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drm/i915: Rearrange acquisition of mutex during pwrite
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... to avoid reacquiring it to drop the object reference count on
exit. Note we have to make sure we now drop (and reacquire) the lock
around acquiring the mm semaphore on the slow paths.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
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@ickle
ickle committed Oct 19, 2010
1 parent b5e4feb commit fbd5a26
Showing 1 changed file with 65 additions and 105 deletions.
170 changes: 65 additions & 105 deletions drivers/gpu/drm/i915/i915_gem.c
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Original file line number Diff line number Diff line change
Expand Up @@ -635,9 +635,7 @@ fast_user_write(struct io_mapping *mapping,
unwritten = __copy_from_user_inatomic_nocache(vaddr_atomic + page_offset,
user_data, length);
io_mapping_unmap_atomic(vaddr_atomic, KM_USER0);
if (unwritten)
return -EFAULT;
return 0;
return unwritten;
}

/* Here's the write path which can sleep for
Expand Down Expand Up @@ -670,14 +668,14 @@ fast_shmem_write(struct page **pages,
char __user *data,
int length)
{
int unwritten;
char *vaddr;
int ret;

vaddr = kmap_atomic(pages[page_base >> PAGE_SHIFT], KM_USER0);
unwritten = __copy_from_user_inatomic(vaddr + page_offset, data, length);
ret = __copy_from_user_inatomic(vaddr + page_offset, data, length);
kunmap_atomic(vaddr, KM_USER0);

return unwritten ? -EFAULT : 0;
return ret;
}

/**
Expand All @@ -695,24 +693,10 @@ i915_gem_gtt_pwrite_fast(struct drm_device *dev, struct drm_gem_object *obj,
loff_t offset, page_base;
char __user *user_data;
int page_offset, page_length;
int ret;

user_data = (char __user *) (uintptr_t) args->data_ptr;
remain = args->size;

ret = i915_mutex_lock_interruptible(dev);
if (ret)
return ret;

ret = i915_gem_object_pin(obj, 0);
if (ret) {
mutex_unlock(&dev->struct_mutex);
return ret;
}
ret = i915_gem_object_set_to_gtt_domain(obj, 1);
if (ret)
goto fail;

obj_priv = to_intel_bo(obj);
offset = obj_priv->gtt_offset + args->offset;

Expand All @@ -729,26 +713,21 @@ i915_gem_gtt_pwrite_fast(struct drm_device *dev, struct drm_gem_object *obj,
if ((page_offset + remain) > PAGE_SIZE)
page_length = PAGE_SIZE - page_offset;

ret = fast_user_write (dev_priv->mm.gtt_mapping, page_base,
page_offset, user_data, page_length);

/* If we get a fault while copying data, then (presumably) our
* source page isn't available. Return the error and we'll
* retry in the slow path.
*/
if (ret)
goto fail;
if (fast_user_write(dev_priv->mm.gtt_mapping, page_base,
page_offset, user_data, page_length))

return -EFAULT;

remain -= page_length;
user_data += page_length;
offset += page_length;
}

fail:
i915_gem_object_unpin(obj);
mutex_unlock(&dev->struct_mutex);

return ret;
return 0;
}

/**
Expand Down Expand Up @@ -785,30 +764,24 @@ i915_gem_gtt_pwrite_slow(struct drm_device *dev, struct drm_gem_object *obj,
last_data_page = (data_ptr + args->size - 1) / PAGE_SIZE;
num_pages = last_data_page - first_data_page + 1;

user_pages = drm_calloc_large(num_pages, sizeof(struct page *));
user_pages = drm_malloc_ab(num_pages, sizeof(struct page *));
if (user_pages == NULL)
return -ENOMEM;

mutex_unlock(&dev->struct_mutex);
down_read(&mm->mmap_sem);
pinned_pages = get_user_pages(current, mm, (uintptr_t)args->data_ptr,
num_pages, 0, 0, user_pages, NULL);
up_read(&mm->mmap_sem);
mutex_lock(&dev->struct_mutex);
if (pinned_pages < num_pages) {
ret = -EFAULT;
goto out_unpin_pages;
}

