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Use __get_free_pages() for emergency objects

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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>
This commit is contained in:
Brian Behlendorf 2015-01-15 15:11:45 -08:00
parent 436ad60faa
commit ee33517452
2 changed files with 13 additions and 11 deletions
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2
include/sys/kmem_cache.h
View File

@ -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 {

22
module/spl/spl-kmem-cache.c
View File

@ -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);