dmaengine: stm32-dma3: Set lli_size after allocation

With the new __counted_by annotation, the "lli_size" variable needs to
valid for accesses to the "lli" array. This requirement is not met in
stm32_dma3_chan_desc_alloc(), since "lli_size" starts at "0", so "lli"
index "0" will not be considered valid during the initialization for loop.

Fix this by setting lli_size immediately after allocation (similar to
how this is handled in stm32_mdma_alloc_desc() for the node/count
relationship).

Fixes: f561ec8b2b33 ("dmaengine: Add STM32 DMA3 support")
Signed-off-by: Kees Cook <[e-mail]>
Reviewed-by: Gustavo A. R. Silva <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Vinod Koul <[e-mail]>

drivers/dma/stm32/stm32-dma3.c

···
 	swdesc = kzalloc(struct_size(swdesc, lli, count), GFP_NOWAIT);
 	if (!swdesc)
 		return NULL;
+	swdesc->lli_size = count;
 
 	for (i = 0; i < count; i++) {
 		swdesc->lli[i].hwdesc = dma_pool_zalloc(chan->lli_pool, GFP_NOWAIT,
···
 		if (!swdesc->lli[i].hwdesc)
 			goto err_pool_free;
 	}
-	swdesc->lli_size = count;
 	swdesc->ccr = 0;
 
 	/* Set LL base address */