Every pci_dev is on a valid pci_bus, so we don't need to test whether
dev->bus is NULL or not.
The only exceptions are a few legacy cases like alpha_core_agp_setup(),
parisc_agp_setup(), and megaraid's make_local_pdev(), where we allocate a
pci_dev with a NULL bus pointer. These are dubious uses (especially the
megaraid one), and I don't think it's possible to exercise this
pci_configure_slot() path with any of them.
Found by Coverity (CID 146446).
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Based on a patch by Jon Mason (see URL below).
All users of pcie_bus_configure_settings() pass arguments of the form
"bus, bus->self->pcie_mpss". The "mpss" argument is redundant since we
can easily look it up internally. In addition, all callers check
"bus->self" for NULL, which we can also do internally.
This patch simplifies the interface and the callers. No functional change.
Reference: http://lkml.kernel.org/r/1317048850-30728-2-git-send-email-mason@myri.com
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
They were implicitly getting it from device.h --> module.h but
we want to clean that up. So add the minimal header for these
macros.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Commit b03e7495a8 ("PCI: Set PCI-E Max Payload Size on fabric")
introduced a potential NULL pointer dereference in calls to
pcie_bus_configure_settings due to attempts to access pci_bus self
variables when the self pointer is NULL.
To correct this, verify that the self pointer in pci_bus is non-NULL
before dereferencing it.
Reported-by: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: Shyam Iyer <shyam_iyer@dell.com>
Signed-off-by: Jon Mason <mason@myri.com>
Acked-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
On a given PCI-E fabric, each device, bridge, and root port can have a
different PCI-E maximum payload size. There is a sizable performance
boost for having the largest possible maximum payload size on each PCI-E
device. However, if improperly configured, fatal bus errors can occur.
Thus, it is important to ensure that PCI-E payloads sends by a device
are never larger than the MPS setting of all devices on the way to the
destination.
This can be achieved two ways:
- A conservative approach is to use the smallest common denominator of
the entire tree below a root complex for every device on that fabric.
This means for example that having a 128 bytes MPS USB controller on one
leg of a switch will dramatically reduce performances of a video card or
10GE adapter on another leg of that same switch.
It also means that any hierarchy supporting hotplug slots (including
expresscard or thunderbolt I suppose, dbl check that) will have to be
entirely clamped to 128 bytes since we cannot predict what will be
plugged into those slots, and we cannot change the MPS on a "live"
system.
- A more optimal way is possible, if it falls within a couple of
constraints:
* The top-level host bridge will never generate packets larger than the
smallest TLP (or if it can be controlled independently from its MPS at
least)
* The device will never generate packets larger than MPS (which can be
configured via MRRS)
* No support of direct PCI-E <-> PCI-E transfers between devices without
some additional code to specifically deal with that case
Then we can use an approach that basically ignores downstream requests
and focuses exclusively on upstream requests. In that case, all we need
to care about is that a device MPS is no larger than its parent MPS,
which allows us to keep all switches/bridges to the max MPS supported by
their parent and eventually the PHB.
In this case, your USB controller would no longer "starve" your 10GE
Ethernet and your hotplug slots won't affect your global MPS.
Additionally, the hotplugged devices themselves can be configured to a
larger MPS up to the value configured in the hotplug bridge.
To choose between the two available options, two PCI kernel boot args
have been added to the PCI calls. "pcie_bus_safe" will provide the
former behavior, while "pcie_bus_perf" will perform the latter behavior.
By default, the latter behavior is used.
NOTE: due to the location of the enablement, each arch will need to add
calls to this function. This patch only enables x86.
This patch includes a number of changes recommended by Benjamin
Herrenschmidt.
Tested-by: Jordan_Hargrave@dell.com
Signed-off-by: Jon Mason <mason@myri.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
The following patch sets the MaxPayload setting to match the parent
reading when inserting a PCIE card into a hotplug slot. On our system,
the upstream bridge is set to 256, but when inserting a card, the card
setting defaults to 128. As soon as I/O is performed to the card it
starts receiving errors since the payload size is too small.
Reviewed-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Jordan Hargrave <jordan_hargrave@dell.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Change for PCI hotplug to use pci_is_pcie() instead of checking
pci_dev->is_pcie.
Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Use pci_pcie_cap() instead of pci_find_capability() to get PCIe capability
offset in PCI hotplug core. This avoids unnecessary search in PCI
configuration space.
Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
This patch adds a new pci_configure_slot() function that programs the
PCI bus characteristics for a newly-added device. This is based on
code in pciehp_pci.c, but should be generic enough to be used by pciehp,
shpchp, and acpiphp.
The hotplug_params struct and the program_hpp_typeX() functions are based
on the ACPI definitions, but they aren't really ACPI-specific, and there's
no alternate implementation, so I don't see the need to abstract them yet.
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Reviewed-by: Alex Chiang <achiang@hp.com>
Reviewed-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Acked-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Bjorn Helgaas