*/
#include <linux/types.h>
#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/idr.h>
+#include <linux/rhashtable.h>
#include <net/xdp.h>
#define REG_STATE_UNREGISTERED 0x2
#define REG_STATE_UNUSED 0x3
+static DEFINE_IDA(mem_id_pool);
+static DEFINE_MUTEX(mem_id_lock);
+#define MEM_ID_MAX 0xFFFE
+#define MEM_ID_MIN 1
+static int mem_id_next = MEM_ID_MIN;
+
+static bool mem_id_init; /* false */
+static struct rhashtable *mem_id_ht;
+
+struct xdp_mem_allocator {
+ struct xdp_mem_info mem;
+ void *allocator;
+ struct rhash_head node;
+ struct rcu_head rcu;
+};
+
+static u32 xdp_mem_id_hashfn(const void *data, u32 len, u32 seed)
+{
+ const u32 *k = data;
+ const u32 key = *k;
+
+ BUILD_BUG_ON(FIELD_SIZEOF(struct xdp_mem_allocator, mem.id)
+ != sizeof(u32));
+
+ /* Use cyclic increasing ID as direct hash key, see rht_bucket_index */
+ return key << RHT_HASH_RESERVED_SPACE;
+}
+
+static int xdp_mem_id_cmp(struct rhashtable_compare_arg *arg,
+ const void *ptr)
+{
+ const struct xdp_mem_allocator *xa = ptr;
+ u32 mem_id = *(u32 *)arg->key;
+
+ return xa->mem.id != mem_id;
+}
+
+static const struct rhashtable_params mem_id_rht_params = {
+ .nelem_hint = 64,
+ .head_offset = offsetof(struct xdp_mem_allocator, node),
+ .key_offset = offsetof(struct xdp_mem_allocator, mem.id),
+ .key_len = FIELD_SIZEOF(struct xdp_mem_allocator, mem.id),
+ .max_size = MEM_ID_MAX,
+ .min_size = 8,
+ .automatic_shrinking = true,
+ .hashfn = xdp_mem_id_hashfn,
+ .obj_cmpfn = xdp_mem_id_cmp,
+};
+
+static void __xdp_mem_allocator_rcu_free(struct rcu_head *rcu)
+{
+ struct xdp_mem_allocator *xa;
+
+ xa = container_of(rcu, struct xdp_mem_allocator, rcu);
+
+ /* Allow this ID to be reused */
+ ida_simple_remove(&mem_id_pool, xa->mem.id);
+
+ /* TODO: Depending on allocator type/pointer free resources */
+
+ /* Poison memory */
+ xa->mem.id = 0xFFFF;
+ xa->mem.type = 0xF0F0;
+ xa->allocator = (void *)0xDEAD9001;
+
+ kfree(xa);
+}
+
+static void __xdp_rxq_info_unreg_mem_model(struct xdp_rxq_info *xdp_rxq)
+{
+ struct xdp_mem_allocator *xa;
+ int id = xdp_rxq->mem.id;
+ int err;
+
+ if (id == 0)
+ return;
+
+ mutex_lock(&mem_id_lock);
+
+ xa = rhashtable_lookup(mem_id_ht, &id, mem_id_rht_params);
+ if (!xa) {
+ mutex_unlock(&mem_id_lock);
+ return;
+ }
+
+ err = rhashtable_remove_fast(mem_id_ht, &xa->node, mem_id_rht_params);
+ WARN_ON(err);
+
+ call_rcu(&xa->rcu, __xdp_mem_allocator_rcu_free);
+
+ mutex_unlock(&mem_id_lock);
+}
+
void xdp_rxq_info_unreg(struct xdp_rxq_info *xdp_rxq)
{
/* Simplify driver cleanup code paths, allow unreg "unused" */
WARN(!(xdp_rxq->reg_state == REG_STATE_REGISTERED), "Driver BUG");
+ __xdp_rxq_info_unreg_mem_model(xdp_rxq);
+
xdp_rxq->reg_state = REG_STATE_UNREGISTERED;
xdp_rxq->dev = NULL;
+
+ /* Reset mem info to defaults */
+ xdp_rxq->mem.id = 0;
+ xdp_rxq->mem.type = 0;
}
EXPORT_SYMBOL_GPL(xdp_rxq_info_unreg);
}
EXPORT_SYMBOL_GPL(xdp_rxq_info_is_reg);
+static int __mem_id_init_hash_table(void)
+{
+ struct rhashtable *rht;
+ int ret;
+
+ if (unlikely(mem_id_init))
+ return 0;
+
+ rht = kzalloc(sizeof(*rht), GFP_KERNEL);
+ if (!rht)
+ return -ENOMEM;
+
+ ret = rhashtable_init(rht, &mem_id_rht_params);
+ if (ret < 0) {
+ kfree(rht);
+ return ret;
+ }
+ mem_id_ht = rht;
+ smp_mb(); /* mutex lock should provide enough pairing */
+ mem_id_init = true;
+
+ return 0;
+}
+
+/* Allocate a cyclic ID that maps to allocator pointer.
