7 files changed, 40 insertions, 42 deletions

diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index f8cee205618a..ea63a51c148c 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -1659,8 +1659,7 @@ again:
 
 static ssize_t __btrfs_direct_write(struct kiocb *iocb,
                                     struct iov_iter *from,
-                                    loff_t pos,
-                                    size_t count, size_t ocount)
+                                    loff_t pos)
 {
         struct file *file = iocb->ki_filp;
         ssize_t written;
@@ -1668,9 +1667,9 @@ static ssize_t __btrfs_direct_write(struct kiocb *iocb,
         loff_t endbyte;
         int err;
 
-        written = generic_file_direct_write(iocb, from, pos, count, ocount);
+        written = generic_file_direct_write(iocb, from, pos);
 
-        if (written < 0 || written == count)
+        if (written < 0 || !iov_iter_count(from))
                 return written;
 
         pos += written;
@@ -1720,13 +1719,14 @@ static ssize_t btrfs_file_aio_write(struct kiocb *iocb,
         u64 end_pos;
         ssize_t num_written = 0;
         ssize_t err = 0;
-        size_t count, ocount;
+        size_t count;
         bool sync = (file->f_flags & O_DSYNC) || IS_SYNC(file->f_mapping->host);
         struct iov_iter i;
 
         mutex_lock(&inode->i_mutex);
 
-        count = ocount = iov_length(iov, nr_segs);
+        count = iov_length(iov, nr_segs);
+        iov_iter_init(&i, WRITE, iov, nr_segs, count);
 
         current->backing_dev_info = inode->i_mapping->backing_dev_info;
         err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
@@ -1740,7 +1740,7 @@ static ssize_t btrfs_file_aio_write(struct kiocb *iocb,
                 goto out;
         }
 
-        iov_iter_init(&i, WRITE, iov, nr_segs, count);
+        iov_iter_truncate(&i, count);
 
         err = file_remove_suid(file);
         if (err) {
@@ -1783,8 +1783,7 @@ static ssize_t btrfs_file_aio_write(struct kiocb *iocb,
                 atomic_inc(&BTRFS_I(inode)->sync_writers);
 
         if (unlikely(file->f_flags & O_DIRECT)) {
-                num_written = __btrfs_direct_write(iocb, &i,
-                                                   pos, count, ocount);
+                num_written = __btrfs_direct_write(iocb, &i, pos);
         } else {
                 num_written = __btrfs_buffered_write(file, &i, pos);
                 if (num_written > 0)
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 7026014717bc..66d2d5de19d2 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -1188,8 +1188,7 @@ static ssize_t fuse_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
 {
         struct file *file = iocb->ki_filp;
         struct address_space *mapping = file->f_mapping;
-        size_t count = 0;
-        size_t ocount = 0;
+        size_t count;
         ssize_t written = 0;
         ssize_t written_buffered = 0;
         struct inode *inode = mapping->host;
@@ -1208,7 +1207,8 @@ static ssize_t fuse_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
 
         WARN_ON(iocb->ki_pos != pos);
 
-        count = ocount = iov_length(iov, nr_segs);
+        count = iov_length(iov, nr_segs);
+        iov_iter_init(&i, WRITE, iov, nr_segs, count);
         mutex_lock(&inode->i_mutex);
 
         /* We can write back this queue in page reclaim */
@@ -1217,11 +1217,11 @@ static ssize_t fuse_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
         err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
         if (err)
                 goto out;
-        iov_iter_init(&i, WRITE, iov, nr_segs, count);
 
         if (count == 0)
                 goto out;
 
+        iov_iter_truncate(&i, count);
         err = file_remove_suid(file);
         if (err)
                 goto out;
@@ -1231,8 +1231,8 @@ static ssize_t fuse_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
                 goto out;
 
         if (file->f_flags & O_DIRECT) {
-                written = generic_file_direct_write(iocb, &i, pos, count, ocount);
-                if (written < 0 || written == count)
+                written = generic_file_direct_write(iocb, &i, pos);
+                if (written < 0 || !iov_iter_count(&i))
                         goto out;
 
                 pos += written;
@@ -1469,8 +1469,7 @@ static ssize_t __fuse_direct_write(struct fuse_io_priv *io,
 
         res = generic_write_checks(file, ppos, &count, 0);
         if (!res) {
-                if (iter->count > count)
-                        iter->count = count;
+                iov_iter_truncate(iter, count);
                 res = fuse_direct_io(io, iter, ppos, FUSE_DIO_WRITE);
         }
 
