The refcount_* APIs are designed to address known issues with the
atomic_t APIs for reference counting. They provide following distinct
advantages:
- protect the reference counters from overflow/underflow
- avoid use-after-free errors
- provide improved memory ordering guarantee schemes
- neater and safer.
Hence, convert the atomic_t count member variable and associated
atomic_*() API calls to equivalent refcount_t type and refcount_*() API
calls.
This patch proposal address the following warnings generated by
the atomic_as_refcounter.cocci coccinelle script
atomic_add_unless
Signed-off-by: Deepak R Varma <[email protected]>
---
Please note:
1. Proposed changes are compile tested only.
2. This patch 1/2 is required to be applied before patch 2/2 due to
interdependency.
Changes in v2:
1. Patch added to the patch series.
2. Handle build issues Reported-by: kernel test robot <[email protected]>
Earlier a standalone patch was sent for the i915 base driver only. The
Kernel Test Robot reported build failure for additional atomic_*() calls
specific to i915 debugging support when enabled. This version now includes
those changes as well.
drivers/gpu/drm/i915/i915_active.c | 28 +++++++++++++-----------
drivers/gpu/drm/i915/i915_active.h | 6 ++---
drivers/gpu/drm/i915/i915_active_types.h | 4 ++--
3 files changed, 20 insertions(+), 18 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_active.c b/drivers/gpu/drm/i915/i915_active.c
index 7412abf166a8..5e58d8b1e947 100644
--- a/drivers/gpu/drm/i915/i915_active.c
+++ b/drivers/gpu/drm/i915/i915_active.c
@@ -92,14 +92,14 @@ static void debug_active_init(struct i915_active *ref)
static void debug_active_activate(struct i915_active *ref)
{
lockdep_assert_held(&ref->tree_lock);
- if (!atomic_read(&ref->count)) /* before the first inc */
+ if (!refcount_read(&ref->count)) /* before the first inc */
debug_object_activate(ref, &active_debug_desc);
}
static void debug_active_deactivate(struct i915_active *ref)
{
lockdep_assert_held(&ref->tree_lock);
- if (!atomic_read(&ref->count)) /* after the last dec */
+ if (!refcount_read(&ref->count)) /* after the last dec */
debug_object_deactivate(ref, &active_debug_desc);
}
@@ -133,7 +133,7 @@ __active_retire(struct i915_active *ref)
GEM_BUG_ON(i915_active_is_idle(ref));
/* return the unused nodes to our slabcache -- flushing the allocator */
- if (!atomic_dec_and_lock_irqsave(&ref->count, &ref->tree_lock, flags))
+ if (!refcount_dec_and_lock_irqsave(&ref->count, &ref->tree_lock, &flags))
return;
GEM_BUG_ON(rcu_access_pointer(ref->excl.fence));
@@ -179,8 +179,8 @@ active_work(struct work_struct *wrk)
{
struct i915_active *ref = container_of(wrk, typeof(*ref), work);
- GEM_BUG_ON(!atomic_read(&ref->count));
- if (atomic_add_unless(&ref->count, -1, 1))
+ GEM_BUG_ON(!refcount_read(&ref->count));
+ if (refcount_dec_not_one(&ref->count))
return;
__active_retire(ref);
@@ -189,8 +189,8 @@ active_work(struct work_struct *wrk)
static void
active_retire(struct i915_active *ref)
