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

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
......@@ -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;
......
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