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drm/exynos: use a new anon file for exynos gem mmaper

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This patch resolves potential deadlock issue that can be incurred
by changing file->f_op and filp->private_data to exynos specific
mapper ops and gem object temporarily.

To resolve this issue, this patch creates a new anon file dedicated
to exynos specific mmaper, and making it used instead of existing one.

Signed-off-by: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
This commit is contained in:
Inki Dae 2013-12-20 19:16:24 +09:00
parent fe3c703c3d
commit 96f5421523
4 changed files with 38 additions and 61 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

21
drivers/gpu/drm/exynos/exynos_drm_drv.c
View File

@ -14,6 +14,8 @@
#include <drm/drmP.h>
#include <drm/drm_crtc_helper.h>
#include <linux/anon_inodes.h>
#include <drm/exynos_drm.h>
#include "exynos_drm_drv.h"
@ -152,9 +154,14 @@ static int exynos_drm_unload(struct drm_device *dev)
return 0;
}
static const struct file_operations exynos_drm_gem_fops = {
.mmap = exynos_drm_gem_mmap_buffer,
};
static int exynos_drm_open(struct drm_device *dev, struct drm_file *file)
{
struct drm_exynos_file_private *file_priv;
struct file *anon_filp;
int ret;
file_priv = kzalloc(sizeof(*file_priv), GFP_KERNEL);
@ -169,6 +176,16 @@ static int exynos_drm_open(struct drm_device *dev, struct drm_file *file)
file->driver_priv = NULL;
}
anon_filp = anon_inode_getfile("exynos_gem", &exynos_drm_gem_fops,
NULL, 0);
if (IS_ERR(anon_filp)) {
kfree(file_priv);
return PTR_ERR(anon_filp);
}
anon_filp->f_mode = FMODE_READ | FMODE_WRITE;
file_priv->anon_filp = anon_filp;
return ret;
}
@ -181,6 +198,7 @@ static void exynos_drm_preclose(struct drm_device *dev,
static void exynos_drm_postclose(struct drm_device *dev, struct drm_file *file)
{
struct exynos_drm_private *private = dev->dev_private;
struct drm_exynos_file_private *file_priv;
struct drm_pending_vblank_event *v, *vt;
struct drm_pending_event *e, *et;
unsigned long flags;
@ -206,6 +224,9 @@ static void exynos_drm_postclose(struct drm_device *dev, struct drm_file *file)
}
spin_unlock_irqrestore(&dev->event_lock, flags);
file_priv = file->driver_priv;
if (file_priv->anon_filp)
fput(file_priv->anon_filp);
kfree(file->driver_priv);
file->driver_priv = NULL;

1
drivers/gpu/drm/exynos/exynos_drm_drv.h
View File

@ -226,6 +226,7 @@ struct exynos_drm_ipp_private {
struct drm_exynos_file_private {
struct exynos_drm_g2d_private *g2d_priv;
struct exynos_drm_ipp_private *ipp_priv;
struct file *anon_filp;
};
/*

