From: Herbert Xu <herbert@gondor.apana.org.au>
Date: Sat, 8 Mar 2025 12:45:23 +0000 (+0800)
Subject: crypto: scatterwalk - Add memcpy_sglist
X-Git-Tag: v6.15-rc1~118^2~61
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=131bdceca1f0a2d9381270dc40f898458e5e184b;p=thirdparty%2Fkernel%2Flinux.git

crypto: scatterwalk - Add memcpy_sglist

Add memcpy_sglist which copies one SG list to another.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
---

diff --git a/crypto/scatterwalk.c b/crypto/scatterwalk.c
index 20a28c6d94da2..8225801488d5c 100644
--- a/crypto/scatterwalk.c
+++ b/crypto/scatterwalk.c
@@ -86,6 +86,33 @@ void memcpy_to_sglist(struct scatterlist *sg, unsigned int start,
 }
 EXPORT_SYMBOL_GPL(memcpy_to_sglist);
 
+void memcpy_sglist(struct scatterlist *dst, struct scatterlist *src,
+		   unsigned int nbytes)
+{
+	struct scatter_walk swalk;
+	struct scatter_walk dwalk;
+
+	if (unlikely(nbytes == 0)) /* in case sg == NULL */
+		return;
+
+	scatterwalk_start(&swalk, src);
+	scatterwalk_start(&dwalk, dst);
+
+	do {
+		unsigned int slen, dlen;
+		unsigned int len;
+
+		slen = scatterwalk_next(&swalk, nbytes);
+		dlen = scatterwalk_next(&dwalk, nbytes);
+		len = min(slen, dlen);
+		memcpy(dwalk.addr, swalk.addr, len);
+		scatterwalk_done_dst(&dwalk, len);
+		scatterwalk_done_src(&swalk, len);
+		nbytes -= len;
+	} while (nbytes);
+}
+EXPORT_SYMBOL_GPL(memcpy_sglist);
+
 struct scatterlist *scatterwalk_ffwd(struct scatterlist dst[2],
 				     struct scatterlist *src,
 				     unsigned int len)
diff --git a/include/crypto/scatterwalk.h b/include/crypto/scatterwalk.h
index 8523c7591d95c..c62f47d04eb10 100644
--- a/include/crypto/scatterwalk.h
+++ b/include/crypto/scatterwalk.h
@@ -210,6 +210,9 @@ void memcpy_from_sglist(void *buf, struct scatterlist *sg,
 void memcpy_to_sglist(struct scatterlist *sg, unsigned int start,
 		      const void *buf, unsigned int nbytes);
 
+void memcpy_sglist(struct scatterlist *dst, struct scatterlist *src,
+		   unsigned int nbytes);
+
 /* In new code, please use memcpy_{from,to}_sglist() directly instead. */
 static inline void scatterwalk_map_and_copy(void *buf, struct scatterlist *sg,
 					    unsigned int start,