[dpdk-dev] [PATCH v4 3/4] compressdev: replace mbuf scatter gather flag

[Pablo de Lara <pablo.de.lara.guarch@intel.com>]

The current mbuf scatter gather feature flag is
too ambiguous, as it is not clear if input and/or output
buffers can be scatter gather mbufs or not.

Therefore, three new flags will replace this flag:
- RTE_COMP_FF_OOP_SGL_IN_SGL_OUT
- RTE_COMP_FF_OOP_SGL_IN_FB_OUT
- RTE_COMP_FF_OOP_LB_IN_SGL_OUT

Note that out-of-place flat buffers is supported by default
and in-place is not supported by the library.

Signed-off-by: Pablo de Lara <pablo.de.lara.guarch@intel.com>
Acked-by: Fiona Trahe <fiona.trahe@intel.com>
---

v4:
- Replaced FB (Flat Buffers) with LB (Linear Buffers) (Shally)
- Add extra explanation on comments about Linear Buffers vs
  Scatter-gather lists

v3:
- Replaced Out-of-place with OOP
- Added new feature flags in default.ini

v2:
- Fixed typos
- Rephrased comments

 doc/guides/compressdevs/features/default.ini | 34 +++++++++++++++-------------
 doc/guides/compressdevs/overview.rst         | 14 ++++++++++++
 doc/guides/rel_notes/release_18_08.rst       |  6 +++++
 lib/librte_compressdev/rte_comp.c            |  8 +++++--
 lib/librte_compressdev/rte_comp.h            | 31 +++++++++++++++++--------
 5 files changed, 65 insertions(+), 28 deletions(-)

diff --git a/doc/guides/compressdevs/features/default.ini b/doc/guides/compressdevs/features/default.ini
index a88414d23..829e4df61 100644
--- a/doc/guides/compressdevs/features/default.ini
+++ b/doc/guides/compressdevs/features/default.ini
@@ -6,19 +6,21 @@
 ; the features table in the documentation.
 ;
 [Features]
-HW Accelerated =
-CPU SSE        =
-CPU AVX        =
-CPU AVX2       =
-CPU AVX512     =
-CPU NEON       =
-Stateful       =
-Pass-through   =
-Chained mbufs  =
-Deflate        =
-LZS            =
-Adler32        =
-Crc32          =
-Adler32&Crc32  =
-Fixed          =
-Dynamic        =
+HW Accelerated      =
+CPU SSE             =
+CPU AVX             =
+CPU AVX2            =
+CPU AVX512          =
+CPU NEON            =
+Stateful            =
+Pass-through        =
+OOP SGL In SGL Out  =
+OOP SGL In LB  Out  =
+OOP LB  In SGL Out  =
+Deflate             =
+LZS                 =
+Adler32             =
+Crc32               =
+Adler32&Crc32       =
+Fixed               =
+Dynamic             =
diff --git a/doc/guides/compressdevs/overview.rst b/doc/guides/compressdevs/overview.rst
index d01c1a966..6d12c3bd6 100644
--- a/doc/guides/compressdevs/overview.rst
+++ b/doc/guides/compressdevs/overview.rst
@@ -16,3 +16,17 @@ Supported Feature Flags
    - "Pass-through" feature flag refers to the ability of the PMD
      to let input buffers pass-through it, copying the input to the output,
      without making any modifications to it (no compression done).
+
+   - "OOP SGL In SGL Out" feature flag stands for
+     "Out-of-place Scatter-gather list Input, Scatter-gater list Output",
+     which means that the input and output buffers can consist of multiple segments.
+
+   - "OOP SGL In LB Out" feature flag stands for
+     "Out-of-place Scatter-gather list Input, Flat Buffers Output",
+     which means that the input buffer can consist of multiple segments combined
+     with a single segment buffer in the output.
+
+   - "OOP LB In SGL Out" feature flag stands for
+     "Out-of-place Flat Buffers Input, Scatter-gather list Output",
+     which means that the output buffer can consist of multiple segments combined
+     with a single segment buffer in the input.
diff --git a/doc/guides/rel_notes/release_18_08.rst b/doc/guides/rel_notes/release_18_08.rst
index bc0124295..3487e3fb9 100644
--- a/doc/guides/rel_notes/release_18_08.rst
+++ b/doc/guides/rel_notes/release_18_08.rst
@@ -60,6 +60,12 @@ API Changes
    Also, make sure to start the actual text at the margin.
    =========================================================
 
+* compressdev: Feature flag ``RTE_COMP_FF_MBUF_SCATTER_GATHER`` is
+  replaced with the following more explicit flags:
+  - ``RTE_COMP_FF_OOP_SGL_IN_SGL_OUT``
+  - ``RTE_COMP_FF_OOP_SGL_IN_LB_OUT``
+  - ``RTE_COMP_FF_OOP_LB_IN_SGL_OUT``
+
 
