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Commit 63ab46ab authored by Chuck Lever's avatar Chuck Lever Committed by Trond Myklebust
Browse files

NFS: create common routine for handling direct I/O completion 



Factor out the common piece of completing an NFS direct I/O request.

Test plan:
Compile kernel with CONFIG_NFS and CONFIG_NFS_DIRECTIO enabled.

Signed-off-by: default avatarChuck Lever <cel@netapp.com>
Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
parent 93619e59

fs/nfs/direct.c

+26 −20
Original line number Diff line number Diff line
@@ -200,6 +200,30 @@ static ssize_t nfs_direct_wait(struct nfs_direct_req *dreq) 
	return (ssize_t) result;

}



/*

 * We must hold a reference to all the pages in this direct read request

 * until the RPCs complete.  This could be long *after* we are woken up in

 * nfs_direct_wait (for instance, if someone hits ^C on a slow server).

 *

 * In addition, synchronous I/O uses a stack-allocated iocb.  Thus we

 * can't trust the iocb is still valid here if this is a synchronous

 * request.  If the waiter is woken prematurely, the iocb is long gone.

 */

static void nfs_direct_complete(struct nfs_direct_req *dreq)

{

	nfs_free_user_pages(dreq->pages, dreq->npages, 1);



	if (dreq->iocb) {

		long res = atomic_read(&dreq->error);

		if (!res)

			res = atomic_read(&dreq->count);

		aio_complete(dreq->iocb, res, 0);

	} else

		wake_up(&dreq->wait);



	kref_put(&dreq->kref, nfs_direct_req_release);

}



/*

 * Note we also set the number of requests we have in the dreq when we are

 * done.  This prevents races with I/O completion so we will always wait
@@ -245,15 +269,6 @@ static struct nfs_direct_req *nfs_direct_read_alloc(size_t nbytes, size_t rsize) 
	return dreq;

}



/*

 * We must hold a reference to all the pages in this direct read request

 * until the RPCs complete.  This could be long *after* we are woken up in

 * nfs_direct_wait (for instance, if someone hits ^C on a slow server).

 *

 * In addition, synchronous I/O uses a stack-allocated iocb.  Thus we

 * can't trust the iocb is still valid here if this is a synchronous

 * request.  If the waiter is woken prematurely, the iocb is long gone.

 */

static void nfs_direct_read_result(struct rpc_task *task, void *calldata)

{

	struct nfs_read_data *data = calldata;
@@ -266,17 +281,8 @@ static void nfs_direct_read_result(struct rpc_task *task, void *calldata) 
	else

		atomic_set(&dreq->error, task->tk_status);



	if (unlikely(atomic_dec_and_test(&dreq->complete))) {

		nfs_free_user_pages(dreq->pages, dreq->npages, 1);

		if (dreq->iocb) {

			long res = atomic_read(&dreq->error);

			if (!res)

				res = atomic_read(&dreq->count);

			aio_complete(dreq->iocb, res, 0);

		} else

			wake_up(&dreq->wait);

		kref_put(&dreq->kref, nfs_direct_req_release);

	}

	if (unlikely(atomic_dec_and_test(&dreq->complete)))

		nfs_direct_complete(dreq);

}



static const struct rpc_call_ops nfs_read_direct_ops = {