ret = i915_mutex_lock_interruptible(dev);
if (ret)
goto out_unpin_pages;

ret = i915_gem_object_pin(obj, 0);
if (ret)
goto out_unlock;

ret = i915_gem_object_set_to_gtt_domain(obj, 1);
if (ret)
goto out_unpin_object;
goto out_unpin_pages;

obj_priv = to_intel_bo(obj);
offset = obj_priv->gtt_offset + args->offset;
Expand Down Expand Up @@ -844,10 +817,6 @@ i915_gem_gtt_pwrite_slow(struct drm_device *dev, struct drm_gem_object *obj,
data_ptr += page_length;
}

out_unpin_object:
i915_gem_object_unpin(obj);
out_unlock:
mutex_unlock(&dev->struct_mutex);
out_unpin_pages:
for (i = 0; i < pinned_pages; i++)
page_cache_release(user_pages[i]);
Expand All @@ -870,23 +839,10 @@ i915_gem_shmem_pwrite_fast(struct drm_device *dev, struct drm_gem_object *obj,
loff_t offset, page_base;
char __user *user_data;
int page_offset, page_length;
int ret;

user_data = (char __user *) (uintptr_t) args->data_ptr;
remain = args->size;

ret = i915_mutex_lock_interruptible(dev);
if (ret)
return ret;

ret = i915_gem_object_get_pages(obj, 0);
if (ret != 0)
goto fail_unlock;

ret = i915_gem_object_set_to_cpu_domain(obj, 1);
if (ret != 0)
goto fail_put_pages;

obj_priv = to_intel_bo(obj);
offset = args->offset;
obj_priv->dirty = 1;
Expand All @@ -904,23 +860,17 @@ i915_gem_shmem_pwrite_fast(struct drm_device *dev, struct drm_gem_object *obj,
if ((page_offset + remain) > PAGE_SIZE)
page_length = PAGE_SIZE - page_offset;

ret = fast_shmem_write(obj_priv->pages,
if (fast_shmem_write(obj_priv->pages,
page_base, page_offset,
user_data, page_length);
if (ret)
goto fail_put_pages;
user_data, page_length))
return -EFAULT;

remain -= page_length;
user_data += page_length;
offset += page_length;
}

fail_put_pages:
i915_gem_object_put_pages(obj);
fail_unlock:
mutex_unlock(&dev->struct_mutex);

return ret;
return 0;
}

/**
Expand Down Expand Up @@ -962,28 +912,22 @@ i915_gem_shmem_pwrite_slow(struct drm_device *dev, struct drm_gem_object *obj,
if (user_pages == NULL)
return -ENOMEM;

mutex_unlock(&dev->struct_mutex);
down_read(&mm->mmap_sem);
pinned_pages = get_user_pages(current, mm, (uintptr_t)args->data_ptr,
num_pages, 0, 0, user_pages, NULL);
up_read(&mm->mmap_sem);
mutex_lock(&dev->struct_mutex);
if (pinned_pages < num_pages) {
ret = -EFAULT;
goto fail_put_user_pages;
goto out;
}

do_bit17_swizzling = i915_gem_object_needs_bit17_swizzle(obj);

ret = i915_mutex_lock_interruptible(dev);
if (ret)
goto fail_put_user_pages;

ret = i915_gem_object_get_pages_or_evict(obj);
ret = i915_gem_object_set_to_cpu_domain(obj, 1);
if (ret)
goto fail_unlock;
goto out;

ret = i915_gem_object_set_to_cpu_domain(obj, 1);
if (ret != 0)
goto fail_put_pages;
do_bit17_swizzling = i915_gem_object_needs_bit17_swizzle(obj);

