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-rw-r--r--include/linux/swiotlb.h23
1 files changed, 16 insertions, 7 deletions
diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
index b4536626f8ff..ecde0312dd52 100644
--- a/include/linux/swiotlb.h
+++ b/include/linux/swiotlb.h
@@ -172,14 +172,23 @@ static inline bool is_swiotlb_buffer(struct device *dev, phys_addr_t paddr)
if (!mem)
return false;
- if (IS_ENABLED(CONFIG_SWIOTLB_DYNAMIC)) {
- /* Pairs with smp_wmb() in swiotlb_find_slots() and
- * swiotlb_dyn_alloc(), which modify the RCU lists.
- */
- smp_rmb();
- return swiotlb_find_pool(dev, paddr);
- }
+#ifdef CONFIG_SWIOTLB_DYNAMIC
+ /*
+ * All SWIOTLB buffer addresses must have been returned by
+ * swiotlb_tbl_map_single() and passed to a device driver.
+ * If a SWIOTLB address is checked on another CPU, then it was
+ * presumably loaded by the device driver from an unspecified private
+ * data structure. Make sure that this load is ordered before reading
+ * dev->dma_uses_io_tlb here and mem->pools in swiotlb_find_pool().
+ *
+ * This barrier pairs with smp_mb() in swiotlb_find_slots().
+ */
+ smp_rmb();
+ return READ_ONCE(dev->dma_uses_io_tlb) &&
+ swiotlb_find_pool(dev, paddr);
+#else
return paddr >= mem->defpool.start && paddr < mem->defpool.end;
+#endif
}
static inline bool is_swiotlb_force_bounce(struct device *dev)