nagai/kernel
3
0
Fork 0
forked from mirrors/linux
Code Pull requests Activity

dma-buf: remove shared fence staging in reservation object

Browse source 
No need for that any more. Just replace the list when there isn't enough
room any more for the additional fence.

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Junwei Zhang <Jerry.Zhang@amd.com>
Reviewed-by: Huang Rui <ray.huang@amd.com>
Link: https://patchwork.kernel.org/patch/10626143/
This commit is contained in:
Christian König 2018-08-08 16:01:22 +02:00
parent 9d32bdbb5b
commit 27836b641c
2 changed files with 58 additions and 124 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

178
drivers/dma-buf/reservation.c
View file

@ -68,105 +68,23 @@ EXPORT_SYMBOL(reservation_seqcount_string);
*/ */
int reservation_object_reserve_shared(struct reservation_object *obj) int reservation_object_reserve_shared(struct reservation_object *obj)
{ {
struct reservation_object_list *fobj, *old; struct reservation_object_list *old, *new;
u32 max; unsigned int i, j, k, max;
old = reservation_object_get_list(obj); old = reservation_object_get_list(obj);
if (old && old->shared_max) { if (old && old->shared_max) {
if (old->shared_count < old->shared_max) { if (old->shared_count < old->shared_max)
/* perform an in-place update */
kfree(obj->staged);
obj->staged = NULL;
return 0; return 0;
} else else
max = old->shared_max * 2; max = old->shared_max * 2;
} else
max = 4;
/*
* resize obj->staged or allocate if it doesn't exist,
* noop if already correct size
*/
fobj = krealloc(obj->staged, offsetof(typeof(*fobj), shared[max]),
GFP_KERNEL);
if (!fobj)
return -ENOMEM;
obj->staged = fobj;
fobj->shared_max = max;
return 0;
}
EXPORT_SYMBOL(reservation_object_reserve_shared);
static void
reservation_object_add_shared_inplace(struct reservation_object *obj,
struct reservation_object_list *fobj,
struct dma_fence *fence)
{
struct dma_fence *signaled = NULL;
u32 i, signaled_idx;
dma_fence_get(fence);
preempt_disable();
write_seqcount_begin(&obj->seq);
for (i = 0; i < fobj->shared_count; ++i) {
struct dma_fence *old_fence;
old_fence = rcu_dereference_protected(fobj->shared[i],
reservation_object_held(obj));
if (old_fence->context == fence->context) {
/* memory barrier is added by write_seqcount_begin */
RCU_INIT_POINTER(fobj->shared[i], fence);
write_seqcount_end(&obj->seq);
preempt_enable();
dma_fence_put(old_fence);
return;
}
if (!signaled && dma_fence_is_signaled(old_fence)) {
signaled = old_fence;
signaled_idx = i;
}
}
/*
* memory barrier is added by write_seqcount_begin,
* fobj->shared_count is protected by this lock too
*/
if (signaled) {
RCU_INIT_POINTER(fobj->shared[signaled_idx], fence);
} else { } else {
BUG_ON(fobj->shared_count >= fobj->shared_max); max = 4;
RCU_INIT_POINTER(fobj->shared[fobj->shared_count], fence);
fobj->shared_count++;
} }
write_seqcount_end(&obj->seq); new = kmalloc(offsetof(typeof(*new), shared[max]), GFP_KERNEL);
preempt_enable(); if (!new)
return -ENOMEM;
dma_fence_put(signaled);
}
static void
reservation_object_add_shared_replace(struct reservation_object *obj,
struct reservation_object_list *old,
struct reservation_object_list *fobj,
struct dma_fence *fence)
{
unsigned i, j, k;
dma_fence_get(fence);
if (!old) {
RCU_INIT_POINTER(fobj->shared[0], fence);
fobj->shared_count = 1;
goto done;
}
/* /*
* no need to bump fence refcounts, rcu_read access * no need to bump fence refcounts, rcu_read access
@ -174,46 +92,45 @@ reservation_object_add_shared_replace(struct reservation_object *obj,
* references from the old struct are carried over to * references from the old struct are carried over to
* the new. * the new.
*/ */
for (i = 0, j = 0, k = fobj->shared_max; i < old->shared_count; ++i) { for (i = 0, j = 0, k = max; i < (old ? old->shared_count : 0); ++i) {
struct dma_fence *check; struct dma_fence *fence;
check = rcu_dereference_protected(old->shared[i], fence = rcu_dereference_protected(old->shared[i],
reservation_object_held(obj)); reservation_object_held(obj));
if (dma_fence_is_signaled(fence))
if (check->context == fence->context || RCU_INIT_POINTER(new->shared[--k], fence);
dma_fence_is_signaled(check))
RCU_INIT_POINTER(fobj->shared[--k], check);
else else
RCU_INIT_POINTER(fobj->shared[j++], check); RCU_INIT_POINTER(new->shared[j++], fence);
} }
fobj->shared_count = j; new->shared_count = j;
RCU_INIT_POINTER(fobj->shared[fobj->shared_count], fence); new->shared_max = max;
fobj->shared_count++;
done:
preempt_disable(); preempt_disable();
write_seqcount_begin(&obj->seq); write_seqcount_begin(&obj->seq);
/* /*
* RCU_INIT_POINTER can be used here, * RCU_INIT_POINTER can be used here,
* seqcount provides the necessary barriers * seqcount provides the necessary barriers
*/ */
RCU_INIT_POINTER(obj->fence, fobj); RCU_INIT_POINTER(obj->fence, new);
write_seqcount_end(&obj->seq); write_seqcount_end(&obj->seq);
preempt_enable(); preempt_enable();
if (!old) if (!old)
return; return 0;
/* Drop the references to the signaled fences */ /* Drop the references to the signaled fences */
for (i = k; i < fobj->shared_max; ++i) { for (i = k; i < new->shared_max; ++i) {
struct dma_fence *f; struct dma_fence *fence;
f = rcu_dereference_protected(fobj->shared[i], fence = rcu_dereference_protected(new->shared[i],
reservation_object_held(obj)); reservation_object_held(obj));
dma_fence_put(f); dma_fence_put(fence);
} }
kfree_rcu(old, rcu); kfree_rcu(old, rcu);
return 0;
} }
EXPORT_SYMBOL(reservation_object_reserve_shared);
/** /**
* reservation_object_add_shared_fence - Add a fence to a shared slot * reservation_object_add_shared_fence - Add a fence to a shared slot
@ -226,15 +143,39 @@ reservation_object_add_shared_replace(struct reservation_object *obj,
void reservation_object_add_shared_fence(struct reservation_object *obj, void reservation_object_add_shared_fence(struct reservation_object *obj,
struct dma_fence *fence) struct dma_fence *fence)
{ {
struct reservation_object_list *old, *fobj = obj->staged; struct reservation_object_list *fobj;
unsigned int i;
old = reservation_object_get_list(obj); dma_fence_get(fence);
obj->staged = NULL;
if (!fobj) fobj = reservation_object_get_list(obj);
reservation_object_add_shared_inplace(obj, old, fence);
else preempt_disable();
reservation_object_add_shared_replace(obj, old, fobj, fence); write_seqcount_begin(&obj->seq);
for (i = 0; i < fobj->shared_count; ++i) {
struct dma_fence *old_fence;
old_fence = rcu_dereference_protected(fobj->shared[i],
reservation_object_held(obj));
if (old_fence->context == fence->context ||
dma_fence_is_signaled(old_fence)) {
dma_fence_put(old_fence);
goto replace;
}
}
BUG_ON(fobj->shared_count >= fobj->shared_max);
fobj->shared_count++;
replace:
/*
* memory barrier is added by write_seqcount_begin,
* fobj->shared_count is protected by this lock too
*/
RCU_INIT_POINTER(fobj->shared[i], fence);
write_seqcount_end(&obj->seq);
preempt_enable();
} }
EXPORT_SYMBOL(reservation_object_add_shared_fence); EXPORT_SYMBOL(reservation_object_add_shared_fence);
@ -343,9 +284,6 @@ int reservation_object_copy_fences(struct reservation_object *dst,
new = dma_fence_get_rcu_safe(&src->fence_excl); new = dma_fence_get_rcu_safe(&src->fence_excl);
rcu_read_unlock(); rcu_read_unlock();
kfree(dst->staged);
dst->staged = NULL;
src_list = reservation_object_get_list(dst); src_list = reservation_object_get_list(dst);
old = reservation_object_get_excl(dst); old = reservation_object_get_excl(dst);

