[dpdk-dev] [PATCH] compressdev: clarify destination buffer size for corner case

Fiona Trahe fiona.trahe at intel.com
Thu Jul 25 19:04:09 CEST 2019


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 at intel.com>
---
 lib/librte_compressdev/rte_comp.h |    6 ++++++
 1 files changed, 6 insertions(+), 0 deletions(-)

diff --git a/lib/librte_compressdev/rte_comp.h b/lib/librte_compressdev/rte_comp.h
index b7474c4..95306c5 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 {
-- 
1.7.0.7



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