// SPDX-License-Identifier: GPL-2.0-only
/*
* Framework for buffer objects that can be shared across devices/subsystems.
*
* Copyright(C) 2011 Linaro Limited. All rights reserved.
* Author: Sumit Semwal <[email protected]>
*
* Many thanks to linaro-mm-sig list, and specially
* Arnd Bergmann <[email protected]>, Rob Clark <[email protected]> and
* Daniel Vetter <[email protected]> for their support in creation and
* refining of this idea.
*/
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/dma-buf.h>
#include <linux/dma-fence.h>
#include <linux/dma-fence-unwrap.h>
#include <linux/anon_inodes.h>
#include <linux/export.h>
#include <linux/debugfs.h>
#include <linux/module.h>
#include <linux/seq_file.h>
#include <linux/sync_file.h>
#include <linux/poll.h>
#include <linux/dma-resv.h>
#include <linux/mm.h>
#include <linux/mount.h>
#include <linux/pseudo_fs.h>
#include <uapi/linux/dma-buf.h>
#include <uapi/linux/magic.h>
#include "dma-buf-sysfs-stats.h"
static inline int is_dma_buf_file(struct file *);
#if IS_ENABLED(CONFIG_DEBUG_FS)
static DEFINE_MUTEX(debugfs_list_mutex);
static LIST_HEAD(debugfs_list);
static void __dma_buf_debugfs_list_add(struct dma_buf *dmabuf)
{
mutex_lock(&debugfs_list_mutex);
list_add(&dmabuf->list_node, &debugfs_list);
mutex_unlock(&debugfs_list_mutex);
}
static void __dma_buf_debugfs_list_del(struct dma_buf *dmabuf)
{
if (!dmabuf)
return;
mutex_lock(&debugfs_list_mutex);
list_del(&dmabuf->list_node);
mutex_unlock(&debugfs_list_mutex);
}
#else
static void __dma_buf_debugfs_list_add(struct dma_buf *dmabuf)
{
}
static void __dma_buf_debugfs_list_del(struct file *file)
{
}
#endif
static char *dmabuffs_dname(struct dentry *dentry, char *buffer, int buflen)
{
struct dma_buf *dmabuf;
char name[DMA_BUF_NAME_LEN];
ssize_t ret = 0;
dmabuf = dentry->d_fsdata;
spin_lock(&dmabuf->name_lock);
if (dmabuf->name)
ret = strscpy(name, dmabuf->name, sizeof(name));
spin_unlock(&dmabuf->name_lock);
return dynamic_dname(buffer, buflen, "/%s:%s",
dentry->d_name.name, ret > 0 ? name : "");
}
static void dma_buf_release(struct dentry *dentry)
{
struct dma_buf *dmabuf;
dmabuf = dentry->d_fsdata;
if (unlikely(!dmabuf))
return;
BUG_ON(dmabuf->vmapping_counter);
/*
* If you hit this BUG() it could mean:
* * There's a file reference imbalance in dma_buf_poll / dma_buf_poll_cb or somewhere else
* * dmabuf->cb_in/out.active are non-0 despite no pending fence callback
*/
BUG_ON(dmabuf->cb_in.active || dmabuf->cb_out.active);
dma_buf_stats_teardown(dmabuf);
dmabuf->ops->release(dmabuf);
if (dmabuf->resv == (struct dma_resv *)&dmabuf[1])
dma_resv_fini(dmabuf->resv);
WARN_ON(!list_empty(&dmabuf->attachments));
module_put(dmabuf->owner);
kfree(dmabuf->name);
kfree(dmabuf);
}
static int dma_buf_file_release(struct inode *inode, struct file *file)
{
if (!is_dma_buf_file(file))
return -EINVAL;
__dma_buf_debugfs_list_del(file->private_data);
return 0;
}
static const struct dentry_operations dma_buf_dentry_ops = {
.d_dname = dmabuffs_dname,
.d_release = dma_buf_release,
};
static struct vfsmount *dma_buf_mnt;
static int dma_buf_fs_init_context(struct fs_context *fc)
{
struct pseudo_fs_context *ctx;
ctx = init_pseudo(fc, DMA_BUF_MAGIC);
if (!ctx)
return -ENOMEM;
ctx->dops = &dma_buf_dentry_ops;
return 0;
}
static struct file_system_type dma_buf_fs_type = {
.name = "dmabuf",
.init_fs_context = dma_buf_fs_init_context,
.kill_sb = kill_anon_super,
};
static int dma_buf_mmap_internal(struct file *file, struct vm_area_struct *vma)
{
struct dma_buf *dmabuf;
if (!is_dma_buf_file(file))
return -EINVAL;
dmabuf = file->private_data;
/* check if buffer supports mmap */
if (!dmabuf->ops->mmap)
return -EINVAL;
/* check for overflowing the buffer's size */
if (vma->vm_pgoff + vma_pages(vma) >
dmabuf->size >> PAGE_SHIFT)
return -EINVAL;
return dmabuf->ops->mmap(dmabuf, vma);
}
static loff_t dma_buf_llseek(struct file *file, loff_t offset, int whence)
{
struct dma_buf *dmabuf;
loff_t base;
if (!is_dma_buf_file(file))
return -EBADF;
dmabuf = file->private_data;
/* only support discovering the end of the buffer,
but also allow SEEK_SET to maintain the idiomatic
SEEK_END(0), SEEK_CUR(0) pattern */
if (whence == SEEK_END)
base = dmabuf->size;
else if (whence == SEEK_SET)
base = 0;
else
return -EINVAL;
if (offset != 0)
return -EINVAL;
return base + offset;
}
/**
* DOC: implicit fence polling
*
* To support cross-device and cross-driver synchronization of buffer access
* implicit fences (represented internally in the kernel with &struct dma_fence)
* can be attached to a &dma_buf. The glue for that and a few related things are
* provided in the &dma_resv structure.
*
* Userspace can query the state of these implicitly tracked fences using poll()
* and related system calls:
*
* - Checking for EPOLLIN, i.e. read access, can be use to query the state of the
* most recent write or exclusive fence.
*
* - Checking for EPOLLOUT, i.e. write access, can be used to query the state of
* all attached fences, shared and exclusive ones.
*
* Note that this only signals the completion of the respective fences, i.e. the
* DMA transfers are complete. Cache flushing and any other necessary
* preparations before CPU access can begin still need to happen.
*
* As an alternative to poll(), the set of fences on DMA buffer can be
* exported as a &sync_file using &dma_buf_sync_file_export.
