linux/drivers/gpu/drm/vmwgfx/vmwgfx_cmdbuf_res.c
Thomas Hellstrom 508108ea27 drm/vmwgfx: Don't refcount command-buffer managed resource lookups during command buffer validation
The typical pattern of these lookups are
-Lookup
-Put on validate list if not already there.
-Unreference
And since we are the exclusive user of the context during lookup time,
we can be sure that the resource will stay alive during the sequence.
So avoid taking a reference during lookup, and also avoid unreferencing
when done.

Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: Sinclair Yeh <syeh@vmware.com>
2018-09-28 08:57:08 +02:00

347 lines
9.9 KiB
C

// SPDX-License-Identifier: GPL-2.0 OR MIT
/**************************************************************************
*
* Copyright 2014-2015 VMware, Inc., Palo Alto, CA., USA
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the
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* 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.
*
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* FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
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**************************************************************************/
#include "vmwgfx_drv.h"
#include "vmwgfx_resource_priv.h"
#define VMW_CMDBUF_RES_MAN_HT_ORDER 12
/**
* struct vmw_cmdbuf_res - Command buffer managed resource entry.
*
* @res: Refcounted pointer to a struct vmw_resource.
* @hash: Hash entry for the manager hash table.
* @head: List head used either by the staging list or the manager list
* of commited resources.
* @state: Staging state of this resource entry.
* @man: Pointer to a resource manager for this entry.
*/
struct vmw_cmdbuf_res {
struct vmw_resource *res;
struct drm_hash_item hash;
struct list_head head;
enum vmw_cmdbuf_res_state state;
struct vmw_cmdbuf_res_manager *man;
};
/**
* struct vmw_cmdbuf_res_manager - Command buffer resource manager.
*
* @resources: Hash table containing staged and commited command buffer
* resources
* @list: List of commited command buffer resources.
* @dev_priv: Pointer to a device private structure.
*
* @resources and @list are protected by the cmdbuf mutex for now.
*/
struct vmw_cmdbuf_res_manager {
struct drm_open_hash resources;
struct list_head list;
struct vmw_private *dev_priv;
};
/**
* vmw_cmdbuf_res_lookup - Look up a command buffer resource
*
* @man: Pointer to the command buffer resource manager
* @resource_type: The resource type, that combined with the user key
* identifies the resource.
* @user_key: The user key.
*
* Returns a valid refcounted struct vmw_resource pointer on success,
* an error pointer on failure.
*/
struct vmw_resource *
vmw_cmdbuf_res_lookup(struct vmw_cmdbuf_res_manager *man,
enum vmw_cmdbuf_res_type res_type,
u32 user_key)
{
struct drm_hash_item *hash;
int ret;
unsigned long key = user_key | (res_type << 24);
ret = drm_ht_find_item(&man->resources, key, &hash);
if (unlikely(ret != 0))
return ERR_PTR(ret);
return drm_hash_entry(hash, struct vmw_cmdbuf_res, hash)->res;
}
/**
* vmw_cmdbuf_res_free - Free a command buffer resource.
*
* @man: Pointer to the command buffer resource manager
* @entry: Pointer to a struct vmw_cmdbuf_res.
*
* Frees a struct vmw_cmdbuf_res entry and drops its reference to the
* struct vmw_resource.
*/
static void vmw_cmdbuf_res_free(struct vmw_cmdbuf_res_manager *man,
struct vmw_cmdbuf_res *entry)
{
list_del(&entry->head);
WARN_ON(drm_ht_remove_item(&man->resources, &entry->hash));
vmw_resource_unreference(&entry->res);
kfree(entry);
}
/**
* vmw_cmdbuf_res_commit - Commit a list of command buffer resource actions
*
* @list: Caller's list of command buffer resource actions.
*
* This function commits a list of command buffer resource
* additions or removals.
* It is typically called when the execbuf ioctl call triggering these
* actions has commited the fifo contents to the device.
*/
void vmw_cmdbuf_res_commit(struct list_head *list)
{
struct vmw_cmdbuf_res *entry, *next;
list_for_each_entry_safe(entry, next, list, head) {
list_del(&entry->head);
if (entry->res->func->commit_notify)
entry->res->func->commit_notify(entry->res,
entry->state);
switch (entry->state) {
case VMW_CMDBUF_RES_ADD:
entry->state = VMW_CMDBUF_RES_COMMITTED;
list_add_tail(&entry->head, &entry->man->list);
break;
case VMW_CMDBUF_RES_DEL:
vmw_resource_unreference(&entry->res);
kfree(entry);
break;
default:
BUG();
break;
}
}
}
/**
* vmw_cmdbuf_res_revert - Revert a list of command buffer resource actions
*
* @man: Pointer to the command buffer resource manager
* @list: Caller's list of command buffer resource action
*
* This function reverts a list of command buffer resource
* additions or removals.
* It is typically called when the execbuf ioctl call triggering these
