[PATCH] bochs: convert to drm_fb_helper_fbdev_setup/teardown

From: Peter Wu
Date: Wed Sep 05 2018 - 10:41:41 EST


Currently unloading bochs_drm (after unbinding the vtconsole) results in
a warning about a leaked connector:

[drm:drm_mode_config_cleanup] *ERROR* connector Virtual-3 leaked!

While investigating a potential fix I noticed that a lot of open-coded
functionality is already implemented elsewhere, so start converting it:
bochs_fbdev_init -> drm_fb_helper_fbdev_setup: trivial (similar impl).
bochs_fbdev_fini -> drm_fb_helper_fbdev_teardown: requires unembedding
"struct drm_framebuffer" from "struct bochs_framebuffer".

Unembedding drm_framebuffer is made easy using drm_gem_fbdev_fb_create
which can replace bochs_fbdev_destroy and custom routines in bochs_mm.c.
For this to work, the GEM object is moved into "drm_framebuffer". After
that, "bochs_framebuffer" is no longer needed and therefore removed.

Remove the unused "size" and "initialized" fields from fb, the latter is
not necessary as drm_fb_helper_fbdev_teardown can be called even if
bochsfb_create fails. This theory was tested by returning early and
late (just before drm_gem_fbdev_fb_create). Both scenarios fail
gracefully although the latter seems to leak the object from
bochsfb_create_object (not a regression).

Guess on the reason for the encoder leak: drm_framebuffer_cleanup was
previously used, but did not destroy much. drm_fb_helper_fbdev_teardown
is now used and calls drm_framebuffer_remove which does a bit more work.

Tested with 'echo 0 > /sys/class/vtconsole/vtcon1/bind; rmmod bochs_drm'
and also with Xorg + fbdev (startx -> xterm). The latter triggered a
warning in ttm_bo_vm_open that existed before, see
https://lkml.kernel.org/r/1464000533-13140-4-git-send-email-mstaudt@xxxxxxx

Signed-off-by: Peter Wu <peter@xxxxxxxxxxxxx>
---
drivers/gpu/drm/bochs/bochs.h | 19 ++-----
drivers/gpu/drm/bochs/bochs_fbdev.c | 79 +++++++----------------------
drivers/gpu/drm/bochs/bochs_kms.c | 7 +--
drivers/gpu/drm/bochs/bochs_mm.c | 74 ---------------------------
4 files changed, 22 insertions(+), 157 deletions(-)

diff --git a/drivers/gpu/drm/bochs/bochs.h b/drivers/gpu/drm/bochs/bochs.h
index 375bf92cd04f..8514a84fbdbe 100644
--- a/drivers/gpu/drm/bochs/bochs.h
+++ b/drivers/gpu/drm/bochs/bochs.h
@@ -51,11 +51,6 @@ enum bochs_types {
BOCHS_UNKNOWN,
};

-struct bochs_framebuffer {
- struct drm_framebuffer base;
- struct drm_gem_object *obj;
-};
-
struct bochs_device {
/* hw */
void __iomem *mmio;
@@ -88,15 +83,11 @@ struct bochs_device {

/* fbdev */
struct {
- struct bochs_framebuffer gfb;
+ struct drm_framebuffer *fb;
struct drm_fb_helper helper;
- int size;
- bool initialized;
} fb;
};

-#define to_bochs_framebuffer(x) container_of(x, struct bochs_framebuffer, base)
-
struct bochs_bo {
struct ttm_buffer_object bo;
struct ttm_placement placement;
@@ -148,15 +139,9 @@ int bochs_dumb_create(struct drm_file *file, struct drm_device *dev,
int bochs_dumb_mmap_offset(struct drm_file *file, struct drm_device *dev,
uint32_t handle, uint64_t *offset);

-int bochs_framebuffer_init(struct drm_device *dev,
- struct bochs_framebuffer *gfb,
- const struct drm_mode_fb_cmd2 *mode_cmd,
- struct drm_gem_object *obj);
int bochs_bo_pin(struct bochs_bo *bo, u32 pl_flag, u64 *gpu_addr);
int bochs_bo_unpin(struct bochs_bo *bo);

-extern const struct drm_mode_config_funcs bochs_mode_funcs;
-
/* bochs_kms.c */
int bochs_kms_init(struct bochs_device *bochs);
void bochs_kms_fini(struct bochs_device *bochs);
@@ -164,3 +149,5 @@ void bochs_kms_fini(struct bochs_device *bochs);
/* bochs_fbdev.c */
int bochs_fbdev_init(struct bochs_device *bochs);
void bochs_fbdev_fini(struct bochs_device *bochs);
+
+extern const struct drm_mode_config_funcs bochs_mode_funcs;
diff --git a/drivers/gpu/drm/bochs/bochs_fbdev.c b/drivers/gpu/drm/bochs/bochs_fbdev.c
index 14eb8d0d5a00..8f4d6c052f7b 100644
--- a/drivers/gpu/drm/bochs/bochs_fbdev.c
+++ b/drivers/gpu/drm/bochs/bochs_fbdev.c
@@ -6,6 +6,7 @@
*/

