[v4,3/4] compressdev: replace mbuf scatter gather flag

  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(-)
  

Hi Pablo

Looks fine. Just minor comments:

>-----Original Message-----
>From: Pablo de Lara [mailto:pablo.de.lara.guarch@intel.com]
>Sent: 06 July 2018 08:24
>To: Verma, Shally <Shally.Verma@cavium.com>; Gupta, Ashish <Ashish.Gupta@cavium.com>; fiona.trahe@intel.com;
>lee.daly@intel.com
>Cc: dev@dpdk.org; Pablo de Lara <pablo.de.lara.guarch@intel.com>
>Subject: [PATCH v4 3/4] compressdev: replace mbuf scatter gather flag
>
...

>@@ -6,19 +6,21 @@
>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.
>+
May be its simpler to rephrase it and following somewhat this way:

Which means " PMD support different scatter-gather styled input and output buffers i.e. both can consists 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.

Which means "PMD support input from scatter-gathered styled buffers , but can output to linear buffers.
And better to replace "flat" by "linear" to be consistent with name.

>+
>+   - "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.

Thanks
Shally

>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