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dma-buf/fence-array: Add flex array to struct dma_fence_array

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This is an effort to get rid of all multiplications from allocation
functions in order to prevent integer overflows [1][2].

The "struct dma_fence_array" can be refactored to add a flex array in order
to have the "callback structures allocated behind the array" be more
explicit.

Do so:
   - makes the code more readable and safer.
   - allows using __counted_by() for additional checks
   - avoids some pointer arithmetic in dma_fence_array_enable_signaling()

Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#open-coded-arithmetic-in-allocator-arguments [1]
Link: https://github.com/KSPP/linux/issues/160 [2]
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Christian König <christian.koenig@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/8b4e556e07b5dd78bb8a39b67ea0a43b199083c8.1716652811.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Christian König <christian.koenig@amd.com>
This commit is contained in:
Christophe JAILLET 2024-05-25 18:00:31 +02:00 committed by Christian König
parent 3d9d313d51
commit 983095eaf6
2 changed files with 7 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
drivers/dma-buf/dma-fence-array.c
View File

@ -70,7 +70,7 @@ static void dma_fence_array_cb_func(struct dma_fence *f,
static bool dma_fence_array_enable_signaling(struct dma_fence *fence)
{
struct dma_fence_array *array = to_dma_fence_array(fence);
struct dma_fence_array_cb *cb = (void *)(&array[1]);
struct dma_fence_array_cb *cb = array->callbacks;
unsigned i;
for (i = 0; i < array->num_fences; ++i) {
@ -168,22 +168,20 @@ struct dma_fence_array *dma_fence_array_create(int num_fences,
bool signal_on_any)
{
struct dma_fence_array *array;
size_t size = sizeof(*array);
WARN_ON(!num_fences || !fences);
/* Allocate the callback structures behind the array. */
size += num_fences * sizeof(struct dma_fence_array_cb);
array = kzalloc(size, GFP_KERNEL);
array = kzalloc(struct_size(array, callbacks, num_fences), GFP_KERNEL);
if (!array)
return NULL;
array->num_fences = num_fences;
spin_lock_init(&array->lock);
dma_fence_init(&array->base, &dma_fence_array_ops, &array->lock,
context, seqno);
init_irq_work(&array->work, irq_dma_fence_array_work);
array->num_fences = num_fences;
atomic_set(&array->num_pending, signal_on_any ? 1 : num_fences);
array->fences = fences;

3
include/linux/dma-fence-array.h
View File

@ -33,6 +33,7 @@ struct dma_fence_array_cb {
* @num_pending: fences in the array still pending
* @fences: array of the fences
* @work: internal irq_work function
* @callbacks: array of callback helpers
*/
struct dma_fence_array {
struct dma_fence base;
@ -43,6 +44,8 @@ struct dma_fence_array {
struct dma_fence **fences;
struct irq_work work;
struct dma_fence_array_cb callbacks[] __counted_by(num_fences);
};
/**