*/
static void dma_buf_poll_cb(struct dma_fence *fence, struct dma_fence_cb *cb)
{
struct dma_buf_poll_cb_t *dcb = (struct dma_buf_poll_cb_t *)cb;
struct dma_buf *dmabuf = container_of(dcb->poll, struct dma_buf, poll);
unsigned long flags;
spin_lock_irqsave(&dcb->poll->lock, flags);
wake_up_locked_poll(dcb->poll, dcb->active);
dcb->active = 0;
spin_unlock_irqrestore(&dcb->poll->lock, flags);
dma_fence_put(fence);
/* Paired with get_file in dma_buf_poll */
fput(dmabuf->file);
}
static bool dma_buf_poll_add_cb(struct dma_resv *resv, bool write,
struct dma_buf_poll_cb_t *dcb)
{
struct dma_resv_iter cursor;
struct dma_fence *fence;
int r;
dma_resv_for_each_fence(&cursor, resv, dma_resv_usage_rw(write),
fence) {
dma_fence_get(fence);
r = dma_fence_add_callback(fence, &dcb->cb, dma_buf_poll_cb);
if (!r)
return true;
dma_fence_put(fence);
}
return false;
}
static __poll_t dma_buf_poll(struct file *file, poll_table *poll)
{
struct dma_buf *dmabuf;
struct dma_resv *resv;
__poll_t events;
dmabuf = file->private_data;
if (!dmabuf || !dmabuf->resv)
return EPOLLERR;
resv = dmabuf->resv;
poll_wait(file, &dmabuf->poll, poll);
events = poll_requested_events(poll) & (EPOLLIN | EPOLLOUT);
if (!events)
return 0;
dma_resv_lock(resv, NULL);
if (events & EPOLLOUT) {
struct dma_buf_poll_cb_t *dcb = &dmabuf->cb_out;
/* Check that callback isn't busy */
spin_lock_irq(&dmabuf->poll.lock);
if (dcb->active)
events &= ~EPOLLOUT;
else
dcb->active = EPOLLOUT;
spin_unlock_irq(&dmabuf->poll.lock);
if (events & EPOLLOUT) {
/* Paired with fput in dma_buf_poll_cb */
get_file(dmabuf->file);
if (!dma_buf_poll_add_cb(resv, true, dcb))
/* No callback queued, wake up any other waiters */
dma_buf_poll_cb(NULL, &dcb->cb);
else
events &= ~EPOLLOUT;
}
}
if (events & EPOLLIN) {
struct dma_buf_poll_cb_t *dcb = &dmabuf->cb_in;
/* Check that callback isn't busy */
spin_lock_irq(&dmabuf->poll.lock);
if (dcb->active)
events &= ~EPOLLIN;
else
dcb->active = EPOLLIN;
spin_unlock_irq(&dmabuf->poll.lock);
if (events & EPOLLIN) {
/* Paired with fput in dma_buf_poll_cb */
get_file(dmabuf->file);
if (!dma_buf_poll_add_cb(resv, false, dcb))
/* No callback queued, wake up any other waiters */
dma_buf_poll_cb(NULL, &dcb->cb);
else
events &= ~EPOLLIN;
}
}
dma_resv_unlock(resv);
return events;
}
/**
* dma_buf_set_name - Set a name to a specific dma_buf to track the usage.
* It could support changing the name of the dma-buf if the same
* piece of memory is used for multiple purpose between different devices.
*
* @dmabuf: [in] dmabuf buffer that will be renamed.
* @buf: [in] A piece of userspace memory that contains the name of
* the dma-buf.
*
* Returns 0 on success. If the dma-buf buffer is already attached to
* devices, return -EBUSY.
*
*/
static long dma_buf_set_name(struct dma_buf *dmabuf, const char __user *buf)
{
char *name = strndup_user(buf, DMA_BUF_NAME_LEN);
if (IS_ERR(name))
return PTR_ERR(name);
spin_lock(&dmabuf->name_lock);
kfree(dmabuf->name);
dmabuf->name = name;
spin_unlock(&dmabuf->name_lock);
return 0;
}
#if IS_ENABLED(CONFIG_SYNC_FILE)
static long dma_buf_export_sync_file(struct dma_buf *dmabuf,
void __user *user_data)
{
struct dma_buf_export_sync_file arg;
enum dma_resv_usage usage;
struct dma_fence *fence = NULL;
struct sync_file *sync_file;
int fd, ret;
if (copy_from_user(&arg, user_data, sizeof(arg)))
return -EFAULT;
if (arg.flags & ~DMA_BUF_SYNC_RW)
return -EINVAL;
if ((arg.flags & DMA_BUF_SYNC_RW) == 0)
return -EINVAL;
fd = get_unused_fd_flags(O_CLOEXEC);
if (fd < 0)
return fd;
usage = dma_resv_usage_rw(arg.flags & DMA_BUF_SYNC_WRITE);
ret = dma_resv_get_singleton(dmabuf->resv, usage, &fence);
if (ret)
goto err_put_fd;
if (!fence)
fence = dma_fence_get_stub();
sync_file = sync_file_create(fence);
dma_fence_put(fence);
if (!sync_file) {
ret = -ENOMEM;
goto err_put_fd;
}
arg.fd = fd;
if (copy_to_user(user_data, &arg, sizeof(arg))) {
ret = -EFAULT;
goto err_put_file;
}
fd_install(fd, sync_file->file);
return 0;
err_put_file:
fput(sync_file->file);
err_put_fd:
put_unused_fd(fd);
return ret;
}
static long dma_buf_import_sync_file(struct dma_buf *dmabuf,
const void __user *user_data)
{
struct dma_buf_import_sync_file arg;
struct dma_fence *fence, *f;
enum dma_resv_usage usage;
struct dma_fence_unwrap iter;
unsigned int num_fences;
int ret = 0;
if (copy_from_user(&arg, user_data, sizeof(arg)))
return -EFAULT;
if (arg.flags & ~DMA_BUF_SYNC_RW)
return -EINVAL;
if ((arg.flags & DMA_BUF_SYNC_RW) == 0)
return -EINVAL;
fence = sync_file_get_fence(arg.fd);
if (!fence)
return -EINVAL;
usage = (arg.flags & DMA_BUF_SYNC_WRITE) ? DMA_RESV_USAGE_WRITE :
DMA_RESV_USAGE_READ;
num_fences = 0;
dma_fence_unwrap_for_each(f, &iter, fence)
++num_fences;
if (num_fences > 0) {
dma_resv_lock(dmabuf->resv, NULL);
ret = dma_resv_reserve_fences(dmabuf->resv, num_fences);
if (!ret) {
dma_fence_unwrap_for_each(f, &iter, fence)
dma_resv_add_fence(dmabuf->resv, f, usage);
}
dma_resv_unlock(dmabuf->resv);
}
dma_fence_put(fence);
return ret;
}
#endif
static long dma_buf_ioctl(struct file *file,
unsigned int cmd, unsigned long arg)
{
struct dma_buf *dmabuf;
struct dma_buf_sync sync;
enum dma_data_direction direction;
int ret;
dmabuf = file->private_data;
switch (cmd) {
case DMA_BUF_IOCTL_SYNC:
if (copy_from_user(&sync, (void __user *) arg, sizeof(sync)))
return -EFAULT;
if (sync.flags & ~DMA_BUF_SYNC_VALID_FLAGS_MASK)
return -EINVAL;
switch (sync.flags & DMA_BUF_SYNC_RW) {
case DMA_BUF_SYNC_READ:
direction = DMA_FROM_DEVICE;
break;
case DMA_BUF_SYNC_WRITE:
direction = DMA_TO_DEVICE;
break;
case DMA_BUF_SYNC_RW:
direction = DMA_BIDIRECTIONAL;
break;
default:
return -EINVAL;
}
if (sync.flags & DMA_BUF_SYNC_END)
ret = dma_buf_end_cpu_access(dmabuf, direction);
else
ret = dma_buf_begin_cpu_access(dmabuf, direction);
return ret;
case DMA_BUF_SET_NAME_A:
case DMA_BUF_SET_NAME_B:
return dma_buf_set_name(dmabuf, (const char __user *)arg);
#if IS_ENABLED(CONFIG_SYNC_FILE)
