dma_free_coherent不能在IRQ disabled下跑..

dma_free_coherent不能在IRQ disabled下跑
但是有些東西非得在IRQ時free掉的話
把實際的free移到workqueue來跑即可

ref dev_kfree_skb_any, net_tx_action, completion_queue

LIST_HEAD(tofree_list);
spinlock_t tofree_list_lock=SPIN_LOCK_UNLOCKED;

struct free_param {
        struct list_head list;

        void* addr;
        dma_addr_t dma_addr;
        uint32_t size;
};
void free_list_agent_fn(void *data){
        struct list_head free_list;
        struct free_param *cur,*next;

        spin_lock(tofree_list_lock);
        list_add(&free_list,&tofree_list);
        list_del_init(&tofree_list);
        spin_unlock(tofree_list_lock);

        list_for_each_entry_safe(cur,next,&free_list,list){
                if(cur==&free_list) break;
                dma_free_coherent(NULL,cur->size,cur->addr,cur->dma_addr);
                list_del(&cur->list);
                kfree(cur);
        }
}
DECLARE_WORK(free_list_agent,free_list_agent_fn);


void some_free_func(){
        if(irqs_disabled()){
                struct free_param* fp=kmalloc(sizeof(struct free_param),GFP_KERNEL);
                fp->addr=desc_addr;
                fp->dma_addr=dma_desc_addr;
                fp->size=count*sizeof(dwc_otg_dma_desc_t);

                spin_lock(tofree_list_lock);
                list_add(&fp->list,&tofree_list);
                spin_unlock(tofree_list_lock);

                schedule_work(&free_list_agent);
                return ;
        }
        dma_free_coherent(blablabla);
}