drm/vmwgfx: Remove the reservation semaphore

Now since Christian reworked TTM to always keep objects on the LRU
list unless they are pinned we shouldn't need the reservation
semaphore. It makes the driver code a lot cleaner, especially
because it was a little hard to reason when and where the
reservation semaphore needed to be held.

Signed-off-by: Zack Rusin <[e-mail]>
Reviewed-by: Roland Scheidegger <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

drivers/gpu/drm/vmwgfx/Makefile

···
 	    vmwgfx_cotable.o vmwgfx_so.o vmwgfx_binding.o vmwgfx_msg.o \
 	    vmwgfx_simple_resource.o vmwgfx_va.o vmwgfx_blit.o \
 	    vmwgfx_validation.o vmwgfx_page_dirty.o vmwgfx_streamoutput.o \
-	    ttm_object.o ttm_lock.o ttm_memory.o
+	    ttm_object.o ttm_memory.o
 
 vmwgfx-$(CONFIG_DRM_FBDEV_EMULATION) += vmwgfx_fb.o
 vmwgfx-$(CONFIG_TRANSPARENT_HUGEPAGE) += vmwgfx_thp.o

drivers/gpu/drm/vmwgfx/ttm_lock.c

···
-/* SPDX-License-Identifier: GPL-2.0 OR MIT */
-/**************************************************************************
- *
- * Copyright (c) 2007-2009 VMware, Inc., Palo Alto, CA., USA
- * All Rights Reserved.
- *
- * Permission is hereby granted, free of charge, to any person obtaining a
- * copy of this software and associated documentation files (the
- * "Software"), to deal in the Software without restriction, including
- * without limitation the rights to use, copy, modify, merge, publish,
- * distribute, sub license, and/or sell copies of the Software, and to
- * permit persons to whom the Software is furnished to do so, subject to
- * the following conditions:
- *
- * The above copyright notice and this permission notice (including the
- * next paragraph) shall be included in all copies or substantial portions
- * of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
- * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
- * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
- * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
- * USE OR OTHER DEALINGS IN THE SOFTWARE.
- *
- **************************************************************************/
-/*
- * Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
- */
-
-#include <linux/atomic.h>
-#include <linux/errno.h>
-#include <linux/wait.h>
-#include <linux/sched/signal.h>
-#include "ttm_lock.h"
-#include "ttm_object.h"
-
-#define TTM_WRITE_LOCK_PENDING    (1 << 0)
-#define TTM_VT_LOCK_PENDING       (1 << 1)
-#define TTM_SUSPEND_LOCK_PENDING  (1 << 2)
-#define TTM_VT_LOCK               (1 << 3)
-#define TTM_SUSPEND_LOCK          (1 << 4)
-
-void ttm_lock_init(struct ttm_lock *lock)
-{
-	spin_lock_init(&lock->lock);
-	init_waitqueue_head(&lock->queue);
-	lock->rw = 0;
-	lock->flags = 0;
-}
-
-void ttm_read_unlock(struct ttm_lock *lock)
-{
-	spin_lock(&lock->lock);
-	if (--lock->rw == 0)
-		wake_up_all(&lock->queue);
