PCI: work_on_cpu: use in drivers/pci/pci-driver.c

This uses work_on_cpu(), rather than altering the cpumask of the
thread which we happen to be.

Note the cleanups:

1) I've removed the CONFIG_NUMA test, since dev_to_node() returns -1
   for !CONFIG_NUMA anyway and the compiler will eliminate it.

2) No need to reset mempolicy to default (a bad idea anyway) since
   work_on_cpu is run from a workqueue.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

1 files changed, 32 insertions, 20 deletions

diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
index 888191a3b0d1..c3f76be832d4 100644
--- a/drivers/pci/pci-driver.c
+++ b/drivers/pci/pci-driver.c
@@ -16,6 +16,7 @@
 #include <linux/string.h>
 #include <linux/slab.h>
 #include <linux/sched.h>
+#include <linux/cpu.h>
 #include "pci.h"
 
 /*
@@ -185,32 +186,43 @@ static const struct pci_device_id *pci_match_device(struct pci_driver *drv,
         return pci_match_id(drv->id_table, dev);
 }
 
+struct drv_dev_and_id {
+        struct pci_driver *drv;
+        struct pci_dev *dev;
+        const struct pci_device_id *id;
+};
+
+static long local_pci_probe(void *_ddi)
+{
+        struct drv_dev_and_id *ddi = _ddi;
+
+        return ddi->drv->probe(ddi->dev, ddi->id);
+}
+
 static int pci_call_probe(struct pci_driver *drv, struct pci_dev *dev,
                           const struct pci_device_id *id)
 {
-        int error;
-#ifdef CONFIG_NUMA
-        /* Execute driver initialization on node where the
-           device's bus is attached to.  This way the driver likely
-           allocates its local memory on the right node without
-           any need to change it. */
-        struct mempolicy *oldpol;
-        cpumask_t oldmask = current->cpus_allowed;
-        int node = dev_to_node(&dev->dev);
+        int error, node;
+        struct drv_dev_and_id ddi = { drv, dev, id };
 
+        /* Execute driver initialization on node where the device's
+           bus is attached to.  This way the driver likely allocates
+           its local memory on the right node without any need to
+           change it. */
+        node = dev_to_node(&dev->dev);
         if (node >= 0) {
+                int cpu;
                 node_to_cpumask_ptr(nodecpumask, node);
-                set_cpus_allowed_ptr(current, nodecpumask);
-        }
-        /* And set default memory allocation policy */
-        oldpol = current->mempolicy;
-        current->mempolicy = NULL;      /* fall back to system default policy */
-#endif
-        error = drv->probe(dev, id);
-#ifdef CONFIG_NUMA
-        set_cpus_allowed_ptr(current, &oldmask);
-        current->mempolicy = oldpol;
-#endif
+
+                get_online_cpus();
+                cpu = cpumask_any_and(nodecpumask, cpu_online_mask);
+                if (cpu < nr_cpu_ids)
+                        error = work_on_cpu(cpu, local_pci_probe, &ddi);
+                else
+                        error = local_pci_probe(&ddi);
+                put_online_cpus();
+        } else
+                error = local_pci_probe(&ddi);
         return error;
 }