* actions failed for some reason, and the command stream was never
* submitted.
*/
void vmw_cmdbuf_res_revert(struct list_head *list)
{
struct vmw_cmdbuf_res *entry, *next;
int ret;
list_for_each_entry_safe(entry, next, list, head) {
switch (entry->state) {
case VMW_CMDBUF_RES_ADD:
vmw_cmdbuf_res_free(entry->man, entry);
break;
case VMW_CMDBUF_RES_DEL:
ret = drm_ht_insert_item(&entry->man->resources,
&entry->hash);
list_del(&entry->head);
list_add_tail(&entry->head, &entry->man->list);
entry->state = VMW_CMDBUF_RES_COMMITTED;
break;
default:
BUG();
break;
}
}
}
/**
* vmw_cmdbuf_res_add - Stage a command buffer managed resource for addition.
*
* @man: Pointer to the command buffer resource manager.
* @res_type: The resource type.
* @user_key: The user-space id of the resource.
* @res: Valid (refcount != 0) pointer to a struct vmw_resource.
* @list: The staging list.
*
* This function allocates a struct vmw_cmdbuf_res entry and adds the
* resource to the hash table of the manager identified by @man. The
* entry is then put on the staging list identified by @list.
*/
int vmw_cmdbuf_res_add(struct vmw_cmdbuf_res_manager *man,
enum vmw_cmdbuf_res_type res_type,
u32 user_key,
struct vmw_resource *res,
struct list_head *list)
{
struct vmw_cmdbuf_res *cres;
int ret;
cres = kzalloc(sizeof(*cres), GFP_KERNEL);
if (unlikely(!cres))
return -ENOMEM;
cres->hash.key = user_key | (res_type << 24);
ret = drm_ht_insert_item(&man->resources, &cres->hash);
if (unlikely(ret != 0))
goto out_invalid_key;
cres->state = VMW_CMDBUF_RES_ADD;
cres->res = vmw_resource_reference(res);
cres->man = man;
list_add_tail(&cres->head, list);
out_invalid_key:
return ret;
}
/**
* vmw_cmdbuf_res_remove - Stage a command buffer managed resource for removal.
*
* @man: Pointer to the command buffer resource manager.
* @res_type: The resource type.
* @user_key: The user-space id of the resource.
* @list: The staging list.
* @res_p: If the resource is in an already committed state, points to the
* struct vmw_resource on successful return. The pointer will be
* non ref-counted.
*
* This function looks up the struct vmw_cmdbuf_res entry from the manager
* hash table and, if it exists, removes it. Depending on its current staging
* state it then either removes the entry from the staging list or adds it
* to it with a staging state of removal.
*/
int vmw_cmdbuf_res_remove(struct vmw_cmdbuf_res_manager *man,
enum vmw_cmdbuf_res_type res_type,
u32 user_key,
struct list_head *list,
struct vmw_resource **res_p)
{
struct vmw_cmdbuf_res *entry;
struct drm_hash_item *hash;
int ret;
ret = drm_ht_find_item(&man->resources, user_key | (res_type << 24),
&hash);
if (likely(ret != 0))
return -EINVAL;
entry = drm_hash_entry(hash, struct vmw_cmdbuf_res, hash);
switch (entry->state) {
case VMW_CMDBUF_RES_ADD:
vmw_cmdbuf_res_free(man, entry);
*res_p = NULL;
break;
case VMW_CMDBUF_RES_COMMITTED:
(void) drm_ht_remove_item(&man->resources, &entry->hash);
list_del(&entry->head);
entry->state = VMW_CMDBUF_RES_DEL;
list_add_tail(&entry->head, list);
*res_p = entry->res;
break;
default:
BUG();
break;
}
return 0;
}
/**
* vmw_cmdbuf_res_man_create - Allocate a command buffer managed resource
* manager.
*
* @dev_priv: Pointer to a struct vmw_private
*
* Allocates and initializes a command buffer managed resource manager. Returns
* an error pointer on failure.
*/
struct vmw_cmdbuf_res_manager *
vmw_cmdbuf_res_man_create(struct vmw_private *dev_priv)
{
struct vmw_cmdbuf_res_manager *man;
int ret;
man = kzalloc(sizeof(*man), GFP_KERNEL);
if (!man)
return ERR_PTR(-ENOMEM);
man->dev_priv = dev_priv;
INIT_LIST_HEAD(&man->list);
ret = drm_ht_create(&man->resources, VMW_CMDBUF_RES_MAN_HT_ORDER);
if (ret == 0)
return man;
kfree(man);
return ERR_PTR(ret);
}
/**
* vmw_cmdbuf_res_man_destroy - Destroy a command buffer managed resource
* manager.
*
* @man: Pointer to the manager to destroy.
*
* This function destroys a command buffer managed resource manager and
* unreferences / frees all command buffer managed resources and -entries
* associated with it.
*/
void vmw_cmdbuf_res_man_destroy(struct vmw_cmdbuf_res_manager *man)
{
struct vmw_cmdbuf_res *entry, *next;
list_for_each_entry_safe(entry, next, &man->list, head)
vmw_cmdbuf_res_free(man, entry);
drm_ht_remove(&man->resources);
kfree(man);
}
/**
*
* vmw_cmdbuf_res_man_size - Return the size of a command buffer managed
* resource manager
*
* Returns the approximate allocation size of a command buffer managed
* resource manager.
*/
size_t vmw_cmdbuf_res_man_size(void)
{
static size_t res_man_size;
if (unlikely(res_man_size == 0))
res_man_size =
ttm_round_pot(sizeof(struct vmw_cmdbuf_res_manager)) +
ttm_round_pot(sizeof(struct hlist_head) <<
VMW_CMDBUF_RES_MAN_HT_ORDER);
return res_man_size;
}