Bug Summary

File:dev/pci/drm/i915/gt/intel_gt_buffer_pool.c
Warning:line 241, column 31
Value stored to 'pool' during its initialization is never read

Annotated Source Code

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clang -cc1 -cc1 -triple amd64-unknown-openbsd7.4 -analyze -disable-free -clear-ast-before-backend -disable-llvm-verifier -discard-value-names -main-file-name intel_gt_buffer_pool.c -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -setup-static-analyzer -mrelocation-model static -mframe-pointer=all -relaxed-aliasing -ffp-contract=on -fno-rounding-math -mconstructor-aliases -ffreestanding -mcmodel=kernel -target-cpu x86-64 -target-feature +retpoline-indirect-calls -target-feature +retpoline-indirect-branches -target-feature -sse2 -target-feature -sse -target-feature -3dnow -target-feature -mmx -target-feature +save-args -target-feature +retpoline-external-thunk -disable-red-zone -no-implicit-float -tune-cpu generic -debugger-tuning=gdb -fcoverage-compilation-dir=/usr/src/sys/arch/amd64/compile/GENERIC.MP/obj -nostdsysteminc -nobuiltininc -resource-dir /usr/local/llvm16/lib/clang/16 -I /usr/src/sys -I /usr/src/sys/arch/amd64/compile/GENERIC.MP/obj -I /usr/src/sys/arch -I /usr/src/sys/dev/pci/drm/include -I /usr/src/sys/dev/pci/drm/include/uapi -I /usr/src/sys/dev/pci/drm/amd/include/asic_reg -I /usr/src/sys/dev/pci/drm/amd/include -I /usr/src/sys/dev/pci/drm/amd/amdgpu -I /usr/src/sys/dev/pci/drm/amd/display -I /usr/src/sys/dev/pci/drm/amd/display/include -I /usr/src/sys/dev/pci/drm/amd/display/dc -I /usr/src/sys/dev/pci/drm/amd/display/amdgpu_dm -I /usr/src/sys/dev/pci/drm/amd/pm/inc -I /usr/src/sys/dev/pci/drm/amd/pm/legacy-dpm -I /usr/src/sys/dev/pci/drm/amd/pm/swsmu -I /usr/src/sys/dev/pci/drm/amd/pm/swsmu/inc -I /usr/src/sys/dev/pci/drm/amd/pm/swsmu/smu11 -I /usr/src/sys/dev/pci/drm/amd/pm/swsmu/smu12 -I /usr/src/sys/dev/pci/drm/amd/pm/swsmu/smu13 -I /usr/src/sys/dev/pci/drm/amd/pm/powerplay/inc -I /usr/src/sys/dev/pci/drm/amd/pm/powerplay/hwmgr -I /usr/src/sys/dev/pci/drm/amd/pm/powerplay/smumgr -I /usr/src/sys/dev/pci/drm/amd/pm/swsmu/inc -I /usr/src/sys/dev/pci/drm/amd/pm/swsmu/inc/pmfw_if -I /usr/src/sys/dev/pci/drm/amd/display/dc/inc -I /usr/src/sys/dev/pci/drm/amd/display/dc/inc/hw -I /usr/src/sys/dev/pci/drm/amd/display/dc/clk_mgr -I /usr/src/sys/dev/pci/drm/amd/display/modules/inc -I /usr/src/sys/dev/pci/drm/amd/display/modules/hdcp -I /usr/src/sys/dev/pci/drm/amd/display/dmub/inc -I /usr/src/sys/dev/pci/drm/i915 -D DDB -D DIAGNOSTIC -D KTRACE -D ACCOUNTING -D KMEMSTATS -D PTRACE -D POOL_DEBUG -D CRYPTO -D SYSVMSG -D SYSVSEM -D SYSVSHM -D UVM_SWAP_ENCRYPT -D FFS -D FFS2 -D FFS_SOFTUPDATES -D UFS_DIRHASH -D QUOTA -D EXT2FS -D MFS -D NFSCLIENT -D NFSSERVER -D CD9660 -D UDF -D MSDOSFS -D FIFO -D FUSE -D SOCKET_SPLICE -D TCP_ECN -D TCP_SIGNATURE -D INET6 -D IPSEC -D PPP_BSDCOMP -D PPP_DEFLATE -D PIPEX -D MROUTING -D MPLS -D BOOT_CONFIG -D USER_PCICONF -D APERTURE -D MTRR -D NTFS -D SUSPEND -D HIBERNATE -D PCIVERBOSE -D USBVERBOSE -D WSDISPLAY_COMPAT_USL -D WSDISPLAY_COMPAT_RAWKBD -D WSDISPLAY_DEFAULTSCREENS=6 -D X86EMU -D ONEWIREVERBOSE -D MULTIPROCESSOR -D MAXUSERS=80 -D _KERNEL -O2 -Wno-pointer-sign -Wno-address-of-packed-member -Wno-constant-conversion -Wno-unused-but-set-variable -Wno-gnu-folding-constant -fdebug-compilation-dir=/usr/src/sys/arch/amd64/compile/GENERIC.MP/obj -ferror-limit 19 -fwrapv -D_RET_PROTECTOR -ret-protector -fcf-protection=branch -fgnuc-version=4.2.1 -vectorize-loops -vectorize-slp -fno-builtin-malloc -fno-builtin-calloc -fno-builtin-realloc -fno-builtin-valloc -fno-builtin-free -fno-builtin-strdup -fno-builtin-strndup -analyzer-output=html -faddrsig -o /home/ben/Projects/scan/2024-01-11-110808-61670-1 -x c /usr/src/sys/dev/pci/drm/i915/gt/intel_gt_buffer_pool.c
1// SPDX-License-Identifier: MIT
2/*
3 * Copyright © 2014-2018 Intel Corporation
4 */
5
6#include "gem/i915_gem_internal.h"
7#include "gem/i915_gem_object.h"
8
9#include "i915_drv.h"
10#include "intel_engine_pm.h"
11#include "intel_gt_buffer_pool.h"
12
13static struct list_head *
14bucket_for_size(struct intel_gt_buffer_pool *pool, size_t sz)
15{
16 int n;
17
18 /*
19 * Compute a power-of-two bucket, but throw everything greater than
20 * 16KiB into the same bucket: i.e. the buckets hold objects of
21 * (1 page, 2 pages, 4 pages, 8+ pages).
22 */
23 n = fls(sz >> PAGE_SHIFT12) - 1;
24 if (n >= ARRAY_SIZE(pool->cache_list)(sizeof((pool->cache_list)) / sizeof((pool->cache_list)
[0]))
)
25 n = ARRAY_SIZE(pool->cache_list)(sizeof((pool->cache_list)) / sizeof((pool->cache_list)
[0]))
- 1;
26
27 return &pool->cache_list[n];
28}
29
30static void node_free(struct intel_gt_buffer_pool_node *node)
31{
32 i915_gem_object_put(node->obj);
33 i915_active_fini(&node->active);
34 kfree_rcu(node, rcu)do { free((void *)node, 145, 0); } while(0);
35}
36
37static bool_Bool pool_free_older_than(struct intel_gt_buffer_pool *pool, long keep)
38{
39 struct intel_gt_buffer_pool_node *node, *stale = NULL((void *)0);
40 bool_Bool active = false0;
41 int n;
42
43 /* Free buffers that have not been used in the past second */
44 for (n = 0; n < ARRAY_SIZE(pool->cache_list)(sizeof((pool->cache_list)) / sizeof((pool->cache_list)
[0]))
; n++) {
45 struct list_head *list = &pool->cache_list[n];
46
47 if (list_empty(list))
48 continue;
49
50 if (spin_trylock_irq(&pool->lock)mtx_enter_try(&pool->lock)) {
51 struct list_head *pos;
52
53 /* Most recent at head; oldest at tail */
54 list_for_each_prev(pos, list)for (pos = (list)->prev; pos != (list); pos = pos->prev
)
{
55 unsigned long age;
56
57 node = list_entry(pos, typeof(*node), link)({ const __typeof( ((typeof(*node) *)0)->link ) *__mptr = (
pos); (typeof(*node) *)( (char *)__mptr - __builtin_offsetof(
typeof(*node), link) );})
;
58
59 age = READ_ONCE(node->age)({ typeof(node->age) __tmp = *(volatile typeof(node->age
) *)&(node->age); membar_datadep_consumer(); __tmp; })
;
60 if (!age || jiffies - age < keep)
61 break;
62
63 /* Check we are the first to claim this node */
64 if (!xchg(&node->age, 0)__sync_lock_test_and_set(&node->age, 0))
65 break;
66
67 node->free = stale;
68 stale = node;
69 }
70 if (!list_is_last(pos, list))
71 __list_del_many(pos, list);
72
73 spin_unlock_irq(&pool->lock)mtx_leave(&pool->lock);
74 }
75
