9 files changed, 465 insertions, 42 deletions

diff --git a/lib/Kconfig b/lib/Kconfig
index 0ee67e08ad3e..3a55a43c43eb 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -201,6 +201,10 @@ config DISABLE_OBSOLETE_CPUMASK_FUNCTIONS
        bool "Disable obsolete cpumask functions" if DEBUG_PER_CPU_MAPS
        depends on EXPERIMENTAL && BROKEN
 
+config CPU_RMAP
+        bool
+        depends on SMP
+
 #
 # Netlink attribute parsing support is select'ed if needed
 #
@@ -217,6 +221,13 @@ config LRU_CACHE
         tristate
 
 config AVERAGE
-        bool
+        bool "Averaging functions"
+        help
+          This option is provided for the case where no in-kernel-tree
+          modules require averaging functions, but a module built outside
+          the kernel tree does. Such modules that use library averaging
+          functions require Y here.
+
+          If unsure, say N.
 
 endmenu
diff --git a/lib/Makefile b/lib/Makefile
index de6c609bb4e4..ef7ed71a6ffd 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -109,6 +109,8 @@ obj-$(CONFIG_ATOMIC64_SELFTEST) += atomic64_test.o
 
 obj-$(CONFIG_AVERAGE) += average.o
 
+obj-$(CONFIG_CPU_RMAP) += cpu_rmap.o
+
 hostprogs-y     := gen_crc32table
 clean-files     := crc32table.h
 
