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Commit 19f73787 authored by Chuck Lever's avatar Chuck Lever Committed by Trond Myklebust
Browse files

NFS: Introduce iovec I/O helpers to fs/nfs/direct.c 



Add helpers that iterate over multi-segment iovecs.  These will
be used to support multi-segment scatter/gather direct I/O in a
later patch.

Signed-off-by: default avatarChuck Lever <cel@netapp.com>
Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
parent 014313a9

fs/nfs/direct.c

+71 −0
Original line number Diff line number Diff line
@@ -355,6 +355,41 @@ static ssize_t nfs_direct_read_schedule(struct nfs_direct_req *dreq, unsigned lo 
	return result < 0 ? (ssize_t) result : -EFAULT;

}



static ssize_t nfs_direct_read_schedule_iovec(struct nfs_direct_req *dreq,

					      const struct iovec *iov,

					      unsigned long nr_segs,

					      loff_t pos)

{

	ssize_t result = -EINVAL;

	size_t requested_bytes = 0;

	unsigned long seg;



	get_dreq(dreq);



	for (seg = 0; seg < nr_segs; seg++) {

		const struct iovec *vec = &iov[seg];

		result = nfs_direct_read_schedule(dreq,

					(unsigned long)vec->iov_base,

						  vec->iov_len, pos);

		if (result < 0)

			break;

		requested_bytes += result;

		if ((size_t)result < vec->iov_len)

			break;

		pos += vec->iov_len;

	}



	if (put_dreq(dreq))

		nfs_direct_complete(dreq);



	if (requested_bytes != 0)

		return 0;



	if (result < 0)

		return result;

	return -EIO;

}



static ssize_t nfs_direct_read(struct kiocb *iocb, unsigned long user_addr, size_t count, loff_t pos)

{

	ssize_t result = 0;
@@ -697,6 +732,42 @@ static ssize_t nfs_direct_write_schedule(struct nfs_direct_req *dreq, unsigned l 
	return result < 0 ? (ssize_t) result : -EFAULT;

}



static ssize_t nfs_direct_write_schedule_iovec(struct nfs_direct_req *dreq,

					       const struct iovec *iov,

					       unsigned long nr_segs,

					       loff_t pos, int sync)

{

	ssize_t result = 0;

	size_t requested_bytes = 0;

	unsigned long seg;



	get_dreq(dreq);



	for (seg = 0; seg < nr_segs; seg++) {

		const struct iovec *vec = &iov[seg];

		result = nfs_direct_write_schedule(dreq,

					(unsigned long)vec->iov_base,

						   vec->iov_len,

						   pos, sync);

		if (result < 0)

			break;

		requested_bytes += result;

		if ((size_t)result < vec->iov_len)

			break;

		pos += vec->iov_len;

	}



	if (put_dreq(dreq))

		nfs_direct_write_complete(dreq, dreq->inode);



	if (requested_bytes != 0)

		return 0;



	if (result < 0)

		return result;

	return -EIO;

}



static ssize_t nfs_direct_write(struct kiocb *iocb, unsigned long user_addr, size_t count, loff_t pos)

{

	ssize_t result = 0;