* Protected by kmmio_lock, when linked into kmmio_page_table.
*/
int count;
+
+ bool scheduled_for_release;
};
struct kmmio_delayed_release {
BUG_ON(f->count < 0);
if (!f->count) {
disarm_kmmio_fault_page(f);
- f->release_next = *release_list;
- *release_list = f;
+ if (!f->scheduled_for_release) {
+ f->release_next = *release_list;
+ *release_list = f;
+ f->scheduled_for_release = true;
+ }
}
}
prevp = &f->release_next;
} else {
*prevp = f->release_next;
+ f->release_next = NULL;
+ f->scheduled_for_release = false;
}
- f = f->release_next;
+ f = *prevp;
}
spin_unlock_irqrestore(&kmmio_lock, flags);
kmmio_count--;
spin_unlock_irqrestore(&kmmio_lock, flags);
+ if (!release_list)
+ return;
+
drelease = kmalloc(sizeof(*drelease), GFP_ATOMIC);
if (!drelease) {
pr_crit("leaking kmmio_fault_page objects.\n");
iounmap(p);
}
+/*
+ * Tests how mmiotrace behaves in face of multiple ioremap / iounmaps in
+ * a short time. We had a bug in deferred freeing procedure which tried
+ * to free this region multiple times (ioremap can reuse the same address
+ * for many mappings).
+ */
+static void do_test_bulk_ioremapping(void)
+{
+ void __iomem *p;
+ int i;
+
+ for (i = 0; i < 10; ++i) {
+ p = ioremap_nocache(mmio_address, PAGE_SIZE);
+ if (p)
+ iounmap(p);
+ }
+
+ /* Force freeing. If it will crash we will know why. */
+ synchronize_rcu();
+}
+
static int __init init(void)
{
unsigned long size = (read_far) ? (8 << 20) : (16 << 10);
"and writing 16 kB of rubbish in there.\n",
size >> 10, mmio_address);
do_test(size);
+ do_test_bulk_ioremapping();
pr_info("All done.\n");
return 0;
}