| Message ID | 20190821123147.110736-4-christian.koenig@amd.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [01/10] dma-buf: make to_dma_fence_array NULL safe | expand |
Quoting Christian König (2019-08-21 13:31:40) > Try to recycle an dma_fence_array object by dropping the last > reference to it without freeing it. > > Signed-off-by: Christian König <christian.koenig@amd.com> > --- > drivers/dma-buf/dma-fence-array.c | 27 +++++++++++++++++++++++++++ > include/linux/dma-fence-array.h | 1 + > 2 files changed, 28 insertions(+) > > diff --git a/drivers/dma-buf/dma-fence-array.c b/drivers/dma-buf/dma-fence-array.c > index e82f30551aa1..314cf0e881d9 100644 > --- a/drivers/dma-buf/dma-fence-array.c > +++ b/drivers/dma-buf/dma-fence-array.c > @@ -188,6 +188,33 @@ void dma_fence_array_init(struct dma_fence_array *array, u64 context, > } > EXPORT_SYMBOL(dma_fence_array_init); > > +/** > + * dma_fence_array_reuse - dummy for dma_fence_array_recycle > + */ > +static void dma_fence_array_reuse(struct kref *kref) > +{ > + struct dma_fence_array *array = container_of(kref, typeof(*array), > + base.refcount); > + > + WARN_ON_ONCE(!list_empty(&array->base.cb_list)); [ 77.584694] WARNING: CPU: 3 PID: 627 at drivers/dma-buf/dma-fence-array.c:199 dma_fence_array_recycle+0x1d/0x20 [ 77.584702] Modules linked in: nls_ascii nls_cp437 vfat fat crct10dif_pclmul i915 crc32_pclmul crc32c_intel aesni_intel aes_x86_64 glue_helper crypto_simd cryptd intel_cstate intel_gtt drm_kms_helper intel_uncore intel_rapl_perf ahci i2c_i801 libahci efivars video button efivarfs [ 77.584716] CPU: 3 PID: 627 Comm: gem_busy Tainted: G U 5.3.0-rc5+ #72 [ 77.584719] Hardware name: Intel Corporation NUC7i5BNK/NUC7i5BNB, BIOS BNKBL357.86A.0052.2017.0918.1346 09/18/2017 [ 77.584723] RIP: 0010:dma_fence_array_recycle+0x1d/0x20 [ 77.584726] Code: 5d c3 5b 5d e9 54 f5 ff ff 0f 1f 40 00 f0 ff 4f 38 0f 88 d3 85 14 00 0f 94 c0 74 01 c3 48 8b 57 10 48 83 c7 10 48 39 d7 74 f2 <0f> 0b c3 48 c7 c0 62 88 be 81 c3 0f 1f 84 00 00 00 00 00 48 c7 c0 [ 77.584730] RSP: 0018:ffffc900001c3c78 EFLAGS: 00010292 [ 77.584733] RAX: 0000000000000001 RBX: ffff88885ac14b40 RCX: cccccccccccccccd [ 77.584735] RDX: 00000012105b0a77 RSI: 0000000000000000 RDI: ffff88885ac14b50 [ 77.584737] RBP: 0000000000000000 R08: 0000000000000004 R09: 000000000001de00 [ 77.584740] R10: 00000030f5224012 R11: 00000000000002df R12: ffff88885b58aff0 [ 77.584742] R13: 0000000000000000 R14: 0000000000000000 R15: ffff88885748e100 [ 77.584745] FS: 00007f1cd47b19c0(0000) GS:ffff88885eb80000(0000) knlGS:0000000000000000 [ 77.584748] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 77.584750] CR2: 00007f1cd6719000 CR3: 000000085ac5b002 CR4: 00000000001606e0 [ 77.584753] Call Trace: [ 77.584758] dma_resv_fences_assign.isra.7+0x8d/0x220 [ 77.584761] dma_resv_prune_fences+0xba/0xc0 [ 77.584796] i915_gem_object_wait_reservation+0x226/0x240 [i915] [ 77.584827] i915_gem_object_wait+0x23/0x40 [i915] [ 77.584854] i915_gem_set_domain_ioctl+0xbf/0x240 [i915] If we signal the fence-array, the cb_list is replaced by the timestamp and is no longer considered empty. -Chris
Am 21.08.19 um 18:24 schrieb Chris Wilson: > Quoting Christian König (2019-08-21 13:31:40) >> Try to recycle an dma_fence_array object by dropping the last >> reference to it without freeing it. >> >> Signed-off-by: Christian König <christian.koenig@amd.com> >> --- >> drivers/dma-buf/dma-fence-array.c | 27 +++++++++++++++++++++++++++ >> include/linux/dma-fence-array.h | 1 + >> 2 files changed, 28 insertions(+) >> >> diff --git a/drivers/dma-buf/dma-fence-array.c b/drivers/dma-buf/dma-fence-array.c >> index e82f30551aa1..314cf0e881d9 100644 >> --- a/drivers/dma-buf/dma-fence-array.c >> +++ b/drivers/dma-buf/dma-fence-array.c >> @@ -188,6 +188,33 @@ void dma_fence_array_init(struct dma_fence_array *array, u64 context, >> } >> EXPORT_SYMBOL(dma_fence_array_init); >> >> +/** >> + * dma_fence_array_reuse - dummy for dma_fence_array_recycle >> + */ >> +static void dma_fence_array_reuse(struct kref *kref) >> +{ >> + struct dma_fence_array *array = container_of(kref, typeof(*array), >> + base.refcount); >> + >> + WARN_ON_ONCE(!list_empty(&array->base.cb_list)); > [ 