diff options
Diffstat (limited to 'linux-core/mmfs_drv.c')
-rw-r--r-- | linux-core/mmfs_drv.c | 447 |
1 files changed, 0 insertions, 447 deletions
diff --git a/linux-core/mmfs_drv.c b/linux-core/mmfs_drv.c deleted file mode 100644 index 88246297..00000000 --- a/linux-core/mmfs_drv.c +++ /dev/null @@ -1,447 +0,0 @@ -/* - * Copyright © 2008 Intel Corporation - * - * Permission is hereby granted, free of charge, to any person obtaining a - * copy of this software and associated documentation files (the "Software"), - * to deal in the Software without restriction, including without limitation - * the rights to use, copy, modify, merge, publish, distribute, sublicense, - * and/or sell copies of the Software, and to permit persons to whom the - * Software is furnished to do so, subject to the following conditions: - * - * The above copyright notice and this permission notice (including the next - * paragraph) shall be included in all copies or substantial portions of the - * Software. - * - * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR - * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, - * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL - * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER - * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING - * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS - * IN THE SOFTWARE. - * - * Authors: - * Eric Anholt <eric@anholt.net> - * - */ - -#include <linux/types.h> -#include <linux/slab.h> -#include <linux/mm.h> -#include <linux/uaccess.h> -#include <linux/fs.h> -#include <linux/file.h> -#include <linux/module.h> -#include <linux/mman.h> -#include <linux/pagemap.h> -#include "mmfs.h" - -/** @file mmfs.c - * - * This file provides the filesystem for memory manager objects used by the - * DRM. - * - * The goal is to have swap-backed object allocation managed through - * struct file. However, file descriptors as handles to a struct file have - * two major failings: - * - Process limits prevent more than 1024 or so being used at a time by - * default. - * - Inability to allocate high fds will aggravate the X Server's select() - * handling, and likely that of many GL client applications as well. - * - * This led to a plan of using our own integer IDs (called handles, following - * DRM terminology) to mimic fds, and implement the fd syscalls we need as - * ioctls. The objects themselves will still include the struct file so - * that we can transition to fds if the required kernel infrastructure shows - * up at a later data, and as our interface with shmfs for memory allocation. - */ - -static struct mmfs_object * -mmfs_object_alloc(size_t size) -{ - struct mmfs_object *obj; - - BUG_ON((size & (PAGE_SIZE - 1)) != 0); - - obj = kcalloc(1, sizeof(*obj), GFP_KERNEL); - - obj->filp = shmem_file_setup("mmfs object", size, 0); - if (IS_ERR(obj->filp)) { - kfree(obj); - return NULL; - } - - obj->refcount = 1; - - return obj; -} - -/** - * Removes the mapping from handle to filp for this object. - */ -static int -mmfs_handle_delete(struct mmfs_file *mmfs_filp, int handle) -{ - struct mmfs_object *obj; - - /* This is gross. The idr system doesn't let us try a delete and - * return an error code. It just spews if you fail at deleting. - * So, we have to grab a lock around finding the object and then - * doing the delete on it and dropping the refcount, or the user - * could race us to double-decrement the refcount and cause a - * use-after-free later. Given the frequency of our handle lookups, - * we may want to use ida for number allocation and a hash table - * for the pointers, anyway. - */ - spin_lock(&mmfs_filp->table_lock); - - /* Check if we currently have a reference on the object */ - obj = idr_find(&mmfs_filp->object_idr, handle); - if (obj == NULL) { - spin_unlock(&mmfs_filp->table_lock); - return -EINVAL; - } - - /* Release