+++ /dev/null
-/*
- * Copyright (C) 2013-2015 Kay Sievers
- * Copyright (C) 2013-2015 Greg Kroah-Hartman <gregkh@linuxfoundation.org>
- * Copyright (C) 2013-2015 Daniel Mack <daniel@zonque.org>
- * Copyright (C) 2013-2015 David Herrmann <dh.herrmann@gmail.com>
- * Copyright (C) 2013-2015 Linux Foundation
- * Copyright (C) 2014-2015 Djalal Harouni <tixxdz@opendz.org>
- *
- * kdbus is free software; you can redistribute it and/or modify it under
- * the terms of the GNU Lesser General Public License as published by the
- * Free Software Foundation; either version 2.1 of the License, or (at
- * your option) any later version.
- */
-
-#include <linux/aio.h>
-#include <linux/file.h>
-#include <linux/fs.h>
-#include <linux/highmem.h>
-#include <linux/init.h>
-#include <linux/mm.h>
-#include <linux/module.h>
-#include <linux/pagemap.h>
-#include <linux/rbtree.h>
-#include <linux/sched.h>
-#include <linux/shmem_fs.h>
-#include <linux/sizes.h>
-#include <linux/slab.h>
-#include <linux/uaccess.h>
-#include <linux/uio.h>
-
-#include "pool.h"
-#include "util.h"
-
-/**
- * struct kdbus_pool - the receiver's buffer
- * @f: The backing shmem file
- * @size: The size of the file
- * @accounted_size: Currently accounted memory in bytes
- * @lock: Pool data lock
- * @slices: All slices sorted by address
- * @slices_busy: Tree of allocated slices
- * @slices_free: Tree of free slices
- *
- * The receiver's buffer, managed as a pool of allocated and free
- * slices containing the queued messages.
- *
- * Messages sent with KDBUS_CMD_SEND are copied direcly by the
- * sending process into the receiver's pool.
- *
- * Messages received with KDBUS_CMD_RECV just return the offset
- * to the data placed in the pool.
- *
- * The internally allocated memory needs to be returned by the receiver
- * with KDBUS_CMD_FREE.
- */
-struct kdbus_pool {
- struct file *f;
- size_t size;
- size_t accounted_size;
- struct mutex lock;
-
- struct list_head slices;
- struct rb_root slices_busy;
- struct rb_root slices_free;
-};
-
-/**
- * struct kdbus_pool_slice - allocated element in kdbus_pool
- * @pool: Pool this slice belongs to
- * @off: Offset of slice in the shmem file
- * @size: Size of slice
- * @entry: Entry in "all slices" list
- * @rb_node: Entry in free or busy list
- * @free: Unused slice
- * @accounted: Accounted as queue slice
- * @ref_kernel: Kernel holds a reference
- * @ref_user: Userspace holds a reference
- *
- * The pool has one or more slices, always spanning the entire size of the
- * pool.
- *
- * Every slice is an element in a list sorted by the buffer address, to
- * provide access to the next neighbor slice.
- *
- * Every slice is member in either the busy or the free tree. The free
- * tree is organized by slice size, the busy tree organized by buffer
- * offset.
- */
-struct kdbus_pool_slice {
- struct kdbus_pool *pool;
- size_t off;
- size_t size;
-
- struct list_head entry;
- struct rb_node rb_node;
-
- bool free:1;
- bool accounted:1;
- bool ref_kernel:1;
- bool ref_user:1;
-};
-
-static struct kdbus_pool_slice *kdbus_pool_slice_new(struct kdbus_pool *pool,
- size_t off, size_t size)
-{
- struct kdbus_pool_slice *slice;
-
- slice = kzalloc(sizeof(*slice), GFP_KERNEL);
- if (!slice)
- return NULL;
-
- slice->pool = pool;
- slice->off = off;
- slice->size = size;
- slice->free = true;
- return slice;
-}
-
-/* insert a slice into the free tree */
-static void kdbus_pool_add_free_slice(struct kdbus_pool *pool,
- struct kdbus_pool_slice *slice)
-{
- struct rb_node **n;
- struct rb_node *pn = NULL;
-
- n = &pool->slices_free.rb_node;
- while (*n) {
- struct kdbus_pool_slice *pslice;
-
- pn = *n;
- pslice = rb_entry(pn, struct kdbus_pool_slice, rb_node);
- if (slice->size < pslice->size)
- n = &pn->rb_left;
- else
- n = &pn->rb_right;
- }
-
- rb_link_node(&slice->rb_node, pn, n);
- rb_insert_color(&slice->rb_node, &pool->slices_free);
-}
-
-/* insert a slice into the busy tree */
-static void kdbus_pool_add_busy_slice(struct kdbus_pool *pool,
- struct kdbus_pool_slice *slice)
-{
- struct rb_node **n;
- struct rb_node *pn = NULL;
-
- n = &pool->slices_busy.rb_node;
- while (*n) {
- struct kdbus_pool_slice *pslice;
-
- pn = *n;
