[PATCH 12/18] drm/i915: Handle stolen objects for pread

Chris Wilson
2012-10-19T17:05:03Z

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
---
drivers/gpu/drm/i915/i915_gem.c | 175 ++++++++++++++++++++++++++-------------
1 file changed, 116 insertions(+), 59 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 2108761..d75c5c3 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -324,24 +324,21 @@ __copy_from_user_swizzled(char *gpu_vaddr, int gpu_offset,
* Flushes invalid cachelines before reading the target if
* needs_clflush is set. */
static int
-shmem_pread_fast(struct page *page, int shmem_page_offset, int page_length,
+shmem_pread_fast(char *vaddr, int shmem_page_offset, int page_length,
char __user *user_data,
bool page_do_bit17_swizzling, bool needs_clflush)
{
- char *vaddr;
int ret;

if (unlikely(page_do_bit17_swizzling))
return -EINVAL;

- vaddr = kmap_atomic(page);
if (needs_clflush)
drm_clflush_virt_range(vaddr + shmem_page_offset,
page_length);
ret = __copy_to_user_inatomic(user_data,
vaddr + shmem_page_offset,
page_length);
- kunmap_atomic(vaddr);

return ret ? -EFAULT : 0;
}
@@ -371,14 +368,12 @@ shmem_clflush_swizzled_range(char *addr, unsigned long length,
/* Only difference to the fast-path function is that this can handle bit17
* and uses non-atomic copy and kmap functions. */
static int
-shmem_pread_slow(struct page *page, int shmem_page_offset, int page_length,
+shmem_pread_slow(char *vaddr, int shmem_page_offset, int page_length,
char __user *user_data,
bool page_do_bit17_swizzling, bool needs_clflush)
{
- char *vaddr;
int ret;

- vaddr = kmap(page);
if (needs_clflush)
shmem_clflush_swizzled_range(vaddr + shmem_page_offset,
page_length,
@@ -392,7 +387,6 @@ shmem_pread_slow(struct page *page, int shmem_page_offset, int page_length,
ret = __copy_to_user(user_data,
vaddr + shmem_page_offset,
page_length);
- kunmap(page);

return ret ? - EFAULT : 0;
}
@@ -403,6 +397,7 @@ i915_gem_shmem_pread(struct drm_device *dev,
struct drm_i915_gem_pread *args,
struct drm_file *file)
{
+ struct drm_i915_private *dev_priv = dev->dev_private;
char __user *user_data;
ssize_t remain;
loff_t offset;
@@ -433,76 +428,138 @@ i915_gem_shmem_pread(struct drm_device *dev,
}
}

- ret = i915_gem_object_get_pages(obj);
- if (ret)
- return ret;
+ offset = args->offset;

- i915_gem_object_pin_pages(obj);
+ if (obj->stolen) {
+ char *vaddr;

- offset = args->offset;
+ vaddr = (char *)dev_priv->mm.stolen_base;
+ vaddr += obj->stolen->start + offset;

- for_each_sg(obj->pages->sgl, sg, obj->pages->nents, i) {
- struct page *page;
+ shmem_page_offset = offset_in_page(offset);
+ while (remain > 0) {
+ /* Operation in this page
+ *
+ * shmem_page_offset = offset within page in shmem file
+ * page_length = bytes to copy for this page
+ */
+ page_length = remain;
+ if ((shmem_page_offset + page_length) > PAGE_SIZE)
+ page_length = PAGE_SIZE - shmem_page_offset;

- if (i < offset >> PAGE_SHIFT)
- continue;
+ page_do_bit17_swizzling = obj_do_bit17_swizzling &&
+ ((uintptr_t)vaddr & (1 << 17)) != 0;

- if (remain <= 0)
- break;
+ ret = shmem_pread_fast(vaddr, shmem_page_offset, page_length,
+ user_data, page_do_bit17_swizzling,
+ needs_clflush);
+ if (ret == 0)
+ goto next_stolen;

- /* Operation in this page
- *
- * shmem_page_offset = offset within page in shmem file
- * page_length = bytes to copy for this page
- */
- shmem_page_offset = offset_in_page(offset);
- page_length = remain;
- if ((shmem_page_offset + page_length) > PAGE_SIZE)
- page_length = PAGE_SIZE - shmem_page_offset;
+ hit_slowpath = 1;
+ mutex_unlock(&dev->struct_mutex);

