convert the guts of nfs_direct_IO() to iov_iter

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

2 files changed, 33 insertions, 31 deletions

diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c
index e9cde3935001..21723149668b 100644
--- a/fs/nfs/direct.c
+++ b/fs/nfs/direct.c
@@ -132,9 +132,9 @@ ssize_t nfs_direct_IO(int rw, struct kiocb *iocb, struct iov_iter *iter, loff_t
         VM_BUG_ON(iocb->ki_nbytes != PAGE_SIZE);
 
         if (rw == READ || rw == KERNEL_READ)
-                return nfs_file_direct_read(iocb, iter->iov, iter->nr_segs, pos,
+                return nfs_file_direct_read(iocb, iter, pos,
                                 rw == READ ? true : false);
-        return nfs_file_direct_write(iocb, iter->iov, iter->nr_segs, pos,
+        return nfs_file_direct_write(iocb, iter, pos,
                                 rw == WRITE ? true : false);
 #endif /* CONFIG_NFS_SWAP */
 }
@@ -414,8 +414,7 @@ static ssize_t nfs_direct_read_schedule_segment(struct nfs_pageio_descriptor *de
 }
 
 static ssize_t nfs_direct_read_schedule_iovec(struct nfs_direct_req *dreq,
-                                              const struct iovec *iov,
-                                              unsigned long nr_segs,
+                                              struct iov_iter *iter,
                                               loff_t pos, bool uio)
 {
         struct nfs_pageio_descriptor desc;
@@ -430,8 +429,8 @@ static ssize_t nfs_direct_read_schedule_iovec(struct nfs_direct_req *dreq,
         desc.pg_dreq = dreq;
         atomic_inc(&inode->i_dio_count);
 
-        for (seg = 0; seg < nr_segs; seg++) {
-                const struct iovec *vec = &iov[seg];
+        for (seg = 0; seg < iter->nr_segs; seg++) {
+                const struct iovec *vec = &iter->iov[seg];
                 result = nfs_direct_read_schedule_segment(&desc, vec, pos, uio);
                 if (result < 0)
                         break;
@@ -461,8 +460,7 @@ static ssize_t nfs_direct_read_schedule_iovec(struct nfs_direct_req *dreq,
 /**
  * nfs_file_direct_read - file direct read operation for NFS files
  * @iocb: target I/O control block
- * @iov: vector of user buffers into which to read data
- * @nr_segs: size of iov vector
+ * @iter: vector of user buffers into which to read data
  * @pos: byte offset in file where reading starts
  *
  * We use this function for direct reads instead of calling
@@ -479,8 +477,8 @@ static ssize_t nfs_direct_read_schedule_iovec(struct nfs_direct_req *dreq,
  * client must read the updated atime from the server back into its
  * cache.
  */
-ssize_t nfs_file_direct_read(struct kiocb *iocb, const struct iovec *iov,
-                                unsigned long nr_segs, loff_t pos, bool uio)
+ssize_t nfs_file_direct_read(struct kiocb *iocb, struct iov_iter *iter,
+                                loff_t pos, bool uio)
 {
         struct file *file = iocb->ki_filp;
         struct address_space *mapping = file->f_mapping;
@@ -490,7 +488,7 @@ ssize_t nfs_file_direct_read(struct kiocb *iocb, const struct iovec *iov,
         ssize_t result = -EINVAL;
         size_t count;
 
-        count = iov_length(iov, nr_segs);
+        count = iov_length(iter->iov, iter->nr_segs);
         nfs_add_stats(mapping->host, NFSIOS_DIRECTREADBYTES, count);
 
         dfprintk(FILE, "NFS: direct read(%pD2, %zd@%Ld)\n",
@@ -513,7 +511,7 @@ ssize_t nfs_file_direct_read(struct kiocb *iocb, const struct iovec *iov,
                 goto out_unlock;
 
         dreq->inode = inode;
-        dreq->bytes_left = iov_length(iov, nr_segs);
+        dreq->bytes_left = count;
         dreq->ctx = get_nfs_open_context(nfs_file_open_context(iocb->ki_filp));
         l_ctx = nfs_get_lock_context(dreq->ctx);
         if (IS_ERR(l_ctx)) {
@@ -524,8 +522,8 @@ ssize_t nfs_file_direct_read(struct kiocb *iocb, const struct iovec *iov,
         if (!is_sync_kiocb(iocb))
                 dreq->iocb = iocb;
 
-        NFS_I(inode)->read_io += iov_length(iov, nr_segs);
-        result = nfs_direct_read_schedule_iovec(dreq, iov, nr_segs, pos, uio);
+        NFS_I(inode)->read_io += count;
+        result = nfs_direct_read_schedule_iovec(dreq, iter, pos, uio);
 
         mutex_unlock(&inode->i_mutex);
 
@@ -864,8 +862,7 @@ static const struct nfs_pgio_completion_ops nfs_direct_write_completion_ops = {
 };
 
 static ssize_t nfs_direct_write_schedule_iovec(struct nfs_direct_req *dreq,
-                                               const struct iovec *iov,
-                                               unsigned long nr_segs,
+                                               struct iov_iter *iter,
                                                loff_t pos, bool uio)
 {
         struct nfs_pageio_descriptor desc;
@@ -880,9 +877,9 @@ static ssize_t nfs_direct_write_schedule_iovec(struct nfs_direct_req *dreq,
         get_dreq(dreq);
         atomic_inc(&inode->i_dio_count);
 