case DMA_BUF_IOCTL_EXPORT_SYNC_FILE:
return dma_buf_export_sync_file(dmabuf, (void __user *)arg);
case DMA_BUF_IOCTL_IMPORT_SYNC_FILE:
return dma_buf_import_sync_file(dmabuf, (const void __user *)arg);
#endif
default:
return -ENOTTY;
}
}
static void dma_buf_show_fdinfo(struct seq_file *m, struct file *file)
{
struct dma_buf *dmabuf = file->private_data;
seq_printf(m, "size:\t%zu\n", dmabuf->size);
/* Don't count the temporary reference taken inside procfs seq_show */
seq_printf(m, "count:\t%ld\n", file_count(dmabuf->file) - 1);
seq_printf(m, "exp_name:\t%s\n", dmabuf->exp_name);
spin_lock(&dmabuf->name_lock);
if (dmabuf->name)
seq_printf(m, "name:\t%s\n", dmabuf->name);
spin_unlock(&dmabuf->name_lock);
}
static const struct file_operations dma_buf_fops = {
.release = dma_buf_file_release,
.mmap = dma_buf_mmap_internal,
.llseek = dma_buf_llseek,
.poll = dma_buf_poll,
.unlocked_ioctl = dma_buf_ioctl,
.compat_ioctl = compat_ptr_ioctl,
.show_fdinfo = dma_buf_show_fdinfo,
};
/*
* is_dma_buf_file - Check if struct file* is associated with dma_buf
*/
static inline int is_dma_buf_file(struct file *file)
{
return file->f_op == &dma_buf_fops;
}
static struct file *dma_buf_getfile(size_t size, int flags)
{
static atomic64_t dmabuf_inode = ATOMIC64_INIT(0);
struct inode *inode = alloc_anon_inode(dma_buf_mnt->mnt_sb);
struct file *file;
if (IS_ERR(inode))
return ERR_CAST(inode);
inode->i_size = size;
inode_set_bytes(inode, size);
/*
* The ->i_ino acquired from get_next_ino() is not unique thus
* not suitable for using it as dentry name by dmabuf stats.
* Override ->i_ino with the unique and dmabuffs specific
* value.
*/
inode->i_ino = atomic64_add_return(1, &dmabuf_inode);
flags &= O_ACCMODE | O_NONBLOCK;
file = alloc_file_pseudo(inode, dma_buf_mnt, "dmabuf",
flags, &dma_buf_fops);
if (IS_ERR(file))
goto err_alloc_file;
return file;
err_alloc_file:
iput(inode);
return file;
}
/**
* DOC: dma buf device access
*
* For device DMA access to a shared DMA buffer the usual sequence of operations
* is fairly simple:
*
* 1. The exporter defines his exporter instance using
* DEFINE_DMA_BUF_EXPORT_INFO() and calls dma_buf_export() to wrap a private
* buffer object into a &dma_buf. It then exports that &dma_buf to userspace
* as a file descriptor by calling dma_buf_fd().
*
* 2. Userspace passes this file-descriptors to all drivers it wants this buffer
* to share with: First the file descriptor is converted to a &dma_buf using
* dma_buf_get(). Then the buffer is attached to the device using
* dma_buf_attach().
*
* Up to this stage the exporter is still free to migrate or reallocate the
* backing storage.
*
* 3. Once the buffer is attached to all devices userspace can initiate DMA
* access to the shared buffer. In the kernel this is done by calling
* dma_buf_map_attachment() and dma_buf_unmap_attachment().
*
* 4. Once a driver is done with a shared buffer it needs to call
* dma_buf_detach() (after cleaning up any mappings) and then release the
* reference acquired with dma_buf_get() by calling dma_buf_put().
*
* For the detailed semantics exporters are expected to implement see
* &dma_buf_ops.
*/
/**
* dma_buf_export - Creates a new dma_buf, and associates an anon file
* with this buffer, so it can be exported.
* Also connect the allocator specific data and ops to the buffer.
* Additionally, provide a name string for exporter; useful in debugging.
*
* @exp_info: [in] holds all the export related information provided
* by the exporter. see &struct dma_buf_export_info
* for further details.
*
* Returns, on success, a newly created struct dma_buf object, which wraps the
* supplied private data and operations for struct dma_buf_ops. On either
* missing ops, or error in allocating struct dma_buf, will return negative
* error.
*
* For most cases the easiest way to create @exp_info is through the
* %DEFINE_DMA_BUF_EXPORT_INFO macro.
*/
struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info)
{
struct dma_buf *dmabuf;
struct dma_resv *resv = exp_info->resv;
struct file *file;
size_t alloc_size = sizeof(struct dma_buf);
int ret;
if (WARN_ON(!exp_info->priv || !exp_info->ops
|| !exp_info->ops->map_dma_buf
|| !exp_info->ops->unmap_dma_buf
|| !exp_info->ops->release))
return ERR_PTR(-EINVAL);
if (WARN_ON(exp_info->ops->cache_sgt_mapping &&
(exp_info->ops->pin || exp_info->ops->unpin)))
return ERR_PTR(-EINVAL);
if (WARN_ON(!exp_info->ops->pin != !exp_info->ops->unpin))
return ERR_PTR(-EINVAL);
if (!try_module_get(exp_info->owner))
return ERR_PTR(-ENOENT);
file = dma_buf_getfile(exp_info->size, exp_info->flags);
if (IS_ERR(file)) {
ret = PTR_ERR(file);
goto err_module;
}
if (!exp_info->resv)
alloc_size += sizeof(struct dma_resv);
else
/* prevent &dma_buf[1] == dma_buf->resv */
alloc_size += 1;
dmabuf = kzalloc(alloc_size, GFP_KERNEL);
if (!dmabuf) {
ret = -ENOMEM;
goto err_file;
}
dmabuf->priv = exp_info->priv;
dmabuf->ops = exp_info->ops;
dmabuf->size = exp_info->size;
dmabuf->exp_name = exp_info->exp_name;
dmabuf->owner = exp_info->owner;
spin_lock_init(&dmabuf->name_lock);
init_waitqueue_head(&dmabuf->poll);
dmabuf->cb_in.poll = dmabuf->cb_out.poll = &dmabuf->poll;
dmabuf->cb_in.active = dmabuf->cb_out.active = 0;
INIT_LIST_HEAD(&dmabuf->attachments);
if (!resv) {
dmabuf->resv = (struct dma_resv *)&dmabuf[1];
dma_resv_init(dmabuf->resv);
} else {
dmabuf->resv = resv;
}
ret = dma_buf_stats_setup(dmabuf, file);
if (ret)
goto err_dmabuf;
file->private_data = dmabuf;
file->f_path.dentry->d_fsdata = dmabuf;
dmabuf->file = file;
__dma_buf_debugfs_list_add(dmabuf);
return dmabuf;
err_dmabuf:
if (!resv)
dma_resv_fini(dmabuf->resv);
kfree(dmabuf);
err_file:
fput(file);
err_module:
module_put(exp_info->owner);
return ERR_PTR(ret);
}
EXPORT_SYMBOL_NS_GPL(dma_buf_export, DMA_BUF);
/**
* dma_buf_fd - returns a file descriptor for the given struct dma_buf
* @dmabuf: [in] pointer to dma_buf for which fd is required.