- pslice = rb_entry(pn, struct kdbus_pool_slice, rb_node);
- if (slice->off < pslice->off)
- n = &pn->rb_left;
- else if (slice->off > pslice->off)
- n = &pn->rb_right;
- else
- BUG();
- }
-
- rb_link_node(&slice->rb_node, pn, n);
- rb_insert_color(&slice->rb_node, &pool->slices_busy);
-}
-
-static struct kdbus_pool_slice *kdbus_pool_find_slice(struct kdbus_pool *pool,
- size_t off)
-{
- struct rb_node *n;
-
- n = pool->slices_busy.rb_node;
- while (n) {
- struct kdbus_pool_slice *s;
-
- s = rb_entry(n, struct kdbus_pool_slice, rb_node);
- if (off < s->off)
- n = n->rb_left;
- else if (off > s->off)
- n = n->rb_right;
- else
- return s;
- }
-
- return NULL;
-}
-
-/**
- * kdbus_pool_slice_alloc() - allocate memory from a pool
- * @pool: The receiver's pool
- * @size: The number of bytes to allocate
- * @accounted: Whether this slice should be accounted for
- *
- * The returned slice is used for kdbus_pool_slice_release() to
- * free the allocated memory. If either @kvec or @iovec is non-NULL, the data
- * will be copied from kernel or userspace memory into the new slice at
- * offset 0.
- *
- * Return: the allocated slice on success, ERR_PTR on failure.
- */
-struct kdbus_pool_slice *kdbus_pool_slice_alloc(struct kdbus_pool *pool,
- size_t size, bool accounted)
-{
- size_t slice_size = KDBUS_ALIGN8(size);
- struct rb_node *n, *found = NULL;
- struct kdbus_pool_slice *s;
- int ret = 0;
-
- if (WARN_ON(!size))
- return ERR_PTR(-EINVAL);
-
- /* search a free slice with the closest matching size */
- mutex_lock(&pool->lock);
- n = pool->slices_free.rb_node;
- while (n) {
- s = rb_entry(n, struct kdbus_pool_slice, rb_node);
- if (slice_size < s->size) {
- found = n;
- n = n->rb_left;
- } else if (slice_size > s->size) {
- n = n->rb_right;
- } else {
- found = n;
- break;
- }
- }
-
- /* no slice with the minimum size found in the pool */
- if (!found) {
- ret = -EXFULL;
- goto exit_unlock;
- }
-
- /* no exact match, use the closest one */
- if (!n) {
- struct kdbus_pool_slice *s_new;
-
- s = rb_entry(found, struct kdbus_pool_slice, rb_node);
-
- /* split-off the remainder of the size to its own slice */
- s_new = kdbus_pool_slice_new(pool, s->off + slice_size,
- s->size - slice_size);
- if (!s_new) {
- ret = -ENOMEM;
- goto exit_unlock;
- }
-
- list_add(&s_new->entry, &s->entry);
- kdbus_pool_add_free_slice(pool, s_new);
-
- /* adjust our size now that we split-off another slice */
- s->size = slice_size;
- }
-
- /* move slice from free to the busy tree */
- rb_erase(found, &pool->slices_free);
- kdbus_pool_add_busy_slice(pool, s);
-
- WARN_ON(s->ref_kernel || s->ref_user);
-
- s->ref_kernel = true;
- s->free = false;
- s->accounted = accounted;
- if (accounted)
- pool->accounted_size += s->size;
- mutex_unlock(&pool->lock);
-
- return s;
-
-exit_unlock:
- mutex_unlock(&pool->lock);
- return ERR_PTR(ret);
-}
-
-static void __kdbus_pool_slice_release(struct kdbus_pool_slice *slice)
-{
- struct kdbus_pool *pool = slice->pool;
-
- /* don't free the slice if either has a reference */
- if (slice->ref_kernel || slice->ref_user)
- return;
-
- if (WARN_ON(slice->free))
- return;
-
- rb_erase(&slice->rb_node, &pool->slices_busy);
-
- /* merge with the next free slice */
- if (!list_is_last(&slice->entry, &pool->slices)) {
- struct kdbus_pool_slice *s;
-
- s = list_entry(slice->entry.next,
- struct kdbus_pool_slice, entry);
- if (s->free) {
- rb_erase(&s->rb_node, &pool->slices_free);
- list_del(&s->entry);
- slice->size += s->size;
- kfree(s);
- }
- }
-
- /* merge with previous free slice */
- if (pool->slices.next != &slice->entry) {
- struct kdbus_pool_slice *s;
-
- s = list_entry(slice->entry.prev,
- struct kdbus_pool_slice, entry);
- if (s->free) {
- rb_erase(&s->rb_node, &pool->slices_free);
- list_del(&slice->entry);
- s->size += slice->size;
- kfree(slice);
- slice = s;
- }
- }
-
- slice->free = true;
- kdbus_pool_add_free_slice(pool, slice);
-}
-
-/**
- * kdbus_pool_slice_release() - drop kernel-reference on allocated slice
- * @slice: Slice allocated from the pool
- *
- * This releases the kernel-reference on the given slice. If the
- * kernel-reference and the user-reference on a slice are dropped, the slice is
- * returned to the pool.