diff --git a/lib/cpu_rmap.c b/lib/cpu_rmap.c
new file mode 100644
index 000000000000..987acfafeb83
--- /dev/null
+++ b/lib/cpu_rmap.c
@@ -0,0 +1,269 @@
+/*
+ * cpu_rmap.c: CPU affinity reverse-map support
+ * Copyright 2011 Solarflare Communications Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation, incorporated herein by reference.
+ */
+
+#include <linux/cpu_rmap.h>
+#ifdef CONFIG_GENERIC_HARDIRQS
+#include <linux/interrupt.h>
+#endif
+#include <linux/module.h>
+
+/*
+ * These functions maintain a mapping from CPUs to some ordered set of
+ * objects with CPU affinities.  This can be seen as a reverse-map of
+ * CPU affinity.  However, we do not assume that the object affinities
+ * cover all CPUs in the system.  For those CPUs not directly covered
+ * by object affinities, we attempt to find a nearest object based on
+ * CPU topology.
+ */
+
+/**
+ * alloc_cpu_rmap - allocate CPU affinity reverse-map
+ * @size: Number of objects to be mapped
+ * @flags: Allocation flags e.g. %GFP_KERNEL
+ */
+struct cpu_rmap *alloc_cpu_rmap(unsigned int size, gfp_t flags)
+{
+        struct cpu_rmap *rmap;
+        unsigned int cpu;
+        size_t obj_offset;
+
+        /* This is a silly number of objects, and we use u16 indices. */
+        if (size > 0xffff)
+                return NULL;
+
+        /* Offset of object pointer array from base structure */
+        obj_offset = ALIGN(offsetof(struct cpu_rmap, near[nr_cpu_ids]),
+                           sizeof(void *));
+
+        rmap = kzalloc(obj_offset + size * sizeof(rmap->obj[0]), flags);
+        if (!rmap)
+                return NULL;
+
+        rmap->obj = (void **)((char *)rmap + obj_offset);
+
+        /* Initially assign CPUs to objects on a rota, since we have
+         * no idea where the objects are.  Use infinite distance, so
+         * any object with known distance is preferable.  Include the
+         * CPUs that are not present/online, since we definitely want
+         * any newly-hotplugged CPUs to have some object assigned.
+         */
+        for_each_possible_cpu(cpu) {
+                rmap->near[cpu].index = cpu % size;
+                rmap->near[cpu].dist = CPU_RMAP_DIST_INF;
+        }
+
+        rmap->size = size;
+        return rmap;
+}
+EXPORT_SYMBOL(alloc_cpu_rmap);
+
+/* Reevaluate nearest object for given CPU, comparing with the given
+ * neighbours at the given distance.
+ */
+static bool cpu_rmap_copy_neigh(struct cpu_rmap *rmap, unsigned int cpu,
+                                const struct cpumask *mask, u16 dist)
+{
+        int neigh;
+
+        for_each_cpu(neigh, mask) {
+                if (rmap->near[cpu].dist > dist &&
+                    rmap->near[neigh].dist <= dist) {
+                        rmap->near[cpu].index = rmap->near[neigh].index;
+                        rmap->near[cpu].dist = dist;
+                        return true;
+                }
+        }
+        return false;
+}
+
+#ifdef DEBUG
+static void debug_print_rmap(const struct cpu_rmap *rmap, const char *prefix)
+{
+        unsigned index;
+        unsigned int cpu;
+
+        pr_info("cpu_rmap %p, %s:\n", rmap, prefix);
+
+        for_each_possible_cpu(cpu) {
+                index = rmap->near[cpu].index;
+                pr_info("cpu %d -> obj %u (distance %u)\n",
+                        cpu, index, rmap->near[cpu].dist);
+        }
+}
+#else
+static inline void
+debug_print_rmap(const struct cpu_rmap *rmap, const char *prefix)
+{
+}
+#endif
+
+/**
+ * cpu_rmap_add - add object to a rmap
+ * @rmap: CPU rmap allocated with alloc_cpu_rmap()
+ * @obj: Object to add to rmap
+ *
+ * Return index of object.
+ */
+int cpu_rmap_add(struct cpu_rmap *rmap, void *obj)
+{
+        u16 index;
+
+        BUG_ON(rmap->used >= rmap->size);
+        index = rmap->used++;
+        rmap->obj[index] = obj;
+        return index;
+}
+EXPORT_SYMBOL(cpu_rmap_add);
+
+/**
+ * cpu_rmap_update - update CPU rmap following a change of object affinity
+ * @rmap: CPU rmap to update
+ * @index: Index of object whose affinity changed
+ * @affinity: New CPU affinity of object
+ */
+int cpu_rmap_update(struct cpu_rmap *rmap, u16 index,
+                    const struct cpumask *affinity)
+{
+        cpumask_var_t update_mask;
+        unsigned int cpu;
+
+        if (unlikely(!zalloc_cpumask_var(&update_mask, GFP_KERNEL)))
+                return -ENOMEM;
+
+        /* Invalidate distance for all CPUs for which this used to be
+         * the nearest object.  Mark those CPUs for update.
+         */
+        for_each_online_cpu(cpu) {
+                if (rmap->near[cpu].index == index) {
+                        rmap->near[cpu].dist = CPU_RMAP_DIST_INF;
+                        cpumask_set_cpu(cpu, update_mask);
+                }
+        }
+
+        debug_print_rmap(rmap, "after invalidating old distances");
+
+        /* Set distance to 0 for all CPUs in the new affinity mask.
+         * Mark all CPUs within their NUMA nodes for update.
+         */
+        for_each_cpu(cpu, affinity) {
+                rmap->near[cpu].index = index;
+                rmap->near[cpu].dist = 0;
+                cpumask_or(update_mask, update_mask,
+                           cpumask_of_node(cpu_to_node(cpu)));
+        }
+
+        debug_print_rmap(rmap, "after updating neighbours");
+
+        /* Update distances based on topology */
+        for_each_cpu(cpu, update_mask) {
+                if (cpu_rmap_copy_neigh(rmap, cpu,
+                                        topology_thread_cpumask(cpu), 1))
+                        continue;
+                if (cpu_rmap_copy_neigh(rmap, cpu,
+                                        topology_core_cpumask(cpu), 2))
+                        continue;
+                if (cpu_rmap_copy_neigh(rmap, cpu,
+                                        cpumask_of_node(cpu_to_node(cpu)), 3))
+                        continue;
+                /* We could continue into NUMA node distances, but for now
+                 * we give up.
+                 */
+        }
+
+        debug_print_rmap(rmap, "after copying neighbours");
+
+        free_cpumask_var(update_mask);
+        return 0;
+}
+EXPORT_SYMBOL(cpu_rmap_update);
+
+#ifdef CONFIG_GENERIC_HARDIRQS
+
+/* Glue between IRQ affinity notifiers and CPU rmaps */
+
+struct irq_glue {
+        struct irq_affinity_notify notify;
+        struct cpu_rmap *rmap;
+        u16 index;
+};
+
+/**
+ * free_irq_cpu_rmap - free a CPU affinity reverse-map used for IRQs
+ * @rmap: Reverse-map allocated with alloc_irq_cpu_map(), or %NULL
+ *
+ * Must be called in process context, before freeing the IRQs, and
+ * without holding any locks required by global workqueue items.
+ */
+void free_irq_cpu_rmap(struct cpu_rmap *rmap)
+{
+        struct irq_glue *glue;
+        u16 index;
+
+        if (!rmap)
+                return;
+
+        for (index = 0; index < rmap->used; index++) {
+                glue = rmap->obj[index];
+                irq_set_affinity_notifier(glue->notify.irq, NULL);
+        }
+        irq_run_affinity_notifiers();
+
+        kfree(rmap);
+}
+EXPORT_SYMBOL(free_irq_cpu_rmap);
+
+static void
+irq_cpu_rmap_notify(struct irq_affinity_notify *notify, const cpumask_t *mask)
+{
+        struct irq_glue *glue =
+                container_of(notify, struct irq_glue, notify);
+        int rc;
+
+        rc = cpu_rmap_update(glue->rmap, glue->index, mask);
+        if (rc)
+                pr_warning("irq_cpu_rmap_notify: update failed: %d\n", rc);
+}
+
+static void irq_cpu_rmap_release(struct kref *ref)
+{
+        struct irq_glue *glue =
+                container_of(ref, struct irq_glue, notify.kref);
+        kfree(glue);
+}
+
+/**
+ * irq_cpu_rmap_add - add an IRQ to a CPU affinity reverse-map
+ * @rmap: The reverse-map
+ * @irq: The IRQ number
+ *
+ * This adds an IRQ affinity notifier that will update the reverse-map
+ * automatically.
+ *
+ * Must be called in process context, after the IRQ is allocated but
+ * before it is bound with request_irq().
+ */
+int irq_cpu_rmap_add(struct cpu_rmap *rmap, int irq)
+{
+        struct irq_glue *glue = kzalloc(sizeof(*glue), GFP_KERNEL);
+        int rc;
+
+        if (!glue)
+                return -ENOMEM;
+        glue->notify.notify = irq_cpu_rmap_notify;
+        glue->notify.release = irq_cpu_rmap_release;
+        glue->rmap = rmap;
+        glue->index = cpu_rmap_add(rmap, glue);
+        rc = irq_set_affinity_notifier(irq, &glue->notify);
+        if (rc)
+                kfree(glue);
+        return rc;
+}
+EXPORT_SYMBOL(irq_cpu_rmap_add);
+
+#endif /* CONFIG_GENERIC_HARDIRQS */
diff --git a/lib/debugobjects.c b/lib/debugobjects.c
index deebcc57d4e6..9d86e45086f5 100644
--- a/lib/debugobjects.c
+++ b/lib/debugobjects.c
@@ -249,14 +249,17 @@ static struct debug_bucket *get_bucket(unsigned long addr)
 