* @flags: [in] flags to give to fd
*
* On success, returns an associated 'fd'. Else, returns error.
*/
int dma_buf_fd(struct dma_buf *dmabuf, int flags)
{
int fd;
if (!dmabuf || !dmabuf->file)
return -EINVAL;
fd = get_unused_fd_flags(flags);
if (fd < 0)
return fd;
fd_install(fd, dmabuf->file);
return fd;
}
EXPORT_SYMBOL_NS_GPL(dma_buf_fd, DMA_BUF);
/**
* dma_buf_get - returns the struct dma_buf related to an fd
* @fd: [in] fd associated with the struct dma_buf to be returned
*
* On success, returns the struct dma_buf associated with an fd; uses
* file's refcounting done by fget to increase refcount. returns ERR_PTR
* otherwise.
*/
struct dma_buf *dma_buf_get(int fd)
{
struct file *file;
file = fget(fd);
if (!file)
return ERR_PTR(-EBADF);
if (!is_dma_buf_file(file)) {
fput(file);
return ERR_PTR(-EINVAL);
}
return file->private_data;
}
EXPORT_SYMBOL_NS_GPL(dma_buf_get, DMA_BUF);
/**
* dma_buf_put - decreases refcount of the buffer
* @dmabuf: [in] buffer to reduce refcount of
*
* Uses file's refcounting done implicitly by fput().
*
* If, as a result of this call, the refcount becomes 0, the 'release' file
* operation related to this fd is called. It calls &dma_buf_ops.release vfunc
* in turn, and frees the memory allocated for dmabuf when exported.
*/
void dma_buf_put(struct dma_buf *dmabuf)
{
if (WARN_ON(!dmabuf || !dmabuf->file))
return;
fput(dmabuf->file);
}
EXPORT_SYMBOL_NS_GPL(dma_buf_put, DMA_BUF);
static void mangle_sg_table(struct sg_table *sg_table)
{
#ifdef CONFIG_DMABUF_DEBUG
int i;
struct scatterlist *sg;
/* To catch abuse of the underlying struct page by importers mix
* up the bits, but take care to preserve the low SG_ bits to
* not corrupt the sgt. The mixing is undone in __unmap_dma_buf
* before passing the sgt back to the exporter. */
for_each_sgtable_sg(sg_table, sg, i)
sg->page_link ^= ~0xffUL;
#endif
}
static struct sg_table * __map_dma_buf(struct dma_buf_attachment *attach,
enum dma_data_direction direction)
{
struct sg_table *sg_table;
signed long ret;
sg_table = attach->dmabuf->ops->map_dma_buf(attach, direction);
if (IS_ERR_OR_NULL(sg_table))
return sg_table;
if (!dma_buf_attachment_is_dynamic(attach)) {
ret = dma_resv_wait_timeout(attach->dmabuf->resv,
DMA_RESV_USAGE_KERNEL, true,
MAX_SCHEDULE_TIMEOUT);
if (ret < 0) {
attach->dmabuf->ops->unmap_dma_buf(attach, sg_table,
direction);
return ERR_PTR(ret);
}
}
mangle_sg_table(sg_table);
return sg_table;
}
/**
* DOC: locking convention
*
* In order to avoid deadlock situations between dma-buf exports and importers,
* all dma-buf API users must follow the common dma-buf locking convention.
*
* Convention for importers
*
* 1. Importers must hold the dma-buf reservation lock when calling these
* functions:
*
* - dma_buf_pin()
* - dma_buf_unpin()
* - dma_buf_map_attachment()
* - dma_buf_unmap_attachment()
* - dma_buf_vmap()
* - dma_buf_vunmap()
*
* 2. Importers must not hold the dma-buf reservation lock when calling these
* functions:
*
* - dma_buf_attach()
* - dma_buf_dynamic_attach()
* - dma_buf_detach()
* - dma_buf_export()
* - dma_buf_fd()
* - dma_buf_get()
* - dma_buf_put()
* - dma_buf_mmap()
* - dma_buf_begin_cpu_access()
* - dma_buf_end_cpu_access()
* - dma_buf_map_attachment_unlocked()
* - dma_buf_unmap_attachment_unlocked()
* - dma_buf_vmap_unlocked()
* - dma_buf_vunmap_unlocked()
*
* Convention for exporters
*
* 1. These &dma_buf_ops callbacks are invoked with unlocked dma-buf
* reservation and exporter can take the lock:
*
* - &dma_buf_ops.attach()
* - &dma_buf_ops.detach()
* - &dma_buf_ops.release()
* - &dma_buf_ops.begin_cpu_access()
* - &dma_buf_ops.end_cpu_access()
* - &dma_buf_ops.mmap()
*
* 2. These &dma_buf_ops callbacks are invoked with locked dma-buf
* reservation and exporter can't take the lock:
*
* - &dma_buf_ops.pin()
* - &dma_buf_ops.unpin()
* - &dma_buf_ops.map_dma_buf()
* - &dma_buf_ops.unmap_dma_buf()
* - &dma_buf_ops.vmap()
* - &dma_buf_ops.vunmap()
*
* 3. Exporters must hold the dma-buf reservation lock when calling these
* functions:
*
* - dma_buf_move_notify()
*/
/**
* dma_buf_dynamic_attach - Add the device to dma_buf's attachments list
* @dmabuf: [in] buffer to attach device to.
* @dev: [in] device to be attached.
* @importer_ops: [in] importer operations for the attachment
* @importer_priv: [in] importer private pointer for the attachment
*
* Returns struct dma_buf_attachment pointer for this attachment. Attachments
* must be cleaned up by calling dma_buf_detach().
*
* Optionally this calls &dma_buf_ops.attach to allow device-specific attach
* functionality.
*
* Returns:
*
* A pointer to newly created &dma_buf_attachment on success, or a negative
* error code wrapped into a pointer on failure.
*
* Note that this can fail if the backing storage of @dmabuf is in a place not
* accessible to @dev, and cannot be moved to a more suitable place. This is
* indicated with the error code -EBUSY.
