1 files changed, 42 insertions, 2 deletions

diff --git a/fs/smb/client/compress.h b/fs/smb/client/compress.h
index f3ed1d3e52fb..717076bcd343 100644
--- a/fs/smb/client/compress.h
+++ b/fs/smb/client/compress.h
@@ -17,19 +17,48 @@
 
 #include <linux/uio.h>
 #include <linux/kernel.h>
+#include <linux/minmax.h>
+
 #include "../common/smb2pdu.h"
-#include "cifsglob.h"
 
 /* sizeof(smb2_compression_hdr) - sizeof(OriginalPayloadSize) */
 #define SMB_COMPRESS_HDR_LEN		16
 /* sizeof(smb2_compression_payload_hdr) - sizeof(OriginalPayloadSize) */
 #define SMB_COMPRESS_PAYLOAD_HDR_LEN	8
-#define SMB_COMPRESS_MIN_LEN		PAGE_SIZE
+#define SMB_COMPRESS_MIN_LEN		SZ_64K
+#define SMB_DECOMPRESS_MAX_LEN(_srv)		\
+	(256 + SMB_COMPRESS_HDR_LEN + max3((_srv)->maxBuf, (_srv)->max_read, (_srv)->max_write))
+
+static __always_inline u32 decompressed_size(const void *buf)
+{
+	const struct smb2_compression_hdr *hdr = buf;
+
+	if (!buf || !IS_ENABLED(CONFIG_CIFS_COMPRESSION))
+		return 0;
+
+	return le32_to_cpu(hdr->Offset) +
+	       le32_to_cpu(hdr->OriginalCompressedSegmentSize);
+}
+
+static __always_inline bool is_compress_hdr(const void *buf)
+{
+	const struct smb2_compression_hdr *hdr = buf;
+
+	if (!buf)
+		return false;
+
+	return (hdr->ProtocolId == SMB2_COMPRESSION_TRANSFORM_ID);
+}
 
 #ifdef CONFIG_CIFS_COMPRESSION
+struct TCP_Server_Info;
+struct cifs_tcon;
+struct smb_rqst;
+
 typedef int (*compress_send_fn)(struct TCP_Server_Info *, int, struct smb_rqst *);
 
 int smb_compress(struct TCP_Server_Info *server, struct smb_rqst *rq, compress_send_fn send_fn);
+int smb_decompress(const void *src, u32 slen, void *dst, u32 *dlen);
 
 /**
  * should_compress() - Determines if a request (write) or the response to a
@@ -47,6 +76,7 @@ int smb_compress(struct TCP_Server_Info *server, struct smb_rqst *rq, compress_s
  * Return false otherwise.
  */
 bool should_compress(const struct cifs_tcon *tcon, const struct smb_rqst *rq);
+bool should_decompress(struct TCP_Server_Info *server, const void *buf);
 
 /**
  * smb_compress_alg_valid() - Validate a compression algorithm.
@@ -77,11 +107,21 @@ static inline int smb_compress(void *unused1, void *unused2, void *unused3)
 	return -EOPNOTSUPP;
 }
 
+static inline int smb_decompress(const void *unused1, u32 unused2, void *unused3, u32 unused4)
+{
+	return -EOPNOTSUPP;
+}
+
 static inline bool should_compress(void *unused1, void *unused2)
 {
 	return false;
 }
 
+static inline bool should_decompress(void *unused1, void *unused2)
+{
+	return false;
+}
+
 static inline int smb_compress_alg_valid(__le16 unused1, bool unused2)
 {
 	return -EOPNOTSUPP;