[PATCH] genirq: msi: simplify the msi irq limit policy

Currently we attempt to predict how many irqs we will be able to allocate with
msi using pci_vector_resources and some complicated accounting, and then we
only allow each device as many irqs as we think are available on average.

Only the s2io driver even takes advantage of this feature all other drivers
have a fixed number of irqs they need and bail if they can't get them.

pci_vector_resources is inaccurate if anyone ever frees an irq.  The whole
implmentation is racy.  The current irq limit policy does not appear to make
sense with current drivers.  So I have simplified things.  We can revisit this
we we need a more sophisticated policy.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Rajesh Shah <rajesh.shah@intel.com>
Cc: Andi Kleen <ak@muc.de>
Cc: "Protasevich, Natalie" <Natalie.Protasevich@UNISYS.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

2 files changed, 0 insertions, 39 deletions

diff --git a/arch/i386/pci/irq.c b/arch/i386/pci/irq.c
index 4a8995c9c762..960f364cab6b 100644
--- a/arch/i386/pci/irq.c
+++ b/arch/i386/pci/irq.c
@@ -1169,33 +1169,3 @@ static int pirq_enable_irq(struct pci_dev *dev)
         }
         return 0;
 }
-
-int pci_vector_resources(int last, int nr_released)
-{
-        int count = nr_released;
-
-        int next = last;
-        int offset = (last % 8);
-
-        while (next < FIRST_SYSTEM_VECTOR) {
-                next += 8;
-#ifdef CONFIG_X86_64
-                if (next == IA32_SYSCALL_VECTOR)
-                        continue;
-#else
-                if (next == SYSCALL_VECTOR)
-                        continue;
-#endif
-                count++;
-                if (next >= FIRST_SYSTEM_VECTOR) {
-                        if (offset%8) {
-                                next = FIRST_DEVICE_VECTOR + offset;
-                                offset++;
-                                continue;
-                        }
-                        count--;
-                }
-        }
-
-        return count;
-}
diff --git a/arch/ia64/pci/pci.c b/arch/ia64/pci/pci.c
index 15c7c670da39..b30be7c48ba8 100644
--- a/arch/ia64/pci/pci.c
+++ b/arch/ia64/pci/pci.c
@@ -810,12 +810,3 @@ pcibios_prep_mwi (struct pci_dev *dev)
         }
         return rc;
 }
-
-int pci_vector_resources(int last, int nr_released)
-{
-        int count = nr_released;
-
-        count += (IA64_LAST_DEVICE_VECTOR - last);
-
-        return count;
-}