[PATCH v7 12/39] dmadev: use C11 alignas

[Tyler Retzlaff <roretzla@linux.microsoft.com>]

The current location used for __rte_aligned(a) for alignment of types
and variables is not compatible with MSVC. There is only a single
location accepted by both toolchains.

For variables standard C11 offers alignas(a) supported by conformant
compilers i.e. both MSVC and GCC.

For types the standard offers no alignment facility that compatibly
interoperates with C and C++ but may be achieved by relocating the
placement of __rte_aligned(a) to the aforementioned location accepted
by all currently supported toolchains.

To allow alignment for both compilers do the following:

* Move __rte_aligned from the end of {struct,union} definitions to
  be between {struct,union} and tag.

  The placement between {struct,union} and the tag allows the desired
  alignment to be imparted on the type regardless of the toolchain being
  used for all of GCC, LLVM, MSVC compilers building both C and C++.

* Replace use of __rte_aligned(a) on variables/fields with alignas(a).

Signed-off-by: Tyler Retzlaff <roretzla@linux.microsoft.com>
Acked-by: Morten Brørup <mb@smartsharesystems.com>
Acked-by: Chengwen Feng <fengchengwen@huawei.com>
---
 lib/dmadev/rte_dmadev_core.h | 4 ++--
 lib/dmadev/rte_dmadev_pmd.h  | 8 ++++----
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/lib/dmadev/rte_dmadev_core.h b/lib/dmadev/rte_dmadev_core.h
index e8239c2..29f5251 100644
--- a/lib/dmadev/rte_dmadev_core.h
+++ b/lib/dmadev/rte_dmadev_core.h
@@ -61,7 +61,7 @@ typedef uint16_t (*rte_dma_completed_status_t)(void *dev_private,
  * The 'dev_private' field was placed in the first cache line to optimize
  * performance because the PMD mainly depends on this field.
  */
-struct rte_dma_fp_object {
+struct __rte_cache_aligned rte_dma_fp_object {
 	/** PMD-specific private data. The driver should copy
 	 * rte_dma_dev.data->dev_private to this field during initialization.
 	 */
@@ -73,7 +73,7 @@ struct rte_dma_fp_object {
 	rte_dma_completed_t        completed;
 	rte_dma_completed_status_t completed_status;
 	rte_dma_burst_capacity_t   burst_capacity;
-} __rte_cache_aligned;
+};
 
 extern struct rte_dma_fp_object *rte_dma_fp_objs;
 
diff --git a/lib/dmadev/rte_dmadev_pmd.h b/lib/dmadev/rte_dmadev_pmd.h
index 7f354f6..5872908 100644
--- a/lib/dmadev/rte_dmadev_pmd.h
+++ b/lib/dmadev/rte_dmadev_pmd.h
@@ -94,7 +94,7 @@ struct rte_dma_dev_ops {
  *
  * @see struct rte_dma_dev::data
  */
-struct rte_dma_dev_data {
+struct __rte_cache_aligned rte_dma_dev_data {
 	char dev_name[RTE_DEV_NAME_MAX_LEN]; /**< Unique identifier name */
 	int16_t dev_id; /**< Device [external] identifier. */
 	int16_t numa_node; /**< Local NUMA memory ID. -1 if unknown. */
@@ -103,7 +103,7 @@ struct rte_dma_dev_data {
 	__extension__
 	uint8_t dev_started : 1; /**< Device state: STARTED(1)/STOPPED(0). */
 	uint64_t reserved[2]; /**< Reserved for future fields */
-} __rte_cache_aligned;
+};
 
 /**
  * Possible states of a DMA device.
@@ -122,7 +122,7 @@ enum rte_dma_dev_state {
  * @internal
  * The generic data structure associated with each DMA device.
  */
-struct rte_dma_dev {
+struct __rte_cache_aligned rte_dma_dev {
 	/** Device info which supplied during device initialization. */
 	struct rte_device *device;
 	struct rte_dma_dev_data *data; /**< Pointer to shared device data. */
@@ -132,7 +132,7 @@ struct rte_dma_dev {
 	const struct rte_dma_dev_ops *dev_ops;
 	enum rte_dma_dev_state state; /**< Flag indicating the device state. */
 	uint64_t reserved[2]; /**< Reserved for future fields. */
-} __rte_cache_aligned;
+};
 
 /**
  * @internal
-- 
1.8.3.1