{
- GEM_BUG_ON(!atomic_read(&ref->count));
- if (atomic_add_unless(&ref->count, -1, 1))
+ GEM_BUG_ON(!refcount_read(&ref->count));
+ if (refcount_dec_not_one(&ref->count))
return;
if (ref->flags & I915_ACTIVE_RETIRE_SLEEPS) {
@@ -354,7 +354,7 @@ void __i915_active_init(struct i915_active *ref,
ref->cache = NULL;
init_llist_head(&ref->preallocated_barriers);
- atomic_set(&ref->count, 0);
+ refcount_set(&ref->count, 0);
__mutex_init(&ref->mutex, "i915_active", mkey);
__i915_active_fence_init(&ref->excl, NULL, excl_retire);
INIT_WORK(&ref->work, active_work);
@@ -445,7 +445,7 @@ int i915_active_add_request(struct i915_active *ref, struct i915_request *rq)
if (replace_barrier(ref, active)) {
RCU_INIT_POINTER(active->fence, NULL);
- atomic_dec(&ref->count);
+ refcount_dec(&ref->count);
}
if (!__i915_active_fence_set(active, fence))
__i915_active_acquire(ref);
@@ -488,14 +488,16 @@ i915_active_set_exclusive(struct i915_active *ref, struct dma_fence *f)
bool i915_active_acquire_if_busy(struct i915_active *ref)
{
debug_active_assert(ref);
- return atomic_add_unless(&ref->count, 1, 0);
+ return refcount_add_not_zero(1, &ref->count);
}
static void __i915_active_activate(struct i915_active *ref)
{
spin_lock_irq(&ref->tree_lock); /* __active_retire() */
- if (!atomic_fetch_inc(&ref->count))
+ if (!refcount_inc_not_zero(&ref->count)) {
+ refcount_inc(&ref->count);
debug_active_activate(ref);
+ }
spin_unlock_irq(&ref->tree_lock);
}
@@ -757,7 +759,7 @@ int i915_sw_fence_await_active(struct i915_sw_fence *fence,
void i915_active_fini(struct i915_active *ref)
{
debug_active_fini(ref);
- GEM_BUG_ON(atomic_read(&ref->count));
+ GEM_BUG_ON(refcount_read(&ref->count));
GEM_BUG_ON(work_pending(&ref->work));
mutex_destroy(&ref->mutex);
@@ -927,7 +929,7 @@ int i915_active_acquire_preallocate_barrier(struct i915_active *ref,
first = first->next;
- atomic_dec(&ref->count);
+ refcount_dec(&ref->count);
intel_engine_pm_put(barrier_to_engine(node));
kmem_cache_free(slab_cache, node);
diff --git a/drivers/gpu/drm/i915/i915_active.h b/drivers/gpu/drm/i915/i915_active.h
index 7eb44132183a..116c7c28466a 100644
--- a/drivers/gpu/drm/i915/i915_active.h
+++ b/drivers/gpu/drm/i915/i915_active.h
@@ -193,14 +193,14 @@ void i915_active_release(struct i915_active *ref);
static inline void __i915_active_acquire(struct i915_active *ref)
{
- GEM_BUG_ON(!atomic_read(&ref->count));
- atomic_inc(&ref->count);
+ GEM_BUG_ON(!refcount_read(&ref->count));
+ refcount_inc(&ref->count);
}
static inline bool
i915_active_is_idle(const struct i915_active *ref)
{
- return !atomic_read(&ref->count);
+ return !refcount_read(&ref->count);
}
void i915_active_fini(struct i915_active *ref);
diff --git a/drivers/gpu/drm/i915/i915_active_types.h b/drivers/gpu/drm/i915/i915_active_types.h
index b02a78ac87db..152a3a25d9f7 100644
--- a/drivers/gpu/drm/i915/i915_active_types.h
+++ b/drivers/gpu/drm/i915/i915_active_types.h
@@ -7,7 +7,7 @@
#ifndef _I915_ACTIVE_TYPES_H_