-	spin_unlock(&lock->lock);
-}
-
-static bool __ttm_read_lock(struct ttm_lock *lock)
-{
-	bool locked = false;
-
-	spin_lock(&lock->lock);
-	if (lock->rw >= 0 && lock->flags == 0) {
-		++lock->rw;
-		locked = true;
-	}
-	spin_unlock(&lock->lock);
-	return locked;
-}
-
-int ttm_read_lock(struct ttm_lock *lock, bool interruptible)
-{
-	int ret = 0;
-
-	if (interruptible)
-		ret = wait_event_interruptible(lock->queue,
-					       __ttm_read_lock(lock));
-	else
-		wait_event(lock->queue, __ttm_read_lock(lock));
-	return ret;
-}
-
-static bool __ttm_read_trylock(struct ttm_lock *lock, bool *locked)
-{
-	bool block = true;
-
-	*locked = false;
-
-	spin_lock(&lock->lock);
-	if (lock->rw >= 0 && lock->flags == 0) {
-		++lock->rw;
-		block = false;
-		*locked = true;
-	} else if (lock->flags == 0) {
-		block = false;
-	}
-	spin_unlock(&lock->lock);
-
-	return !block;
-}
-
-int ttm_read_trylock(struct ttm_lock *lock, bool interruptible)
-{
-	int ret = 0;
-	bool locked;
-
-	if (interruptible)
-		ret = wait_event_interruptible
-			(lock->queue, __ttm_read_trylock(lock, &locked));
-	else
-		wait_event(lock->queue, __ttm_read_trylock(lock, &locked));
-
-	if (unlikely(ret != 0)) {
-		BUG_ON(locked);
-		return ret;
-	}
-
-	return (locked) ? 0 : -EBUSY;
-}
-
-void ttm_write_unlock(struct ttm_lock *lock)
-{
-	spin_lock(&lock->lock);
-	lock->rw = 0;
-	wake_up_all(&lock->queue);
-	spin_unlock(&lock->lock);
-}
-
-static bool __ttm_write_lock(struct ttm_lock *lock)
-{
-	bool locked = false;
-
-	spin_lock(&lock->lock);
-	if (lock->rw == 0 && ((lock->flags & ~TTM_WRITE_LOCK_PENDING) == 0)) {
-		lock->rw = -1;
-		lock->flags &= ~TTM_WRITE_LOCK_PENDING;
-		locked = true;
-	} else {
-		lock->flags |= TTM_WRITE_LOCK_PENDING;
-	}
-	spin_unlock(&lock->lock);
-	return locked;
-}
-
-int ttm_write_lock(struct ttm_lock *lock, bool interruptible)
-{
-	int ret = 0;
-
-	if (interruptible) {
-		ret = wait_event_interruptible(lock->queue,
-					       __ttm_write_lock(lock));
-		if (unlikely(ret != 0)) {
-			spin_lock(&lock->lock);
-			lock->flags &= ~TTM_WRITE_LOCK_PENDING;
-			wake_up_all(&lock->queue);
-			spin_unlock(&lock->lock);
-		}
-	} else
-		wait_event(lock->queue, __ttm_write_lock(lock));
-
-	return ret;
-}
-
-void ttm_suspend_unlock(struct ttm_lock *lock)
-{
-	spin_lock(&lock->lock);
-	lock->flags &= ~TTM_SUSPEND_LOCK;
-	wake_up_all(&lock->queue);
-	spin_unlock(&lock->lock);
-}
-
-static bool __ttm_suspend_lock(struct ttm_lock *lock)
-{
-	bool locked = false;
-
-	spin_lock(&lock->lock);
-	if (lock->rw == 0) {
-		lock->flags &= ~TTM_SUSPEND_LOCK_PENDING;
-		lock->flags |= TTM_SUSPEND_LOCK;
-		locked = true;
-	} else {
-		lock->flags |= TTM_SUSPEND_LOCK_PENDING;
-	}
-	spin_unlock(&lock->lock);
-	return locked;
-}
-
-void ttm_suspend_lock(struct ttm_lock *lock)
-{
-	wait_event(lock->queue, __ttm_suspend_lock(lock));
-}