 static void debug_print_object(struct debug_obj *obj, char *msg)
 {
+        struct debug_obj_descr *descr = obj->descr;
         static int limit;
 
-        if (limit < 5 && obj->descr != descr_test) {
+        if (limit < 5 && descr != descr_test) {
+                void *hint = descr->debug_hint ?
+                        descr->debug_hint(obj->object) : NULL;
                 limit++;
                 WARN(1, KERN_ERR "ODEBUG: %s %s (active state %u) "
-                                 "object type: %s\n",
+                                 "object type: %s hint: %pS\n",
                         msg, obj_states[obj->state], obj->astate,
-                        obj->descr->name);
+                        descr->name, hint);
         }
         debug_objects_warnings++;
 }
diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index b335acb43be2..75ca78f3a8c9 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -7,6 +7,7 @@
  * Copyright (C) 2008 Jason Baron <jbaron@redhat.com>
  * By Greg Banks <gnb@melbourne.sgi.com>
  * Copyright (c) 2008 Silicon Graphics Inc.  All Rights Reserved.
+ * Copyright (C) 2011 Bart Van Assche.  All Rights Reserved.
  */
 
 #include <linux/kernel.h>
@@ -27,6 +28,8 @@
 #include <linux/debugfs.h>
 #include <linux/slab.h>
 #include <linux/jump_label.h>
+#include <linux/hardirq.h>
+#include <linux/sched.h>
 
 extern struct _ddebug __start___verbose[];
 extern struct _ddebug __stop___verbose[];
@@ -63,15 +66,25 @@ static inline const char *basename(const char *path)
         return tail ? tail+1 : path;
 }
 