#define _I915_ACTIVE_TYPES_H_
-#include <linux/atomic.h>
+#include <linux/refcount.h>
#include <linux/dma-fence.h>
#include <linux/llist.h>
#include <linux/mutex.h>
@@ -23,7 +23,7 @@ struct i915_active_fence {
struct active_node;
struct i915_active {
- atomic_t count;
+ refcount_t count;
struct mutex mutex;
spinlock_t tree_lock;
--
2.34.1
Greeting,
FYI, we noticed WARNING:at_lib/refcount.c:#refcount_warn_saturate due to commit (built with gcc-11):
commit: 22c498b9fea46946f06b30a699b496116c36dddb ("[PATCH v2 1/2] drm/i915: convert i915_active.count from atomic_t to refcount_t")
url: https://github.com/intel-lab-lkp/linux/commits/Deepak-R-Varma/drm-i915-convert-i915_active-count-from-atomic_t-to-refcount_t/20221225-154850
base: git://anongit.freedesktop.org/drm-intel for-linux-next
patch link: https://lore.kernel.org/all/fe31efd659622839c7f7bc2890d9e3411bbfa7cd.1671952191.git.drv@mailo.com/
patch subject: [PATCH v2 1/2] drm/i915: convert i915_active.count from atomic_t to refcount_t
in testcase: hwsim
version: hwsim-x86_64-717e5d7-1_20220525
with following parameters:
test: group-17
on test machine: 4 threads Intel(R) Core(TM) i5-6500 CPU @ 3.20GHz (Skylake) with 32G memory
caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace):
If you fix the issue, kindly add following tag
| Reported-by: kernel test robot <[email protected]>
| Link: https://lore.kernel.org/oe-lkp/[email protected]
[ 34.427757][ T207] ------------[ cut here ]------------
[ 34.438445][ T207] refcount_t: addition on 0; use-after-free.
[ 34.444241][ T207] WARNING: CPU: 1 PID: 207 at lib/refcount.c:25 refcount_warn_saturate+0xdd/0x140
[ 34.449776][ T402] raid6: avx2x4 gen() 27042 MB/s
[ 34.453208][ T207] Modules linked in: raid6_pq(+) zstd_compress x86_pkg_temp_thermal libcrc32c intel_powerclamp coretemp i915(+) sd_mod t10_pi ipmi_devintf ipmi_msghandler kvm_intel crc64_rocksoft_generic crc64_rocksoft crc64 drm_buddy kvm sg irqbypass intel_gtt crct10dif_pclmul crc32_pclmul crc32c_intel ghash_clmulni_intel sha512_ssse3 drm_display_helper mei_wdt ttm rapl drm_kms_helper mei_me ahci syscopyarea intel_cstate wmi_bmof sysfillrect video i2c_i801 libahci intel_uncore mei libata sysimgblt i2c_smbus intel_pch_thermal wmi intel_pmc_core acpi_pad drm fuse ip_tables
[ 34.474778][ T402] raid6: avx2x2 gen() 28719 MB/s
[ 34.508560][ T207] CPU: 1 PID: 207 Comm: systemd-udevd Tainted: G S I 6.1.0-rc6-01446-g22c498b9fea4 #1
[ 34.508566][ T207] Hardware name: Dell Inc. OptiPlex 7040/0Y7WYT, BIOS 1.1.1 10/07/2015
[ 34.508568][ T207] RIP: 0010:refcount_warn_saturate+0xdd/0x140
[ 34.529776][ T402] raid6: avx2x1 gen() 23869 MB/s
[ 34.532014][ T207] Code: ca 91 08 03 01 e8 01 78 37 01 0f 0b eb 9d 80 3d b9 91 08 03 00 75 94 48 c7 c7 80 23 c2 83 c6 05 a9 91 08 03 01 e8 e1 77 37 01 <0f> 0b e9 7a ff ff ff 80 3d 93 91 08 03 00 0f 85 6d ff ff ff 48 c7
[ 34.532017][ T207] RSP: 0018:ffffc900009671c8 EFLAGS: 00010082
[ 34.537880][ T402] raid6: using algorithm avx2x2 gen() 28719 MB/s
[ 34.542794][ T207]
