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-rw-r--r--lib/scatterlist.c35
1 files changed, 35 insertions, 0 deletions
diff --git a/lib/scatterlist.c b/lib/scatterlist.c
index c6cf82242d65..be7b4dd6b68d 100644
--- a/lib/scatterlist.c
+++ b/lib/scatterlist.c
@@ -751,3 +751,38 @@ size_t sg_pcopy_to_buffer(struct scatterlist *sgl, unsigned int nents,
return sg_copy_buffer(sgl, nents, buf, buflen, skip, true);
}
EXPORT_SYMBOL(sg_pcopy_to_buffer);
+
+/**
+ * sg_zero_buffer - Zero-out a part of a SG list
+ * @sgl: The SG list
+ * @nents: Number of SG entries
+ * @buflen: The number of bytes to zero out
+ * @skip: Number of bytes to skip before zeroing
+ *
+ * Returns the number of bytes zeroed.
+ **/
+size_t sg_zero_buffer(struct scatterlist *sgl, unsigned int nents,
+ size_t buflen, off_t skip)
+{
+ unsigned int offset = 0;
+ struct sg_mapping_iter miter;
+ unsigned int sg_flags = SG_MITER_ATOMIC | SG_MITER_TO_SG;
+
+ sg_miter_start(&miter, sgl, nents, sg_flags);
+
+ if (!sg_miter_skip(&miter, skip))
+ return false;
+
+ while (offset < buflen && sg_miter_next(&miter)) {
+ unsigned int len;
+
+ len = min(miter.length, buflen - offset);
+ memset(miter.addr, 0, len);
+
+ offset += len;
+ }
+
+ sg_miter_stop(&miter);
+ return offset;
+}
+EXPORT_SYMBOL(sg_zero_buffer);

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