*/
struct dma_buf_attachment *
dma_buf_dynamic_attach(struct dma_buf *dmabuf, struct device *dev,
const struct dma_buf_attach_ops *importer_ops,
void *importer_priv)
{
struct dma_buf_attachment *attach;
int ret;
if (WARN_ON(!dmabuf || !dev))
return ERR_PTR(-EINVAL);
if (WARN_ON(importer_ops && !importer_ops->move_notify))
return ERR_PTR(-EINVAL);
attach = kzalloc(sizeof(*attach), GFP_KERNEL);
if (!attach)
return ERR_PTR(-ENOMEM);
attach->dev = dev;
attach->dmabuf = dmabuf;
if (importer_ops)
attach->peer2peer = importer_ops->allow_peer2peer;
attach->importer_ops = importer_ops;
attach->importer_priv = importer_priv;
if (dmabuf->ops->attach) {
ret = dmabuf->ops->attach(dmabuf, attach);
if (ret)
goto err_attach;
}
dma_resv_lock(dmabuf->resv, NULL);
list_add(&attach->node, &dmabuf->attachments);
dma_resv_unlock(dmabuf->resv);
/* When either the importer or the exporter can't handle dynamic
* mappings we cache the mapping here to avoid issues with the
* reservation object lock.
*/
if (dma_buf_attachment_is_dynamic(attach) !=
dma_buf_is_dynamic(dmabuf)) {
struct sg_table *sgt;
dma_resv_lock(attach->dmabuf->resv, NULL);
if (dma_buf_is_dynamic(attach->dmabuf)) {
ret = dmabuf->ops->pin(attach);
if (ret)
goto err_unlock;
}
sgt = __map_dma_buf(attach, DMA_BIDIRECTIONAL);
if (!sgt)
sgt = ERR_PTR(-ENOMEM);
if (IS_ERR(sgt)) {
ret = PTR_ERR(sgt);
goto err_unpin;
}
dma_resv_unlock(attach->dmabuf->resv);
attach->sgt = sgt;
attach->dir = DMA_BIDIRECTIONAL;
}
return attach;
err_attach:
kfree(attach);
return ERR_PTR(ret);
err_unpin:
if (dma_buf_is_dynamic(attach->dmabuf))
dmabuf->ops->unpin(attach);
err_unlock:
dma_resv_unlock(attach->dmabuf->resv);
dma_buf_detach(dmabuf, attach);
return ERR_PTR(ret);
}
EXPORT_SYMBOL_NS_GPL(dma_buf_dynamic_attach, DMA_BUF);
/**
* dma_buf_attach - Wrapper for dma_buf_dynamic_attach
* @dmabuf: [in] buffer to attach device to.
* @dev: [in] device to be attached.
*
* Wrapper to call dma_buf_dynamic_attach() for drivers which still use a static
* mapping.
*/
struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf,
struct device *dev)
{
return dma_buf_dynamic_attach(dmabuf, dev, NULL, NULL);
}
EXPORT_SYMBOL_NS_GPL(dma_buf_attach, DMA_BUF);
static void __unmap_dma_buf(struct dma_buf_attachment *attach,
struct sg_table *sg_table,
enum dma_data_direction direction)
{
/* uses XOR, hence this unmangles */
mangle_sg_table(sg_table);
attach->dmabuf->ops->unmap_dma_buf(attach, sg_table, direction);
}
/**
* dma_buf_detach - Remove the given attachment from dmabuf's attachments list
* @dmabuf: [in] buffer to detach from.
* @attach: [in] attachment to be detached; is free'd after this call.
*
* Clean up a device attachment obtained by calling dma_buf_attach().
*
* Optionally this calls &dma_buf_ops.detach for device-specific detach.
*/
void dma_buf_detach(struct dma_buf *dmabuf, struct dma_buf_attachment *attach)
{
if (WARN_ON(!dmabuf || !attach || dmabuf != attach->dmabuf))
return;
dma_resv_lock(dmabuf->resv, NULL);
if (attach->sgt) {
__unmap_dma_buf(attach, attach->sgt, attach->dir);
if (dma_buf_is_dynamic(attach->dmabuf))
dmabuf->ops->unpin(attach);
}
list_del(&attach->node);
dma_resv_unlock(dmabuf->resv);
if (dmabuf->ops->detach)
dmabuf->ops->detach(dmabuf, attach);
kfree(attach);
}
EXPORT_SYMBOL_NS_GPL(dma_buf_detach, DMA_BUF);
/**
* dma_buf_pin - Lock down the DMA-buf
* @attach: [in] attachment which should be pinned
*
* Only dynamic importers (who set up @attach with dma_buf_dynamic_attach()) may
* call this, and only for limited use cases like scanout and not for temporary
* pin operations. It is not permitted to allow userspace to pin arbitrary
* amounts of buffers through this interface.
*
* Buffers must be unpinned by calling dma_buf_unpin().
*
* Returns:
* 0 on success, negative error code on failure.
*/
int dma_buf_pin(struct dma_buf_attachment *attach)
{
struct dma_buf *dmabuf = attach->dmabuf;
int ret = 0;
WARN_ON(!dma_buf_attachment_is_dynamic(attach));
dma_resv_assert_held(dmabuf->resv);
if (dmabuf->ops->pin)
ret = dmabuf->ops->pin(attach);
return ret;
}
EXPORT_SYMBOL_NS_GPL(dma_buf_pin, DMA_BUF);
/**
* dma_buf_unpin - Unpin a DMA-buf
* @attach: [in] attachment which should be unpinned
*
* This unpins a buffer pinned by dma_buf_pin() and allows the exporter to move
* any mapping of @attach again and inform the importer through
* &dma_buf_attach_ops.move_notify.
*/
void dma_buf_unpin(struct dma_buf_attachment *attach)
{
struct dma_buf *dmabuf = attach->dmabuf;
WARN_ON(!dma_buf_attachment_is_dynamic(attach));
dma_resv_assert_held(dmabuf->resv);
if (dmabuf->ops->unpin)
dmabuf->ops->unpin(attach);
}
EXPORT_SYMBOL_NS_GPL(dma_buf_unpin, DMA_BUF);
/**
* dma_buf_map_attachment - Returns the scatterlist table of the attachment;
* mapped into _device_ address space. Is a wrapper for map_dma_buf() of the
* dma_buf_ops.
* @attach: [in] attachment whose scatterlist is to be returned
* @direction: [in] direction of DMA transfer
*
* Returns sg_table containing the scatterlist to be returned; returns ERR_PTR
* on error. May return -EINTR if it is interrupted by a signal.
*
* On success, the DMA addresses and lengths in the returned scatterlist are
* PAGE_SIZE aligned.
*
* A mapping must be unmapped by using dma_buf_unmap_attachment(). Note that
* the underlying backing storage is pinned for as long as a mapping exists,
* therefore users/importers should not hold onto a mapping for undue amounts of
* time.
*
* Important: Dynamic importers must wait for the exclusive fence of the struct
* dma_resv attached to the DMA-BUF first.
*/
struct sg_table *dma_buf_map_attachment(struct dma_buf_attachment *attach,
enum dma_data_direction direction)
{
struct sg_table *sg_table;
int r;
might_sleep();
if (WARN_ON(!attach || !attach->dmabuf))
return ERR_PTR(-EINVAL);
dma_resv_assert_held(attach->dmabuf->resv);
if (attach->sgt) {
/*
* Two mappings with different directions for the same
* attachment are not allowed.
