Re: [PATCH 01/10] drm/gma500: Move helpers for struct gtt_range from gtt.c to gem.c

Hi

Am 03.10.21 um 00:13 schrieb Patrik Jakobsson:

On Tue, Sep 28, 2021 at 10:44 AM Thomas Zimmermann tzimmermann@suse.de wrote:

...

Allocation and pinning helpers for struct gtt_range are GEM functions, so move them to gem.c. No functional changes.

Signed-off-by: Thomas Zimmermann tzimmermann@suse.de

drivers/gpu/drm/gma500/framebuffer.c | 1 - drivers/gpu/drm/gma500/gem.c | 133 +++++++++++++-- drivers/gpu/drm/gma500/gem.h | 8 + drivers/gpu/drm/gma500/gma_display.c | 1 + drivers/gpu/drm/gma500/gtt.c | 190 +-------------------- drivers/gpu/drm/gma500/gtt.h | 11 +- drivers/gpu/drm/gma500/psb_intel_display.c | 1 + 7 files changed, 136 insertions(+), 209 deletions(-)

diff --git a/drivers/gpu/drm/gma500/framebuffer.c b/drivers/gpu/drm/gma500/framebuffer.c index 321e416489a9..ce92d11bd20f 100644 --- a/drivers/gpu/drm/gma500/framebuffer.c +++ b/drivers/gpu/drm/gma500/framebuffer.c @@ -25,7 +25,6 @@

#include "framebuffer.h" #include "gem.h" -#include "gtt.h" #include "psb_drv.h" #include "psb_intel_drv.h" #include "psb_intel_reg.h" diff --git a/drivers/gpu/drm/gma500/gem.c b/drivers/gpu/drm/gma500/gem.c index 5ae54c9d2819..734bcb7a80c8 100644 --- a/drivers/gpu/drm/gma500/gem.c +++ b/drivers/gpu/drm/gma500/gem.c @@ -19,6 +19,89 @@ #include "gem.h" #include "psb_drv.h"

+static int psb_gtt_attach_pages(struct gtt_range *gt) +{

•   struct page **pages;
  

•   WARN_ON(gt->pages);
  

•   pages = drm_gem_get_pages(&gt->gem);
  

•   if (IS_ERR(pages))
  

•           return PTR_ERR(pages);
  

•   gt->npage = gt->gem.size / PAGE_SIZE;
  

•   gt->pages = pages;
  

•   return 0;
  

+}

+static void psb_gtt_detach_pages(struct gtt_range *gt) +{

•   drm_gem_put_pages(&gt->gem, gt->pages, true, false);
  

•   gt->pages = NULL;
  

+}

+int psb_gtt_pin(struct gtt_range *gt) +{

•   int ret = 0;
  

•   struct drm_device *dev = gt->gem.dev;
  

•   struct drm_psb_private *dev_priv = to_drm_psb_private(dev);
  

•   u32 gpu_base = dev_priv->gtt.gatt_start;
  

•   mutex_lock(&dev_priv->gtt_mutex);
  

•   if (gt->in_gart == 0 && gt->stolen == 0) {
  

•           ret = psb_gtt_attach_pages(gt);
  

•           if (ret < 0)
  

•                   goto out;
  

•           ret = psb_gtt_insert(dev, gt, 0);
  

•           if (ret < 0) {
  

•                   psb_gtt_detach_pages(gt);
  

•                   goto out;
  

•           }
  

•           psb_mmu_insert_pages(psb_mmu_get_default_pd(dev_priv->mmu),
  

•                                gt->pages, (gpu_base + gt->offset),
  

•                                gt->npage, 0, 0, PSB_MMU_CACHED_MEMORY);
  

•   }
  

•   gt->in_gart++;
  

+out:

•   mutex_unlock(&dev_priv->gtt_mutex);
  

•   return ret;
  

+}

+void psb_gtt_unpin(struct gtt_range *gt) +{

•   struct drm_device *dev = gt->gem.dev;
  

