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33#include <linux/kref.h>
34#include <linux/slab.h>
35#include <rdma/ib_umem.h>
36
37#include "mlx5_ib.h"
38
39struct mlx5_ib_user_db_page {
40 struct list_head list;
41 struct ib_umem *umem;
42 unsigned long user_virt;
43 int refcnt;
44};
45
46int mlx5_ib_db_map_user(struct mlx5_ib_ucontext *context, unsigned long virt,
47 struct mlx5_db *db)
48{
49 struct mlx5_ib_user_db_page *page;
50 struct ib_umem_chunk *chunk;
51 int err = 0;
52
53 mutex_lock(&context->db_page_mutex);
54
55 list_for_each_entry(page, &context->db_page_list, list)
56 if (page->user_virt == (virt & PAGE_MASK))
57 goto found;
58
59 page = kmalloc(sizeof(*page), GFP_KERNEL);
60 if (!page) {
61 err = -ENOMEM;
62 goto out;
63 }
64
65 page->user_virt = (virt & PAGE_MASK);
66 page->refcnt = 0;
67 page->umem = ib_umem_get(&context->ibucontext, virt & PAGE_MASK,
68 PAGE_SIZE, 0, 0);
69 if (IS_ERR(page->umem)) {
70 err = PTR_ERR(page->umem);
71 kfree(page);
72 goto out;
73 }
74
75 list_add(&page->list, &context->db_page_list);
76
77found:
78 chunk = list_entry(page->umem->chunk_list.next, struct ib_umem_chunk, list);
79 db->dma = sg_dma_address(chunk->page_list) + (virt & ~PAGE_MASK);
80 db->u.user_page = page;
81 ++page->refcnt;
82
83out:
84 mutex_unlock(&context->db_page_mutex);
85
86 return err;
87}
88
89void mlx5_ib_db_unmap_user(struct mlx5_ib_ucontext *context, struct mlx5_db *db)
90{
91 mutex_lock(&context->db_page_mutex);
92
93 if (!--db->u.user_page->refcnt) {
94 list_del(&db->u.user_page->list);
95 ib_umem_release(db->u.user_page->umem);
96 kfree(db->u.user_page);
97 }
98
99 mutex_unlock(&context->db_page_mutex);
100}
101