drivers/gpu/drm/vmwgfx/ttm_lock.h

···
-/**************************************************************************
- *
- * Copyright (c) 2007-2009 VMware, Inc., Palo Alto, CA., USA
- * All Rights Reserved.
- *
- * Permission is hereby granted, free of charge, to any person obtaining a
- * copy of this software and associated documentation files (the
- * "Software"), to deal in the Software without restriction, including
- * without limitation the rights to use, copy, modify, merge, publish,
- * distribute, sub license, and/or sell copies of the Software, and to
- * permit persons to whom the Software is furnished to do so, subject to
- * the following conditions:
- *
- * The above copyright notice and this permission notice (including the
- * next paragraph) shall be included in all copies or substantial portions
- * of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
- * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
- * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
- * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
- * USE OR OTHER DEALINGS IN THE SOFTWARE.
- *
- **************************************************************************/
-/*
- * Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
- */
-
-/** @file ttm_lock.h
- * This file implements a simple replacement for the buffer manager use
- * of the DRM heavyweight hardware lock.
- * The lock is a read-write lock. Taking it in read mode and write mode
- * is relatively fast, and intended for in-kernel use only.
- *
- * The vt mode is used only when there is a need to block all
- * user-space processes from validating buffers.
- * It's allowed to leave kernel space with the vt lock held.
- * If a user-space process dies while having the vt-lock,
- * it will be released during the file descriptor release. The vt lock
- * excludes write lock and read lock.
- *
- * The suspend mode is used to lock out all TTM users when preparing for
- * and executing suspend operations.
- *
- */
-
-#ifndef _TTM_LOCK_H_
-#define _TTM_LOCK_H_
-
-#include <linux/atomic.h>
-#include <linux/wait.h>
-
-#include "ttm_object.h"
-
-/**
- * struct ttm_lock
- *
- * @base: ttm base object used solely to release the lock if the client
- * holding the lock dies.
- * @queue: Queue for processes waiting for lock change-of-status.
- * @lock: Spinlock protecting some lock members.
- * @rw: Read-write lock counter. Protected by @lock.
- * @flags: Lock state. Protected by @lock.
- */
-
-struct ttm_lock {
-	struct ttm_base_object base;
-	wait_queue_head_t queue;
-	spinlock_t lock;
-	int32_t rw;
-	uint32_t flags;
-};
-
-
-/**
- * ttm_lock_init
- *
- * @lock: Pointer to a struct ttm_lock
- * Initializes the lock.
- */
-extern void ttm_lock_init(struct ttm_lock *lock);
-
-/**
- * ttm_read_unlock
- *
- * @lock: Pointer to a struct ttm_lock
- *
- * Releases a read lock.
- */
-extern void ttm_read_unlock(struct ttm_lock *lock);
-
-/**
- * ttm_read_lock
- *
- * @lock: Pointer to a struct ttm_lock
- * @interruptible: Interruptible sleeping while waiting for a lock.
- *
- * Takes the lock in read mode.
- * Returns:
- * -ERESTARTSYS If interrupted by a signal and interruptible is true.
- */
-extern int ttm_read_lock(struct ttm_lock *lock, bool interruptible);
-
-/**
- * ttm_read_trylock
- *
- * @lock: Pointer to a struct ttm_lock
- * @interruptible: Interruptible sleeping while waiting for a lock.
- *
- * Tries to take the lock in read mode. If the lock is already held
- * in write mode, the function will return -EBUSY. If the lock is held
- * in vt or suspend mode, the function will sleep until these modes
- * are unlocked.
- *
- * Returns:
- * -EBUSY The lock was already held in write mode.
- * -ERESTARTSYS If interrupted by a signal and interruptible is true.
- */
-extern int ttm_read_trylock(struct ttm_lock *lock, bool interruptible);
-
-/**
- * ttm_write_unlock
- *
- * @lock: Pointer to a struct ttm_lock
- *
- * Releases a write lock.
- */
-extern void ttm_write_unlock(struct ttm_lock *lock);
-
-/**
- * ttm_write_lock
- *
- * @lock: Pointer to a struct ttm_lock
- * @interruptible: Interruptible sleeping while waiting for a lock.
- *
- * Takes the lock in write mode.
- * Returns:
- * -ERESTARTSYS If interrupted by a signal and interruptible is true.
- */
-extern int ttm_write_lock(struct ttm_lock *lock, bool interruptible);
-
-/**
- * ttm_lock_downgrade
- *
- * @lock: Pointer to a struct ttm_lock
- *
- * Downgrades a write lock to a read lock.
- */
-extern void ttm_lock_downgrade(struct ttm_lock *lock);
-
-/**
- * ttm_suspend_lock
- *
- * @lock: Pointer to a struct ttm_lock
- *
- * Takes the lock in suspend mode. Excludes read and write mode.
- */
-extern void ttm_suspend_lock(struct ttm_lock *lock);
-
-/**
- * ttm_suspend_unlock
- *
- * @lock: Pointer to a struct ttm_lock
- *
- * Releases a suspend lock
- */
-extern void ttm_suspend_unlock(struct ttm_lock *lock);
-
-/**
- * ttm_vt_lock
- *
- * @lock: Pointer to a struct ttm_lock
- * @interruptible: Interruptible sleeping while waiting for a lock.
- * @tfile: Pointer to a struct ttm_object_file to register the lock with.
- *
- * Takes the lock in vt mode.
- * Returns:
- * -ERESTARTSYS If interrupted by a signal and interruptible is true.
- * -ENOMEM: Out of memory when locking.
- */
-extern int ttm_vt_lock(struct ttm_lock *lock, bool interruptible,
-		       struct ttm_object_file *tfile);
-
-/**
- * ttm_vt_unlock
- *
- * @lock: Pointer to a struct ttm_lock
- *
- * Releases a vt lock.
- * Returns:
- * -EINVAL If the lock was not held.
- */
-extern int ttm_vt_unlock(struct ttm_lock *lock);
-
-/**
- * ttm_write_unlock
- *
- * @lock: Pointer to a struct ttm_lock
- *
- * Releases a write lock.
- */
-extern void ttm_write_unlock(struct ttm_lock *lock);
-
-/**
- * ttm_write_lock
- *
- * @lock: Pointer to a struct ttm_lock
- * @interruptible: Interruptible sleeping while waiting for a lock.
- *
- * Takes the lock in write mode.
- * Returns:
- * -ERESTARTSYS If interrupted by a signal and interruptible is true.
- */
-extern int ttm_write_lock(struct ttm_lock *lock, bool interruptible);
-
-#endif

