4 * Copyright (C) 2002-2005 - Tom Zanussi <zanussi@us.ibm.com>, IBM Corp
5 * Copyright (C) 1999-2005 - Karim Yaghmour <karim@opersys.com>
6 * Copyright (C) 2008-2012 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; only version 2 of the License.
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
17 * You should have received a copy of the GNU General Public License along
18 * with this program; if not, write to the Free Software Foundation, Inc.,
19 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
21 * Re-using code from kernel/relay.c, hence the GPLv2 license for this
25 #include <linux/module.h>
28 #include <wrapper/ringbuffer/backend.h>
29 #include <wrapper/ringbuffer/frontend.h>
30 #include <wrapper/ringbuffer/vfs.h>
33 * fault() vm_op implementation for ring buffer file mapping.
35 #if (LINUX_VERSION_CODE >= KERNEL_VERSION(5,1,0))
36 static vm_fault_t
lib_ring_buffer_fault_compat(struct vm_area_struct
*vma
, struct vm_fault
*vmf
)
38 static int lib_ring_buffer_fault_compat(struct vm_area_struct
*vma
, struct vm_fault
*vmf
)
41 struct lib_ring_buffer
*buf
= vma
->vm_private_data
;
42 struct channel
*chan
= buf
->backend
.chan
;
43 const struct lib_ring_buffer_config
*config
= &chan
->backend
.config
;
44 pgoff_t pgoff
= vmf
->pgoff
;
47 unsigned long offset
, sb_bindex
;
50 * Verify that faults are only done on the range of pages owned by the
53 offset
= pgoff
<< PAGE_SHIFT
;
54 sb_bindex
= subbuffer_id_get_index(config
, buf
->backend
.buf_rsb
.id
);
55 if (!(offset
>= buf
->backend
.array
[sb_bindex
]->mmap_offset
56 && offset
< buf
->backend
.array
[sb_bindex
]->mmap_offset
+
57 buf
->backend
.chan
->backend
.subbuf_size
))
58 return VM_FAULT_SIGBUS
;
60 * ring_buffer_read_get_pfn() gets the page frame number for the
61 * current reader's pages.
63 pfnp
= lib_ring_buffer_read_get_pfn(&buf
->backend
, offset
, &virt
);
65 return VM_FAULT_SIGBUS
;
66 get_page(pfn_to_page(*pfnp
));
67 vmf
->page
= pfn_to_page(*pfnp
);
72 #if (LINUX_VERSION_CODE >= KERNEL_VERSION(5,1,0))
73 static vm_fault_t
lib_ring_buffer_fault(struct vm_fault
*vmf
)
75 struct vm_area_struct
*vma
= vmf
->vma
;
76 return lib_ring_buffer_fault_compat(vma
, vmf
);
78 #elif (LINUX_VERSION_CODE >= KERNEL_VERSION(4,11,0))
79 static int lib_ring_buffer_fault(struct vm_fault
*vmf
)
81 struct vm_area_struct
*vma
= vmf
->vma
;
82 return lib_ring_buffer_fault_compat(vma
, vmf
);
84 #else /* #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,11,0)) */
85 static int lib_ring_buffer_fault(struct vm_area_struct
*vma
, struct vm_fault
*vmf
)
87 return lib_ring_buffer_fault_compat(vma
, vmf
);
89 #endif /* #else #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,11,0)) */
92 * vm_ops for ring buffer file mappings.
94 static const struct vm_operations_struct lib_ring_buffer_mmap_ops
= {
95 .fault
= lib_ring_buffer_fault
,
99 * lib_ring_buffer_mmap_buf: - mmap channel buffer to process address space
100 * @buf: ring buffer to map
101 * @vma: vm_area_struct describing memory to be mapped
103 * Returns 0 if ok, negative on error
105 * Caller should already have grabbed mmap_sem.
107 static int lib_ring_buffer_mmap_buf(struct lib_ring_buffer
*buf
,
108 struct vm_area_struct
*vma
)
110 unsigned long length
= vma
->vm_end
- vma
->vm_start
;
111 struct channel
*chan
= buf
->backend
.chan
;
112 const struct lib_ring_buffer_config
*config
= &chan
->backend
.config
;
113 unsigned long mmap_buf_len
;
115 if (config
->output
!= RING_BUFFER_MMAP
)
118 mmap_buf_len
= chan
->backend
.buf_size
;
119 if (chan
->backend
.extra_reader_sb
)
120 mmap_buf_len
+= chan
->backend
.subbuf_size
;
122 if (length
!= mmap_buf_len
)
125 vma
->vm_ops
= &lib_ring_buffer_mmap_ops
;
126 vma
->vm_flags
|= VM_DONTEXPAND
;
127 vma
->vm_private_data
= buf
;
132 int lib_ring_buffer_mmap(struct file
*filp
, struct vm_area_struct
*vma
,
133 struct lib_ring_buffer
*buf
)
135 return lib_ring_buffer_mmap_buf(buf
, vma
);
137 EXPORT_SYMBOL_GPL(lib_ring_buffer_mmap
);
140 * vfs_lib_ring_buffer_mmap - mmap file op
142 * @vma: the vma describing what to map
144 * Calls upon lib_ring_buffer_mmap_buf() to map the file into user space.
146 int vfs_lib_ring_buffer_mmap(struct file
*filp
, struct vm_area_struct
*vma
)
148 struct lib_ring_buffer
*buf
= filp
->private_data
;
149 return lib_ring_buffer_mmap(filp
, vma
, buf
);
151 EXPORT_SYMBOL_GPL(vfs_lib_ring_buffer_mmap
);