•   struct drm_psb_private *dev_priv = to_drm_psb_private(dev);
  

•   u32 gpu_base = dev_priv->gtt.gatt_start;
  

•   mutex_lock(&dev_priv->gtt_mutex);
  

•   WARN_ON(!gt->in_gart);
  

•   gt->in_gart--;
  

•   if (gt->in_gart == 0 && gt->stolen == 0) {
  

•           psb_mmu_remove_pages(psb_mmu_get_default_pd(dev_priv->mmu),
  

•                                (gpu_base + gt->offset), gt->npage, 0, 0);
  

•           psb_gtt_remove(dev, gt);
  

•           psb_gtt_detach_pages(gt);
  

•   }
  

•   mutex_unlock(&dev_priv->gtt_mutex);
  

+}

+void psb_gtt_free_range(struct drm_device *dev, struct gtt_range *gt) +{

•   /* Undo the mmap pin if we are destroying the object */
  

•   if (gt->mmapping) {
  

•           psb_gtt_unpin(gt);
  

•           gt->mmapping = 0;
  

•   }
  

•   WARN_ON(gt->in_gart && !gt->stolen);
  

•   release_resource(&gt->resource);
  

•   kfree(gt);
  

+}

• static vm_fault_t psb_gem_fault(struct vm_fault *vmf);

  static void psb_gem_free_object(struct drm_gem_object *obj)

@@ -44,19 +127,43 @@ const struct drm_gem_object_funcs psb_gem_object_funcs = { .vm_ops = &psb_gem_vm_ops, };

-/**

• • psb_gem_create          -       create a mappable object
    

• • @file: the DRM file of the client
    

• • @dev: our device
    

• • @size: the size requested
    

• • @handlep: returned handle (opaque number)
    

• • @stolen: unused
    

• • @align: unused
    

• • Create a GEM object, fill in the boilerplate and attach a handle to
    

• • it so that userspace can speak about it. This does the core work
    

• • for the various methods that do/will create GEM objects for things
    

• */

+struct gtt_range *psb_gtt_alloc_range(struct drm_device *dev, int len,

•                                 const char *name, int backed, u32 align)
  

+{

•   struct drm_psb_private *dev_priv = to_drm_psb_private(dev);
  

•   struct gtt_range *gt;
  

•   struct resource *r = dev_priv->gtt_mem;
  

•   int ret;
  

•   unsigned long start, end;
  

•   if (backed) {
  

•           /* The start of the GTT is the stolen pages */
  

•           start = r->start;
  

•           end = r->start + dev_priv->gtt.stolen_size - 1;
  

•   } else {
  

•           /* The rest we will use for GEM backed objects */
  

•           start = r->start + dev_priv->gtt.stolen_size;
  

•           end = r->end;
  

•   }
  

•   gt = kzalloc(sizeof(struct gtt_range), GFP_KERNEL);
  

•   if (gt == NULL)
  

•           return NULL;
  

•   gt->resource.name = name;
  

•   gt->stolen = backed;
  

•   gt->in_gart = backed;
  

•   /* Ensure this is set for non GEM objects */
  

•   gt->gem.dev = dev;
  

•   ret = allocate_resource(dev_priv->gtt_mem, &gt->resource,
  

•                           len, start, end, align, NULL, NULL);
  

Not something for this patch but I think we're missing locking around resource alloc and release.

There's a lock being taken within the function. [1]

...

•   if (ret == 0) {
  

•           gt->offset = gt->resource.start - r->start;
  

•           return gt;
  

•   }
  

•   kfree(gt);
  

•   return NULL;
  

+}

• int psb_gem_create(struct drm_file *file, struct drm_device *dev, u64 size, u32 *handlep, int stolen, u32 align) {

diff --git a/drivers/gpu/drm/gma500/gem.h b/drivers/gpu/drm/gma500/gem.h index bae6454ead29..275494aedd4c 100644 --- a/drivers/gpu/drm/gma500/gem.h +++ b/drivers/gpu/drm/gma500/gem.h @@ -8,6 +8,8 @@ #ifndef _GEM_H #define _GEM_H