drivers/gpu/drm/vmwgfx/vmwgfx_bo.c

···
 	int ret;
 	uint32_t new_flags;
 
-	ret = ttm_write_lock(&dev_priv->reservation_sem, interruptible);
-	if (unlikely(ret != 0))
-		return ret;
-
 	vmw_execbuf_release_pinned_bo(dev_priv);
 
 	ret = ttm_bo_reserve(bo, interruptible, false, NULL);
···
 		vmw_bo_pin_reserved(buf, true);
 
 	ttm_bo_unreserve(bo);
-
 err:
-	ttm_write_unlock(&dev_priv->reservation_sem);
 	return ret;
 }
 
···
 	int ret;
 	uint32_t new_flags;
 
-	ret = ttm_write_lock(&dev_priv->reservation_sem, interruptible);
-	if (unlikely(ret != 0))
-		return ret;
-
 	vmw_execbuf_release_pinned_bo(dev_priv);
 
 	ret = ttm_bo_reserve(bo, interruptible, false, NULL);
···
 
 	ttm_bo_unreserve(bo);
 err:
-	ttm_write_unlock(&dev_priv->reservation_sem);
 	return ret;
 }
 
···
 	placement.num_busy_placement = 1;
 	placement.busy_placement = &place;
 
-	ret = ttm_write_lock(&dev_priv->reservation_sem, interruptible);
-	if (unlikely(ret != 0))
-		return ret;
-
 	vmw_execbuf_release_pinned_bo(dev_priv);
 	ret = ttm_bo_reserve(bo, interruptible, false, NULL);
 	if (unlikely(ret != 0))
···
 
 	ttm_bo_unreserve(bo);
 err_unlock:
-	ttm_write_unlock(&dev_priv->reservation_sem);
 
 	return ret;
 }
···
 	struct ttm_buffer_object *bo = &buf->base;
 	int ret;
 
-	ret = ttm_read_lock(&dev_priv->reservation_sem, interruptible);
-	if (unlikely(ret != 0))
-		return ret;
-
 	ret = ttm_bo_reserve(bo, interruptible, false, NULL);
 	if (unlikely(ret != 0))
 		goto err;
···
 	ttm_bo_unreserve(bo);
 
 err:
-	ttm_read_unlock(&dev_priv->reservation_sem);
 	return ret;
 }
 
···
 	uint32_t handle;
 	int ret;
 
