Can you give the attached patch a whirl and let me know if it fixes the
problem?
As I indicated in my previous note, vmwgfx should be the only affected
driver because it looks at dev_mapping in the open hook (others do it when
they create an object, so they are not affected).
I'll probably revise it (and I'll have some general questions about
drm_open syscall) before officially send the patch, but I wanted to get
something quickly to you to check if it fixes your problem. I hope that
your vmwgfx test environment is such that you can reproduce the original
problem.
thanks,
-- Ilija
From 18a489e7415f495c7ba48cc61733d6c7d8f3fd68 Mon Sep 17 00:00:00 2001
From: Ilija Hadzic <ihadzic@xxxxxxxxxxxxxxxxxxxxxx>
Date: Thu, 25 Oct 2012 15:28:05 -0400
Subject: [PATCH] drm: set dev_mapping before calling drm_open_helper
Some drivers (specifically vmwgfx) look at dev_mapping
in their open hook, so we have to set dev->dev_mapping
earlier in the process.
Signed-off-by: Ilija Hadzic <ihadzic@xxxxxxxxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/drm_fops.c | 43 +++++++++++++++++++++++++++++--------------
1 files changed, 29 insertions(+), 14 deletions(-)
diff --git a/drivers/gpu/drm/drm_fops.c b/drivers/gpu/drm/drm_fops.c
index 7ef1b67..50b7b47 100644
--- a/drivers/gpu/drm/drm_fops.c
+++ b/drivers/gpu/drm/drm_fops.c
@@ -121,6 +121,8 @@ int drm_open(struct inode *inode, struct file *filp)
int minor_id = iminor(inode);
struct drm_minor *minor;
int retcode = 0;
+ int need_setup = 0;
+ struct address_space *old_mapping;
minor = idr_find(&drm_minors_idr, minor_id);
if (!minor)
@@ -132,23 +134,36 @@ int drm_open(struct inode *inode, struct file *filp)
if (drm_device_is_unplugged(dev))
return -ENODEV;
+ if (!dev->open_count++)
+ need_setup = 1;
+ mutex_lock(&dev->struct_mutex);
+ old_mapping = dev->dev_mapping;
+ if (old_mapping == NULL)
+ dev->dev_mapping = &inode->i_data;
+ mutex_unlock(&dev->struct_mutex);
+
retcode = drm_open_helper(inode, filp, dev);
- if (!retcode) {
- atomic_inc(&dev->counts[_DRM_STAT_OPENS]);
- if (!dev->open_count++)
- retcode = drm_setup(dev);
- }
- if (!retcode) {
- mutex_lock(&dev->struct_mutex);
- if (dev->dev_mapping == NULL)
- dev->dev_mapping = &inode->i_data;
- /* ihold ensures nobody can remove inode with our i_data */
- ihold(container_of(dev->dev_mapping, struct inode, i_data));
- inode->i_mapping = dev->dev_mapping;
- filp->f_mapping = dev->dev_mapping;
- mutex_unlock(&dev->struct_mutex);
+ if (retcode)
+ goto err_undo;
+ atomic_inc(&dev->counts[_DRM_STAT_OPENS]);
+ if (need_setup) {
+ retcode = drm_setup(dev);
+ if (retcode)
+ goto err_undo;
}
+ /* ihold ensures nobody can remove inode with our i_data */
+ mutex_lock(&dev->struct_mutex);
+ ihold(container_of(dev->dev_mapping, struct inode, i_data));
+ inode->i_mapping = dev->dev_mapping;
+ filp->f_mapping = dev->dev_mapping;
+ mutex_unlock(&dev->struct_mutex);
+ return 0;
+err_undo:
+ dev->open_count--;
+ mutex_lock(&dev->struct_mutex);
+ dev->dev_mapping = old_mapping;
+ mutex_unlock(&dev->struct_mutex);
return retcode;
}
EXPORT_SYMBOL(drm_open);
--
1.7.4.1
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