-        NFS_I(dreq->inode)->write_io += iov_length(iov, nr_segs);
-        for (seg = 0; seg < nr_segs; seg++) {
-                const struct iovec *vec = &iov[seg];
+        NFS_I(dreq->inode)->write_io += iov_length(iter->iov, iter->nr_segs);
+        for (seg = 0; seg < iter->nr_segs; seg++) {
+                const struct iovec *vec = &iter->iov[seg];
                 result = nfs_direct_write_schedule_segment(&desc, vec, pos, uio);
                 if (result < 0)
                         break;
@@ -911,8 +908,7 @@ static ssize_t nfs_direct_write_schedule_iovec(struct nfs_direct_req *dreq,
 /**
  * nfs_file_direct_write - file direct write operation for NFS files
  * @iocb: target I/O control block
- * @iov: vector of user buffers from which to write data
- * @nr_segs: size of iov vector
+ * @iter: vector of user buffers from which to write data
  * @pos: byte offset in file where writing starts
  *
  * We use this function for direct writes instead of calling
@@ -930,8 +926,8 @@ static ssize_t nfs_direct_write_schedule_iovec(struct nfs_direct_req *dreq,
  * Note that O_APPEND is not supported for NFS direct writes, as there
  * is no atomic O_APPEND write facility in the NFS protocol.
  */
-ssize_t nfs_file_direct_write(struct kiocb *iocb, const struct iovec *iov,
-                                unsigned long nr_segs, loff_t pos, bool uio)
+ssize_t nfs_file_direct_write(struct kiocb *iocb, struct iov_iter *iter,
+                                loff_t pos, bool uio)
 {
         ssize_t result = -EINVAL;
         struct file *file = iocb->ki_filp;
@@ -942,7 +938,7 @@ ssize_t nfs_file_direct_write(struct kiocb *iocb, const struct iovec *iov,
         loff_t end;
         size_t count;
 
-        count = iov_length(iov, nr_segs);
+        count = iov_length(iter->iov, iter->nr_segs);
         end = (pos + count - 1) >> PAGE_CACHE_SHIFT;
 
         nfs_add_stats(mapping->host, NFSIOS_DIRECTWRITTENBYTES, count);
@@ -993,7 +989,7 @@ ssize_t nfs_file_direct_write(struct kiocb *iocb, const struct iovec *iov,
         if (!is_sync_kiocb(iocb))
                 dreq->iocb = iocb;
 
-        result = nfs_direct_write_schedule_iovec(dreq, iov, nr_segs, pos, uio);
+        result = nfs_direct_write_schedule_iovec(dreq, iter, pos, uio);
 
         if (mapping->nrpages) {
                 invalidate_inode_pages2_range(mapping,
diff --git a/fs/nfs/file.c b/fs/nfs/file.c
index 284ca901fe16..3d01b152894e 100644
--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -169,14 +169,18 @@ nfs_file_read(struct kiocb *iocb, const struct iovec *iov,
                 unsigned long nr_segs, loff_t pos)
 {
         struct inode *inode = file_inode(iocb->ki_filp);
+        size_t count = iov_length(iov, nr_segs);
         ssize_t result;
+        struct iov_iter to;
+
+        iov_iter_init(&to, iov, nr_segs, count, 0);
 
         if (iocb->ki_filp->f_flags & O_DIRECT)
-                return nfs_file_direct_read(iocb, iov, nr_segs, pos, true);
+                return nfs_file_direct_read(iocb, &to, pos, true);
 
-        dprintk("NFS: read(%pD2, %lu@%lu)\n",
+        dprintk("NFS: read(%pD2, %zu@%lu)\n",
                 iocb->ki_filp,
-                (unsigned long) iov_length(iov, nr_segs), (unsigned long) pos);
+                count, (unsigned long) pos);
 
         result = nfs_revalidate_mapping(inode, iocb->ki_filp->f_mapping);
         if (!result) {
@@ -643,16 +647,18 @@ ssize_t nfs_file_write(struct kiocb *iocb, const struct iovec *iov,
         unsigned long written = 0;
         ssize_t result;
         size_t count = iov_length(iov, nr_segs);
+        struct iov_iter from;
+        iov_iter_init(&from, iov, nr_segs, count, 0);
 
         result = nfs_key_timeout_notify(file, inode);
         if (result)
                 return result;
 
         if (file->f_flags & O_DIRECT)
-                return nfs_file_direct_write(iocb, iov, nr_segs, pos, true);
+                return nfs_file_direct_write(iocb, &from, pos, true);
 
-        dprintk("NFS: write(%pD2, %lu@%Ld)\n",
-                file, (unsigned long) count, (long long) pos);
+        dprintk("NFS: write(%pD2, %zu@%Ld)\n",
+                file, count, (long long) pos);
 
         result = -EBUSY;
         if (IS_SWAPFILE(inode))