Commit 245a4a7b authored by Christian König's avatar Christian König

dma-buf: generalize dma_fence unwrap & merging v3

Introduce a dma_fence_unwrap_merge() macro which allows to unwrap fences
which potentially can be containers as well and then merge them back
together into a flat dma_fence_array.

v2: rename the function, add some more comments about how the wrapper is
    used, move filtering of signaled fences into the unwrap iterator,
    add complex selftest which covers more cases.
v3: fix signaled fence filtering once more
Signed-off-by: default avatarChristian König <christian.koenig@amd.com>
Reviewed-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20220518135844.3338-5-christian.koenig@amd.com
parent 8f619737
......@@ -11,6 +11,7 @@
#include <linux/dma-fence-array.h>
#include <linux/dma-fence-chain.h>
#include <linux/dma-fence-unwrap.h>
#include <linux/slab.h>
/* Internal helper to start new array iteration, don't use directly */
static struct dma_fence *
......@@ -57,3 +58,105 @@ struct dma_fence *dma_fence_unwrap_next(struct dma_fence_unwrap *cursor)
return __dma_fence_unwrap_array(cursor);
}
EXPORT_SYMBOL_GPL(dma_fence_unwrap_next);
/* Implementation for the dma_fence_merge() marco, don't use directly */
struct dma_fence *__dma_fence_unwrap_merge(unsigned int num_fences,
struct dma_fence **fences,
struct dma_fence_unwrap *iter)
{
struct dma_fence_array *result;
struct dma_fence *tmp, **array;
unsigned int i;
size_t count;
count = 0;
for (i = 0; i < num_fences; ++i) {
dma_fence_unwrap_for_each(tmp, &iter[i], fences[i])
++count;
}
if (count == 0)
return dma_fence_get_stub();
array = kmalloc_array(count, sizeof(*array), GFP_KERNEL);
if (!array)
return NULL;
/*
* This trashes the input fence array and uses it as position for the
* following merge loop. This works because the dma_fence_merge()
* wrapper macro is creating this temporary array on the stack together
* with the iterators.
*/
for (i = 0; i < num_fences; ++i)
fences[i] = dma_fence_unwrap_first(fences[i], &iter[i]);
count = 0;
do {
unsigned int sel;
restart:
tmp = NULL;
for (i = 0; i < num_fences; ++i) {
struct dma_fence *next;
while (fences[i] && dma_fence_is_signaled(fences[i]))
fences[i] = dma_fence_unwrap_next(&iter[i]);
next = fences[i];
if (!next)
continue;
/*
* We can't guarantee that inpute fences are ordered by
* context, but it is still quite likely when this
* function is used multiple times. So attempt to order
* the fences by context as we pass over them and merge
* fences with the same context.
*/
if (!tmp || tmp->context > next->context) {
tmp = next;
sel = i;
} else if (tmp->context < next->context) {
continue;
} else if (dma_fence_is_later(tmp, next)) {
fences[i] = dma_fence_unwrap_next(&iter[i]);
goto restart;
} else {
fences[sel] = dma_fence_unwrap_next(&iter[sel]);
goto restart;
}
}
if (tmp) {
array[count++] = dma_fence_get(tmp);
fences[sel] = dma_fence_unwrap_next(&iter[sel]);
}
} while (tmp);
