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![Sherry Yang](/assets/img/avatar_default.png)
Use binder_alloc struct's mm_struct rather than getting a reference to the mm struct through get_task_mm to avoid a potential deadlock between lru lock, task lock and dentry lock, since a thread can be holding the task lock and the dentry lock while trying to acquire the lru lock. Acked-by: Arve Hjønnevåg <arve@android.com> Signed-off-by: Sherry Yang <sherryy@android.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
186 lines
6.5 KiB
C
186 lines
6.5 KiB
C
/*
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* Copyright (C) 2017 Google, Inc.
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*
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* This software is licensed under the terms of the GNU General Public
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* License version 2, as published by the Free Software Foundation, and
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* may be copied, distributed, and modified under those terms.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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*/
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#ifndef _LINUX_BINDER_ALLOC_H
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#define _LINUX_BINDER_ALLOC_H
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#include <linux/rbtree.h>
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#include <linux/list.h>
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#include <linux/mm.h>
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#include <linux/rtmutex.h>
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#include <linux/vmalloc.h>
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#include <linux/slab.h>
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#include <linux/list_lru.h>
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extern struct list_lru binder_alloc_lru;
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struct binder_transaction;
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/**
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* struct binder_buffer - buffer used for binder transactions
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* @entry: entry alloc->buffers
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* @rb_node: node for allocated_buffers/free_buffers rb trees
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* @free: true if buffer is free
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* @allow_user_free: describe the second member of struct blah,
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* @async_transaction: describe the second member of struct blah,
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* @debug_id: describe the second member of struct blah,
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* @transaction: describe the second member of struct blah,
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* @target_node: describe the second member of struct blah,
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* @data_size: describe the second member of struct blah,
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* @offsets_size: describe the second member of struct blah,
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* @extra_buffers_size: describe the second member of struct blah,
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* @data:i describe the second member of struct blah,
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*
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* Bookkeeping structure for binder transaction buffers
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*/
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struct binder_buffer {
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struct list_head entry; /* free and allocated entries by address */
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struct rb_node rb_node; /* free entry by size or allocated entry */
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/* by address */
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unsigned free:1;
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unsigned allow_user_free:1;
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unsigned async_transaction:1;
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unsigned free_in_progress:1;
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unsigned debug_id:28;
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struct binder_transaction *transaction;
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struct binder_node *target_node;
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size_t data_size;
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size_t offsets_size;
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size_t extra_buffers_size;
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void *data;
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};
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/**
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* struct binder_lru_page - page object used for binder shrinker
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* @page_ptr: pointer to physical page in mmap'd space
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* @lru: entry in binder_alloc_lru
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* @alloc: binder_alloc for a proc
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*/
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struct binder_lru_page {
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struct list_head lru;
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struct page *page_ptr;
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struct binder_alloc *alloc;
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};
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/**
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* struct binder_alloc - per-binder proc state for binder allocator
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* @vma: vm_area_struct passed to mmap_handler
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* (invarient after mmap)
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* @tsk: tid for task that called init for this proc
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* (invariant after init)
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* @vma_vm_mm: copy of vma->vm_mm (invarient after mmap)
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* @buffer: base of per-proc address space mapped via mmap
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* @user_buffer_offset: offset between user and kernel VAs for buffer
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* @buffers: list of all buffers for this proc
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* @free_buffers: rb tree of buffers available for allocation
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* sorted by size
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* @allocated_buffers: rb tree of allocated buffers sorted by address
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* @free_async_space: VA space available for async buffers. This is
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* initialized at mmap time to 1/2 the full VA space
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* @pages: array of binder_lru_page
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* @buffer_size: size of address space specified via mmap
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* @pid: pid for associated binder_proc (invariant after init)
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*
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* Bookkeeping structure for per-proc address space management for binder
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* buffers. It is normally initialized during binder_init() and binder_mmap()
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* calls. The address space is used for both user-visible buffers and for
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* struct binder_buffer objects used to track the user buffers
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*/
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struct binder_alloc {
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struct mutex mutex;
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struct vm_area_struct *vma;
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struct mm_struct *vma_vm_mm;
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void *buffer;
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ptrdiff_t user_buffer_offset;
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struct list_head buffers;
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struct rb_root free_buffers;
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struct rb_root allocated_buffers;
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size_t free_async_space;
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struct binder_lru_page *pages;
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size_t buffer_size;
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uint32_t buffer_free;
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int pid;
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};
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#ifdef CONFIG_ANDROID_BINDER_IPC_SELFTEST
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void binder_selftest_alloc(struct binder_alloc *alloc);
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#else
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static inline void binder_selftest_alloc(struct binder_alloc *alloc) {}
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#endif
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enum lru_status binder_alloc_free_page(struct list_head *item,
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struct list_lru_one *lru,
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spinlock_t *lock, void *cb_arg);
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extern struct binder_buffer *binder_alloc_new_buf(struct binder_alloc *alloc,
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size_t data_size,
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size_t offsets_size,
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size_t extra_buffers_size,
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int is_async);
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extern void binder_alloc_init(struct binder_alloc *alloc);
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void binder_alloc_shrinker_init(void);
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extern void binder_alloc_vma_close(struct binder_alloc *alloc);
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extern struct binder_buffer *
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binder_alloc_prepare_to_free(struct binder_alloc *alloc,
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uintptr_t user_ptr);
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extern void binder_alloc_free_buf(struct binder_alloc *alloc,
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struct binder_buffer *buffer);
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extern int binder_alloc_mmap_handler(struct binder_alloc *alloc,
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struct vm_area_struct *vma);
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extern void binder_alloc_deferred_release(struct binder_alloc *alloc);
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extern int binder_alloc_get_allocated_count(struct binder_alloc *alloc);
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extern void binder_alloc_print_allocated(struct seq_file *m,
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struct binder_alloc *alloc);
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void binder_alloc_print_pages(struct seq_file *m,
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struct binder_alloc *alloc);
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/**
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* binder_alloc_get_free_async_space() - get free space available for async
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* @alloc: binder_alloc for this proc
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*
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* Return: the bytes remaining in the address-space for async transactions
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*/
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static inline size_t
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binder_alloc_get_free_async_space(struct binder_alloc *alloc)
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{
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size_t free_async_space;
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mutex_lock(&alloc->mutex);
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free_async_space = alloc->free_async_space;
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mutex_unlock(&alloc->mutex);
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return free_async_space;
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}
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/**
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* binder_alloc_get_user_buffer_offset() - get offset between kernel/user addrs
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* @alloc: binder_alloc for this proc
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*
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* Return: the offset between kernel and user-space addresses to use for
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* virtual address conversion
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*/
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static inline ptrdiff_t
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binder_alloc_get_user_buffer_offset(struct binder_alloc *alloc)
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{
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/*
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* user_buffer_offset is constant if vma is set and
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* undefined if vma is not set. It is possible to
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* get here with !alloc->vma if the target process
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* is dying while a transaction is being initiated.
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* Returning the old value is ok in this case and
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* the transaction will fail.
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*/
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return alloc->user_buffer_offset;
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}
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#endif /* _LINUX_BINDER_ALLOC_H */
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