+static struct { unsigned flag:8; char opt_char; } opt_array[] = {
+        { _DPRINTK_FLAGS_PRINT, 'p' },
+        { _DPRINTK_FLAGS_INCL_MODNAME, 'm' },
+        { _DPRINTK_FLAGS_INCL_FUNCNAME, 'f' },
+        { _DPRINTK_FLAGS_INCL_LINENO, 'l' },
+        { _DPRINTK_FLAGS_INCL_TID, 't' },
+};
+
 /* format a string into buf[] which describes the _ddebug's flags */
 static char *ddebug_describe_flags(struct _ddebug *dp, char *buf,
                                     size_t maxlen)
 {
         char *p = buf;
+        int i;
 
         BUG_ON(maxlen < 4);
-        if (dp->flags & _DPRINTK_FLAGS_PRINT)
-                *p++ = 'p';
+        for (i = 0; i < ARRAY_SIZE(opt_array); ++i)
+                if (dp->flags & opt_array[i].flag)
+                        *p++ = opt_array[i].opt_char;
         if (p == buf)
                 *p++ = '-';
         *p = '\0';
@@ -343,7 +356,7 @@ static int ddebug_parse_flags(const char *str, unsigned int *flagsp,
                                unsigned int *maskp)
 {
         unsigned flags = 0;
-        int op = '=';
+        int op = '=', i;
 
         switch (*str) {
         case '+':
@@ -358,13 +371,14 @@ static int ddebug_parse_flags(const char *str, unsigned int *flagsp,
                 printk(KERN_INFO "%s: op='%c'\n", __func__, op);
 
         for ( ; *str ; ++str) {
-                switch (*str) {
-                case 'p':
-                        flags |= _DPRINTK_FLAGS_PRINT;
-                        break;
-                default:
-                        return -EINVAL;
+                for (i = ARRAY_SIZE(opt_array) - 1; i >= 0; i--) {
+                        if (*str == opt_array[i].opt_char) {
+                                flags |= opt_array[i].flag;
+                                break;
+                        }
                 }
+                if (i < 0)
+                        return -EINVAL;
         }
         if (flags == 0)
                 return -EINVAL;
@@ -413,6 +427,35 @@ static int ddebug_exec_query(char *query_string)
         return 0;
 }
 
+int __dynamic_pr_debug(struct _ddebug *descriptor, const char *fmt, ...)
+{
+        va_list args;
+        int res;
+
+        BUG_ON(!descriptor);
+        BUG_ON(!fmt);
+
+        va_start(args, fmt);
+        res = printk(KERN_DEBUG);
+        if (descriptor->flags & _DPRINTK_FLAGS_INCL_TID) {
+                if (in_interrupt())
+                        res += printk(KERN_CONT "<intr> ");
+                else
+                        res += printk(KERN_CONT "[%d] ", task_pid_vnr(current));
+        }
+        if (descriptor->flags & _DPRINTK_FLAGS_INCL_MODNAME)
+                res += printk(KERN_CONT "%s:", descriptor->modname);
+        if (descriptor->flags & _DPRINTK_FLAGS_INCL_FUNCNAME)
+                res += printk(KERN_CONT "%s:", descriptor->function);
+        if (descriptor->flags & _DPRINTK_FLAGS_INCL_LINENO)
+                res += printk(KERN_CONT "%d ", descriptor->lineno);
+        res += vprintk(fmt, args);
+        va_end(args);
+
+        return res;
+}
+EXPORT_SYMBOL(__dynamic_pr_debug);
+
 static __initdata char ddebug_setup_string[1024];
 static __init int ddebug_setup_query(char *str)
 {
diff --git a/lib/nlattr.c b/lib/nlattr.c
index 5021cbc34411..ac09f2226dc7 100644
--- a/lib/nlattr.c
+++ b/lib/nlattr.c
@@ -148,7 +148,7 @@ nla_policy_len(const struct nla_policy *p, int n)
 {
         int i, len = 0;
 
-        for (i = 0; i < n; i++) {
+        for (i = 0; i < n; i++, p++) {
                 if (p->len)
                         len += nla_total_size(p->len);
                 else if (nla_attr_minlen[p->type])
diff --git a/lib/plist.c b/lib/plist.c
index 1471988d9190..0ae7e6431726 100644
--- a/lib/plist.c
+++ b/lib/plist.c
@@ -28,6 +28,8 @@
 
