diff mbox series

[v2,1/2] drm/i915: convert i915_active.count from atomic_t to refcount_t

Message ID fe31efd659622839c7f7bc2890d9e3411bbfa7cd.1671952191.git.drv@mailo.com (mailing list archive)
State New, archived
Headers show
Series convert i915_active.count from atomic_t to refcount_t | expand

Commit Message

Deepak R Varma Dec. 25, 2022, 7:47 a.m. UTC 
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 <drv@mailo.com>
---
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 <lkp@intel.com>
      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(-)

--
2.34.1

Comments

kernel test robot Dec. 28, 2022, 11:58 a.m. UTC | #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 <oliver.sang@intel.com>
| Link: https://lore.kernel.org/oe-lkp/202212281735.20cb559d-oliver.sang@intel.com


[   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.
Praveen Kumar Dec. 28, 2022, 2:43 p.m. UTC | #2 
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 <drv@mailo.com>
> ---
> 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 <lkp@intel.com>
>       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.
diff mbox series

Patch

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;