+#include <drm/drm_gem.h>

• struct drm_device;

  extern const struct drm_gem_object_funcs psb_gem_object_funcs;

@@ -15,4 +17,10 @@ extern const struct drm_gem_object_funcs psb_gem_object_funcs; extern int psb_gem_create(struct drm_file *file, struct drm_device *dev, u64 size, u32 *handlep, int stolen, u32 align);

+struct gtt_range *psb_gtt_alloc_range(struct drm_device *dev, int len, const char *name,

•                                 int backed, u32 align);
  

+void psb_gtt_free_range(struct drm_device *dev, struct gtt_range *gt); +int psb_gtt_pin(struct gtt_range *gt); +void psb_gtt_unpin(struct gtt_range *gt);

• #endif

diff --git a/drivers/gpu/drm/gma500/gma_display.c b/drivers/gpu/drm/gma500/gma_display.c index cbcecbaa041b..ecf8153416ac 100644 --- a/drivers/gpu/drm/gma500/gma_display.c +++ b/drivers/gpu/drm/gma500/gma_display.c @@ -15,6 +15,7 @@ #include <drm/drm_vblank.h>

#include "framebuffer.h" +#include "gem.h" #include "gma_display.h" #include "psb_drv.h" #include "psb_intel_drv.h" diff --git a/drivers/gpu/drm/gma500/gtt.c b/drivers/gpu/drm/gma500/gtt.c index 55a2a6919533..0aacf7122e32 100644 --- a/drivers/gpu/drm/gma500/gtt.c +++ b/drivers/gpu/drm/gma500/gtt.c @@ -71,8 +71,7 @@ static u32 __iomem *psb_gtt_entry(struct drm_device *dev, struct gtt_range *r)

• the GTT. This is protected via the gtt mutex which the caller
  

• must hold.
  

*/ -static int psb_gtt_insert(struct drm_device *dev, struct gtt_range *r,

•                     int resume)
  

+int psb_gtt_insert(struct drm_device *dev, struct gtt_range *r, int resume) { u32 __iomem *gtt_slot; u32 pte; @@ -116,7 +115,7 @@ static int psb_gtt_insert(struct drm_device *dev, struct gtt_range *r,

• page table entries with the dummy page. This is protected via the gtt
  

• mutex which the caller must hold.
  

*/ -static void psb_gtt_remove(struct drm_device *dev, struct gtt_range *r) +void psb_gtt_remove(struct drm_device *dev, struct gtt_range *r) { struct drm_psb_private *dev_priv = to_drm_psb_private(dev); u32 __iomem *gtt_slot; @@ -135,191 +134,6 @@ static void psb_gtt_remove(struct drm_device *dev, struct gtt_range *r) set_pages_array_wb(r->pages, r->npage); }

-/**

• • psb_gtt_attach_pages    -       attach and pin GEM pages
    

• • @gt: the gtt range
    

• • Pin and build an in kernel list of the pages that back our GEM object.
    

• • While we hold this the pages cannot be swapped out. This is protected
    

• • via the gtt mutex which the caller must hold.
    

• */

The documentation about locking is still relevant. I'm not a big fan of documenting the obvious but locking is an exception.

Make sense. I'll reduce the kerneldoc comment to the notes on locking.

Best regards Thomas

[1] https://elixir.bootlin.com/linux/latest/source/kernel/resource.c#L745

...

-static int psb_gtt_attach_pages(struct gtt_range *gt) -{

•   struct page **pages;
  

•   WARN_ON(gt->pages);
  

•   pages = drm_gem_get_pages(&gt->gem);
  

•   if (IS_ERR(pages))
  

•           return PTR_ERR(pages);
  

•   gt->npage = gt->gem.size / PAGE_SIZE;
  

•   gt->pages = pages;
  

•   return 0;
  

-}

-/**

• • psb_gtt_detach_pages    -       attach and pin GEM pages
    

• • @gt: the gtt range
    

• • Undo the effect of psb_gtt_attach_pages. At this point the pages
    

• • must have been removed from the GTT as they could now be paged out
    

• • and move bus address. This is protected via the gtt mutex which the
    

• • caller must hold.
    