- *
- * So far, we do not implement full ref-counting on slices. Each, kernel and
- * user-space can have exactly one reference to a slice. If both are dropped at
- * the same time, the slice is released.
- */
-void kdbus_pool_slice_release(struct kdbus_pool_slice *slice)
-{
- struct kdbus_pool *pool;
-
- if (!slice)
- return;
-
- /* @slice may be freed, so keep local ptr to @pool */
- pool = slice->pool;
-
- mutex_lock(&pool->lock);
- /* kernel must own a ref to @slice to drop it */
- WARN_ON(!slice->ref_kernel);
- slice->ref_kernel = false;
- /* no longer kernel-owned, de-account slice */
- if (slice->accounted && !WARN_ON(pool->accounted_size < slice->size))
- pool->accounted_size -= slice->size;
- __kdbus_pool_slice_release(slice);
- mutex_unlock(&pool->lock);
-}
-
-/**
- * kdbus_pool_release_offset() - release a public offset
- * @pool: pool to operate on
- * @off: offset to release
- *
- * This should be called whenever user-space frees a slice given to them. It
- * verifies the slice is available and public, and then drops it. It ensures
- * correct locking and barriers against queues.
- *
- * Return: 0 on success, ENXIO if the offset is invalid or not public.
- */
-int kdbus_pool_release_offset(struct kdbus_pool *pool, size_t off)
-{
- struct kdbus_pool_slice *slice;
- int ret = 0;
-
- /* 'pool->size' is used as dummy offset for empty slices */
- if (off == pool->size)
- return 0;
-
- mutex_lock(&pool->lock);
- slice = kdbus_pool_find_slice(pool, off);
- if (slice && slice->ref_user) {
- slice->ref_user = false;
- __kdbus_pool_slice_release(slice);
- } else {
- ret = -ENXIO;
- }
- mutex_unlock(&pool->lock);
-
- return ret;
-}
-
-/**
- * kdbus_pool_publish_empty() - publish empty slice to user-space
- * @pool: pool to operate on
- * @off: output storage for offset, or NULL
- * @size: output storage for size, or NULL
- *
- * This is the same as kdbus_pool_slice_publish(), but uses a dummy slice with
- * size 0. The returned offset points to the end of the pool and is never
- * returned on real slices.
- */
-void kdbus_pool_publish_empty(struct kdbus_pool *pool, u64 *off, u64 *size)
-{
- if (off)
- *off = pool->size;
- if (size)
- *size = 0;
-}
-
-/**
- * kdbus_pool_slice_publish() - publish slice to user-space
- * @slice: The slice
- * @out_offset: Output storage for offset, or NULL
- * @out_size: Output storage for size, or NULL
- *
- * This prepares a slice to be published to user-space.
- *
- * This call combines the following operations:
- * * the memory region is flushed so the user's memory view is consistent
- * * the slice is marked as referenced by user-space, so user-space has to
- * call KDBUS_CMD_FREE to release it
- * * the offset and size of the slice are written to the given output
- * arguments, if non-NULL
- */
-void kdbus_pool_slice_publish(struct kdbus_pool_slice *slice,
- u64 *out_offset, u64 *out_size)
-{
- mutex_lock(&slice->pool->lock);
- /* kernel must own a ref to @slice to gain a user-space ref */
- WARN_ON(!slice->ref_kernel);
- slice->ref_user = true;
- mutex_unlock(&slice->pool->lock);
-
- if (out_offset)
- *out_offset = slice->off;
- if (out_size)
- *out_size = slice->size;
-}
-
-/**
- * kdbus_pool_slice_offset() - Get a slice's offset inside the pool
- * @slice: Slice to return the offset of
- *
- * Return: The internal offset @slice inside the pool.
