smb: client: compress: allocate dest buffer inside smb_compress()

Change smb_compress() to take as arguments: server, uncompressed
smb_rqst, and the function to send the request (used only with
__smb_send_rqst for now, but maybe take an encryption function,
when support is implemented).

Signed-off-by: Enzo Matsumiya <ematsumiya@suse.de>

2 files changed, 83 insertions, 50 deletions

diff --git a/fs/smb/client/compress.c b/fs/smb/client/compress.c
index dcb563a9dde6..645edde6e328 100644
--- a/fs/smb/client/compress.c
+++ b/fs/smb/client/compress.c
@@ -319,27 +319,68 @@ bool should_compress(const struct cifs_tcon *tcon, const struct smb_rqst *rq)
 	return (shdr->Command == SMB2_READ);
 }
 
-int smb_compress(void *buf, const void *data, size_t *len)
+int smb_compress(struct TCP_Server_Info *server, struct smb_rqst *rq, compress_send_fn send_fn)
 {
-	struct smb2_compression_hdr *hdr;
-	size_t buf_len, data_len;
+	struct iov_iter iter;
+	size_t slen, dlen;
+	void *src, *dst;
 	int ret;
 
-	buf_len = sizeof(struct smb2_write_req);
-	data_len = *len;
-	*len = 0;
-
-	hdr = buf;
-	hdr->ProtocolId = SMB2_COMPRESSION_TRANSFORM_ID;
-	hdr->OriginalCompressedSegmentSize = cpu_to_le32(data_len);
-	hdr->Offset = cpu_to_le32(buf_len);
-	hdr->Flags = SMB2_COMPRESSION_FLAG_NONE;
-	hdr->CompressionAlgorithm = SMB3_COMPRESS_LZ77;
-
-	/* XXX: add other algs here as they're implemented */
-	ret = lz77_compress(data, data_len, buf + SMB_COMPRESS_HDR_LEN + buf_len, &data_len);
-	if (!ret)
-		*len = SMB_COMPRESS_HDR_LEN + buf_len + data_len;
+	if (!server || !rq || !rq->rq_iov || !rq->rq_iov->iov_base)
+		return -EINVAL;
+
+	if (rq->rq_iov->iov_len != sizeof(struct smb2_write_req))
+		return -EINVAL;
+
+	slen = rq->rq_iter_size;
+	src = kvzalloc(slen, GFP_KERNEL);
+	if (!src) {
+		ret = -ENOMEM;
+		goto err_free;
+	}
+
+	/* Keep the original iter intact. */
+	iter = rq->rq_iter;
+
+	if (!copy_from_iter_full(src, slen, &iter)) {
+		ret = -EIO;
+		goto err_free;
+	}
+
+	dlen = round_up(slen, PAGE_SIZE);
+	dst = kvzalloc(dlen, GFP_KERNEL);
+	if (!dst) {
+		ret = -ENOMEM;
+		goto err_free;
+	}
+
+	ret = lz77_compress(src, slen, dst, &dlen);
+	if (!ret) {
+		struct smb2_compression_hdr hdr = { 0 };
+		struct smb_rqst comp_rq = { .rq_nvec = 3, };
+		struct kvec iov[3];
+
+		hdr.ProtocolId = SMB2_COMPRESSION_TRANSFORM_ID;
+		hdr.OriginalCompressedSegmentSize = cpu_to_le32(slen);
+		hdr.CompressionAlgorithm = SMB3_COMPRESS_LZ77;
+		hdr.Flags = SMB2_COMPRESSION_FLAG_NONE;
+		hdr.Offset = cpu_to_le32(rq->rq_iov[0].iov_len);
+
+		iov[0].iov_base = &hdr;
+		iov[0].iov_len = sizeof(hdr);
+		iov[1] = rq->rq_iov[0];
+		iov[2].iov_base = dst;
+		iov[2].iov_len = dlen;
+
+		comp_rq.rq_iov = iov;
+
+		ret = send_fn(server, 1, &comp_rq);
+	} else if (ret == -EMSGSIZE || dlen >= slen) {
+		ret = send_fn(server, 1, rq);
+	}
+err_free:
+	kvfree(dst);
+	kvfree(src);
 
 	return ret;
 }
diff --git a/fs/smb/client/compress.h b/fs/smb/client/compress.h
index 316bb43cb277..f3ed1d3e52fb 100644
--- a/fs/smb/client/compress.h
+++ b/fs/smb/client/compress.h
@@ -26,18 +26,27 @@
 #define SMB_COMPRESS_PAYLOAD_HDR_LEN	8
 #define SMB_COMPRESS_MIN_LEN		PAGE_SIZE
 
-struct smb_compress_ctx {
-	struct TCP_Server_Info *server;
-	struct work_struct work;
-	struct mid_q_entry *mid;
+#ifdef CONFIG_CIFS_COMPRESSION
+typedef int (*compress_send_fn)(struct TCP_Server_Info *, int, struct smb_rqst *);
 
-	void *buf; /* compressed data */
-	void *data; /* uncompressed data */
-	size_t len;
-};
+int smb_compress(struct TCP_Server_Info *server, struct smb_rqst *rq, compress_send_fn send_fn);
 
-#ifdef CONFIG_CIFS_COMPRESSION
-int smb_compress(void *buf, const void *data, size_t *len);
+/**
+ * should_compress() - Determines if a request (write) or the response to a
+ *		       request (read) should be compressed.
+ * @tcon: tcon of the request is being sent to
+ * @rqst: request to evaluate
+ *
+ * Return: true iff:
+ * - compression was successfully negotiated with server
+ * - server has enabled compression for the share
+ * - it's a read or write request
+ * - (write only) request length is >= SMB_COMPRESS_MIN_LEN
+ * - (write only) is_compressible() returns 1
+ *
+ * Return false otherwise.
+ */
+bool should_compress(const struct cifs_tcon *tcon, const struct smb_rqst *rq);
 
 /**
  * smb_compress_alg_valid() - Validate a compression algorithm.
@@ -62,37 +71,20 @@ static __always_inline int smb_compress_alg_valid(__le16 alg, bool valid_none)
 
 	return false;
 }
-
-/**
- * should_compress() - Determines if a request (write) or the response to a
- *		       request (read) should be compressed.
- * @tcon: tcon of the request is being sent to
- * @rqst: request to evaluate
- *
- * Return: true iff:
- * - compression was successfully negotiated with server
- * - server has enabled compression for the share
- * - it's a read or write request
- * - (write only) request length is >= SMB_COMPRESS_MIN_LEN
- * - (write only) is_compressible() returns 1
- *
- * Return false otherwise.
- */
-bool should_compress(const struct cifs_tcon *tcon, const struct smb_rqst *rq);
 #else /* !CONFIG_CIFS_COMPRESSION */
-static inline int smb_compress(...)
+static inline int smb_compress(void *unused1, void *unused2, void *unused3)
 {
 	return -EOPNOTSUPP;
 }
 
-static inline int smb_compress_alg_valid(__le16 unused1, bool unused2)
+static inline bool should_compress(void *unused1, void *unused2)
 {
-	return -EOPNOTSUPP;
+	return false;
 }
 
-static inline bool should_compress(void *unused1, void *unused2)
+static inline int smb_compress_alg_valid(__le16 unused1, bool unused2)
 {
-	return false;
+	return -EOPNOTSUPP;
 }
 #endif /* !CONFIG_CIFS_COMPRESSION */
 #endif /* _SMB_COMPRESS_H */