+++ /dev/null
-/* SPDX-License-Identifier: GPL-2.0-only
- *
- * ring_buffer_mmap.c
- *
- * Copyright (C) 2002-2005 - Tom Zanussi <zanussi@us.ibm.com>, IBM Corp
- * Copyright (C) 1999-2005 - Karim Yaghmour <karim@opersys.com>
- * Copyright (C) 2008-2012 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
- *
- * Re-using code from kernel/relay.c, hence the GPL-2.0-only license for this
- * file.
- */
-
-#include <linux/module.h>
-#include <linux/mm.h>
-
-#include <ringbuffer/backend.h>
-#include <ringbuffer/frontend.h>
-#include <ringbuffer/vfs.h>
-
-/*
- * fault() vm_op implementation for ring buffer file mapping.
- */
-#if (LINUX_VERSION_CODE >= KERNEL_VERSION(5,1,0))
-static vm_fault_t lib_ring_buffer_fault_compat(struct vm_area_struct *vma, struct vm_fault *vmf)
-#else
-static int lib_ring_buffer_fault_compat(struct vm_area_struct *vma, struct vm_fault *vmf)
-#endif
-{
- struct lib_ring_buffer *buf = vma->vm_private_data;
- struct channel *chan = buf->backend.chan;
- const struct lib_ring_buffer_config *config = &chan->backend.config;
- pgoff_t pgoff = vmf->pgoff;
- unsigned long *pfnp;
- void **virt;
- unsigned long offset, sb_bindex;
-
- /*
- * Verify that faults are only done on the range of pages owned by the
- * reader.
- */
- offset = pgoff << PAGE_SHIFT;
- sb_bindex = subbuffer_id_get_index(config, buf->backend.buf_rsb.id);
- if (!(offset >= buf->backend.array[sb_bindex]->mmap_offset
- && offset < buf->backend.array[sb_bindex]->mmap_offset +
- buf->backend.chan->backend.subbuf_size))
- return VM_FAULT_SIGBUS;
- /*
- * ring_buffer_read_get_pfn() gets the page frame number for the
- * current reader's pages.
- */
- pfnp = lib_ring_buffer_read_get_pfn(&buf->backend, offset, &virt);
- if (!*pfnp)
- return VM_FAULT_SIGBUS;
- get_page(pfn_to_page(*pfnp));
- vmf->page = pfn_to_page(*pfnp);
-
- return 0;
-}
-
-#if (LINUX_VERSION_CODE >= KERNEL_VERSION(5,1,0))
-static vm_fault_t lib_ring_buffer_fault(struct vm_fault *vmf)
-{
- struct vm_area_struct *vma = vmf->vma;
- return lib_ring_buffer_fault_compat(vma, vmf);
-}
-#elif (LINUX_VERSION_CODE >= KERNEL_VERSION(4,11,0))
-static int lib_ring_buffer_fault(struct vm_fault *vmf)
-{
- struct vm_area_struct *vma = vmf->vma;
- return lib_ring_buffer_fault_compat(vma, vmf);
-}
-#else /* #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,11,0)) */
-static int lib_ring_buffer_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
-{
- return lib_ring_buffer_fault_compat(vma, vmf);
-}
-#endif /* #else #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,11,0)) */
-
-/*
- * vm_ops for ring buffer file mappings.
- */
-static const struct vm_operations_struct lib_ring_buffer_mmap_ops = {
- .fault = lib_ring_buffer_fault,
-};
-
-/**
- * lib_ring_buffer_mmap_buf: - mmap channel buffer to process address space
- * @buf: ring buffer to map
- * @vma: vm_area_struct describing memory to be mapped
- *
- * Returns 0 if ok, negative on error
- *
- * Caller should already have grabbed mmap_sem.
- */
-static int lib_ring_buffer_mmap_buf(struct lib_ring_buffer *buf,
- struct vm_area_struct *vma)
-{
- unsigned long length = vma->vm_end - vma->vm_start;
- struct channel *chan = buf->backend.chan;
- const struct lib_ring_buffer_config *config = &chan->backend.config;
- unsigned long mmap_buf_len;
-
- if (config->output != RING_BUFFER_MMAP)
- return -EINVAL;
-
- mmap_buf_len = chan->backend.buf_size;
- if (chan->backend.extra_reader_sb)
- mmap_buf_len += chan->backend.subbuf_size;
-
- if (length != mmap_buf_len)
- return -EINVAL;
-
- vma->vm_ops = &lib_ring_buffer_mmap_ops;
- vma->vm_flags |= VM_DONTEXPAND;
- vma->vm_private_data = buf;
-
- return 0;
-}
-
-int lib_ring_buffer_mmap(struct file *filp, struct vm_area_struct *vma,
- struct lib_ring_buffer *buf)
-{
- return lib_ring_buffer_mmap_buf(buf, vma);
-}
-EXPORT_SYMBOL_GPL(lib_ring_buffer_mmap);
-
-/**
- * vfs_lib_ring_buffer_mmap - mmap file op
- * @filp: the file
- * @vma: the vma describing what to map
- *
- * Calls upon lib_ring_buffer_mmap_buf() to map the file into user space.
- */
-int vfs_lib_ring_buffer_mmap(struct file *filp, struct vm_area_struct *vma)
-{
- struct lib_ring_buffer *buf = filp->private_data;
- return lib_ring_buffer_mmap(filp, vma, buf);
-}
-EXPORT_SYMBOL_GPL(vfs_lib_ring_buffer_mmap);