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Commit d05f4435 authored by Sagi Grimberg's avatar Sagi Grimberg Committed by Christoph Hellwig
Browse files

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: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarSagi Grimberg <sagi@lightbitslabs.com>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
parent 950fcaec

include/linux/uio.h

+3 −0
Original line number Diff line number Diff line
@@ -11,6 +11,7 @@ 


#include <linux/kernel.h>

#include <linux/thread_info.h>

#include <crypto/hash.h>

#include <uapi/linux/uio.h>



struct page;
@@ -269,6 +270,8 @@ static inline void iov_iter_reexpand(struct iov_iter *i, size_t count) 
size_t csum_and_copy_to_iter(const void *addr, size_t bytes, void *csump, struct iov_iter *i);

size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum, struct iov_iter *i);

bool csum_and_copy_from_iter_full(void *addr, size_t bytes, __wsum *csum, struct iov_iter *i);

size_t hash_and_copy_to_iter(const void *addr, size_t bytes, void *hashp,

		struct iov_iter *i);



int import_iovec(int type, const struct iovec __user * uvector,

		 unsigned nr_segs, unsigned fast_segs,

lib/iov_iter.c

+16 −0
Original line number Diff line number Diff line
@@ -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;