4
include/linux/reservation.h
View file

@ -68,7 +68,6 @@ struct reservation_object_list {
* @seq: sequence count for managing RCU read-side synchronization * @seq: sequence count for managing RCU read-side synchronization
* @fence_excl: the exclusive fence, if there is one currently * @fence_excl: the exclusive fence, if there is one currently
* @fence: list of current shared fences * @fence: list of current shared fences
* @staged: staged copy of shared fences for RCU updates
*/ */
struct reservation_object { struct reservation_object {
struct ww_mutex lock; struct ww_mutex lock;
@ -76,7 +75,6 @@ struct reservation_object {
struct dma_fence __rcu *fence_excl; struct dma_fence __rcu *fence_excl;
struct reservation_object_list __rcu *fence; struct reservation_object_list __rcu *fence;
struct reservation_object_list *staged;
}; };
#define reservation_object_held(obj) lockdep_is_held(&(obj)->lock.base) #define reservation_object_held(obj) lockdep_is_held(&(obj)->lock.base)
@ -95,7 +93,6 @@ reservation_object_init(struct reservation_object *obj)
__seqcount_init(&obj->seq, reservation_seqcount_string, &reservation_seqcount_class); __seqcount_init(&obj->seq, reservation_seqcount_string, &reservation_seqcount_class);
RCU_INIT_POINTER(obj->fence, NULL); RCU_INIT_POINTER(obj->fence, NULL);
RCU_INIT_POINTER(obj->fence_excl, NULL); RCU_INIT_POINTER(obj->fence_excl, NULL);
obj->staged = NULL;
} }
/** /**
@ -124,7 +121,6 @@ reservation_object_fini(struct reservation_object *obj)
kfree(fobj); kfree(fobj);
} }
kfree(obj->staged);
ww_mutex_destroy(&obj->lock); ww_mutex_destroy(&obj->lock);
} }