 #ifdef CONFIG_DEBUG_PI_LIST
 
+static struct plist_head test_head;
+
 static void plist_check_prev_next(struct list_head *t, struct list_head *p,
                                   struct list_head *n)
 {
@@ -54,12 +56,13 @@ static void plist_check_list(struct list_head *top)
 
 static void plist_check_head(struct plist_head *head)
 {
-        WARN_ON(!head->rawlock && !head->spinlock);
+        WARN_ON(head != &test_head && !head->rawlock && !head->spinlock);
         if (head->rawlock)
                 WARN_ON_SMP(!raw_spin_is_locked(head->rawlock));
         if (head->spinlock)
                 WARN_ON_SMP(!spin_is_locked(head->spinlock));
-        plist_check_list(&head->prio_list);
+        if (!plist_head_empty(head))
+                plist_check_list(&plist_first(head)->prio_list);
         plist_check_list(&head->node_list);
 }
 
@@ -75,25 +78,33 @@ static void plist_check_head(struct plist_head *head)
  */
 void plist_add(struct plist_node *node, struct plist_head *head)
 {
-        struct plist_node *iter;
+        struct plist_node *first, *iter, *prev = NULL;
+        struct list_head *node_next = &head->node_list;
 
         plist_check_head(head);
         WARN_ON(!plist_node_empty(node));
+        WARN_ON(!list_empty(&node->prio_list));
+
+        if (plist_head_empty(head))
+                goto ins_node;
 
-        list_for_each_entry(iter, &head->prio_list, plist.prio_list) {
-                if (node->prio < iter->prio)
-                        goto lt_prio;
-                else if (node->prio == iter->prio) {
-                        iter = list_entry(iter->plist.prio_list.next,
-                                        struct plist_node, plist.prio_list);
-                        goto eq_prio;
+        first = iter = plist_first(head);
+
+        do {
+                if (node->prio < iter->prio) {
+                        node_next = &iter->node_list;
+                        break;
                 }
-        }
 
-lt_prio:
-        list_add_tail(&node->plist.prio_list, &iter->plist.prio_list);
-eq_prio:
-        list_add_tail(&node->plist.node_list, &iter->plist.node_list);
+                prev = iter;
+                iter = list_entry(iter->prio_list.next,
+                                struct plist_node, prio_list);
+        } while (iter != first);
+
+        if (!prev || prev->prio != node->prio)
+                list_add_tail(&node->prio_list, &iter->prio_list);
+ins_node:
+        list_add_tail(&node->node_list, node_next);
 
         plist_check_head(head);
 }
@@ -108,14 +119,98 @@ void plist_del(struct plist_node *node, struct plist_head *head)
 {
         plist_check_head(head);
 
-        if (!list_empty(&node->plist.prio_list)) {
-                struct plist_node *next = plist_first(&node->plist);
+        if (!list_empty(&node->prio_list)) {
+                if (node->node_list.next != &head->node_list) {
+                        struct plist_node *next;
+
+                        next = list_entry(node->node_list.next,
+                                        struct plist_node, node_list);
 
-                list_move_tail(&next->plist.prio_list, &node->plist.prio_list);
-                list_del_init(&node->plist.prio_list);
+                        /* add the next plist_node into prio_list */
+                        if (list_empty(&next->prio_list))
+                                list_add(&next->prio_list, &node->prio_list);
+                }
+                list_del_init(&node->prio_list);
         }
 
-        list_del_init(&node->plist.node_list);
+        list_del_init(&node->node_list);
 