*/
if (attach->dir != direction &&
attach->dir != DMA_BIDIRECTIONAL)
return ERR_PTR(-EBUSY);
return attach->sgt;
}
if (dma_buf_is_dynamic(attach->dmabuf)) {
if (!IS_ENABLED(CONFIG_DMABUF_MOVE_NOTIFY)) {
r = attach->dmabuf->ops->pin(attach);
if (r)
return ERR_PTR(r);
}
}
sg_table = __map_dma_buf(attach, direction);
if (!sg_table)
sg_table = ERR_PTR(-ENOMEM);
if (IS_ERR(sg_table) && dma_buf_is_dynamic(attach->dmabuf) &&
!IS_ENABLED(CONFIG_DMABUF_MOVE_NOTIFY))
attach->dmabuf->ops->unpin(attach);
if (!IS_ERR(sg_table) && attach->dmabuf->ops->cache_sgt_mapping) {
attach->sgt = sg_table;
attach->dir = direction;
}
#ifdef CONFIG_DMA_API_DEBUG
if (!IS_ERR(sg_table)) {
struct scatterlist *sg;
u64 addr;
int len;
int i;
for_each_sgtable_dma_sg(sg_table, sg, i) {
addr = sg_dma_address(sg);
len = sg_dma_len(sg);
if (!PAGE_ALIGNED(addr) || !PAGE_ALIGNED(len)) {
pr_debug("%s: addr %llx or len %x is not page aligned!\n",
__func__, addr, len);
}
}
}
#endif /* CONFIG_DMA_API_DEBUG */
return sg_table;
}
EXPORT_SYMBOL_NS_GPL(dma_buf_map_attachment, DMA_BUF);
/**
* dma_buf_map_attachment_unlocked - Returns the scatterlist table of the attachment;
* mapped into _device_ address space. Is a wrapper for map_dma_buf() of the
* dma_buf_ops.
* @attach: [in] attachment whose scatterlist is to be returned
* @direction: [in] direction of DMA transfer
*
* Unlocked variant of dma_buf_map_attachment().
*/
struct sg_table *
dma_buf_map_attachment_unlocked(struct dma_buf_attachment *attach,
enum dma_data_direction direction)
{
struct sg_table *sg_table;
might_sleep();
if (WARN_ON(!attach || !attach->dmabuf))
return ERR_PTR(-EINVAL);
dma_resv_lock(attach->dmabuf->resv, NULL);
sg_table = dma_buf_map_attachment(attach, direction);
dma_resv_unlock(attach->dmabuf->resv);
return sg_table;
}
EXPORT_SYMBOL_NS_GPL(dma_buf_map_attachment_unlocked, DMA_BUF);
/**
* dma_buf_unmap_attachment - unmaps and decreases usecount of the buffer;might
* deallocate the scatterlist associated. Is a wrapper for unmap_dma_buf() of
* dma_buf_ops.
* @attach: [in] attachment to unmap buffer from
* @sg_table: [in] scatterlist info of the buffer to unmap
* @direction: [in] direction of DMA transfer
*
* This unmaps a DMA mapping for @attached obtained by dma_buf_map_attachment().
*/
void dma_buf_unmap_attachment(struct dma_buf_attachment *attach,
struct sg_table *sg_table,
enum dma_data_direction direction)
{
might_sleep();
if (WARN_ON(!attach || !attach->dmabuf || !sg_table))
return;
dma_resv_assert_held(attach->dmabuf->resv);
if (attach->sgt == sg_table)
return;
__unmap_dma_buf(attach, sg_table, direction);
if (dma_buf_is_dynamic(attach->dmabuf) &&
!IS_ENABLED(CONFIG_DMABUF_MOVE_NOTIFY))
dma_buf_unpin(attach);
}
EXPORT_SYMBOL_NS_GPL(dma_buf_unmap_attachment, DMA_BUF);
/**
* dma_buf_unmap_attachment_unlocked - unmaps and decreases usecount of the buffer;might
* deallocate the scatterlist associated. Is a wrapper for unmap_dma_buf() of
* dma_buf_ops.
* @attach: [in] attachment to unmap buffer from
* @sg_table: [in] scatterlist info of the buffer to unmap
* @direction: [in] direction of DMA transfer
*
* Unlocked variant of dma_buf_unmap_attachment().
*/
void dma_buf_unmap_attachment_unlocked(struct dma_buf_attachment *attach,
struct sg_table *sg_table,
enum dma_data_direction direction)
{
might_sleep();
if (WARN_ON(!attach || !attach->dmabuf || !sg_table))
return;
dma_resv_lock(attach->dmabuf->resv, NULL);
dma_buf_unmap_attachment(attach, sg_table, direction);
dma_resv_unlock(attach->dmabuf->resv);
}
EXPORT_SYMBOL_NS_GPL(dma_buf_unmap_attachment_unlocked, DMA_BUF);
/**
* dma_buf_move_notify - notify attachments that DMA-buf is moving
*
* @dmabuf: [in] buffer which is moving
*
* Informs all attachments that they need to destroy and recreate all their
* mappings.
*/
void dma_buf_move_notify(struct dma_buf *dmabuf)
{
struct dma_buf_attachment *attach;
dma_resv_assert_held(dmabuf->resv);
list_for_each_entry(attach, &dmabuf->attachments, node)
if (attach->importer_ops)
attach->importer_ops->move_notify(attach);
}
EXPORT_SYMBOL_NS_GPL(dma_buf_move_notify, DMA_BUF);
/**
* DOC: cpu access
*
* There are multiple reasons for supporting CPU access to a dma buffer object:
*
* - Fallback operations in the kernel, for example when a device is connected
* over USB and the kernel needs to shuffle the data around first before
* sending it away. Cache coherency is handled by bracketing any transactions
* with calls to dma_buf_begin_cpu_access() and dma_buf_end_cpu_access()
* access.
*
* Since for most kernel internal dma-buf accesses need the entire buffer, a
* vmap interface is introduced. Note that on very old 32-bit architectures
* vmalloc space might be limited and result in vmap calls failing.
*
* Interfaces::
*
* void \*dma_buf_vmap(struct dma_buf \*dmabuf, struct iosys_map \*map)
* void dma_buf_vunmap(struct dma_buf \*dmabuf, struct iosys_map \*map)
*
* The vmap call can fail if there is no vmap support in the exporter, or if
* it runs out of vmalloc space. Note that the dma-buf layer keeps a reference
* count for all vmap access and calls down into the exporter's vmap function
* only when no vmapping exists, and only unmaps it once. Protection against
* concurrent vmap/vunmap calls is provided by taking the &dma_buf.lock mutex.
*
* - For full compatibility on the importer side with existing userspace
* interfaces, which might already support mmap'ing buffers. This is needed in
* many processing pipelines (e.g. feeding a software rendered image into a
* hardware pipeline, thumbnail creation, snapshots, ...). Also, Android's ION
* framework already supported this and for DMA buffer file descriptors to
* replace ION buffers mmap support was needed.
*
* There is no special interfaces, userspace simply calls mmap on the dma-buf
* fd. But like for CPU access there's a need to bracket the actual access,
* which is handled by the ioctl (DMA_BUF_IOCTL_SYNC). Note that
* DMA_BUF_IOCTL_SYNC can fail with -EAGAIN or -EINTR, in which case it must
* be restarted.
