dma-mapping fixes for 5.8

- add a warning when the atomic pool is depleted (David Rientjes)
  - protect the parameters of the new scatterlist helper macros
    (Marek Szyprowski )
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Merge tag 'dma-mapping-5.8-5' of git://git.infradead.org/users/hch/dma-mapping

Pull dma-mapping fixes from Christoph Hellwig:

 - add a warning when the atomic pool is depleted (David Rientjes)

 - protect the parameters of the new scatterlist helper macros (Marek
   Szyprowski )

* tag 'dma-mapping-5.8-5' of git://git.infradead.org/users/hch/dma-mapping:
  scatterlist: protect parameters of the sg_table related macros
  dma-mapping: warn when coherent pool is depleted

include/linux/scatterlist.h

@@ -155,7 +155,7 @@ static inline void sg_set_buf(struct scatterlist *sg, const void *buf,
  * Loop over each sg element in the given sg_table object.
  */
 #define for_each_sgtable_sg(sgt, sg, i)		\
-	for_each_sg(sgt->sgl, sg, sgt->orig_nents, i)
+	for_each_sg((sgt)->sgl, sg, (sgt)->orig_nents, i)
 
 /*
  * Loop over each sg element in the given *DMA mapped* sg_table object.
@@ -163,7 +163,7 @@ static inline void sg_set_buf(struct scatterlist *sg, const void *buf,
  * of the each element.
  */
 #define for_each_sgtable_dma_sg(sgt, sg, i)	\
-	for_each_sg(sgt->sgl, sg, sgt->nents, i)
+	for_each_sg((sgt)->sgl, sg, (sgt)->nents, i)
 
 /**
  * sg_chain - Chain two sglists together
@@ -451,7 +451,7 @@ sg_page_iter_dma_address(struct sg_dma_page_iter *dma_iter)
  * See also for_each_sg_page(). In each loop it operates on PAGE_SIZE unit.
  */
 #define for_each_sgtable_page(sgt, piter, pgoffset)	\
-	for_each_sg_page(sgt->sgl, piter, sgt->orig_nents, pgoffset)
+	for_each_sg_page((sgt)->sgl, piter, (sgt)->orig_nents, pgoffset)
 
 /**
  * for_each_sgtable_dma_page - iterate over the DMA mapped sg_table object
@@ -465,7 +465,7 @@ sg_page_iter_dma_address(struct sg_dma_page_iter *dma_iter)
  * unit.
  */
 #define for_each_sgtable_dma_page(sgt, dma_iter, pgoffset)	\
-	for_each_sg_dma_page(sgt->sgl, dma_iter, sgt->nents, pgoffset)
+	for_each_sg_dma_page((sgt)->sgl, dma_iter, (sgt)->nents, pgoffset)
 
 
 /*

kernel/dma/pool.c

@@ -239,12 +239,16 @@ void *dma_alloc_from_pool(struct device *dev, size_t size,
 	}
 
 	val = gen_pool_alloc(pool, size);
-	if (val) {
+	if (likely(val)) {
 		phys_addr_t phys = gen_pool_virt_to_phys(pool, val);
 
 		*ret_page = pfn_to_page(__phys_to_pfn(phys));
 		ptr = (void *)val;
 		memset(ptr, 0, size);
+	} else {
+		WARN_ONCE(1, "DMA coherent pool depleted, increase size "
+			     "(recommended min coherent_pool=%zuK)\n",
+			  gen_pool_size(pool) >> 9);
 	}
 	if (gen_pool_avail(pool) < atomic_pool_size)
 		schedule_work(&atomic_pool_work);