74
drivers/gpu/drm/exynos/exynos_drm_gem.c
View File

@ -338,46 +338,22 @@ int exynos_drm_gem_map_offset_ioctl(struct drm_device *dev, void *data,
&args->offset);
}
static struct drm_file *exynos_drm_find_drm_file(struct drm_device *drm_dev,
struct file *filp)
{
struct drm_file *file_priv;
/* find current process's drm_file from filelist. */
list_for_each_entry(file_priv, &drm_dev->filelist, lhead)
if (file_priv->filp == filp)
return file_priv;
WARN_ON(1);
return ERR_PTR(-EFAULT);
}
static int exynos_drm_gem_mmap_buffer(struct file *filp,
int exynos_drm_gem_mmap_buffer(struct file *filp,
struct vm_area_struct *vma)
{
struct drm_gem_object *obj = filp->private_data;
struct exynos_drm_gem_obj *exynos_gem_obj = to_exynos_gem_obj(obj);
struct drm_device *drm_dev = obj->dev;
struct exynos_drm_gem_buf *buffer;
struct drm_file *file_priv;
unsigned long vm_size;
int ret;
WARN_ON(!mutex_is_locked(&obj->dev->struct_mutex));
vma->vm_flags |= VM_IO | VM_DONTEXPAND | VM_DONTDUMP;
vma->vm_private_data = obj;
vma->vm_ops = drm_dev->driver->gem_vm_ops;
/* restore it to driver's fops. */
filp->f_op = fops_get(drm_dev->driver->fops);
file_priv = exynos_drm_find_drm_file(drm_dev, filp);
if (IS_ERR(file_priv))
return PTR_ERR(file_priv);
/* restore it to drm_file. */
filp->private_data = file_priv;
update_vm_cache_attr(exynos_gem_obj, vma);
vm_size = vma->vm_end - vma->vm_start;
@ -411,15 +387,13 @@ static int exynos_drm_gem_mmap_buffer(struct file *filp,
return 0;
}
static const struct file_operations exynos_drm_gem_fops = {
.mmap = exynos_drm_gem_mmap_buffer,
};
int exynos_drm_gem_mmap_ioctl(struct drm_device *dev, void *data,
struct drm_file *file_priv)
{
struct drm_exynos_file_private *exynos_file_priv;
struct drm_exynos_gem_mmap *args = data;
struct drm_gem_object *obj;
struct file *anon_filp;
unsigned long addr;
if (!(dev->driver->driver_features & DRIVER_GEM)) {
@ -427,47 +401,25 @@ int exynos_drm_gem_mmap_ioctl(struct drm_device *dev, void *data,
return -ENODEV;
}
mutex_lock(&dev->struct_mutex);
obj = drm_gem_object_lookup(dev, file_priv, args->handle);
if (!obj) {
DRM_ERROR("failed to lookup gem object.\n");
mutex_unlock(&dev->struct_mutex);
return -EINVAL;
}
/*
* We have to use gem object and its fops for specific mmaper,
* but vm_mmap() can deliver only filp. So we have to change
* filp->f_op and filp->private_data temporarily, then restore
* again. So it is important to keep lock until restoration the
* settings to prevent others from misuse of filp->f_op or
* filp->private_data.
*/
mutex_lock(&dev->struct_mutex);
exynos_file_priv = file_priv->driver_priv;
anon_filp = exynos_file_priv->anon_filp;
anon_filp->private_data = obj;
/*
* Set specific mmper's fops. And it will be restored by
* exynos_drm_gem_mmap_buffer to dev->driver->fops.
* This is used to call specific mapper temporarily.
*/
file_priv->filp->f_op = &exynos_drm_gem_fops;
/*
* Set gem object to private_data so that specific mmaper
* can get the gem object. And it will be restored by
* exynos_drm_gem_mmap_buffer to drm_file.
*/
file_priv->filp->private_data = obj;
addr = vm_mmap(file_priv->filp, 0, args->size,
PROT_READ | PROT_WRITE, MAP_SHARED, 0);
addr = vm_mmap(anon_filp, 0, args->size, PROT_READ | PROT_WRITE,
MAP_SHARED, 0);
drm_gem_object_unreference(obj);
if (IS_ERR_VALUE(addr)) {
/* check filp->f_op, filp->private_data are restored */
if (file_priv->filp->f_op == &exynos_drm_gem_fops) {
file_priv->filp->f_op = fops_get(dev->driver->fops);
file_priv->filp->private_data = file_priv;
}
mutex_unlock(&dev->struct_mutex);
return (int)addr;
}

3
drivers/gpu/drm/exynos/exynos_drm_gem.h
View File

@ -122,6 +122,9 @@ int exynos_drm_gem_map_offset_ioctl(struct drm_device *dev, void *data,
int exynos_drm_gem_mmap_ioctl(struct drm_device *dev, void *data,
struct drm_file *file_priv);
int exynos_drm_gem_mmap_buffer(struct file *filp,
struct vm_area_struct *vma);
/* map user space allocated by malloc to pages. */
int exynos_drm_gem_userptr_ioctl(struct drm_device *dev, void *data,
struct drm_file *file_priv);