functions, which will be
used by VFIO PCI driver. The VFIO PCI driver would be built as
a module.
Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
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>
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>
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>
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>
Michael S. Tsirkin