[ 34.542795][ T207] RAX: 0000000000000000 RBX: ffff88884b15b410 RCX: 0000000000000000
[ 34.542798][ T207] RDX: 0000000000000027 RSI: 0000000000000004 RDI: fffff5200012ce2b
[ 34.542799][ T207] RBP: 0000000000000002 R08: 0000000000000001 R09: ffff8887c98a76eb
[ 34.542801][ T207] R10: ffffed10f9314edd R11: 0000000000000001 R12: ffff88884b15b438
[ 34.578775][ T402] raid6: .... xor() 18702 MB/s, rmw enabled
[ 34.583984][ T207] R13: ffffc90000967200 R14: 0000000000000001 R15: ffffc90000967298
[ 34.583986][ T207] FS: 00007f0bc66948c0(0000) GS:ffff8887c9880000(0000) knlGS:0000000000000000
[ 34.591744][ T402] raid6: using avx2x2 recovery algorithm
[ 34.599493][ T207] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 34.599497][ T207] CR2: 00007fe21aecfd95 CR3: 0000000861710002 CR4: 00000000003706e0
[ 34.599498][ T207] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 34.599499][ T207] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 34.607256][ T402] initcall init_module+0x0/0x1000 [raid6_pq] returned 0 after 174058 usecs
[ 34.612941][ T207] Call Trace:
[ 34.612945][ T207] <TASK>
[ 34.612946][ T207] __i915_active_activate+0x185/0x190 [i915]
[ 34.684563][ T207] ? node_retire+0xf0/0xf0 [i915]
[ 34.689583][ T207] i915_active_acquire+0x230/0x2a0 [i915]
[ 34.695268][ T207] ? i915_active_acquire_if_busy+0x130/0x130 [i915]
[ 34.701820][ T207] ? __mutex_lock_interruptible_slowpath+0x10/0x10
[ 34.708137][ T207] ? kmem_cache_alloc+0x16e/0x2f0
[ 34.712980][ T207] i915_vma_pin_ww+0x495/0x1240 [i915]
[ 34.718455][ T207] ? vma_invalidate_tlb+0xd0/0xd0 [i915]
[ 34.724088][ T207] ? allocate_slab+0x116/0x290
[ 34.728679][ T207] ? __cond_resched+0x1c/0x90
[ 34.733178][ T207] __i915_ggtt_pin+0x97/0x1f0 [i915]
[ 34.738462][ T207] i915_ggtt_pin+0x161/0x360 [i915]
[ 34.743645][ T207] ? __i915_ggtt_pin+0x1f0/0x1f0 [i915]
[ 34.749212][ T207] intel_gt_init+0x110/0x640 [i915]
[ 34.754380][ T207] i915_gem_init+0x23e/0x480 [i915]
[ 34.759556][ T207] i915_driver_probe+0x1bd/0x6c0 [i915]
[ 34.765056][ T207] ? __mutex_unlock_slowpath+0x2a0/0x2a0
[ 34.771529][ T207] ? i915_print_iommu_status+0x40/0x40 [i915]
[ 34.777560][ T207] ? drm_privacy_screen_get+0x281/0x2f0 [drm]
[ 34.783471][ T207] i915_pci_probe+0x20b/0x4c0 [i915]
[ 34.788730][ T207] ? i915_pci_remove+0x80/0x80 [i915]
[ 34.794060][ T207] ? _raw_read_unlock_irqrestore+0x40/0x40
[ 34.799671][ T207] ? __cond_resched+0x1c/0x90
[ 34.804169][ T207] ? i915_pci_remove+0x80/0x80 [i915]
[ 34.809515][ T207] local_pci_probe+0xdc/0x170
[ 34.814007][ T207] pci_call_probe+0x15f/0x500
[ 34.818498][ T207] ? _raw_spin_lock+0x81/0xd0
[ 34.822990][ T207] ? pci_pm_suspend_noirq+0x8c0/0x8c0
[ 34.828172][ T207] ? pci_assign_irq+0x81/0x280
[ 34.832753][ T207] ? pci_match_device+0x351/0x6a0
[ 34.837589][ T207] ? kernfs_put+0x18/0x30
[ 34.841742][ T207] pci_device_probe+0xee/0x230
[ 34.846320][ T207] really_probe+0x1da/0xa60
[ 34.850643][ T207] __driver_probe_device+0x2a1/0x460
[ 34.855739][ T207] driver_probe_device+0x49/0x120