- page = sg_page(sg);
- page_do_bit17_swizzling = obj_do_bit17_swizzling &&
- (page_to_phys(page) & (1 << 17)) != 0;
+ if (!prefaulted) {
+ ret = fault_in_multipages_writeable(user_data, remain);
+ /* Userspace is tricking us, but we've already clobbered
+ * its pages with the prefault and promised to write the
+ * data up to the first fault. Hence ignore any errors
+ * and just continue. */
+ (void)ret;
+ prefaulted = 1;
+ }

- ret = shmem_pread_fast(page, shmem_page_offset, page_length,
- user_data, page_do_bit17_swizzling,
- needs_clflush);
- if (ret == 0)
- goto next_page;
+ ret = shmem_pread_slow(vaddr, shmem_page_offset, page_length,
+ user_data, page_do_bit17_swizzling,
+ needs_clflush);

- hit_slowpath = 1;
- mutex_unlock(&dev->struct_mutex);
+ mutex_lock(&dev->struct_mutex);
+ if (ret)
+ goto out;

- if (!prefaulted) {
- ret = fault_in_multipages_writeable(user_data, remain);
- /* Userspace is tricking us, but we've already clobbered
- * its pages with the prefault and promised to write the
- * data up to the first fault. Hence ignore any errors
- * and just continue. */
- (void)ret;
- prefaulted = 1;
+next_stolen:
+ remain -= page_length;
+ user_data += page_length;
+ vaddr += page_length;
+ shmem_page_offset = 0;
}
+ } else {
+ ret = i915_gem_object_get_pages(obj);
+ if (ret)
+ return ret;

- ret = shmem_pread_slow(page, shmem_page_offset, page_length,
- user_data, page_do_bit17_swizzling,
- needs_clflush);
+ i915_gem_object_pin_pages(obj);

- mutex_lock(&dev->struct_mutex);
+ for_each_sg(obj->pages->sgl, sg, obj->pages->nents, i) {
+ char *vaddr;
+ struct page *page;

-next_page:
- mark_page_accessed(page);
+ if (i < offset >> PAGE_SHIFT)
+ continue;

- if (ret)
- goto out;
+ if (remain <= 0)
+ break;

- remain -= page_length;
- user_data += page_length;
- offset += page_length;
+ /* Operation in this page
+ *
+ * shmem_page_offset = offset within page in shmem file
+ * page_length = bytes to copy for this page
+ */
+ shmem_page_offset = offset_in_page(offset);
+ page_length = remain;
+ if ((shmem_page_offset + page_length) > PAGE_SIZE)
+ page_length = PAGE_SIZE - shmem_page_offset;
+
+ page = sg_page(sg);
+ mark_page_accessed(page);
+
+ page_do_bit17_swizzling = obj_do_bit17_swizzling &&
+ (page_to_phys(page) & (1 << 17)) != 0;
+
+ vaddr = kmap_atomic(page);
+ ret = shmem_pread_fast(vaddr, shmem_page_offset, page_length,
+ user_data, page_do_bit17_swizzling,
+ needs_clflush);
+ kunmap_atomic(vaddr);
+
+ if (ret == 0)
+ goto next_page;
+
+ hit_slowpath = 1;
+ mutex_unlock(&dev->struct_mutex);
+
+ if (!prefaulted) {
+ ret = fault_in_multipages_writeable(user_data, remain);
+ /* Userspace is tricking us, but we've already clobbered
+ * its pages with the prefault and promised to write the
+ * data up to the first fault. Hence ignore any errors
+ * and just continue. */
+ (void)ret;
+ prefaulted = 1;
+ }
+
+ vaddr = kmap(page);
+ ret = shmem_pread_slow(vaddr, shmem_page_offset, page_length,
+ user_data, page_do_bit17_swizzling,
+ needs_clflush);
+ kunmap(page);
+
+ mutex_lock(&dev->struct_mutex);
+
+ if (ret)
+ goto out_unpin;
+
+next_page:
+ remain -= page_length;
+ user_data += page_length;
+ offset += page_length;
+ }
+out_unpin:
+ i915_gem_object_unpin_pages(obj);
}

-out:
- i915_gem_object_unpin_pages(obj);

+out:
if (hit_slowpath) {
/* Fixup: Kill any reinstated backing storage pages */
if (obj->madv == __I915_MADV_PURGED)
--
1.7.10.4