• */

Same thing about locking here

...

-static void psb_gtt_detach_pages(struct gtt_range *gt) -{

•   drm_gem_put_pages(&gt->gem, gt->pages, true, false);
  

•   gt->pages = NULL;
  

-}

-/**

• • psb_gtt_pin             -       pin pages into the GTT
    

• • @gt: range to pin
    

• • Pin a set of pages into the GTT. The pins are refcounted so that
    

• • multiple pins need multiple unpins to undo.
    

• • Non GEM backed objects treat this as a no-op as they are always GTT
    

• • backed objects.
    

• */

-int psb_gtt_pin(struct gtt_range *gt) -{

•   int ret = 0;
  

•   struct drm_device *dev = gt->gem.dev;
  

•   struct drm_psb_private *dev_priv = to_drm_psb_private(dev);
  

•   u32 gpu_base = dev_priv->gtt.gatt_start;
  

•   mutex_lock(&dev_priv->gtt_mutex);
  

•   if (gt->in_gart == 0 && gt->stolen == 0) {
  

•           ret = psb_gtt_attach_pages(gt);
  

•           if (ret < 0)
  

•                   goto out;
  

•           ret = psb_gtt_insert(dev, gt, 0);
  

•           if (ret < 0) {
  

•                   psb_gtt_detach_pages(gt);
  

•                   goto out;
  

•           }
  

•           psb_mmu_insert_pages(psb_mmu_get_default_pd(dev_priv->mmu),
  

•                                gt->pages, (gpu_base + gt->offset),
  

•                                gt->npage, 0, 0, PSB_MMU_CACHED_MEMORY);
  

•   }
  

•   gt->in_gart++;
  

-out:

•   mutex_unlock(&dev_priv->gtt_mutex);
  

•   return ret;
  

-}

-/**

• • psb_gtt_unpin           -       Drop a GTT pin requirement
    

• • @gt: range to pin
    

• • Undoes the effect of psb_gtt_pin. On the last drop the GEM object
    

• • will be removed from the GTT which will also drop the page references
    

• • and allow the VM to clean up or page stuff.
    

• • Non GEM backed objects treat this as a no-op as they are always GTT
    

• • backed objects.
    

• */

-void psb_gtt_unpin(struct gtt_range *gt) -{

•   struct drm_device *dev = gt->gem.dev;
  

•   struct drm_psb_private *dev_priv = to_drm_psb_private(dev);
  

•   u32 gpu_base = dev_priv->gtt.gatt_start;
  

•   mutex_lock(&dev_priv->gtt_mutex);
  

•   WARN_ON(!gt->in_gart);
  

•   gt->in_gart--;
  

•   if (gt->in_gart == 0 && gt->stolen == 0) {
  

•           psb_mmu_remove_pages(psb_mmu_get_default_pd(dev_priv->mmu),
  

•                                (gpu_base + gt->offset), gt->npage, 0, 0);
  

•           psb_gtt_remove(dev, gt);
  

•           psb_gtt_detach_pages(gt);
  

•   }
  

•   mutex_unlock(&dev_priv->gtt_mutex);
  

-}

-/*

• • GTT resource allocator - allocate and manage GTT address space
    

• */

-/**

• • psb_gtt_alloc_range     -       allocate GTT address space
    

• • @dev: Our DRM device
    

• • @len: length (bytes) of address space required
    

• • @name: resource name
    

• • @backed: resource should be backed by stolen pages
    

• • @align: requested alignment
    

• • Ask the kernel core to find us a suitable range of addresses
    

• • to use for a GTT mapping.
    

• • Returns a gtt_range structure describing the object, or NULL on
    

• • error. On successful return the resource is both allocated and marked
    

• • as in use.
    