[ 34.860578][ T207] __driver_attach+0x178/0x4b0
[ 34.865160][ T207] ? __device_attach_driver+0x260/0x260
[ 34.870513][ T207] bus_for_each_dev+0x11b/0x1a0
[ 34.875179][ T207] ? subsys_dev_iter_exit+0x10/0x10
[ 34.880188][ T207] ? __kmem_cache_alloc_node+0x17e/0x2a0
[ 34.885628][ T207] ? klist_add_tail+0x12f/0x270
[ 34.890296][ T207] bus_add_driver+0x423/0x570
[ 34.894792][ T207] driver_register+0x20f/0x390
[ 34.899372][ T207] i915_init+0x54/0x15d [i915]
[ 34.904112][ T207] ? 0xffffffffa17f5000
[ 34.908086][ T207] do_one_initcall+0x87/0x2c0
[ 34.912582][ T207] ? trace_event_raw_event_initcall_level+0x190/0x190
[ 34.919141][ T207] ? kasan_poison+0x1f/0x40
[ 34.923463][ T207] ? kasan_unpoison+0x23/0x50
[ 34.927957][ T207] do_init_module+0x18a/0x620
[ 34.932455][ T207] load_module+0x1c34/0x2450
[ 34.936863][ T207] ? post_relocation+0x370/0x370
[ 34.941617][ T207] ? __x64_sys_fspick+0x290/0x290
[ 34.946455][ T207] ? do_mmap+0x709/0x10c0
[ 34.950610][ T207] ? __do_sys_finit_module+0x113/0x1b0
[ 34.955888][ T207] __do_sys_finit_module+0x113/0x1b0
[ 34.960991][ T207] ? __ia32_sys_init_module+0xa0/0xa0
[ 34.966186][ T207] ? fput+0x19/0x120
[ 34.969912][ T207] do_syscall_64+0x35/0x80
[ 34.974158][ T207] entry_SYSCALL_64_after_hwframe+0x5e/0xc8
[ 34.979868][ T207] RIP: 0033:0x7f0bc6b4d9b9
[ 34.984103][ T207] Code: 00 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d a7 54 0c 00 f7 d8 64 89 01 48
[ 35.003389][ T207] RSP: 002b:00007ffedd49dcf8 EFLAGS: 00000246 ORIG_RAX: 0000000000000139
[ 35.011584][ T207] RAX: ffffffffffffffda RBX: 0000560156f63b90 RCX: 00007f0bc6b4d9b9
[ 35.019346][ T207] RDX: 0000000000000000 RSI: 00007f0bc6cd8e2d RDI: 0000000000000016
[ 35.027105][ T207] RBP: 0000000000020000 R08: 0000000000000000 R09: 0000560156f63d90
[ 35.034868][ T207] R10: 0000000000000016 R11: 0000000000000246 R12: 00007f0bc6cd8e2d
[ 35.042630][ T207] R13: 0000000000000000 R14: 0000560156f63e10 R15: 0000560156f63b90
[ 35.050392][ T207] </TASK>
[ 35.053249][ T207] ---[ end trace 0000000000000000 ]---
To reproduce:
git clone https://github.com/intel/lkp-tests.git
cd lkp-tests
sudo bin/lkp install job.yaml # job file is attached in this email
bin/lkp split-job --compatible job.yaml # generate the yaml file for lkp run
sudo bin/lkp run generated-yaml-file
# if come across any failure that blocks the test,
# please remove ~/.lkp and /lkp dir to run from a clean state.
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests
On 25-12-2022 13:17, Deepak R Varma wrote:
> The refcount_* APIs are designed to address known issues with the
> atomic_t APIs for reference counting. They provide following distinct
> advantages:
> - protect the reference counters from overflow/underflow
> - avoid use-after-free errors
> - provide improved memory ordering guarantee schemes
> - neater and safer.
> Hence, convert the atomic_t count member variable and associated
> atomic_*() API calls to equivalent refcount_t type and refcount_*() API
> calls.
