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[2/4] PCI: Skip allocate_resource() if too little space available

Message ID 20221202211838.1061278-3-helgaas@kernel.org
State New
Headers show
Series PCI: Continue E820 vs host bridge window saga | expand

Commit Message

Bjorn Helgaas Dec. 2, 2022, 9:18 p.m. UTC 
From: Bjorn Helgaas <bhelgaas@google.com>

pci_bus_alloc_from_region() allocates MMIO space by iterating through all
the resources available on the bus.  The available resource might be
reduced if the caller requires 32-bit space or we're avoiding BIOS or E820
areas.

Don't bother calling allocate_resource() if we need more space than is
available in this resource.  This prevents some pointless and annoying
messages about avoided areas.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Hans de Goede <hdegoede@redhat.com>
---
 drivers/pci/bus.c | 4 ++++
 1 file changed, 4 insertions(+)
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Patch

diff --git a/drivers/pci/bus.c b/drivers/pci/bus.c
index 3cef835b375f..83ae838ceb5f 100644
--- a/drivers/pci/bus.c
+++ b/drivers/pci/bus.c
@@ -197,6 +197,10 @@  static int pci_bus_alloc_from_region(struct pci_bus *bus, struct resource *res,
 
 		max = avail.end;
 
+		/* Don't bother if available space isn't large enough */
+		if (size > max - min_used + 1)
+			continue;
+
 		/* Ok, try it out.. */
 		ret = allocate_resource(r, res, size, min_used, max,
 					align, alignf, alignf_data);