76 active |= !list_empty(list);
77 }
78
79 while ((node = stale)) {
80 stale = stale->free;
81 node_free(node);
82 }
83
84 return active;
85}
86
87static void pool_free_work(struct work_struct *wrk)
88{
89 struct intel_gt_buffer_pool *pool =
90 container_of(wrk, typeof(*pool), work.work)({ const __typeof( ((typeof(*pool) *)0)->work.work ) *__mptr
= (wrk); (typeof(*pool) *)( (char *)__mptr - __builtin_offsetof
(typeof(*pool), work.work) );})
;
91
92 if (pool_free_older_than(pool, HZhz))
93 schedule_delayed_work(&pool->work,
94 round_jiffies_up_relative(HZhz));
95}
96
97static void pool_retire(struct i915_active *ref)
98{
99 struct intel_gt_buffer_pool_node *node =
100 container_of(ref, typeof(*node), active)({ const __typeof( ((typeof(*node) *)0)->active ) *__mptr =
(ref); (typeof(*node) *)( (char *)__mptr - __builtin_offsetof
(typeof(*node), active) );})
;
101 struct intel_gt_buffer_pool *pool = node->pool;
102 struct list_head *list = bucket_for_size(pool, node->obj->base.size);
103 unsigned long flags;
104
105 if (node->pinned) {
106 i915_gem_object_unpin_pages(node->obj);
107
108 /* Return this object to the shrinker pool */
109 i915_gem_object_make_purgeable(node->obj);
110 node->pinned = false0;
111 }
112
113 GEM_BUG_ON(node->age)((void)0);
114 spin_lock_irqsave(&pool->lock, flags)do { flags = 0; mtx_enter(&pool->lock); } while (0);
115 list_add_rcu(&node->link, list)list_add(&node->link, list);
116 WRITE_ONCE(node->age, jiffies ?: 1)({ typeof(node->age) __tmp = (jiffies ?: 1); *(volatile typeof
(node->age) *)&(node->age) = __tmp; __tmp; })
; /* 0 reserved for active nodes */
117 spin_unlock_irqrestore(&pool->lock, flags)do { (void)(flags); mtx_leave(&pool->lock); } while (0
)
;
118
119 schedule_delayed_work(&pool->work,
120 round_jiffies_up_relative(HZhz));
121}
122
123void intel_gt_buffer_pool_mark_used(struct intel_gt_buffer_pool_node *node)
124{
125 assert_object_held(node->obj)do { (void)(&((node->obj)->base.resv)->lock.base
); } while(0)
;
126
127 if (node->pinned)
128 return;
129
130 __i915_gem_object_pin_pages(node->obj);
131 /* Hide this pinned object from the shrinker until retired */
132 i915_gem_object_make_unshrinkable(node->obj);
133 node->pinned = true1;
134}
135
136static struct intel_gt_buffer_pool_node *
137node_create(struct intel_gt_buffer_pool *pool, size_t sz,
138 enum i915_map_type type)
139{
140 struct intel_gt *gt = container_of(pool, struct intel_gt, buffer_pool)({ const __typeof( ((struct intel_gt *)0)->buffer_pool ) *
__mptr = (pool); (struct intel_gt *)( (char *)__mptr - __builtin_offsetof
(struct intel_gt, buffer_pool) );})
;
141 struct intel_gt_buffer_pool_node *node;
142 struct drm_i915_gem_object *obj;
143
144 node = kmalloc(sizeof(*node),
145 GFP_KERNEL(0x0001 | 0x0004) | __GFP_RETRY_MAYFAIL0 | __GFP_NOWARN0);
146 if (!node)
147 return ERR_PTR(-ENOMEM12);
148
149 node->age = 0;
150 node->pool = pool;
151 node->pinned = false0;
152 i915_active_init(&node->active, NULL, pool_retire, 0)do { static struct lock_class_key __mkey; static struct lock_class_key
__wkey; __i915_active_init(&node->active, ((void *)0)
, pool_retire, 0, &__mkey, &__wkey); } while (0)
;