if (count == 0) {
tmp = dma_fence_get_stub();
goto return_tmp;
}
if (count == 1) {
tmp = array[0];
goto return_tmp;
}
result = dma_fence_array_create(count, array,
dma_fence_context_alloc(1),
1, false);
if (!result) {
tmp = NULL;
goto return_tmp;
}
return &result->base;
return_tmp:
kfree(array);
return tmp;
}
EXPORT_SYMBOL_GPL(__dma_fence_unwrap_merge);
......@@ -238,6 +238,113 @@ static int unwrap_chain_array(void *arg)
return err;
}
static int unwrap_merge(void *arg)
{
struct dma_fence *fence, *f1, *f2, *f3;
struct dma_fence_unwrap iter;
int err = 0;
f1 = mock_fence();
if (!f1)
return -ENOMEM;
f2 = mock_fence();
if (!f2) {
err = -ENOMEM;
goto error_put_f1;
}
f3 = dma_fence_unwrap_merge(f1, f2);
if (!f3) {
err = -ENOMEM;
goto error_put_f2;
}
dma_fence_unwrap_for_each(fence, &iter, f3) {
if (fence == f1) {
dma_fence_put(f1);
f1 = NULL;
} else if (fence == f2) {
dma_fence_put(f2);
f2 = NULL;
} else {
pr_err("Unexpected fence!\n");
err = -EINVAL;
}
}
if (f1 || f2) {
pr_err("Not all fences seen!\n");
err = -EINVAL;
}
dma_fence_put(f3);
error_put_f2:
dma_fence_put(f2);
error_put_f1:
dma_fence_put(f1);
return err;
}
static int unwrap_merge_complex(void *arg)
{
struct dma_fence *fence, *f1, *f2, *f3, *f4, *f5;
struct dma_fence_unwrap iter;
int err = -ENOMEM;
f1 = mock_fence();
if (!f1)
return -ENOMEM;
f2 = mock_fence();
if (!f2)
goto error_put_f1;
f3 = dma_fence_unwrap_merge(f1, f2);
if (!f3)
goto error_put_f2;
/* The resulting array has the fences in reverse */
f4 = dma_fence_unwrap_merge(f2, f1);
if (!f4)
goto error_put_f3;
/* Signaled fences should be filtered, the two arrays merged. */
f5 = dma_fence_unwrap_merge(f3, f4, dma_fence_get_stub());
if (!f5)
goto error_put_f4;
err = 0;
dma_fence_unwrap_for_each(fence, &iter, f5) {
if (fence == f1) {
dma_fence_put(f1);
f1 = NULL;
} else if (fence == f2) {
dma_fence_put(f2);
f2 = NULL;
} else {
pr_err("Unexpected fence!\n");
err = -EINVAL;
}
}
if (f1 || f2) {
pr_err("Not all fences seen!\n");
err = -EINVAL;
}
dma_fence_put(f5);
error_put_f4:
dma_fence_put(f4);
error_put_f3:
dma_fence_put(f3);
error_put_f2:
dma_fence_put(f2);
error_put_f1:
dma_fence_put(f1);
return err;
}
int dma_fence_unwrap(void)
{
static const struct subtest tests[] = {
......@@ -245,6 +352,8 @@ int dma_fence_unwrap(void)
SUBTEST(unwrap_array),
SUBTEST(unwrap_chain),
SUBTEST(unwrap_chain_array),
SUBTEST(unwrap_merge),
SUBTEST(unwrap_merge_complex),
};
return subtests(tests, NULL);
......
......@@ -146,50 +146,6 @@ char *sync_file_get_name(struct sync_file *sync_file, char *buf, int len)
return buf;
}
static int sync_file_set_fence(struct sync_file *sync_file,
struct dma_fence **fences, int num_fences)
{
struct dma_fence_array *array;
/*
* The reference for the fences in the new sync_file and held
* in add_fence() during the merge procedure, so for num_fences == 1
* we already own a new reference to the fence. For num_fence > 1
* we own the reference of the dma_fence_array creation.