obj_priv = to_intel_bo(obj);
offset = args->offset;
Expand Down Expand Up @@ -1029,11 +973,7 @@ i915_gem_shmem_pwrite_slow(struct drm_device *dev, struct drm_gem_object *obj,
offset += page_length;
}

fail_put_pages:
i915_gem_object_put_pages(obj);
fail_unlock:
mutex_unlock(&dev->struct_mutex);
fail_put_user_pages:
out:
for (i = 0; i < pinned_pages; i++)
page_cache_release(user_pages[i]);
drm_free_large(user_pages);
Expand All @@ -1048,18 +988,24 @@ i915_gem_shmem_pwrite_slow(struct drm_device *dev, struct drm_gem_object *obj,
*/
int
i915_gem_pwrite_ioctl(struct drm_device *dev, void *data,
struct drm_file *file_priv)
struct drm_file *file)
{
struct drm_i915_gem_pwrite *args = data;
struct drm_gem_object *obj;
struct drm_i915_gem_object *obj_priv;
int ret = 0;

obj = drm_gem_object_lookup(dev, file_priv, args->handle);
obj = drm_gem_object_lookup(dev, file, args->handle);
if (obj == NULL)
return -ENOENT;
obj_priv = to_intel_bo(obj);

ret = i915_mutex_lock_interruptible(dev);
if (ret) {
drm_gem_object_unreference_unlocked(obj);
return ret;
}

/* Bounds check destination. */
if (args->offset > obj->size || args->size > obj->size - args->offset) {
ret = -EINVAL;
Expand Down Expand Up @@ -1090,32 +1036,46 @@ i915_gem_pwrite_ioctl(struct drm_device *dev, void *data,
* perspective, requiring manual detiling by the client.
*/
if (obj_priv->phys_obj)
ret = i915_gem_phys_pwrite(dev, obj, args, file_priv);
ret = i915_gem_phys_pwrite(dev, obj, args, file);
else if (obj_priv->tiling_mode == I915_TILING_NONE &&
obj_priv->gtt_space &&
obj->write_domain != I915_GEM_DOMAIN_CPU) {
ret = i915_gem_gtt_pwrite_fast(dev, obj, args, file_priv);
if (ret == -EFAULT) {
ret = i915_gem_gtt_pwrite_slow(dev, obj, args,
file_priv);
}
} else if (i915_gem_object_needs_bit17_swizzle(obj)) {
ret = i915_gem_shmem_pwrite_slow(dev, obj, args, file_priv);
ret = i915_gem_object_pin(obj, 0);
if (ret)
goto out;

ret = i915_gem_object_set_to_gtt_domain(obj, 1);
if (ret)
goto out_unpin;

ret = i915_gem_gtt_pwrite_fast(dev, obj, args, file);
if (ret == -EFAULT)
ret = i915_gem_gtt_pwrite_slow(dev, obj, args, file);

out_unpin:
i915_gem_object_unpin(obj);
} else {
ret = i915_gem_shmem_pwrite_fast(dev, obj, args, file_priv);
if (ret == -EFAULT) {
ret = i915_gem_shmem_pwrite_slow(dev, obj, args,
file_priv);
}
}
ret = i915_gem_object_get_pages_or_evict(obj);
if (ret)
goto out;

#if WATCH_PWRITE
if (ret)
DRM_INFO("pwrite failed %d\n", ret);
#endif
ret = i915_gem_object_set_to_cpu_domain(obj, 1);
if (ret)
goto out_put;

ret = -EFAULT;
if (!i915_gem_object_needs_bit17_swizzle(obj))
ret = i915_gem_shmem_pwrite_fast(dev, obj, args, file);
if (ret == -EFAULT)
ret = i915_gem_shmem_pwrite_slow(dev, obj, args, file);

out_put:
i915_gem_object_put_pages(obj);
}

out:
drm_gem_object_unreference_unlocked(obj);
drm_gem_object_unreference(obj);
mutex_unlock(&dev->struct_mutex);
return ret;
}

Expand Down

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