+ * See: https://www.kernel.org/doc/html/latest/core-api/idr.html
+ *
+ * Caller must lock mem_id_lock.
+ */
+static int __mem_id_cyclic_get(gfp_t gfp)
+{
+ int retries = 1;
+ int id;
+
+again:
+ id = ida_simple_get(&mem_id_pool, mem_id_next, MEM_ID_MAX, gfp);
+ if (id < 0) {
+ if (id == -ENOSPC) {
+ /* Cyclic allocator, reset next id */
+ if (retries--) {
+ mem_id_next = MEM_ID_MIN;
+ goto again;
+ }
+ }
+ return id; /* errno */
+ }
+ mem_id_next = id + 1;
+
+ return id;
+}
+
int xdp_rxq_info_reg_mem_model(struct xdp_rxq_info *xdp_rxq,
enum xdp_mem_type type, void *allocator)
{
+ struct xdp_mem_allocator *xdp_alloc;
+ gfp_t gfp = GFP_KERNEL;
+ int id, errno, ret;
+ void *ptr;
+
+ if (xdp_rxq->reg_state != REG_STATE_REGISTERED) {
+ WARN(1, "Missing register, driver bug");
+ return -EFAULT;
+ }
+
if (type >= MEM_TYPE_MAX)
return -EINVAL;
xdp_rxq->mem.type = type;
- if (allocator)
- return -EOPNOTSUPP;
+ if (!allocator)
+ return 0;
+
+ /* Delay init of rhashtable to save memory if feature isn't used */
+ if (!mem_id_init) {
+ mutex_lock(&mem_id_lock);
+ ret = __mem_id_init_hash_table();
+ mutex_unlock(&mem_id_lock);
+ if (ret < 0) {
+ WARN_ON(1);
+ return ret;
+ }
+ }
+
+ xdp_alloc = kzalloc(sizeof(*xdp_alloc), gfp);
+ if (!xdp_alloc)
+ return -ENOMEM;
+
+ mutex_lock(&mem_id_lock);
+ id = __mem_id_cyclic_get(gfp);
+ if (id < 0) {
+ errno = id;
+ goto err;
+ }
+ xdp_rxq->mem.id = id;
+ xdp_alloc->mem = xdp_rxq->mem;
+ xdp_alloc->allocator = allocator;
+
+ /* Insert allocator into ID lookup table */
+ ptr = rhashtable_insert_slow(mem_id_ht, &id, &xdp_alloc->node);
+ if (IS_ERR(ptr)) {
+ errno = PTR_ERR(ptr);
+ goto err;
+ }
+
+ mutex_unlock(&mem_id_lock);
- /* TODO: Allocate an ID that maps to allocator pointer
- * See: https://www.kernel.org/doc/html/latest/core-api/idr.html
- */
return 0;
+err:
+ mutex_unlock(&mem_id_lock);
+ kfree(xdp_alloc);
+ return errno;
}
EXPORT_SYMBOL_GPL(xdp_rxq_info_reg_mem_model);
+
+void xdp_return_frame(void *data, struct xdp_mem_info *mem)
+{
+ if (mem->type == MEM_TYPE_PAGE_SHARED) {
+ page_frag_free(data);
+ return;
+ }
+
+ if (mem->type == MEM_TYPE_PAGE_ORDER0) {
+ struct page *page = virt_to_page(data); /* Assumes order0 page*/
+
+ put_page(page);
+ }
+}
+EXPORT_SYMBOL_GPL(xdp_return_frame);
projects / users / willy / pagecache.git / commitdiff