*/
if (num_fences == 0) {
sync_file->fence = dma_fence_get_stub();
kfree(fences);
} else if (num_fences == 1) {
sync_file->fence = fences[0];
kfree(fences);
} else {
array = dma_fence_array_create(num_fences, fences,
dma_fence_context_alloc(1),
1, false);
if (!array)
return -ENOMEM;
sync_file->fence = &array->base;
}
return 0;
}
static void add_fence(struct dma_fence **fences,
int *i, struct dma_fence *fence)
{
fences[*i] = fence;
if (!dma_fence_is_signaled(fence)) {
dma_fence_get(fence);
(*i)++;
}
}
/**
* sync_file_merge() - merge two sync_files
* @name: name of new fence
......@@ -203,84 +159,21 @@ static void add_fence(struct dma_fence **fences,
static struct sync_file *sync_file_merge(const char *name, struct sync_file *a,
struct sync_file *b)
{
struct dma_fence *a_fence, *b_fence, **fences;
struct dma_fence_unwrap a_iter, b_iter;
unsigned int index, num_fences;
struct sync_file *sync_file;
struct dma_fence *fence;
sync_file = sync_file_alloc();
if (!sync_file)
return NULL;
num_fences = 0;
dma_fence_unwrap_for_each(a_fence, &a_iter, a->fence)
++num_fences;
dma_fence_unwrap_for_each(b_fence, &b_iter, b->fence)
++num_fences;
if (num_fences > INT_MAX)
goto err_free_sync_file;
fences = kcalloc(num_fences, sizeof(*fences), GFP_KERNEL);
if (!fences)
goto err_free_sync_file;
/*
* We can't guarantee that fences in both a and b are ordered, but it is
* still quite likely.
*
* So attempt to order the fences as we pass over them and merge fences
* with the same context.
*/
index = 0;
for (a_fence = dma_fence_unwrap_first(a->fence, &a_iter),
b_fence = dma_fence_unwrap_first(b->fence, &b_iter);
a_fence || b_fence; ) {
if (!b_fence) {
add_fence(fences, &index, a_fence);
a_fence = dma_fence_unwrap_next(&a_iter);
} else if (!a_fence) {
add_fence(fences, &index, b_fence);
b_fence = dma_fence_unwrap_next(&b_iter);
} else if (a_fence->context < b_fence->context) {
add_fence(fences, &index, a_fence);
a_fence = dma_fence_unwrap_next(&a_iter);
} else if (b_fence->context < a_fence->context) {
add_fence(fences, &index, b_fence);
b_fence = dma_fence_unwrap_next(&b_iter);
} else if (__dma_fence_is_later(a_fence->seqno, b_fence->seqno,
a_fence->ops)) {
add_fence(fences, &index, a_fence);
a_fence = dma_fence_unwrap_next(&a_iter);
b_fence = dma_fence_unwrap_next(&b_iter);
} else {
add_fence(fences, &index, b_fence);
a_fence = dma_fence_unwrap_next(&a_iter);
b_fence = dma_fence_unwrap_next(&b_iter);
}
fence = dma_fence_unwrap_merge(a->fence, b->fence);
if (!fence) {
fput(sync_file->file);
return NULL;
}
if (sync_file_set_fence(sync_file, fences, index) < 0)
goto err_put_fences;
sync_file->fence = fence;
strlcpy(sync_file->user_name, name, sizeof(sync_file->user_name));
return sync_file;
err_put_fences:
while (index)
dma_fence_put(fences[--index]);
kfree(fences);
err_free_sync_file:
fput(sync_file->file);
return NULL;
}
static int sync_file_release(struct inode *inode, struct file *file)
......
......@@ -52,4 +52,28 @@ struct dma_fence *dma_fence_unwrap_next(struct dma_fence_unwrap *cursor);
fence = dma_fence_unwrap_next(cursor)) \
if (!dma_fence_is_signaled(fence))
struct dma_fence *__dma_fence_unwrap_merge(unsigned int num_fences,
struct dma_fence **fences,
struct dma_fence_unwrap *cursors);
/**
* dma_fence_unwrap_merge - unwrap and merge fences
*
* All fences given as parameters are unwrapped and merged back together as flat
* dma_fence_array. Useful if multiple containers need to be merged together.
*
* Implemented as a macro to allocate the necessary arrays on the stack and
* account the stack frame size to the caller.
*
* Returns NULL on memory allocation failure, a dma_fence object representing
* all the given fences otherwise.
*/
#define dma_fence_unwrap_merge(...) \
({ \
struct dma_fence *__f[] = { __VA_ARGS__ }; \
struct dma_fence_unwrap __c[ARRAY_SIZE(__f)]; \
\
__dma_fence_unwrap_merge(ARRAY_SIZE(__f), __f, __c); \
})
#endif
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