From: Fiona Trahe <fiona.trahe@intel.com>
Date: Thu, 25 Jul 2019 17:04:09 +0000 (+0100)
Subject: compressdev: clarify destination buffer size
X-Git-Url: http://git.droids-corp.org/?a=commitdiff_plain;h=760d966ab3b48ae13d01abc78456a94c6bbad7b2;p=dpdk.git

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 b7474c49b6..95306c5d03 100644
--- 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 {