From 19f737879cc623c3aa73e655465faa3bff121768 Mon Sep 17 00:00:00 2001 From: Chuck Lever Date: Mon, 12 Nov 2007 12:16:47 -0500 Subject: 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: Chuck Lever Signed-off-by: Chuck Lever Signed-off-by: Trond Myklebust --- fs/nfs/direct.c | 71 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 71 insertions(+) diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c index afcab007a22b..e30d9285a566 100644 --- a/fs/nfs/direct.c +++ b/fs/nfs/direct.c @@ -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; -- cgit v1.2.3