• */

-struct gtt_range *psb_gtt_alloc_range(struct drm_device *dev, int len,

•                                 const char *name, int backed, u32 align)
  

-{

•   struct drm_psb_private *dev_priv = to_drm_psb_private(dev);
  

•   struct gtt_range *gt;
  

•   struct resource *r = dev_priv->gtt_mem;
  

•   int ret;
  

•   unsigned long start, end;
  

•   if (backed) {
  

•           /* The start of the GTT is the stolen pages */
  

•           start = r->start;
  

•           end = r->start + dev_priv->gtt.stolen_size - 1;
  

•   } else {
  

•           /* The rest we will use for GEM backed objects */
  

•           start = r->start + dev_priv->gtt.stolen_size;
  

•           end = r->end;
  

•   }
  

•   gt = kzalloc(sizeof(struct gtt_range), GFP_KERNEL);
  

•   if (gt == NULL)
  

•           return NULL;
  

•   gt->resource.name = name;
  

•   gt->stolen = backed;
  

•   gt->in_gart = backed;
  

•   /* Ensure this is set for non GEM objects */
  

•   gt->gem.dev = dev;
  

•   ret = allocate_resource(dev_priv->gtt_mem, &gt->resource,
  

•                           len, start, end, align, NULL, NULL);
  

•   if (ret == 0) {
  

•           gt->offset = gt->resource.start - r->start;
  

•           return gt;
  

•   }
  

•   kfree(gt);
  

•   return NULL;
  

-}

-/**

• • psb_gtt_free_range      -       release GTT address space
    

• • @dev: our DRM device
    

• • @gt: a mapping created with psb_gtt_alloc_range
    

• • Release a resource that was allocated with psb_gtt_alloc_range. If the
    

• • object has been pinned by mmap users we clean this up here currently.
    

• */

-void psb_gtt_free_range(struct drm_device *dev, struct gtt_range *gt) -{

•   /* Undo the mmap pin if we are destroying the object */
  

•   if (gt->mmapping) {
  

•           psb_gtt_unpin(gt);
  

•           gt->mmapping = 0;
  

•   }
  

•   WARN_ON(gt->in_gart && !gt->stolen);
  

•   release_resource(&gt->resource);
  

•   kfree(gt);
  

-}

• static void psb_gtt_alloc(struct drm_device *dev) { struct drm_psb_private *dev_priv = to_drm_psb_private(dev);

diff --git a/drivers/gpu/drm/gma500/gtt.h b/drivers/gpu/drm/gma500/gtt.h index 2bf165849ebe..36162b545570 100644 --- a/drivers/gpu/drm/gma500/gtt.h +++ b/drivers/gpu/drm/gma500/gtt.h @@ -41,12 +41,9 @@ struct gtt_range {

#define to_gtt_range(x) container_of(x, struct gtt_range, gem)

-extern struct gtt_range *psb_gtt_alloc_range(struct drm_device *dev, int len,

•                                        const char *name, int backed,
  

•                                        u32 align);
  

-extern void psb_gtt_kref_put(struct gtt_range *gt); -extern void psb_gtt_free_range(struct drm_device *dev, struct gtt_range *gt); -extern int psb_gtt_pin(struct gtt_range *gt); -extern void psb_gtt_unpin(struct gtt_range *gt); extern int psb_gtt_restore(struct drm_device *dev);

+int psb_gtt_insert(struct drm_device *dev, struct gtt_range *r, int resume); +void psb_gtt_remove(struct drm_device *dev, struct gtt_range *r);

• #endif

diff --git a/drivers/gpu/drm/gma500/psb_intel_display.c b/drivers/gpu/drm/gma500/psb_intel_display.c index f5f259fde88e..18d5f7e5889e 100644 --- a/drivers/gpu/drm/gma500/psb_intel_display.c +++ b/drivers/gpu/drm/gma500/psb_intel_display.c @@ -12,6 +12,7 @@ #include <drm/drm_plane_helper.h>

#include "framebuffer.h" +#include "gem.h" #include "gma_display.h" #include "power.h"

#include "psb_drv.h"

2.33.0