#include "bochs.h"
+#include <drm/drm_gem_framebuffer_helper.h>

/* ---------------------------------------------------------------------- */

@@ -13,9 +14,7 @@ static int bochsfb_mmap(struct fb_info *info,
struct vm_area_struct *vma)
{
struct drm_fb_helper *fb_helper = info->par;
- struct bochs_device *bochs =
- container_of(fb_helper, struct bochs_device, fb.helper);
- struct bochs_bo *bo = gem_to_bochs_bo(bochs->fb.gfb.obj);
+ struct bochs_bo *bo = gem_to_bochs_bo(fb_helper->fb->obj[0]);

return ttm_fbdev_mmap(vma, &bo->bo);
}
@@ -101,19 +100,20 @@ static int bochsfb_create(struct drm_fb_helper *helper,

/* init fb device */
info = drm_fb_helper_alloc_fbi(helper);
- if (IS_ERR(info))
+ if (IS_ERR(info)) {
+ DRM_ERROR("Failed to allocate fbi: %ld\n", PTR_ERR(info));
return PTR_ERR(info);
+ }

info->par = &bochs->fb.helper;

- ret = bochs_framebuffer_init(bochs->dev, &bochs->fb.gfb, &mode_cmd, gobj);
- if (ret)
- return ret;
-
- bochs->fb.size = size;
+ fb = drm_gem_fbdev_fb_create(bochs->dev, sizes, 0, gobj, NULL);
+ if (IS_ERR(fb)) {
+ DRM_ERROR("Failed to create framebuffer: %ld\n", PTR_ERR(fb));
+ return PTR_ERR(fb);
+ }

/* setup helper */
- fb = &bochs->fb.gfb.base;
bochs->fb.helper.fb = fb;

strcpy(info->fix.id, "bochsdrmfb");
@@ -130,27 +130,6 @@ static int bochsfb_create(struct drm_fb_helper *helper,
drm_vma_offset_remove(&bo->bo.bdev->vma_manager, &bo->bo.vma_node);
info->fix.smem_start = 0;
info->fix.smem_len = size;
-
- bochs->fb.initialized = true;
- return 0;
-}
-
-static int bochs_fbdev_destroy(struct bochs_device *bochs)
-{
- struct bochs_framebuffer *gfb = &bochs->fb.gfb;
-
- DRM_DEBUG_DRIVER("\n");
-
- drm_fb_helper_unregister_fbi(&bochs->fb.helper);
-
- if (gfb->obj) {
- drm_gem_object_unreference_unlocked(gfb->obj);
- gfb->obj = NULL;
- }
-
- drm_framebuffer_unregister_private(&gfb->base);
- drm_framebuffer_cleanup(&gfb->base);
-
return 0;
}

@@ -158,41 +137,17 @@ static const struct drm_fb_helper_funcs bochs_fb_helper_funcs = {
.fb_probe = bochsfb_create,
};

+const struct drm_mode_config_funcs bochs_mode_funcs = {
+ .fb_create = drm_gem_fb_create,
+};
+
int bochs_fbdev_init(struct bochs_device *bochs)
{
- int ret;
-
- drm_fb_helper_prepare(bochs->dev, &bochs->fb.helper,
- &bochs_fb_helper_funcs);
-
- ret = drm_fb_helper_init(bochs->dev, &bochs->fb.helper, 1);
- if (ret)
- return ret;
-
- ret = drm_fb_helper_single_add_all_connectors(&bochs->fb.helper);
- if (ret)
- goto fini;
-
- drm_helper_disable_unused_functions(bochs->dev);
-
- ret = drm_fb_helper_initial_config(&bochs->fb.helper, 32);
- if (ret)
- goto fini;
-
- return 0;
-
-fini:
- drm_fb_helper_fini(&bochs->fb.helper);
- return ret;
+ return drm_fb_helper_fbdev_setup(bochs->dev, &bochs->fb.helper,
+ &bochs_fb_helper_funcs, 32, 1);
}

void bochs_fbdev_fini(struct bochs_device *bochs)
{
- if (bochs->fb.initialized)
- bochs_fbdev_destroy(bochs);
-
- if (bochs->fb.helper.fbdev)
- drm_fb_helper_fini(&bochs->fb.helper);
-
- bochs->fb.initialized = false;
+ drm_fb_helper_fbdev_teardown(bochs->dev);
}
diff --git a/drivers/gpu/drm/bochs/bochs_kms.c b/drivers/gpu/drm/bochs/bochs_kms.c
index 233980a78591..c7e575511d2f 100644
--- a/drivers/gpu/drm/bochs/bochs_kms.c
+++ b/drivers/gpu/drm/bochs/bochs_kms.c
@@ -35,14 +35,12 @@ static int bochs_crtc_mode_set_base(struct drm_crtc *crtc, int x, int y,
{
struct bochs_device *bochs =
container_of(crtc, struct bochs_device, crtc);
- struct bochs_framebuffer *bochs_fb;
struct bochs_bo *bo;
u64 gpu_addr = 0;
int ret;