77.584694] WARNING: CPU: 3 PID: 627 at drivers/dma-buf/dma-fence-array.c:199 dma_fence_array_recycle+0x1d/0x20 > [ 77.584702] Modules linked in: nls_ascii nls_cp437 vfat fat crct10dif_pclmul i915 crc32_pclmul crc32c_intel aesni_intel aes_x86_64 glue_helper crypto_simd cryptd intel_cstate intel_gtt drm_kms_helper intel_uncore intel_rapl_perf ahci i2c_i801 libahci efivars video button efivarfs > [ 77.584716] CPU: 3 PID: 627 Comm: gem_busy Tainted: G U 5.3.0-rc5+ #72 > [ 77.584719] Hardware name: Intel Corporation NUC7i5BNK/NUC7i5BNB, BIOS BNKBL357.86A.0052.2017.0918.1346 09/18/2017 > [ 77.584723] RIP: 0010:dma_fence_array_recycle+0x1d/0x20 > [ 77.584726] Code: 5d c3 5b 5d e9 54 f5 ff ff 0f 1f 40 00 f0 ff 4f 38 0f 88 d3 85 14 00 0f 94 c0 74 01 c3 48 8b 57 10 48 83 c7 10 48 39 d7 74 f2 <0f> 0b c3 48 c7 c0 62 88 be 81 c3 0f 1f 84 00 00 00 00 00 48 c7 c0 > [ 77.584730] RSP: 0018:ffffc900001c3c78 EFLAGS: 00010292 > [ 77.584733] RAX: 0000000000000001 RBX: ffff88885ac14b40 RCX: cccccccccccccccd > [ 77.584735] RDX: 00000012105b0a77 RSI: 0000000000000000 RDI: ffff88885ac14b50 > [ 77.584737] RBP: 0000000000000000 R08: 0000000000000004 R09: 000000000001de00 > [ 77.584740] R10: 00000030f5224012 R11: 00000000000002df R12: ffff88885b58aff0 > [ 77.584742] R13: 0000000000000000 R14: 0000000000000000 R15: ffff88885748e100 > [ 77.584745] FS: 00007f1cd47b19c0(0000) GS:ffff88885eb80000(0000) knlGS:0000000000000000 > [ 77.584748] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > [ 77.584750] CR2: 00007f1cd6719000 CR3: 000000085ac5b002 CR4: 00000000001606e0 > [ 77.584753] Call Trace: > [ 77.584758] dma_resv_fences_assign.isra.7+0x8d/0x220 > [ 77.584761] dma_resv_prune_fences+0xba/0xc0 > [ 77.584796] i915_gem_object_wait_reservation+0x226/0x240 [i915] > [ 77.584827] i915_gem_object_wait+0x23/0x40 [i915] > [ 77.584854] i915_gem_set_domain_ioctl+0xbf/0x240 [i915] > > If we signal the fence-array, the cb_list is replaced by the timestamp > and is no longer considered empty. Ah, yeah good point I actually wrote that before cb_list and timestamp shared the same memory. Christian. > -Chris
diff --git a/drivers/dma-buf/dma-fence-array.c b/drivers/dma-buf/dma-fence-array.c index e82f30551aa1..314cf0e881d9 100644 --- a/drivers/dma-buf/dma-fence-array.c +++ b/drivers/dma-buf/dma-fence-array.c @@ -188,6 +188,33 @@ void dma_fence_array_init(struct dma_fence_array *array, u64 context, } EXPORT_SYMBOL(dma_fence_array_init); +/** + * dma_fence_array_reuse - dummy for dma_fence_array_recycle + */ +static void dma_fence_array_reuse(struct kref *kref) +{ + struct dma_fence_array *array = container_of(kref, typeof(*array), + base.refcount); + + WARN_ON_ONCE(!list_empty(&array->base.cb_list)); +} + +/** + * dma_fence_array_try_reuse - try to reuse a dma_fence_array object + * @array: array which we should try to reuse + * + * Try to drop the last reference to an dma_fence_array and so allow it to be + * reused. + * + * Returns true if this was the last reference then caller can reuse the array. + * In this case the array is reset into a state where it can be used with + * dma_fence_array_init again. + */ +bool dma_fence_array_recycle(struct dma_fence_array *array) +{ + return kref_put(&array->base.refcount, dma_fence_array_reuse); +} + /** * dma_fence_array_free - free a dma_fence_array object * @array: the object to free diff --git a/include/linux/dma-fence-array.h b/include/linux/dma-fence-array.h index be85c06b524d..35d1d1e7c93b 100644 --- a/include/linux/dma-fence-array.h +++ b/include/linux/dma-fence-array.h @@ -93,6 +93,7 @@ struct dma_fence_array *dma_fence_array_alloc(int num_fences, struct dma_fence **fences); void dma_fence_array_init(struct dma_fence_array *array, u64 context, unsigned int seqno, bool signal_on_any); +bool dma_fence_array_recycle(struct dma_fence_array *array); void dma_fence_array_free(struct dma_fence_array *array); /**
Try to recycle an dma_fence_array object by dropping the last reference to it without freeing it. Signed-off-by: Christian König <christian.koenig@amd.com> --- drivers/dma-buf/dma-fence-array.c | 27 +++++++++++++++++++++++++++ include/linux/dma-fence-array.h | 1 + 2 files changed, 28 insertions(+)