Patch "drm/vmwgfx: Check pin count before attempting to move a buffer" has been added to the 4.6-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    drm/vmwgfx: Check pin count before attempting to move a buffer

to the 4.6-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     drm-vmwgfx-check-pin-count-before-attempting-to-move-a-buffer.patch
and it can be found in the queue-4.6 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 4ed7e2242b637bc4af0416e4aa9f945db30fb44a Mon Sep 17 00:00:00 2001
From: Sinclair Yeh <syeh@vmware.com>
Date: Wed, 29 Jun 2016 13:20:26 -0700
Subject: drm/vmwgfx: Check pin count before attempting to move a buffer

From: Sinclair Yeh <syeh@vmware.com>

commit 4ed7e2242b637bc4af0416e4aa9f945db30fb44a upstream.

In certain scenarios, e.g. when fbdev is enabled, we can get into
a situation where a vmw_framebuffer_pin() is called on a buffer
that is already pinned.

When this happens, ttm_bo_validate() will unintentially remove the
TTM_PL_FLAG_NO_EVICT flag, thus unpinning it, and leaving no way
to actually pin the buffer again.

To prevent this, if a buffer is already pinned, then instead of
calling ttm_bo_validate(), just make sure the proposed placement is
compatible with the existing placement.

Signed-off-by: Sinclair Yeh <syeh@vmware.com>
Reviewed-by: Thomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/gpu/drm/vmwgfx/vmwgfx_dmabuf.c |   25 ++++++++++++++++++++++---
 1 file changed, 22 insertions(+), 3 deletions(-)

--- a/drivers/gpu/drm/vmwgfx/vmwgfx_dmabuf.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_dmabuf.c
@@ -49,6 +49,7 @@ int vmw_dmabuf_pin_in_placement(struct v
 {
 	struct ttm_buffer_object *bo = &buf->base;
 	int ret;
+	uint32_t new_flags;
 
 	ret = ttm_write_lock(&dev_priv->reservation_sem, interruptible);
 	if (unlikely(ret != 0))
@@ -60,7 +61,12 @@ int vmw_dmabuf_pin_in_placement(struct v
 	if (unlikely(ret != 0))
 		goto err;
 
-	ret = ttm_bo_validate(bo, placement, interruptible, false);
+	if (buf->pin_count > 0)
+		ret = ttm_bo_mem_compat(placement, &bo->mem,
+					&new_flags) == true ? 0 : -EINVAL;
+	else
+		ret = ttm_bo_validate(bo, placement, interruptible, false);
+
 	if (!ret)
 		vmw_bo_pin_reserved(buf, true);
 
@@ -91,6 +97,7 @@ int vmw_dmabuf_pin_in_vram_or_gmr(struct
 {
 	struct ttm_buffer_object *bo = &buf->base;
 	int ret;
+	uint32_t new_flags;
 
 	ret = ttm_write_lock(&dev_priv->reservation_sem, interruptible);
 	if (unlikely(ret != 0))
@@ -102,6 +109,12 @@ int vmw_dmabuf_pin_in_vram_or_gmr(struct
 	if (unlikely(ret != 0))
 		goto err;
 
+	if (buf->pin_count > 0) {
+		ret = ttm_bo_mem_compat(&vmw_vram_gmr_placement, &bo->mem,
+					&new_flags) == true ? 0 : -EINVAL;
+		goto out_unreserve;
+	}
+
 	ret = ttm_bo_validate(bo, &vmw_vram_gmr_placement, interruptible,
 			      false);
 	if (likely(ret == 0) || ret == -ERESTARTSYS)
@@ -161,6 +174,7 @@ int vmw_dmabuf_pin_in_start_of_vram(stru
 	struct ttm_placement placement;
 	struct ttm_place place;
 	int ret = 0;
+	uint32_t new_flags;
 
 	place = vmw_vram_placement.placement[0];
 	place.lpfn = bo->num_pages;
@@ -185,10 +199,15 @@ int vmw_dmabuf_pin_in_start_of_vram(stru
 	 */
 	if (bo->mem.mem_type == TTM_PL_VRAM &&
 	    bo->mem.start < bo->num_pages &&
-	    bo->mem.start > 0)
+	    bo->mem.start > 0 &&
+	    buf->pin_count == 0)
 		(void) ttm_bo_validate(bo, &vmw_sys_placement, false, false);
 
-	ret = ttm_bo_validate(bo, &placement, interruptible, false);
+	if (buf->pin_count > 0)
+		ret = ttm_bo_mem_compat(&placement, &bo->mem,
+					&new_flags) == true ? 0 : -EINVAL;
+	else
+		ret = ttm_bo_validate(bo, &placement, interruptible, false);
 
 	/* For some reason we didn't end up at the start of vram */
 	WARN_ON(ret == 0 && bo->offset != 0);


Patches currently in stable-queue which might be from syeh@vmware.com are

queue-4.6/drm-ttm-make-ttm_bo_mem_compat-available.patch
queue-4.6/drm-vmwgfx-delay-pinning-fbdev-framebuffer-until-after-mode-set.patch
queue-4.6/drm-vmwgfx-add-an-option-to-change-assumed-fb-bpp.patch
queue-4.6/drm-vmwgfx-fix-corner-case-screen-target-management.patch
queue-4.6/drm-vmwgfx-check-pin-count-before-attempting-to-move-a-buffer.patch
queue-4.6/drm-vmwgfx-work-around-mode-set-failure-in-2d-vms.patch
queue-4.6/drm-vmwgfx-fix-error-paths-when-mapping-framebuffer.patch