 ABI Changes
 -----------
diff --git a/lib/librte_compressdev/rte_comp.c b/lib/librte_compressdev/rte_comp.c
index d596ba872..97ea0d922 100644
--- a/lib/librte_compressdev/rte_comp.c
+++ b/lib/librte_compressdev/rte_comp.c
@@ -14,8 +14,12 @@ rte_comp_get_feature_name(uint64_t flag)
 		return "STATEFUL_COMPRESSION";
 	case RTE_COMP_FF_STATEFUL_DECOMPRESSION:
 		return "STATEFUL_DECOMPRESSION";
-	case RTE_COMP_FF_MBUF_SCATTER_GATHER:
-		return "MBUF_SCATTER_GATHER";
+	case RTE_COMP_FF_OOP_SGL_IN_SGL_OUT:
+		return "OOP_SGL_IN_SGL_OUT";
+	case RTE_COMP_FF_OOP_SGL_IN_LB_OUT:
+		return "OOP_SGL_IN_LB_OUT";
+	case RTE_COMP_FF_OOP_LB_IN_SGL_OUT:
+		return "OOP_LB_IN_SGL_OUT";
 	case RTE_COMP_FF_MULTI_PKT_CHECKSUM:
 		return "MULTI_PKT_CHECKSUM";
 	case RTE_COMP_FF_ADLER32_CHECKSUM:
diff --git a/lib/librte_compressdev/rte_comp.h b/lib/librte_compressdev/rte_comp.h
index 5b513c77e..274b5eadf 100644
--- a/lib/librte_compressdev/rte_comp.h
+++ b/lib/librte_compressdev/rte_comp.h
@@ -30,23 +30,34 @@ extern "C" {
 /**< Stateful compression is supported */
 #define RTE_COMP_FF_STATEFUL_DECOMPRESSION	(1ULL << 1)
 /**< Stateful decompression is supported */
-#define	RTE_COMP_FF_MBUF_SCATTER_GATHER		(1ULL << 2)
-/**< Scatter-gather mbufs are supported */
-#define RTE_COMP_FF_ADLER32_CHECKSUM		(1ULL << 3)
+#define RTE_COMP_FF_OOP_SGL_IN_SGL_OUT		(1ULL << 2)
+/**< Out-of-place Scatter-gather (SGL) buffers,
+ * with multiple segments, are supported in input and output
+ */
+#define RTE_COMP_FF_OOP_SGL_IN_LB_OUT		(1ULL << 3)
+/**< Out-of-place Scatter-gather (SGL) buffers are supported
+ * in input, combined with linear buffers (LB), with a
+ * single segment, in output
+ */
+#define RTE_COMP_FF_OOP_LB_IN_SGL_OUT		(1ULL << 4)
+/**< Out-of-place Scatter-gather (SGL) mbufs are supported
+ * in output, combined with linear buffers (LB) in input
+ */
+#define RTE_COMP_FF_ADLER32_CHECKSUM		(1ULL << 5)
 /**< Adler-32 Checksum is supported */
-#define RTE_COMP_FF_CRC32_CHECKSUM		(1ULL << 4)
+#define RTE_COMP_FF_CRC32_CHECKSUM		(1ULL << 6)
 /**< CRC32 Checksum is supported */
-#define RTE_COMP_FF_CRC32_ADLER32_CHECKSUM	(1ULL << 5)
+#define RTE_COMP_FF_CRC32_ADLER32_CHECKSUM	(1ULL << 7)
 /**< Adler-32/CRC32 Checksum is supported */
-#define RTE_COMP_FF_MULTI_PKT_CHECKSUM		(1ULL << 6)
+#define RTE_COMP_FF_MULTI_PKT_CHECKSUM		(1ULL << 8)
 /**< Generation of checksum across multiple stateless packets is supported */
-#define RTE_COMP_FF_SHA1_HASH			(1ULL << 7)
+#define RTE_COMP_FF_SHA1_HASH			(1ULL << 9)
 /**< SHA1 Hash is supported */
-#define RTE_COMP_FF_SHA2_SHA256_HASH		(1ULL << 8)
+#define RTE_COMP_FF_SHA2_SHA256_HASH		(1ULL << 10)
 /**< SHA256 Hash of SHA2 family is supported */
-#define RTE_COMP_FF_NONCOMPRESSED_BLOCKS	(1ULL << 9)
+#define RTE_COMP_FF_NONCOMPRESSED_BLOCKS	(1ULL << 11)
 /**< Creation of non-compressed blocks using RTE_COMP_LEVEL_NONE is supported */
-#define RTE_COMP_FF_SHAREABLE_PRIV_XFORM	(1ULL << 10)
+#define RTE_COMP_FF_SHAREABLE_PRIV_XFORM	(1ULL << 12)
 /**< Private xforms created by the PMD can be shared
  * across multiple stateless operations. If not set, then app needs
  * to create as many priv_xforms as it expects to have stateless
-- 
2.14.4