         plist_check_head(head);
 }
+
+#ifdef CONFIG_DEBUG_PI_LIST
+#include <linux/sched.h>
+#include <linux/module.h>
+#include <linux/init.h>
+
+static struct plist_node __initdata test_node[241];
+
+static void __init plist_test_check(int nr_expect)
+{
+        struct plist_node *first, *prio_pos, *node_pos;
+
+        if (plist_head_empty(&test_head)) {
+                BUG_ON(nr_expect != 0);
+                return;
+        }
+
+        prio_pos = first = plist_first(&test_head);
+        plist_for_each(node_pos, &test_head) {
+                if (nr_expect-- < 0)
+                        break;
+                if (node_pos == first)
+                        continue;
+                if (node_pos->prio == prio_pos->prio) {
+                        BUG_ON(!list_empty(&node_pos->prio_list));
+                        continue;
+                }
+
+                BUG_ON(prio_pos->prio > node_pos->prio);
+                BUG_ON(prio_pos->prio_list.next != &node_pos->prio_list);
+                prio_pos = node_pos;
+        }
+
+        BUG_ON(nr_expect != 0);
+        BUG_ON(prio_pos->prio_list.next != &first->prio_list);
+}
+
+static int  __init plist_test(void)
+{
+        int nr_expect = 0, i, loop;
+        unsigned int r = local_clock();
+
+        printk(KERN_INFO "start plist test\n");
+        plist_head_init(&test_head, NULL);
+        for (i = 0; i < ARRAY_SIZE(test_node); i++)
+                plist_node_init(test_node + i, 0);
+
+        for (loop = 0; loop < 1000; loop++) {
+                r = r * 193939 % 47629;
+                i = r % ARRAY_SIZE(test_node);
+                if (plist_node_empty(test_node + i)) {
+                        r = r * 193939 % 47629;
+                        test_node[i].prio = r % 99;
+                        plist_add(test_node + i, &test_head);
+                        nr_expect++;
+                } else {
+                        plist_del(test_node + i, &test_head);
+                        nr_expect--;
+                }
+                plist_test_check(nr_expect);
+        }
+
+        for (i = 0; i < ARRAY_SIZE(test_node); i++) {
+                if (plist_node_empty(test_node + i))
+                        continue;
+                plist_del(test_node + i, &test_head);
+                nr_expect--;
+                plist_test_check(nr_expect);
+        }
+
+        printk(KERN_INFO "end plist test\n");
+        return 0;
+}
+
+module_init(plist_test);
+
+#endif
diff --git a/lib/rwsem.c b/lib/rwsem.c
index f236d7cd5cf3..aa7c3052261f 100644
--- a/lib/rwsem.c
+++ b/lib/rwsem.c
@@ -222,8 +222,7 @@ rwsem_down_failed_common(struct rw_semaphore *sem,
 /*
  * wait for the read lock to be granted
  */
-asmregparm struct rw_semaphore __sched *
-rwsem_down_read_failed(struct rw_semaphore *sem)
+struct rw_semaphore __sched *rwsem_down_read_failed(struct rw_semaphore *sem)
 {
         return rwsem_down_failed_common(sem, RWSEM_WAITING_FOR_READ,
                                         -RWSEM_ACTIVE_READ_BIAS);
@@ -232,8 +231,7 @@ rwsem_down_read_failed(struct rw_semaphore *sem)
 /*
  * wait for the write lock to be granted
  */
-asmregparm struct rw_semaphore __sched *
-rwsem_down_write_failed(struct rw_semaphore *sem)
+struct rw_semaphore __sched *rwsem_down_write_failed(struct rw_semaphore *sem)
 {
         return rwsem_down_failed_common(sem, RWSEM_WAITING_FOR_WRITE,
                                         -RWSEM_ACTIVE_WRITE_BIAS);
@@ -243,7 +241,7 @@ rwsem_down_write_failed(struct rw_semaphore *sem)
  * handle waking up a waiter on the semaphore
  * - up_read/up_write has decremented the active part of count if we come here
  */
-asmregparm struct rw_semaphore *rwsem_wake(struct rw_semaphore *sem)
+struct rw_semaphore *rwsem_wake(struct rw_semaphore *sem)
 {
         unsigned long flags;
 
@@ -263,7 +261,7 @@ asmregparm struct rw_semaphore *rwsem_wake(struct rw_semaphore *sem)
  * - caller incremented waiting part of count and discovered it still negative
  * - just wake up any readers at the front of the queue
  */
-asmregparm struct rw_semaphore *rwsem_downgrade_wake(struct rw_semaphore *sem)
+struct rw_semaphore *rwsem_downgrade_wake(struct rw_semaphore *sem)
 {
         unsigned long flags;
 
diff --git a/lib/swiotlb.c b/lib/swiotlb.c
index c47bbe11b804..93ca08b8a451 100644
--- a/lib/swiotlb.c
+++ b/lib/swiotlb.c
@@ -686,8 +686,10 @@ dma_addr_t swiotlb_map_page(struct device *dev, struct page *page,
         /*
          * Ensure that the address returned is DMA'ble
          */
-        if (!dma_capable(dev, dev_addr, size))
-                panic("map_single: bounce buffer is not DMA'ble");
+        if (!dma_capable(dev, dev_addr, size)) {
+                swiotlb_tbl_unmap_single(dev, map, size, dir);
+                dev_addr = swiotlb_virt_to_bus(dev, io_tlb_overflow_buffer);
+        }
 
         return dev_addr;
 }