153
154 obj = i915_gem_object_create_internal(gt->i915, sz);
155 if (IS_ERR(obj)) {
156 i915_active_fini(&node->active);
157 kfree(node);
158 return ERR_CAST(obj);
159 }
160
161 i915_gem_object_set_readonly(obj);
162
163 node->type = type;
164 node->obj = obj;
165 return node;
166}
167
168struct intel_gt_buffer_pool_node *
169intel_gt_get_buffer_pool(struct intel_gt *gt, size_t size,
170 enum i915_map_type type)
171{
172 struct intel_gt_buffer_pool *pool = &gt->buffer_pool;
173 struct intel_gt_buffer_pool_node *node;
174 struct list_head *list;
175 int ret;
176
177 size = PAGE_ALIGN(size)(((size) + ((1 << 12) - 1)) & ~((1 << 12) - 1
))
;
178 list = bucket_for_size(pool, size);
179
180 rcu_read_lock();
181 list_for_each_entry_rcu(node, list, link)for (node = ({ const __typeof( ((__typeof(*node) *)0)->link
) *__mptr = ((list)->next); (__typeof(*node) *)( (char *)
__mptr - __builtin_offsetof(__typeof(*node), link) );}); &
node->link != (list); node = ({ const __typeof( ((__typeof
(*node) *)0)->link ) *__mptr = (node->link.next); (__typeof
(*node) *)( (char *)__mptr - __builtin_offsetof(__typeof(*node
), link) );}))
{
182 unsigned long age;
183
184 if (node->obj->base.size < size)
185 continue;
186
187 if (node->type != type)
188 continue;
189
190 age = READ_ONCE(node->age)({ typeof(node->age) __tmp = *(volatile typeof(node->age
) *)&(node->age); membar_datadep_consumer(); __tmp; })
;
191 if (!age)
192 continue;
193
194 if (cmpxchg(&node->age, age, 0)__sync_val_compare_and_swap(&node->age, age, 0) == age) {
195 spin_lock_irq(&pool->lock)mtx_enter(&pool->lock);
196 list_del_rcu(&node->link)list_del(&node->link);
197 spin_unlock_irq(&pool->lock)mtx_leave(&pool->lock);
198 break;
199 }
200 }
201 rcu_read_unlock();
202
203 if (&node->link == list) {
204 node = node_create(pool, size, type);
205 if (IS_ERR(node))
206 return node;
207 }
208
209 ret = i915_active_acquire(&node->active);
210 if (ret) {
211 node_free(node);
212 return ERR_PTR(ret);
213 }
214
215 return node;
216}
217
218void intel_gt_init_buffer_pool(struct intel_gt *gt)
219{
220 struct intel_gt_buffer_pool *pool = &gt->buffer_pool;
221 int n;
222
223 mtx_init(&pool->lock, IPL_TTY)do { (void)(((void *)0)); (void)(0); __mtx_init((&pool->
lock), ((((0x9)) > 0x0 && ((0x9)) < 0x9) ? 0x9 :
((0x9)))); } while (0)
;
224 for (n = 0; n < ARRAY_SIZE(pool->cache_list)(sizeof((pool->cache_list)) / sizeof((pool->cache_list)
[0]))
; n++)
225 INIT_LIST_HEAD(&pool->cache_list[n]);
226 INIT_DELAYED_WORK(&pool->work, pool_free_work);
227}
228
229void intel_gt_flush_buffer_pool(struct intel_gt *gt)
230{
231 struct intel_gt_buffer_pool *pool = &gt->buffer_pool;
232
233 do {
234 while (pool_free_older_than(pool, 0))
235 ;
236 } while (cancel_delayed_work_sync(&pool->work));
237}
238
239void intel_gt_fini_buffer_pool(struct intel_gt *gt)
240{
241 struct intel_gt_buffer_pool *pool = &gt->buffer_pool;
Value stored to 'pool' during its initialization is never read
242 int n;
243
244 for (n = 0; n < ARRAY_SIZE(pool->cache_list)(sizeof((pool->cache_list)) / sizeof((pool->cache_list)
[0]))
; n++)
245 GEM_BUG_ON(!list_empty(&pool->cache_list[n]))((void)0);
246}