-	ret = ttm_read_lock(&dev_priv->reservation_sem, true);
-	if (unlikely(ret != 0))
-		return ret;
-
 	ret = vmw_user_bo_alloc(dev_priv, vmw_fpriv(file_priv)->tfile,
 				req->size, false, &handle, &vbo,
 				NULL);
···
 	vmw_bo_unreference(&vbo);
 
 out_no_bo:
-	ttm_read_unlock(&dev_priv->reservation_sem);
 
 	return ret;
 }
···
 	args->pitch = args->width * ((args->bpp + 7) / 8);
 	args->size = args->pitch * args->height;
 
-	ret = ttm_read_lock(&dev_priv->reservation_sem, true);
-	if (unlikely(ret != 0))
-		return ret;
-
 	ret = vmw_user_bo_alloc(dev_priv, vmw_fpriv(file_priv)->tfile,
 				    args->size, false, &args->handle,
 				    &vbo, NULL);
···
 
 	vmw_bo_unreference(&vbo);
 out_no_bo:
-	ttm_read_unlock(&dev_priv->reservation_sem);
 	return ret;
 }
 

drivers/gpu/drm/vmwgfx/vmwgfx_context.c

···
 		  ((dev_priv->has_mob) ? vmw_cmdbuf_res_man_size() : 0) +
 		  + VMW_IDA_ACC_SIZE + TTM_OBJ_EXTRA_SIZE;
 
-	ret = ttm_read_lock(&dev_priv->reservation_sem, true);
-	if (unlikely(ret != 0))
-		return ret;
-
 	ret = ttm_mem_global_alloc(vmw_mem_glob(dev_priv),
 				   vmw_user_context_size,
 				   &ttm_opt_ctx);
···
 		if (ret != -ERESTARTSYS)
 			DRM_ERROR("Out of graphics memory for context"
 				  " creation.\n");
-		goto out_unlock;
+		goto out_ret;
 	}
 
 	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
···
 		ttm_mem_global_free(vmw_mem_glob(dev_priv),
 				    vmw_user_context_size);
 		ret = -ENOMEM;
-		goto out_unlock;
+		goto out_ret;
 	}
 
 	res = &ctx->res;
···
 
 	ret = vmw_context_init(dev_priv, res, vmw_user_context_free, dx);
 	if (unlikely(ret != 0))
-		goto out_unlock;
+		goto out_ret;
 
 	tmp = vmw_resource_reference(&ctx->res);
 	ret = ttm_base_object_init(tfile, &ctx->base, false, VMW_RES_CONTEXT,
···
 	arg->cid = ctx->base.handle;
 out_err:
 	vmw_resource_unreference(&res);
-out_unlock:
-	ttm_read_unlock(&dev_priv->reservation_sem);
+out_ret:
 	return ret;
 }
 

drivers/gpu/drm/vmwgfx/vmwgfx_drv.c

···
 
 	mutex_init(&dev_priv->cmdbuf_mutex);
 	mutex_init(&dev_priv->binding_mutex);
-	ttm_lock_init(&dev_priv->reservation_sem);
 	spin_lock_init(&dev_priv->resource_lock);
 	spin_lock_init(&dev_priv->hw_lock);
 	spin_lock_init(&dev_priv->waiter_lock);
···
 		DRM_INFO("SM4_1 support available.\n");
 	if (dev_priv->sm_type == VMW_SM_4)
 		DRM_INFO("SM4 support available.\n");
+	DRM_INFO("Running without reservation semaphore\n");
 
 	snprintf(host_log, sizeof(host_log), "vmwgfx: Module Version: %d.%d.%d",
 		VMWGFX_DRIVER_MAJOR, VMWGFX_DRIVER_MINOR,
···
  */
 void vmw_svga_enable(struct vmw_private *dev_priv)
 {
-	(void) ttm_read_lock(&dev_priv->reservation_sem, false);
 	__vmw_svga_enable(dev_priv);
-	ttm_read_unlock(&dev_priv->reservation_sem);
 }
 