>
> This patch proposal address the following warnings generated by
> the atomic_as_refcounter.cocci coccinelle script
> atomic_add_unless
>
> Signed-off-by: Deepak R Varma <[email protected]>
> ---
> Please note:
> 1. Proposed changes are compile tested only.
> 2. This patch 1/2 is required to be applied before patch 2/2 due to
> interdependency.
>
> Changes in v2:
> 1. Patch added to the patch series.
> 2. Handle build issues Reported-by: kernel test robot <[email protected]>
> Earlier a standalone patch was sent for the i915 base driver only. The
> Kernel Test Robot reported build failure for additional atomic_*() calls
> specific to i915 debugging support when enabled. This version now includes
> those changes as well.
>
>
> drivers/gpu/drm/i915/i915_active.c | 28 +++++++++++++-----------
> drivers/gpu/drm/i915/i915_active.h | 6 ++---
> drivers/gpu/drm/i915/i915_active_types.h | 4 ++--
> 3 files changed, 20 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_active.c b/drivers/gpu/drm/i915/i915_active.c
> index 7412abf166a8..5e58d8b1e947 100644
> --- a/drivers/gpu/drm/i915/i915_active.c
> +++ b/drivers/gpu/drm/i915/i915_active.c
> @@ -92,14 +92,14 @@ static void debug_active_init(struct i915_active *ref)
> static void debug_active_activate(struct i915_active *ref)
> {
> lockdep_assert_held(&ref->tree_lock);
> - if (!atomic_read(&ref->count)) /* before the first inc */
> + if (!refcount_read(&ref->count)) /* before the first inc */
> debug_object_activate(ref, &active_debug_desc);
> }
>
> static void debug_active_deactivate(struct i915_active *ref)
> {
> lockdep_assert_held(&ref->tree_lock);
> - if (!atomic_read(&ref->count)) /* after the last dec */
> + if (!refcount_read(&ref->count)) /* after the last dec */
> debug_object_deactivate(ref, &active_debug_desc);
> }
>
> @@ -133,7 +133,7 @@ __active_retire(struct i915_active *ref)
> GEM_BUG_ON(i915_active_is_idle(ref));
>
> /* return the unused nodes to our slabcache -- flushing the allocator */
> - if (!atomic_dec_and_lock_irqsave(&ref->count, &ref->tree_lock, flags))
> + if (!refcount_dec_and_lock_irqsave(&ref->count, &ref->tree_lock, &flags))
> return;
>
> GEM_BUG_ON(rcu_access_pointer(ref->excl.fence));
> @@ -179,8 +179,8 @@ active_work(struct work_struct *wrk)
> {
> struct i915_active *ref = container_of(wrk, typeof(*ref), work);
>
> - GEM_BUG_ON(!atomic_read(&ref->count));
> - if (atomic_add_unless(&ref->count, -1, 1))
> + GEM_BUG_ON(!refcount_read(&ref->count));
> + if (refcount_dec_not_one(&ref->count))
I'm not sure if this is correct here, I assume we should be adding instead here its decrementing ?