*
* Some systems might need some sort of cache coherency management e.g. when
* CPU and GPU domains are being accessed through dma-buf at the same time.
* To circumvent this problem there are begin/end coherency markers, that
* forward directly to existing dma-buf device drivers vfunc hooks. Userspace
* can make use of those markers through the DMA_BUF_IOCTL_SYNC ioctl. The
* sequence would be used like following:
*
* - mmap dma-buf fd
* - for each drawing/upload cycle in CPU 1. SYNC_START ioctl, 2. read/write
* to mmap area 3. SYNC_END ioctl. This can be repeated as often as you
* want (with the new data being consumed by say the GPU or the scanout
* device)
* - munmap once you don't need the buffer any more
*
* For correctness and optimal performance, it is always required to use
* SYNC_START and SYNC_END before and after, respectively, when accessing the
* mapped address. Userspace cannot rely on coherent access, even when there
* are systems where it just works without calling these ioctls.
*
* - And as a CPU fallback in userspace processing pipelines.
*
* Similar to the motivation for kernel cpu access it is again important that
* the userspace code of a given importing subsystem can use the same
* interfaces with a imported dma-buf buffer object as with a native buffer
* object. This is especially important for drm where the userspace part of
* contemporary OpenGL, X, and other drivers is huge, and reworking them to
* use a different way to mmap a buffer rather invasive.
*
* The assumption in the current dma-buf interfaces is that redirecting the
* initial mmap is all that's needed. A survey of some of the existing
* subsystems shows that no driver seems to do any nefarious thing like
* syncing up with outstanding asynchronous processing on the device or
* allocating special resources at fault time. So hopefully this is good
* enough, since adding interfaces to intercept pagefaults and allow pte
* shootdowns would increase the complexity quite a bit.
*
* Interface::
*
* int dma_buf_mmap(struct dma_buf \*, struct vm_area_struct \*,
* unsigned long);
*
* If the importing subsystem simply provides a special-purpose mmap call to
* set up a mapping in userspace, calling do_mmap with &dma_buf.file will
* equally achieve that for a dma-buf object.
*/
static int __dma_buf_begin_cpu_access(struct dma_buf *dmabuf,
enum dma_data_direction direction)
{
bool write = (direction == DMA_BIDIRECTIONAL ||
direction == DMA_TO_DEVICE);
struct dma_resv *resv = dmabuf->resv;
long ret;
/* Wait on any implicit rendering fences */
ret = dma_resv_wait_timeout(resv, dma_resv_usage_rw(write),
true, MAX_SCHEDULE_TIMEOUT);
if (ret < 0)
return ret;
return 0;
}
/**
* dma_buf_begin_cpu_access - Must be called before accessing a dma_buf from the
* cpu in the kernel context. Calls begin_cpu_access to allow exporter-specific
* preparations. Coherency is only guaranteed in the specified range for the
* specified access direction.
* @dmabuf: [in] buffer to prepare cpu access for.
* @direction: [in] direction of access.
*
* After the cpu access is complete the caller should call
* dma_buf_end_cpu_access(). Only when cpu access is bracketed by both calls is
* it guaranteed to be coherent with other DMA access.
*
* This function will also wait for any DMA transactions tracked through
* implicit synchronization in &dma_buf.resv. For DMA transactions with explicit
* synchronization this function will only ensure cache coherency, callers must
* ensure synchronization with such DMA transactions on their own.
*
* Can return negative error values, returns 0 on success.
*/
int dma_buf_begin_cpu_access(struct dma_buf *dmabuf,
enum dma_data_direction direction)
{
int ret = 0;
if (WARN_ON(!dmabuf))
return -EINVAL;
might_lock(&dmabuf->resv->lock.base);
if (dmabuf->ops->begin_cpu_access)
ret = dmabuf->ops->begin_cpu_access(dmabuf, direction);
/* Ensure that all fences are waited upon - but we first allow
* the native handler the chance to do so more efficiently if it
* chooses. A double invocation here will be reasonably cheap no-op.
*/
if (ret == 0)
ret = __dma_buf_begin_cpu_access(dmabuf, direction);
return ret;
}
EXPORT_SYMBOL_NS_GPL(dma_buf_begin_cpu_access, DMA_BUF);
/**
* dma_buf_end_cpu_access - Must be called after accessing a dma_buf from the
* cpu in the kernel context. Calls end_cpu_access to allow exporter-specific
* actions. Coherency is only guaranteed in the specified range for the
* specified access direction.
* @dmabuf: [in] buffer to complete cpu access for.
* @direction: [in] direction of access.
*
* This terminates CPU access started with dma_buf_begin_cpu_access().
*
* Can return negative error values, returns 0 on success.
*/
int dma_buf_end_cpu_access(struct dma_buf *dmabuf,
enum dma_data_direction direction)
{
int ret = 0;
WARN_ON(!dmabuf);
might_lock(&dmabuf->resv->lock.base);
if (dmabuf->ops->end_cpu_access)
ret = dmabuf->ops->end_cpu_access(dmabuf, direction);
return ret;
}
EXPORT_SYMBOL_NS_GPL(dma_buf_end_cpu_access, DMA_BUF);
/**
* dma_buf_mmap - Setup up a userspace mmap with the given vma
* @dmabuf: [in] buffer that should back the vma
* @vma: [in] vma for the mmap
* @pgoff: [in] offset in pages where this mmap should start within the
* dma-buf buffer.
*
* This function adjusts the passed in vma so that it points at the file of the
* dma_buf operation. It also adjusts the starting pgoff and does bounds
* checking on the size of the vma. Then it calls the exporters mmap function to
* set up the mapping.
*
* Can return negative error values, returns 0 on success.
*/
int dma_buf_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma,
unsigned long pgoff)
{
if (WARN_ON(!dmabuf || !vma))
return -EINVAL;
/* check if buffer supports mmap */
if (!dmabuf->ops->mmap)
return -EINVAL;
/* check for offset overflow */
if (pgoff + vma_pages(vma) < pgoff)
return -EOVERFLOW;
/* check for overflowing the buffer's size */
if (pgoff + vma_pages(vma) >
dmabuf->size >> PAGE_SHIFT)
return -EINVAL;
/* readjust the vma */
vma_set_file(vma, dmabuf->file);
vma->vm_pgoff = pgoff;
return dmabuf->ops->mmap(dmabuf, vma);
}
EXPORT_SYMBOL_NS_GPL(dma_buf_mmap, DMA_BUF);
/**
* dma_buf_vmap - Create virtual mapping for the buffer object into kernel
* address space. Same restrictions as for vmap and friends apply.
* @dmabuf: [in] buffer to vmap
* @map: [out] returns the vmap pointer
*
* This call may fail due to lack of virtual mapping address space.
* These calls are optional in drivers. The intended use for them
* is for mapping objects linear in kernel space for high use objects.
*
* To ensure coherency users must call dma_buf_begin_cpu_access() and
* dma_buf_end_cpu_access() around any cpu access performed through this
* mapping.
*
* Returns 0 on success, or a negative errno code otherwise.
