compressdev: clarify destination buffer size

Clarify the corner case with incompressible data
whereby the output can actually be greater than the
uncompressed data.

Signed-off-by: Fiona Trahe <fiona.trahe@intel.com>
Acked-by: Adam Dybkowski <adamx.dybkowski@intel.com>
Acked-by: Shally Verma <shallyv@marvell.com>

diff --git a/lib/librte_compressdev/rte_comp.h b/lib/librte_compressdev/rte_comp.h
index b7474c4..95306c5 100644 (file)
--- a/lib/librte_compressdev/rte_comp.h
+++ b/lib/librte_compressdev/rte_comp.h
@@ -323,6 +323,12 @@ struct rte_comp_op {
         * If the output data is expected to be bigger than this a chain of
         * mbufs can be passed to the PMD if the PMD's capabilities indicate
         * it supports this.
+        *
+        * @note, if incompressible data is passed to an engine for compression
+        * using RTE_COMP_ALGO_DEFLATE, it's possible for the output data
+        * to be larger than the uncompressed data, due to the inclusion
+        * of the DEFLATE header blocks. The size of m_dst should accommodate
+        * this, else OUT_OF_SPACE errors can be expected in this case.
         */
 
        struct {