if (old_fb) {
- bochs_fb = to_bochs_framebuffer(old_fb);
- bo = gem_to_bochs_bo(bochs_fb->obj);
+ bo = gem_to_bochs_bo(old_fb->obj[0]);
ret = ttm_bo_reserve(&bo->bo, true, false, NULL);
if (ret) {
DRM_ERROR("failed to reserve old_fb bo\n");
@@ -55,8 +53,7 @@ static int bochs_crtc_mode_set_base(struct drm_crtc *crtc, int x, int y,
if (WARN_ON(crtc->primary->fb == NULL))
return -EINVAL;

- bochs_fb = to_bochs_framebuffer(crtc->primary->fb);
- bo = gem_to_bochs_bo(bochs_fb->obj);
+ bo = gem_to_bochs_bo(crtc->primary->fb->obj[0]);
ret = ttm_bo_reserve(&bo->bo, true, false, NULL);
if (ret)
return ret;
diff --git a/drivers/gpu/drm/bochs/bochs_mm.c b/drivers/gpu/drm/bochs/bochs_mm.c
index 39cd08416773..cdbc3ca3ec51 100644
--- a/drivers/gpu/drm/bochs/bochs_mm.c
+++ b/drivers/gpu/drm/bochs/bochs_mm.c
@@ -457,77 +457,3 @@ int bochs_dumb_mmap_offset(struct drm_file *file, struct drm_device *dev,
drm_gem_object_unreference_unlocked(obj);
return 0;
}
-
-/* ---------------------------------------------------------------------- */
-
-static void bochs_user_framebuffer_destroy(struct drm_framebuffer *fb)
-{
- struct bochs_framebuffer *bochs_fb = to_bochs_framebuffer(fb);
-
- drm_gem_object_unreference_unlocked(bochs_fb->obj);
- drm_framebuffer_cleanup(fb);
- kfree(fb);
-}
-
-static const struct drm_framebuffer_funcs bochs_fb_funcs = {
- .destroy = bochs_user_framebuffer_destroy,
-};
-
-int bochs_framebuffer_init(struct drm_device *dev,
- struct bochs_framebuffer *gfb,
- const struct drm_mode_fb_cmd2 *mode_cmd,
- struct drm_gem_object *obj)
-{
- int ret;
-
- drm_helper_mode_fill_fb_struct(dev, &gfb->base, mode_cmd);
- gfb->obj = obj;
- ret = drm_framebuffer_init(dev, &gfb->base, &bochs_fb_funcs);
- if (ret) {
- DRM_ERROR("drm_framebuffer_init failed: %d\n", ret);
- return ret;
- }
- return 0;
-}
-
-static struct drm_framebuffer *
-bochs_user_framebuffer_create(struct drm_device *dev,
- struct drm_file *filp,
- const struct drm_mode_fb_cmd2 *mode_cmd)
-{
- struct drm_gem_object *obj;
- struct bochs_framebuffer *bochs_fb;
- int ret;
-
- DRM_DEBUG_DRIVER("%dx%d, format %c%c%c%c\n",
- mode_cmd->width, mode_cmd->height,
- (mode_cmd->pixel_format) & 0xff,
- (mode_cmd->pixel_format >> 8) & 0xff,
- (mode_cmd->pixel_format >> 16) & 0xff,
- (mode_cmd->pixel_format >> 24) & 0xff);
-
- if (mode_cmd->pixel_format != DRM_FORMAT_XRGB8888)
- return ERR_PTR(-ENOENT);
-
- obj = drm_gem_object_lookup(filp, mode_cmd->handles[0]);
- if (obj == NULL)
- return ERR_PTR(-ENOENT);
-
- bochs_fb = kzalloc(sizeof(*bochs_fb), GFP_KERNEL);
- if (!bochs_fb) {
- drm_gem_object_unreference_unlocked(obj);
- return ERR_PTR(-ENOMEM);
- }
-
- ret = bochs_framebuffer_init(dev, bochs_fb, mode_cmd, obj);
- if (ret) {
- drm_gem_object_unreference_unlocked(obj);
- kfree(bochs_fb);
- return ERR_PTR(ret);
- }
- return &bochs_fb->base;
-}
-
-const struct drm_mode_config_funcs bochs_mode_funcs = {
- .fb_create = bochs_user_framebuffer_create,
-};
--
2.18.0