reference and decrement refcount. */ - idr_remove(&mmfs_filp->object_idr, handle); - mmfs_object_unreference(obj); - - spin_unlock(&mmfs_filp->table_lock); - - return 0; -} - -/** Returns a reference to the object named by the handle. */ -static struct mmfs_object * -mmfs_object_lookup(struct mmfs_file *mmfs_filp, int handle) -{ - struct mmfs_object *obj; - - spin_lock(&mmfs_filp->table_lock); - - /* Check if we currently have a reference on the object */ - obj = idr_find(&mmfs_filp->object_idr, handle); - if (obj == NULL) { - spin_unlock(&mmfs_filp->table_lock); - return NULL; - } - - mmfs_object_reference(obj); - - spin_unlock(&mmfs_filp->table_lock); - - return obj; -} - - -/** - * Allocates a new mmfs object and returns a handle to it. - */ -static int -mmfs_alloc_ioctl(struct inode *inode, struct file *filp, - unsigned int cmd, unsigned long arg) -{ - struct mmfs_file *mmfs_filp = filp->private_data; - struct mmfs_alloc_args args; - struct mmfs_object *obj; - int handle, ret; - - if (copy_from_user(&args, (void __user *)arg, sizeof(args))) - return -EFAULT; - - /* Round requested size up to page size */ - args.size = (args.size + PAGE_SIZE - 1) & ~(PAGE_SIZE - 1); - - /* Allocate the new object */ - obj = mmfs_object_alloc(args.size); - if (obj == NULL) - return -ENOMEM; - - /* Get the user-visible handle using idr. - * - * I'm not really sure why the idr api needs us to do this in two - * repeating steps. It handles internal locking of its data - * structure, yet insists that we keep its memory allocation step - * separate from its slot-finding step for locking purposes. - */ - do { - if (idr_pre_get(&mmfs_filp->object_idr, GFP_KERNEL) == 0) { - kfree(obj); - return -EFAULT; - } - - ret = idr_get_new(&mmfs_filp->object_idr, obj, &handle); - } while (ret == -EAGAIN); - - if (ret != 0) { - mmfs_object_unreference(obj); - return -EFAULT; - } - - args.handle = handle; - - if (copy_to_user((void __user *)arg, &args, sizeof(args))) { - mmfs_handle_delete(mmfs_filp, args.handle); - return -EFAULT; - } - - return 0; -} - -/** - * Releases the handle to an mmfs object. - */ -static int -mmfs_unreference_ioctl(struct inode *inode, struct file *filp, - unsigned int cmd, unsigned long arg) -{ - struct mmfs_file *mmfs_filp = filp->private_data; - struct mmfs_unreference_args args; - int ret; - - if (copy_from_user(&args, (void __user *)arg, sizeof(args))) - return -EFAULT; - - ret = mmfs_handle_delete(mmfs_filp, args.handle); - - return ret; -} - -/** - * Reads data from the object referenced by handle. - * - * On error, the contents of *data are undefined. - */ -static int -mmfs_pread_ioctl(struct inode *inode, struct file *filp, - unsigned int cmd, unsigned long arg) -{ - struct mmfs_file *mmfs_filp = filp->private_data; - struct mmfs_pread_args args; - struct mmfs_object *obj; - ssize_t read; - loff_t offset; - - if (copy_from_user(&args, (void __user *)arg, sizeof(args))) - return -EFAULT; - - obj = mmfs_object_lookup(mmfs_filp, args.handle); - if (obj == NULL) - return -EINVAL; - - offset = args.offset; - - read = obj->filp->f_op->read(obj->filp, (char __user *)args.data, - args.size, &offset); - if (read != args.size) { - mmfs_object_unreference(obj); - if (read < 0) - return read; - else - return -EINVAL; - } - - mmfs_object_unreference(obj); - - return 0; -} - -/** - * Maps the contents of an object, returning the address it is mapped - * into. - * - * While the mapping holds a reference on the contents of the object, it doesn't - * imply a ref on the object itself. - */ -static int -mmfs_mmap_ioctl(struct inode *inode, struct file *filp, - unsigned int cmd, unsigned long arg) -{ - struct mmfs_file *mmfs_filp = filp->private_data; - struct mmfs_mmap_args args; - struct mmfs_object *obj; - loff_t offset; - - if (copy_from_user(&args, (void __user *)arg, sizeof(args))) - return -EFAULT; - - obj = mmfs_object_lookup(mmfs_filp, args.handle); - if (obj == NULL) - return -EINVAL; - - offset = args.offset; - - down_write(¤t->mm->mmap_sem); - args.addr = (void *)do_mmap(obj->filp, 0, args.size, - PROT_READ | PROT_WRITE, MAP_SHARED, - args.offset); - up_write(¤t->mm->mmap_sem); - - mmfs_object_unreference(obj); - - if (copy_to_user((void __user *)arg, &args, sizeof(args))) - return -EFAULT; - - return 0; -} - -/** - * Writes data to the object referenced by handle. - * - * On error, the contents of the buffer that were to be modified are undefined. - */ -static int -mmfs_pwrite_ioctl(struct inode *inode, struct file *filp, - unsigned int cmd, unsigned long arg) -{ - struct mmfs_file *mmfs_filp = filp->private_data; - struct mmfs_pwrite_args args; - struct mmfs_object *obj; - ssize_t written; - loff_t offset; - - if (copy_from_user(&args, (void __user *)arg, sizeof(args))) - return -EFAULT; - - obj = mmfs_object_lookup(mmfs_filp, args.handle); - if (obj == NULL) - return -EINVAL; - - offset = args.offset; - - written = obj->filp->f_op->write(obj->filp, (char __user *)args.data, - args.size, &offset); - if (written != args.size) { - mmfs_object_unreference(obj); - if (written < 0) - return written; - else - return -EINVAL; - } - - mmfs_object_unreference(obj); - - return 0; -} - -static int -mmfs_ioctl(struct inode *inode, struct file *filp, - unsigned int cmd, unsigned long arg) -{ - - switch (cmd) { - case MMFS_IOCTL_ALLOC: - return mmfs_alloc_ioctl(inode, filp, cmd, arg); - case MMFS_IOCTL_UNREFERENCE: - return mmfs_unreference_ioctl(inode, filp, cmd, arg); - case MMFS_IOCTL_PREAD: - return mmfs_pread_ioctl(inode, filp, cmd, arg); - case MMFS_IOCTL_PWRITE: - return mmfs_pwrite_ioctl(inode, filp, cmd, arg); - case MMFS_IOCTL_MMAP: - return mmfs_mmap_ioctl(inode, filp, cmd, arg); - default: - return -EINVAL; - } -} - -/** - * Sets up the file private for keeping track of our mappings of handles to - * mmfs objects. - */ -int -mmfs_open(struct inode *inode, struct file *filp) -{ - struct mmfs_file *mmfs_filp; - - if (filp->f_flags & O_EXCL) - return -EBUSY; /* No exclusive opens */ - - mmfs_filp = kcalloc(1, sizeof(*mmfs_filp), GFP_KERNEL); - if (mmfs_filp == NULL) - return -ENOMEM; - filp->private_data = mmfs_filp; - - idr_init(&mmfs_filp->object_idr); - - return 0; -} - -/** Called at device close to release the file's references on objects. */ -static int -mmfs_object_release(int id, void *ptr, void *data) -{ - struct mmfs_object *obj = ptr; - - mmfs_object_unreference(obj); - - return 0; -} - -/** - * Called at close time when the filp is going away. - * - * Releases any remaining references on objects by this filp. - */ -int -mmfs_close(struct inode *inode, struct file *filp) -{ - struct mmfs_file *mmfs_filp = filp->private_data; - - idr_for_each(&mmfs_filp->object_idr, &mmfs_object_release, NULL); - - idr_destroy(&mmfs_filp->object_idr); - - kfree(mmfs_filp); - filp->private_data = NULL; - - return 0; -} - -void -mmfs_object_reference(struct mmfs_object *obj) -{ - spin_lock(&obj->lock); - obj->refcount++; - spin_unlock(&obj->lock); -} - -void -mmfs_object_unreference(struct mmfs_object *obj) -{ - spin_lock(&obj->lock); - obj->refcount--; - spin_unlock(&obj->lock); - if (obj->refcount == 0) { - fput(obj->filp); - kfree(obj); - } -} - -/** File operations structure */ -static const struct file_operations mmfs_dev_fops = { - .owner = THIS_MODULE, - .open = mmfs_open, - .release = mmfs_close, - .ioctl = mmfs_ioctl, -}; - -static int __init mmfs_init(void) -{ - int ret; - - ret = register_chrdev(MMFS_DEVICE_MAJOR, "mmfs", &mmfs_dev_fops); - if (ret != 0) - return ret; - - return 0; -} - -static void __exit mmfs_exit(void) -{ - unregister_chrdev(MMFS_DEVICE_MAJOR, "mmfs"); -} - -module_init(mmfs_init); -module_exit(mmfs_exit); -MODULE_LICENSE("GPL and additional rights"); |