 /**
···
 	 *
 	 */
 	vmw_kms_lost_device(&dev_priv->drm);
-	ttm_write_lock(&dev_priv->reservation_sem, false);
 	if (ttm_resource_manager_used(man)) {
 		if (ttm_resource_manager_evict_all(&dev_priv->bdev, man))
 			DRM_ERROR("Failed evicting VRAM buffers.\n");
···
 			  SVGA_REG_ENABLE_HIDE |
 			  SVGA_REG_ENABLE_ENABLE);
 	}
-	ttm_write_unlock(&dev_priv->reservation_sem);
 }
 
 static void vmw_remove(struct pci_dev *pdev)
···
 		 * Once user-space processes have been frozen, we can release
 		 * the lock again.
 		 */
-		ttm_suspend_lock(&dev_priv->reservation_sem);
 		dev_priv->suspend_locked = true;
 		break;
 	case PM_POST_HIBERNATION:
 	case PM_POST_RESTORE:
 		if (READ_ONCE(dev_priv->suspend_locked)) {
 			dev_priv->suspend_locked = false;
-			ttm_suspend_unlock(&dev_priv->reservation_sem);
 		}
 		break;
 	default:
···
 	int ret;
 
 	/*
-	 * Unlock for vmw_kms_suspend.
 	 * No user-space processes should be running now.
 	 */
-	ttm_suspend_unlock(&dev_priv->reservation_sem);
 	ret = vmw_kms_suspend(&dev_priv->drm);
 	if (ret) {
-		ttm_suspend_lock(&dev_priv->reservation_sem);
 		DRM_ERROR("Failed to freeze modesetting.\n");
 		return ret;
 	}
 	if (dev_priv->enable_fb)
 		vmw_fb_off(dev_priv);
 
-	ttm_suspend_lock(&dev_priv->reservation_sem);
 	vmw_execbuf_release_pinned_bo(dev_priv);
 	vmw_resource_evict_all(dev_priv);
 	vmw_release_device_early(dev_priv);
···
 			vmw_fifo_resource_inc(dev_priv);
 		WARN_ON(vmw_request_device_late(dev_priv));
 		dev_priv->suspend_locked = false;
-		ttm_suspend_unlock(&dev_priv->reservation_sem);
 		if (dev_priv->suspend_state)
 			vmw_kms_resume(dev);
 		if (dev_priv->enable_fb)
···
 
 	vmw_fence_fifo_up(dev_priv->fman);
 	dev_priv->suspend_locked = false;
-	ttm_suspend_unlock(&dev_priv->reservation_sem);
 	if (dev_priv->suspend_state)
 		vmw_kms_resume(&dev_priv->drm);
 

drivers/gpu/drm/vmwgfx/vmwgfx_drv.h

···
 #include <drm/ttm/ttm_bo_driver.h>
 #include <drm/ttm/ttm_execbuf_util.h>
 
-#include "ttm_lock.h"
 #include "ttm_object.h"
 
 #include "vmwgfx_fence.h"
···
 	bool suspend_locked;
 
 	atomic_t num_fifo_resources;
-
-	/*
-	 * Replace this with an rwsem as soon as we have down_xx_interruptible()
-	 */
-	struct ttm_lock reservation_sem;
 
 	/*
 	 * Query processing. These members

drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c

···
 			goto out;
 	}
 
-	ret = ttm_read_lock(&dev_priv->reservation_sem, true);
-	if (unlikely(ret != 0))
-		return ret;
-
 	ret = vmw_execbuf_process(file_priv, dev_priv,
 				  (void __user *)(unsigned long)arg->commands,
 				  NULL, arg->command_size, arg->throttle_us,
···
 				  (void __user *)(unsigned long)arg->fence_rep,
 				  NULL, arg->flags);
 
-	ttm_read_unlock(&dev_priv->reservation_sem);
 	if (unlikely(ret != 0))
 		goto out;
 

drivers/gpu/drm/vmwgfx/vmwgfx_fb.c

···
 	if (!cur_fb)
 		goto out_unlock;
 
