Use __get_free_pages() for emergency objects

The __get_free_pages() function must be used in place of kmalloc()
to ensure the __GFP_COMP is strictly honored.  This is due to
kmalloc() being layered on the generic Linux slab caches.  It
wasn't until recently that all caches were created using __GFP_COMP.
This means that it is possible for a kmalloc() which passed the
__GFP_COMP flag to be returned a non-compound allocation.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>

diff --git a/include/sys/kmem_cache.h b/include/sys/kmem_cache.h
index 9ac41e6ec08e070361f51f5ae6fb9571117b486c..75a0a55b7d1f18bf6a8870b1a5b17f4a98df405a 100644 (file)
--- a/include/sys/kmem_cache.h
+++ b/include/sys/kmem_cache.h
@@ -163,7 +163,7 @@ typedef struct spl_kmem_alloc {
 
 typedef struct spl_kmem_emergency {
        struct rb_node          ske_node;       /* Emergency tree linkage */
-       void                    *ske_obj;       /* Buffer address */
+       unsigned long           ske_obj;        /* Buffer address */
 } spl_kmem_emergency_t;
 
 typedef struct spl_kmem_cache {

diff --git a/module/spl/spl-kmem-cache.c b/module/spl/spl-kmem-cache.c
index 38fee703db218df5b22106d429b21660eb3ea07d..6fcc7c4e1b6179b4256fc15465bce1da49491359 100644 (file)
--- a/module/spl/spl-kmem-cache.c
+++ b/module/spl/spl-kmem-cache.c
@@ -459,9 +459,9 @@ spl_emergency_search(struct rb_root *root, void *obj)
        while (node) {
                ske = container_of(node, spl_kmem_emergency_t, ske_node);
 
-               if (address < (unsigned long)ske->ske_obj)
+               if (address < ske->ske_obj)
                        node = node->rb_left;
-               else if (address > (unsigned long)ske->ske_obj)
+               else if (address > ske->ske_obj)
                        node = node->rb_right;
                else
                        return (ske);
@@ -475,15 +475,15 @@ spl_emergency_insert(struct rb_root *root, spl_kmem_emergency_t *ske)
 {
        struct rb_node **new = &(root->rb_node), *parent = NULL;
        spl_kmem_emergency_t *ske_tmp;
-       unsigned long address = (unsigned long)ske->ske_obj;
+       unsigned long address = ske->ske_obj;
 
        while (*new) {
                ske_tmp = container_of(*new, spl_kmem_emergency_t, ske_node);
 
                parent = *new;
-               if (address < (unsigned long)ske_tmp->ske_obj)
+               if (address < ske_tmp->ske_obj)
                        new = &((*new)->rb_left);
-               else if (address > (unsigned long)ske_tmp->ske_obj)
+               else if (address > ske_tmp->ske_obj)
                        new = &((*new)->rb_right);
                else
                        return (0);
@@ -503,6 +503,7 @@ spl_emergency_alloc(spl_kmem_cache_t *skc, int flags, void **obj)
 {
        gfp_t lflags = kmem_flags_convert(flags);
        spl_kmem_emergency_t *ske;
+       int order = get_order(skc->skc_obj_size);
        int empty;
 
        /* Last chance use a partial slab if one now exists */
@@ -516,8 +517,8 @@ spl_emergency_alloc(spl_kmem_cache_t *skc, int flags, void **obj)
        if (ske == NULL)
                return (-ENOMEM);
 
-       ske->ske_obj = kmalloc(skc->skc_obj_size, lflags);
-       if (ske->ske_obj == NULL) {
+       ske->ske_obj = __get_free_pages(lflags, order);
+       if (ske->ske_obj == 0) {
                kfree(ske);
                return (-ENOMEM);
        }
@@ -533,12 +534,12 @@ spl_emergency_alloc(spl_kmem_cache_t *skc, int flags, void **obj)
        spin_unlock(&skc->skc_lock);
 
        if (unlikely(!empty)) {
-               kfree(ske->ske_obj);
+               free_pages(ske->ske_obj, order);
                kfree(ske);
                return (-EINVAL);
        }
 
-       *obj = ske->ske_obj;
+       *obj = (void *)ske->ske_obj;
 
        return (0);
 }
@@ -550,6 +551,7 @@ static int
 spl_emergency_free(spl_kmem_cache_t *skc, void *obj)
 {
        spl_kmem_emergency_t *ske;
+       int order = get_order(skc->skc_obj_size);
 
        spin_lock(&skc->skc_lock);
        ske = spl_emergency_search(&skc->skc_emergency_tree, obj);
@@ -563,7 +565,7 @@ spl_emergency_free(spl_kmem_cache_t *skc, void *obj)
        if (ske == NULL)
                return (-ENOENT);
 
-       kfree(ske->ske_obj);
+       free_pages(ske->ske_obj, order);
        kfree(ske);
 
        return (0);