dma-mapping: name SG DMA flag helpers consistently

sg_is_dma_bus_address() is inconsistent with the naming pattern of its
corresponding setters and its own kerneldoc, so take the majority vote and
rename it sg_dma_is_bus_address() (and fix up the missing underscores in
the kerneldoc too).  This gives us a nice clear pattern where SG DMA flags
are SG_DMA_<NAME>, and the helpers for acting on them are
sg_dma_<action>_<name>().

Link: https://lkml.kernel.org/r/20230612153201.554742-14-catalin.marinas@arm.com
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
  Link: https://lore.kernel.org/r/fa2eca2862c7ffc41b50337abffb2dfd2864d3ea.1685036694.git.robin.murphy@arm.com
Tested-by: Isaac J. Manjarres <isaacmanjarres@google.com>
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Jonathan Cameron <jic23@kernel.org>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Mike Snitzer <snitzer@kernel.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Saravana Kannan <saravanak@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

drivers/iommu/dma-iommu.c

@@ -1080,7 +1080,7 @@ static int __finalise_sg(struct device *dev, struct scatterlist *sg, int nents,
 		sg_dma_address(s) = DMA_MAPPING_ERROR;
 		sg_dma_len(s) = 0;
 
-		if (sg_is_dma_bus_address(s)) {
+		if (sg_dma_is_bus_address(s)) {
 			if (i > 0)
 				cur = sg_next(cur);
 
@@ -1136,7 +1136,7 @@ static void __invalidate_sg(struct scatterlist *sg, int nents)
 	int i;
 
 	for_each_sg(sg, s, nents, i) {
-		if (sg_is_dma_bus_address(s)) {
+		if (sg_dma_is_bus_address(s)) {
 			sg_dma_unmark_bus_address(s);
 		} else {
 			if (sg_dma_address(s) != DMA_MAPPING_ERROR)
@@ -1329,7 +1329,7 @@ static void iommu_dma_unmap_sg(struct device *dev, struct scatterlist *sg,
 	 * just have to be determined.
 	 */
 	for_each_sg(sg, tmp, nents, i) {
-		if (sg_is_dma_bus_address(tmp)) {
+		if (sg_dma_is_bus_address(tmp)) {
 			sg_dma_unmark_bus_address(tmp);
 			continue;
 		}
@@ -1343,7 +1343,7 @@ static void iommu_dma_unmap_sg(struct device *dev, struct scatterlist *sg,
 
 	nents -= i;
 	for_each_sg(tmp, tmp, nents, i) {
-		if (sg_is_dma_bus_address(tmp)) {
+		if (sg_dma_is_bus_address(tmp)) {
 			sg_dma_unmark_bus_address(tmp);
 			continue;
 		}

drivers/iommu/iommu.c

@@ -2567,7 +2567,7 @@ ssize_t iommu_map_sg(struct iommu_domain *domain, unsigned long iova,
 			len = 0;
 		}
 
-		if (sg_is_dma_bus_address(sg))
+		if (sg_dma_is_bus_address(sg))
 			goto next;
 
 		if (len) {

include/linux/scatterlist.h

@@ -258,21 +258,21 @@ static inline void sg_unmark_end(struct scatterlist *sg)
 #define SG_DMA_BUS_ADDRESS (1 << 0)
 
 /**
- * sg_dma_is_bus address - Return whether a given segment was marked
+ * sg_dma_is_bus_address - Return whether a given segment was marked
  *			   as a bus address
  * @sg:		 SG entry
  *
  * Description:
  *   Returns true if sg_dma_mark_bus_address() has been called on
  *   this segment.
  **/
-static inline bool sg_is_dma_bus_address(struct scatterlist *sg)
+static inline bool sg_dma_is_bus_address(struct scatterlist *sg)
 {
 	return sg->dma_flags & SG_DMA_BUS_ADDRESS;
 }
 
 /**
- * sg_dma_mark_bus address - Mark the scatterlist entry as a bus address
+ * sg_dma_mark_bus_address - Mark the scatterlist entry as a bus address
  * @sg:		 SG entry
  *
  * Description:
@@ -300,7 +300,7 @@ static inline void sg_dma_unmark_bus_address(struct scatterlist *sg)
 
 #else
 
-static inline bool sg_is_dma_bus_address(struct scatterlist *sg)
+static inline bool sg_dma_is_bus_address(struct scatterlist *sg)
 {
 	return false;
 }

kernel/dma/direct.c

@@ -463,7 +463,7 @@ void dma_direct_unmap_sg(struct device *dev, struct scatterlist *sgl,
 	int i;
 
 	for_each_sg(sgl,  sg, nents, i) {
-		if (sg_is_dma_bus_address(sg))
+		if (sg_dma_is_bus_address(sg))
 			sg_dma_unmark_bus_address(sg);
 		else
 			dma_direct_unmap_page(dev, sg->dma_address,