-	(void) ttm_read_lock(&vmw_priv->reservation_sem, false);
 	(void) ttm_bo_reserve(&vbo->base, false, false, NULL);
 	virtual = vmw_bo_map_and_cache(vbo);
 	if (!virtual)
···
 
 out_unreserve:
 	ttm_bo_unreserve(&vbo->base);
-	ttm_read_unlock(&vmw_priv->reservation_sem);
 	if (w && h) {
 		WARN_ON_ONCE(par->set_fb->funcs->dirty(cur_fb, NULL, 0, 0,
 						       &clip, 1));
···
 	struct vmw_buffer_object *vmw_bo;
 	int ret;
 
-	(void) ttm_write_lock(&vmw_priv->reservation_sem, false);
-
 	vmw_bo = kmalloc(sizeof(*vmw_bo), GFP_KERNEL);
 	if (!vmw_bo) {
 		ret = -ENOMEM;
···
 		goto err_unlock; /* init frees the buffer on failure */
 
 	*out = vmw_bo;
-	ttm_write_unlock(&vmw_priv->reservation_sem);
-
-	return 0;
 
 err_unlock:
-	ttm_write_unlock(&vmw_priv->reservation_sem);
 	return ret;
 }
 

drivers/gpu/drm/vmwgfx/vmwgfx_ioctl.c

···
 	}
 	vfb = vmw_framebuffer_to_vfb(fb);
 
-	ret = ttm_read_lock(&dev_priv->reservation_sem, true);
-	if (unlikely(ret != 0))
-		goto out_no_ttm_lock;
-
 	ret = vmw_user_resource_lookup_handle(dev_priv, tfile, arg->sid,
 					      user_surface_converter,
 					      &res);
···
 	vmw_surface_unreference(&surface);
 
 out_no_surface:
-	ttm_read_unlock(&dev_priv->reservation_sem);
-out_no_ttm_lock:
 	drm_framebuffer_put(fb);
 out_no_fb:
 	drm_modeset_unlock_all(dev);
···
 		goto out_no_ttm_lock;
 	}
 
-	ret = ttm_read_lock(&dev_priv->reservation_sem, true);
-	if (unlikely(ret != 0))
-		goto out_no_ttm_lock;
-
 	ret = vmw_kms_readback(dev_priv, file_priv,
 			       vfb, user_fence_rep,
 			       clips, num_clips);
 
-	ttm_read_unlock(&dev_priv->reservation_sem);
 out_no_ttm_lock:
 	drm_framebuffer_put(fb);
 out_no_fb:

drivers/gpu/drm/vmwgfx/vmwgfx_kms.c

···
 
 	drm_modeset_lock_all(&dev_priv->drm);
 
-	ret = ttm_read_lock(&dev_priv->reservation_sem, true);
-	if (unlikely(ret != 0)) {
-		drm_modeset_unlock_all(&dev_priv->drm);
-		return ret;
-	}
-
 	if (!num_clips) {
 		num_clips = 1;
 		clips = &norect;
···
 	}
 
 	vmw_cmd_flush(dev_priv, false);
-	ttm_read_unlock(&dev_priv->reservation_sem);
 
 	drm_modeset_unlock_all(&dev_priv->drm);
 

drivers/gpu/drm/vmwgfx/vmwgfx_resource.c

···
 	struct vmw_private *dev_priv = res->dev_priv;
 	int ret;
 
-	ttm_write_lock(&dev_priv->reservation_sem, interruptible);
 	mutex_lock(&dev_priv->cmdbuf_mutex);
 	ret = vmw_resource_reserve(res, interruptible, false);
 	if (ret)
···
 	vmw_resource_unreserve(res, false, false, false, NULL, 0UL);
 out_no_reserve:
 	mutex_unlock(&dev_priv->cmdbuf_mutex);
-	ttm_write_unlock(&dev_priv->reservation_sem);
 
 	return ret;
 }
···
 	struct vmw_private *dev_priv = res->dev_priv;
 	int ret;
 