*/
int dma_buf_vmap(struct dma_buf *dmabuf, struct iosys_map *map)
{
struct iosys_map ptr;
int ret;
iosys_map_clear(map);
if (WARN_ON(!dmabuf))
return -EINVAL;
dma_resv_assert_held(dmabuf->resv);
if (!dmabuf->ops->vmap)
return -EINVAL;
if (dmabuf->vmapping_counter) {
dmabuf->vmapping_counter++;
BUG_ON(iosys_map_is_null(&dmabuf->vmap_ptr));
*map = dmabuf->vmap_ptr;
return 0;
}
BUG_ON(iosys_map_is_set(&dmabuf->vmap_ptr));
ret = dmabuf->ops->vmap(dmabuf, &ptr);
if (WARN_ON_ONCE(ret))
return ret;
dmabuf->vmap_ptr = ptr;
dmabuf->vmapping_counter = 1;
*map = dmabuf->vmap_ptr;
return 0;
}
EXPORT_SYMBOL_NS_GPL(dma_buf_vmap, DMA_BUF);
/**
* dma_buf_vmap_unlocked - Create virtual mapping for the buffer object into kernel
* address space. Same restrictions as for vmap and friends apply.
* @dmabuf: [in] buffer to vmap
* @map: [out] returns the vmap pointer
*
* Unlocked version of dma_buf_vmap()
*
* Returns 0 on success, or a negative errno code otherwise.
*/
int dma_buf_vmap_unlocked(struct dma_buf *dmabuf, struct iosys_map *map)
{
int ret;
iosys_map_clear(map);
if (WARN_ON(!dmabuf))
return -EINVAL;
dma_resv_lock(dmabuf->resv, NULL);
ret = dma_buf_vmap(dmabuf, map);
dma_resv_unlock(dmabuf->resv);
return ret;
}
EXPORT_SYMBOL_NS_GPL(dma_buf_vmap_unlocked, DMA_BUF);
/**
* dma_buf_vunmap - Unmap a vmap obtained by dma_buf_vmap.
* @dmabuf: [in] buffer to vunmap
* @map: [in] vmap pointer to vunmap
*/
void dma_buf_vunmap(struct dma_buf *dmabuf, struct iosys_map *map)
{
if (WARN_ON(!dmabuf))
return;
dma_resv_assert_held(dmabuf->resv);
BUG_ON(iosys_map_is_null(&dmabuf->vmap_ptr));
BUG_ON(dmabuf->vmapping_counter == 0);
BUG_ON(!iosys_map_is_equal(&dmabuf->vmap_ptr, map));
if (--dmabuf->vmapping_counter == 0) {
if (dmabuf->ops->vunmap)
dmabuf->ops->vunmap(dmabuf, map);
iosys_map_clear(&dmabuf->vmap_ptr);
}
}
EXPORT_SYMBOL_NS_GPL(dma_buf_vunmap, DMA_BUF);
/**
* dma_buf_vunmap_unlocked - Unmap a vmap obtained by dma_buf_vmap.
* @dmabuf: [in] buffer to vunmap
* @map: [in] vmap pointer to vunmap
*/
void dma_buf_vunmap_unlocked(struct dma_buf *dmabuf, struct iosys_map *map)
{
if (WARN_ON(!dmabuf))
return;
dma_resv_lock(dmabuf->resv, NULL);
dma_buf_vunmap(dmabuf, map);
dma_resv_unlock(dmabuf->resv);
}
EXPORT_SYMBOL_NS_GPL(dma_buf_vunmap_unlocked, DMA_BUF);
#ifdef CONFIG_DEBUG_FS
static int dma_buf_debug_show(struct seq_file *s, void *unused)
{
struct dma_buf *buf_obj;
struct dma_buf_attachment *attach_obj;
int count = 0, attach_count;
size_t size = 0;
int ret;
ret = mutex_lock_interruptible(&debugfs_list_mutex);
if (ret)
return ret;
seq_puts(s, "\nDma-buf Objects:\n");
seq_printf(s, "%-8s\t%-8s\t%-8s\t%-8s\texp_name\t%-8s\tname\n",
"size", "flags", "mode", "count", "ino");
list_for_each_entry(buf_obj, &debugfs_list, list_node) {
ret = dma_resv_lock_interruptible(buf_obj->resv, NULL);
if (ret)
goto error_unlock;
spin_lock(&buf_obj->name_lock);
seq_printf(s, "%08zu\t%08x\t%08x\t%08ld\t%s\t%08lu\t%s\n",
buf_obj->size,
buf_obj->file->f_flags, buf_obj->file->f_mode,
file_count(buf_obj->file),
buf_obj->exp_name,
file_inode(buf_obj->file)->i_ino,
buf_obj->name ?: "<none>");
spin_unlock(&buf_obj->name_lock);
dma_resv_describe(buf_obj->resv, s);
seq_puts(s, "\tAttached Devices:\n");
attach_count = 0;
list_for_each_entry(attach_obj, &buf_obj->attachments, node) {
seq_printf(s, "\t%s\n", dev_name(attach_obj->dev));
attach_count++;
}
dma_resv_unlock(buf_obj->resv);
seq_printf(s, "Total %d devices attached\n\n",
attach_count);
count++;
size += buf_obj->size;
}
seq_printf(s, "\nTotal %d objects, %zu bytes\n", count, size);
mutex_unlock(&debugfs_list_mutex);
return 0;
error_unlock:
mutex_unlock(&debugfs_list_mutex);
return ret;
}
DEFINE_SHOW_ATTRIBUTE(dma_buf_debug);
static struct dentry *dma_buf_debugfs_dir;
static int dma_buf_init_debugfs(void)
{
struct dentry *d;
int err = 0;
d = debugfs_create_dir("dma_buf", NULL);
if (IS_ERR(d))
return PTR_ERR(d);
dma_buf_debugfs_dir = d;
d = debugfs_create_file("bufinfo", S_IRUGO, dma_buf_debugfs_dir,
NULL, &dma_buf_debug_fops);
if (IS_ERR(d)) {
pr_debug("dma_buf: debugfs: failed to create node bufinfo\n");
debugfs_remove_recursive(dma_buf_debugfs_dir);
dma_buf_debugfs_dir = NULL;
err = PTR_ERR(d);
}
return err;
}
static void dma_buf_uninit_debugfs(void)
{
debugfs_remove_recursive(dma_buf_debugfs_dir);
}
#else
static inline int dma_buf_init_debugfs(void)
{
return 0;
}
static inline void dma_buf_uninit_debugfs(void)
{
}
#endif
static int __init dma_buf_init(void)
{
int ret;
ret = dma_buf_init_sysfs_statistics();
if (ret)
return ret;
dma_buf_mnt = kern_mount(&dma_buf_fs_type);
if (IS_ERR(dma_buf_mnt))
return PTR_ERR(dma_buf_mnt);
dma_buf_init_debugfs();
return 0;
}
subsys_initcall(dma_buf_init);
static void __exit dma_buf_deinit(void)
{
dma_buf_uninit_debugfs();
kern_unmount(dma_buf_mnt);
dma_buf_uninit_sysfs_statistics();
}
__exitcall(dma_buf_deinit);
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