From cbf125408d1ca141cc1c3f8376e091e3cdde2cb2 Mon Sep 17 00:00:00 2001
From: Mikhail Zaslonko <zaslonko@linux.ibm.com>
Date: Thu, 26 Jan 2023 14:14:25 +0100
Subject: [PATCH] lib/zlib: DFLTCC not writing header bits when avail_out == 0
This commit is based on:
https://github.com/zlib-ng/zlib-ng/commit/ce409c6
Link: https://lkml.kernel.org/r/20230126131428.1222214-6-zaslonko@linux.ibm.com
Signed-off-by: Mikhail Zaslonko <zaslonko@linux.ibm.com>
Acked-by: Ilya Leoshkevich <iii@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
lib/zlib_dfltcc/dfltcc_deflate.c | 13 +++++++++----
1 file changed, 9 insertions(+), 4 deletions(-)
diff --git a/lib/zlib_dfltcc/dfltcc_deflate.c b/lib/zlib_dfltcc/dfltcc_deflate.c
index 211d344710d5d..d4c92f99808e3 100644
--- a/lib/zlib_dfltcc/dfltcc_deflate.c
+++ b/lib/zlib_dfltcc/dfltcc_deflate.c
@@ -170,13 +170,18 @@ int dfltcc_deflate(
param->bcf = 0;
dfltcc_state->block_threshold =
strm->total_in + dfltcc_state->block_size;
- if (strm->avail_out == 0) {
- *result = need_more;
- return 1;
- }
}
}
+ /* No space for compressed data. If we proceed, dfltcc_cmpr() will return
+ * DFLTCC_CC_OP1_TOO_SHORT without buffering header bits, but we will still
+ * set BCF=1, which is wrong. Avoid complications and return early.
+ */
+ if (strm->avail_out == 0) {
+ *result = need_more;
+ return 1;
+ }
+
/* The caller gave us too much data. Pass only one block worth of
* uncompressed data to DFLTCC and mask the rest, so that on the next
* iteration we start a new block.
--
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