-	(void) ttm_read_lock(&dev_priv->reservation_sem, false);
 	mutex_lock(&dev_priv->cmdbuf_mutex);
 
 	ret = vmw_resource_reserve(res, false, true);
···
 	vmw_resource_unreserve(res, false, false, false, NULL, 0UL);
 
 	mutex_unlock(&dev_priv->cmdbuf_mutex);
-	ttm_read_unlock(&dev_priv->reservation_sem);
 }
 
 /**

drivers/gpu/drm/vmwgfx/vmwgfx_shader.c

···
 		goto out_bad_arg;
 	}
 
-	ret = ttm_read_lock(&dev_priv->reservation_sem, true);
-	if (unlikely(ret != 0))
-		goto out_bad_arg;
-
 	ret = vmw_user_shader_alloc(dev_priv, buffer, size, offset,
 				    shader_type, num_input_sig,
 				    num_output_sig, tfile, shader_handle);
-
-	ttm_read_unlock(&dev_priv->reservation_sem);
 out_bad_arg:
 	vmw_bo_unreference(&buffer);
 	return ret;

drivers/gpu/drm/vmwgfx/vmwgfx_simple_resource.c

···
 	account_size = ttm_round_pot(alloc_size) + VMW_IDA_ACC_SIZE +
 		TTM_OBJ_EXTRA_SIZE;
 
-	ret = ttm_read_lock(&dev_priv->reservation_sem, true);
-	if (ret)
-		return ret;
-
 	ret = ttm_mem_global_alloc(vmw_mem_glob(dev_priv), account_size,
 				   &ctx);
-	ttm_read_unlock(&dev_priv->reservation_sem);
 	if (ret) {
 		if (ret != -ERESTARTSYS)
 			DRM_ERROR("Out of graphics memory for %s"

drivers/gpu/drm/vmwgfx/vmwgfx_surface.c

···
 		return -EINVAL;
 	}
 
-	ret = ttm_read_lock(&dev_priv->reservation_sem, true);
-	if (unlikely(ret != 0))
-		return ret;
-
 	ret = ttm_mem_global_alloc(vmw_mem_glob(dev_priv),
 				   size, &ctx);
 	if (unlikely(ret != 0)) {
···
 	rep->sid = user_srf->prime.base.handle;
 	vmw_resource_unreference(&res);
 
-	ttm_read_unlock(&dev_priv->reservation_sem);
 	return 0;
 out_no_copy:
 	kfree(srf->offsets);
···
 out_no_user_srf:
 	ttm_mem_global_free(vmw_mem_glob(dev_priv), size);
 out_unlock:
-	ttm_read_unlock(&dev_priv->reservation_sem);
 	return ret;
 }
 
···
 	if (drm_is_primary_client(file_priv))
 		user_srf->master = drm_master_get(file_priv->master);
 
-	ret = ttm_read_lock(&dev_priv->reservation_sem, true);
-	if (unlikely(ret != 0))
-		return ret;
-
 	res = &user_srf->srf.res;
 
 	if (req->base.buffer_handle != SVGA3D_INVALID_ID) {
···
 	vmw_resource_unreference(&res);
 
 out_unlock:
-	ttm_read_unlock(&dev_priv->reservation_sem);
 	return ret;
 }
 
···
 	if (req->sizes != NULL)
 		return -EINVAL;
 
-	ret = ttm_read_lock(&dev_priv->reservation_sem, true);
-	if (unlikely(ret != 0))
-		return ret;
-
 	ret = ttm_mem_global_alloc(vmw_mem_glob(dev_priv),
 				   user_accounting_size, &ctx);
 	if (ret != 0) {
···
 	 */
 	ret = vmw_surface_init(dev_priv, srf, vmw_user_surface_free);
 
-	ttm_read_unlock(&dev_priv->reservation_sem);
 	return ret;
 
 out_no_user_srf:
 	ttm_mem_global_free(vmw_mem_glob(dev_priv), user_accounting_size);
 
 out_unlock:
-	ttm_read_unlock(&dev_priv->reservation_sem);
 	return ret;
 }