- */
-off_t kdbus_pool_slice_offset(const struct kdbus_pool_slice *slice)
-{
- return slice->off;
-}
-
-/**
- * kdbus_pool_slice_size() - get size of a pool slice
- * @slice: slice to query
- *
- * Return: size of the given slice
- */
-size_t kdbus_pool_slice_size(const struct kdbus_pool_slice *slice)
-{
- return slice->size;
-}
-
-/**
- * kdbus_pool_new() - create a new pool
- * @name: Name of the (deleted) file which shows up in
- * /proc, used for debugging
- * @size: Maximum size of the pool
- *
- * Return: a new kdbus_pool on success, ERR_PTR on failure.
- */
-struct kdbus_pool *kdbus_pool_new(const char *name, size_t size)
-{
- struct kdbus_pool_slice *s;
- struct kdbus_pool *p;
- struct file *f;
- char *n = NULL;
- int ret;
-
- p = kzalloc(sizeof(*p), GFP_KERNEL);
- if (!p)
- return ERR_PTR(-ENOMEM);
-
- if (name) {
- n = kasprintf(GFP_KERNEL, KBUILD_MODNAME "-conn:%s", name);
- if (!n) {
- ret = -ENOMEM;
- goto exit_free;
- }
- }
-
- f = shmem_file_setup(n ?: KBUILD_MODNAME "-conn", size, 0);
- kfree(n);
-
- if (IS_ERR(f)) {
- ret = PTR_ERR(f);
- goto exit_free;
- }
-
- ret = get_write_access(file_inode(f));
- if (ret < 0)
- goto exit_put_shmem;
-
- /* allocate first slice spanning the entire pool */
- s = kdbus_pool_slice_new(p, 0, size);
- if (!s) {
- ret = -ENOMEM;
- goto exit_put_write;
- }
-
- p->f = f;
- p->size = size;
- p->slices_free = RB_ROOT;
- p->slices_busy = RB_ROOT;
- mutex_init(&p->lock);
-
- INIT_LIST_HEAD(&p->slices);
- list_add(&s->entry, &p->slices);
-
- kdbus_pool_add_free_slice(p, s);
- return p;
-
-exit_put_write:
- put_write_access(file_inode(f));
-exit_put_shmem:
- fput(f);
-exit_free:
- kfree(p);
- return ERR_PTR(ret);
-}
-
-/**
- * kdbus_pool_free() - destroy pool
- * @pool: The receiver's pool
- */
-void kdbus_pool_free(struct kdbus_pool *pool)
-{
- struct kdbus_pool_slice *s, *tmp;
-
- if (!pool)
- return;
-
- list_for_each_entry_safe(s, tmp, &pool->slices, entry) {
- list_del(&s->entry);
- kfree(s);
- }
-
- put_write_access(file_inode(pool->f));
- fput(pool->f);
- kfree(pool);
-}
-
-/**
- * kdbus_pool_accounted() - retrieve accounting information
- * @pool: pool to query
- * @size: output for overall pool size
- * @acc: output for currently accounted size
- *
- * This returns accounting information of the pool. Note that the data might
- * change after the function returns, as the pool lock is dropped. You need to
- * protect the data via other means, if you need reliable accounting.
- */
-void kdbus_pool_accounted(struct kdbus_pool *pool, size_t *size, size_t *acc)
-{
- mutex_lock(&pool->lock);
- if (size)
- *size = pool->size;
- if (acc)
- *acc = pool->accounted_size;
- mutex_unlock(&pool->lock);
-}
-
-/**
- * kdbus_pool_slice_copy_iovec() - copy user memory to a slice
- * @slice: The slice to write to
- * @off: Offset in the slice to write to
- * @iov: iovec array, pointing to data to copy
- * @iov_len: Number of elements in @iov
- * @total_len: Total number of bytes described in members of @iov
- *
- * User memory referenced by @iov will be copied into @slice at offset @off.
- *
- * Return: the numbers of bytes copied, negative errno on failure.
- */
-ssize_t
-kdbus_pool_slice_copy_iovec(const struct kdbus_pool_slice *slice, loff_t off,
- struct iovec *iov, size_t iov_len, size_t total_len)
-{
- struct iov_iter iter;
- ssize_t len;
-
- if (WARN_ON(off + total_len > slice->size))
- return -EFAULT;
-
- off += slice->off;
- iov_iter_init(&iter, WRITE, iov, iov_len, total_len);
- len = vfs_iter_write(slice->pool->f, &iter, &off);
-
- return (len >= 0 && len != total_len) ? -EFAULT : len;
-}
-
-/**
- * kdbus_pool_slice_copy_kvec() - copy kernel memory to a slice
- * @slice: The slice to write to
- * @off: Offset in the slice to write to
- * @kvec: kvec array, pointing to data to copy
- * @kvec_len: Number of elements in @kvec
- * @total_len: Total number of bytes described in members of @kvec
- *
- * Kernel memory referenced by @kvec will be copied into @slice at offset @off.
