[PATCH] ohci-hcd, paranoia

In a test where some memory corruption happened, I noticed an
oops (null pointer exception in_irq) that's avoidable.  Here's
a patch that avoids it ... anyone seeing the err() is likely
to hang some process, but that's better than the alternative.
(Also inlines some used-once routines, saving a bit of space
to make up for the new diagnostic.)

drivers/usb/host/ohci-mem.c

@@ -48,10 +48,10 @@ dma_to_ed_td (struct hash_list_t * entry, dma_addr_t dma)
 	struct hash_t * scan = entry->head;
 	while (scan && scan->dma != dma)
 		scan = scan->next;
-	return scan->virt;
+	return scan ? scan->virt : 0;
 }
 
-static struct td *
+static inline struct td *
 dma_to_td (struct ohci_hcd *hc, dma_addr_t td_dma)
 {
 	td_dma &= TD_MASK;
@@ -62,7 +62,7 @@ dma_to_td (struct ohci_hcd *hc, dma_addr_t td_dma)
 // FIXME:  when updating the hashtables this way, mem_flags is unusable...
 
 /* Add a hash entry for a TD/ED; return true on success */
-static int
+static inline int
 hash_add_ed_td (
 	struct hash_list_t *entry,
 	void *virt,
@@ -97,7 +97,7 @@ hash_add_td (struct ohci_hcd *hc, struct td *td, int mem_flags)
 }
 
 
-static void
+static inline void
 hash_free_ed_td (struct hash_list_t *entry, void *virt)
 {
 	struct hash_t *scan, *prev;

drivers/usb/host/ohci-q.c

@@ -854,6 +854,11 @@ static struct td *dl_reverse_done_list (struct ohci_hcd *ohci)
 	    	int		cc;
 
 		td = dma_to_td (ohci, td_dma);
+		if (!td) {
+			err ("%s bad entry %8x",
+				ohci->hcd.self.bus_name, td_dma);
+			break;
+		}
 
 		td->hwINFO |= cpu_to_le32 (TD_DONE);
 		cc = TD_CC_GET (le32_to_cpup (&td->hwINFO));