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33#include <linux/slab.h>
34
35#include "mlx4_ib.h"
36
37struct mlx4_ib_user_db_page {
38 struct list_head list;
39 struct ib_umem *umem;
40 unsigned long user_virt;
41 int refcnt;
42};
43
44int mlx4_ib_db_map_user(struct mlx4_ib_ucontext *context, unsigned long virt,
45 struct mlx4_db *db)
46{
47 struct mlx4_ib_user_db_page *page;
48 int err = 0;
49
50 mutex_lock(&context->db_page_mutex);
51
52 list_for_each_entry(page, &context->db_page_list, list)
53 if (page->user_virt == (virt & PAGE_MASK))
54 goto found;
55
56 page = kmalloc(sizeof *page, GFP_KERNEL);
57 if (!page) {
58 err = -ENOMEM;
59 goto out;
60 }
61
62 page->user_virt = (virt & PAGE_MASK);
63 page->refcnt = 0;
64 page->umem = ib_umem_get(&context->ibucontext, virt & PAGE_MASK,
65 PAGE_SIZE, 0, 0);
66 if (IS_ERR(page->umem)) {
67 err = PTR_ERR(page->umem);
68 kfree(page);
69 goto out;
70 }
71
72 list_add(&page->list, &context->db_page_list);
73
74found:
75 db->dma = sg_dma_address(page->umem->sg_head.sgl) + (virt & ~PAGE_MASK);
76 db->u.user_page = page;
77 ++page->refcnt;
78
79out:
80 mutex_unlock(&context->db_page_mutex);
81
82 return err;
83}
84
85void mlx4_ib_db_unmap_user(struct mlx4_ib_ucontext *context, struct mlx4_db *db)
86{
87 mutex_lock(&context->db_page_mutex);
88
89 if (!--db->u.user_page->refcnt) {
90 list_del(&db->u.user_page->list);
91 ib_umem_release(db->u.user_page->umem);
92 kfree(db->u.user_page);
93 }
94
95 mutex_unlock(&context->db_page_mutex);
96}
97