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authorSagi Grimberg <sagi@lightbitslabs.com>2018-12-03 17:52:09 -0800
committerChristoph Hellwig <hch@lst.de>2018-12-13 09:58:54 +0100
commitd05f443554b3c7dc6d46e3ba9c3c4de468875d4f (patch)
tree6bc94110dc8dd6ea1540ec26b6b4f6c3029ea0f0 /lib
parent950fcaecd5cc6c014bb96506fd0652a501c85276 (diff)
downloadlinux-d05f443554b3c7dc6d46e3ba9c3c4de468875d4f.tar.bz2
iov_iter: introduce hash_and_copy_to_iter helper
Allow consumers that want to use iov iterator helpers and also update a predefined hash calculation online when copying data. This is useful when copying incoming network buffers to a local iterator and calculate a digest on the incoming stream. nvme-tcp host driver that will be introduced in following patches is the first consumer via skb_copy_and_hash_datagram_iter. Acked-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sagi Grimberg <sagi@lightbitslabs.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
Diffstat (limited to 'lib')
-rw-r--r--lib/iov_iter.c16
1 files changed, 16 insertions, 0 deletions
diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index 63a8999a234d..1928009f506e 100644
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -6,6 +6,7 @@
#include <linux/vmalloc.h>
#include <linux/splice.h>
#include <net/checksum.h>
+#include <linux/scatterlist.h>
#define PIPE_PARANOIA /* for now */
@@ -1511,6 +1512,21 @@ size_t csum_and_copy_to_iter(const void *addr, size_t bytes, void *csump,
}
EXPORT_SYMBOL(csum_and_copy_to_iter);
+size_t hash_and_copy_to_iter(const void *addr, size_t bytes, void *hashp,
+ struct iov_iter *i)
+{
+ struct ahash_request *hash = hashp;
+ struct scatterlist sg;
+ size_t copied;
+
+ copied = copy_to_iter(addr, bytes, i);
+ sg_init_one(&sg, addr, copied);
+ ahash_request_set_crypt(hash, &sg, NULL, copied);
+ crypto_ahash_update(hash);
+ return copied;
+}
+EXPORT_SYMBOL(hash_and_copy_to_iter);
+
int iov_iter_npages(const struct iov_iter *i, int maxpages)
{
size_t size = i->count;