- *
- * Return: the numbers of bytes copied, negative errno on failure.
- */
-ssize_t kdbus_pool_slice_copy_kvec(const struct kdbus_pool_slice *slice,
- loff_t off, struct kvec *kvec,
- size_t kvec_len, size_t total_len)
-{
- struct iov_iter iter;
- mm_segment_t old_fs;
- ssize_t len;
-
- if (WARN_ON(off + total_len > slice->size))
- return -EFAULT;
-
- off += slice->off;
- iov_iter_kvec(&iter, WRITE | ITER_KVEC, kvec, kvec_len, total_len);
-
- old_fs = get_fs();
- set_fs(get_ds());
- len = vfs_iter_write(slice->pool->f, &iter, &off);
- set_fs(old_fs);
-
- return (len >= 0 && len != total_len) ? -EFAULT : len;
-}
-
-/**
- * kdbus_pool_slice_copy() - copy data from one slice into another
- * @slice_dst: destination slice
- * @slice_src: source slice
- *
- * Return: 0 on success, negative error number on failure.
- */
-int kdbus_pool_slice_copy(const struct kdbus_pool_slice *slice_dst,
- const struct kdbus_pool_slice *slice_src)
-{
- struct file *f_src = slice_src->pool->f;
- struct file *f_dst = slice_dst->pool->f;
- struct inode *i_dst = file_inode(f_dst);
- struct address_space *mapping_dst = f_dst->f_mapping;
- const struct address_space_operations *aops = mapping_dst->a_ops;
- unsigned long len = slice_src->size;
- loff_t off_src = slice_src->off;
- loff_t off_dst = slice_dst->off;
- mm_segment_t old_fs;
- int ret = 0;
-
- if (WARN_ON(slice_src->size != slice_dst->size) ||
- WARN_ON(slice_src->free || slice_dst->free))
- return -EINVAL;
-
- mutex_lock(&i_dst->i_mutex);
- old_fs = get_fs();
- set_fs(get_ds());
- while (len > 0) {
- unsigned long page_off;
- unsigned long copy_len;
- char __user *kaddr;
- struct page *page;
- ssize_t n_read;
- void *fsdata;
- long status;
-
- page_off = off_dst & (PAGE_CACHE_SIZE - 1);
- copy_len = min_t(unsigned long,
- PAGE_CACHE_SIZE - page_off, len);
-
- status = aops->write_begin(f_dst, mapping_dst, off_dst,
- copy_len, 0, &page, &fsdata);
- if (unlikely(status < 0)) {
- ret = status;
- break;
- }
-
- kaddr = (char __force __user *)kmap(page) + page_off;
- n_read = f_src->f_op->read(f_src, kaddr, copy_len, &off_src);
- kunmap(page);
- mark_page_accessed(page);
- flush_dcache_page(page);
-
- if (unlikely(n_read != copy_len)) {
- ret = -EFAULT;
- break;
- }
-
- status = aops->write_end(f_dst, mapping_dst, off_dst,
- copy_len, copy_len, page, fsdata);
- if (unlikely(status != copy_len)) {
- ret = -EFAULT;
- break;
- }
-
- off_dst += copy_len;
- len -= copy_len;
- }
- set_fs(old_fs);
- mutex_unlock(&i_dst->i_mutex);
-
- return ret;
-}
-
-/**
- * kdbus_pool_mmap() - map the pool into the process
- * @pool: The receiver's pool
- * @vma: passed by mmap() syscall
- *
- * Return: the result of the mmap() call, negative errno on failure.
- */
-int kdbus_pool_mmap(const struct kdbus_pool *pool, struct vm_area_struct *vma)
-{
- /* deny write access to the pool */
- if (vma->vm_flags & VM_WRITE)
- return -EPERM;
- vma->vm_flags &= ~VM_MAYWRITE;
-
- /* do not allow to map more than the size of the file */
- if ((vma->vm_end - vma->vm_start) > pool->size)
- return -EFAULT;
-
- /* replace the connection file with our shmem file */
- if (vma->vm_file)
- fput(vma->vm_file);
- vma->vm_file = get_file(pool->f);
-
- return pool->f->f_op->mmap(pool->f, vma);
-}
projects / platform / kernel / linux-exynos.git / commitdiff