> return;
>
> __active_retire(ref);
> @@ -189,8 +189,8 @@ active_work(struct work_struct *wrk)
> static void
> active_retire(struct i915_active *ref)
> {
> - GEM_BUG_ON(!atomic_read(&ref->count));
> - if (atomic_add_unless(&ref->count, -1, 1))
> + GEM_BUG_ON(!refcount_read(&ref->count));
> + if (refcount_dec_not_one(&ref->count))
> return;
>
> if (ref->flags & I915_ACTIVE_RETIRE_SLEEPS) {
> @@ -354,7 +354,7 @@ void __i915_active_init(struct i915_active *ref,
> ref->cache = NULL;
>
> init_llist_head(&ref->preallocated_barriers);
> - atomic_set(&ref->count, 0);
> + refcount_set(&ref->count, 0);
> __mutex_init(&ref->mutex, "i915_active", mkey);
> __i915_active_fence_init(&ref->excl, NULL, excl_retire);
> INIT_WORK(&ref->work, active_work);
> @@ -445,7 +445,7 @@ int i915_active_add_request(struct i915_active *ref, struct i915_request *rq)
>
> if (replace_barrier(ref, active)) {
> RCU_INIT_POINTER(active->fence, NULL);
> - atomic_dec(&ref->count);
> + refcount_dec(&ref->count);
> }
> if (!__i915_active_fence_set(active, fence))
> __i915_active_acquire(ref);
> @@ -488,14 +488,16 @@ i915_active_set_exclusive(struct i915_active *ref, struct dma_fence *f)
> bool i915_active_acquire_if_busy(struct i915_active *ref)
> {
> debug_active_assert(ref);
> - return atomic_add_unless(&ref->count, 1, 0);
> + return refcount_add_not_zero(1, &ref->count);
> }
>
> static void __i915_active_activate(struct i915_active *ref)
> {
> spin_lock_irq(&ref->tree_lock); /* __active_retire() */
> - if (!atomic_fetch_inc(&ref->count))
> + if (!refcount_inc_not_zero(&ref->count)) {
> + refcount_inc(&ref->count);
> debug_active_activate(ref);
> + }
> spin_unlock_irq(&ref->tree_lock);
> }
>
> @@ -757,7 +759,7 @@ int i915_sw_fence_await_active(struct i915_sw_fence *fence,
> void i915_active_fini(struct i915_active *ref)
> {
> debug_active_fini(ref);
> - GEM_BUG_ON(atomic_read(&ref->count));
> + GEM_BUG_ON(refcount_read(&ref->count));
> GEM_BUG_ON(work_pending(&ref->work));
> mutex_destroy(&ref->mutex);
>
> @@ -927,7 +929,7 @@ int i915_active_acquire_preallocate_barrier(struct i915_active *ref,
>
> first = first->next;
>
> - atomic_dec(&ref->count);
> + refcount_dec(&ref->count);
> intel_engine_pm_put(barrier_to_engine(node));
>
> kmem_cache_free(slab_cache, node);
> diff --git a/drivers/gpu/drm/i915/i915_active.h b/drivers/gpu/drm/i915/i915_active.h
> index 7eb44132183a..116c7c28466a 100644
> --- a/drivers/gpu/drm/i915/i915_active.h
> +++ b/drivers/gpu/drm/i915/i915_active.h
> @@ -193,14 +193,14 @@ void i915_active_release(struct i915_active *ref);
>
> static inline void __i915_active_acquire(struct i915_active *ref)
> {
> - GEM_BUG_ON(!atomic_read(&ref->count));
> - atomic_inc(&ref->count);
> + GEM_BUG_ON(!refcount_read(&ref->count));
> + refcount_inc(&ref->count);
> }
>
> static inline bool
> i915_active_is_idle(const struct i915_active *ref)
> {
> - return !atomic_read(&ref->count);
> + return !refcount_read(&ref->count);
> }
>
> void i915_active_fini(struct i915_active *ref);
> diff --git a/drivers/gpu/drm/i915/i915_active_types.h b/drivers/gpu/drm/i915/i915_active_types.h
> index b02a78ac87db..152a3a25d9f7 100644
> --- a/drivers/gpu/drm/i915/i915_active_types.h
> +++ b/drivers/gpu/drm/i915/i915_active_types.h
> @@ -7,7 +7,7 @@
> #ifndef _I915_ACTIVE_TYPES_H_
> #define _I915_ACTIVE_TYPES_H_
>
> -#include <linux/atomic.h>
> +#include <linux/refcount.h>
> #include <linux/dma-fence.h>
> #include <linux/llist.h>
> #include <linux/mutex.h>
> @@ -23,7 +23,7 @@ struct i915_active_fence {
> struct active_node;
>
> struct i915_active {
> - atomic_t count;
> + refcount_t count;
> struct mutex mutex;
>
> spinlock_t tree_lock;
> --
> 2.34.1
>
>
Regards,
~Praveen.