@@ -2896,8 +2895,7 @@ fuse_direct_IO(int rw, struct kiocb *iocb, struct iov_iter *iter,
                 if (offset >= i_size)
                         return 0;
                 count = min_t(loff_t, count, fuse_round_up(i_size - offset));
-                if (iter->count > count)
-                        iter->count = count;
+                iov_iter_truncate(iter, count);
         }
 
         io = kmalloc(sizeof(struct fuse_io_priv), GFP_KERNEL);
diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c
index 9ce9ed7615c1..06b6a16d9776 100644
--- a/fs/ocfs2/file.c
+++ b/fs/ocfs2/file.c
@@ -2241,7 +2241,6 @@ static ssize_t ocfs2_file_aio_write(struct kiocb *iocb,
         int ret, direct_io, appending, rw_level, have_alloc_sem  = 0;
         int can_do_direct, has_refcount = 0;
         ssize_t written = 0;
-        size_t ocount;          /* original count */
         size_t count;           /* after file limit checks */
         loff_t old_size, *ppos = &iocb->ki_pos;
         u32 old_clusters;
@@ -2253,6 +2252,9 @@ static ssize_t ocfs2_file_aio_write(struct kiocb *iocb,
         int unaligned_dio = 0;
         struct iov_iter from;
 
+        count = iov_length(iov, nr_segs);
+        iov_iter_init(&from, WRITE, iov, nr_segs, count);
+
         trace_ocfs2_file_aio_write(inode, file, file->f_path.dentry,
                 (unsigned long long)OCFS2_I(inode)->ip_blkno,
                 file->f_path.dentry->d_name.len,
@@ -2355,16 +2357,14 @@ relock:
         /* communicate with ocfs2_dio_end_io */
         ocfs2_iocb_set_rw_locked(iocb, rw_level);
 
-        count = ocount = iov_length(iov, nr_segs);
         ret = generic_write_checks(file, ppos, &count,
                                    S_ISBLK(inode->i_mode));
         if (ret)
                 goto out_dio;
 
-        iov_iter_init(&from, WRITE, iov, nr_segs, count);
+        iov_iter_truncate(&from, count);
         if (direct_io) {
-                written = generic_file_direct_write(iocb, &from, *ppos,
-                                                    count, ocount);
+                written = generic_file_direct_write(iocb, &from, *ppos);
                 if (written < 0) {
                         ret = written;
                         goto out_dio;
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 762bb3e148a6..c997aa2751b2 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -626,7 +626,7 @@ xfs_file_dio_aio_write(
         const struct iovec      *iovp,
         unsigned long           nr_segs,
         loff_t                  pos,
-        size_t                  ocount)
+        size_t                  count)
 {
         struct file             *file = iocb->ki_filp;
         struct address_space    *mapping = file->f_mapping;
@@ -634,7 +634,6 @@ xfs_file_dio_aio_write(
         struct xfs_inode        *ip = XFS_I(inode);
         struct xfs_mount        *mp = ip->i_mount;
         ssize_t                 ret = 0;
-        size_t                  count = ocount;
         int                     unaligned_io = 0;
         int                     iolock;
         struct xfs_buftarg      *target = XFS_IS_REALTIME_INODE(ip) ?
@@ -645,6 +644,8 @@ xfs_file_dio_aio_write(
         if ((pos | count) & target->bt_logical_sectormask)
                 return -XFS_ERROR(EINVAL);
 
+        iov_iter_init(&from, WRITE, iovp, nr_segs, count);
+
         /* "unaligned" here means not aligned to a filesystem block */
         if ((pos & mp->m_blockmask) || ((pos + count) & mp->m_blockmask))
                 unaligned_io = 1;
@@ -676,6 +677,7 @@ xfs_file_dio_aio_write(
         ret = xfs_file_aio_write_checks(file, &pos, &count, &iolock);
         if (ret)
                 goto out;
+        iov_iter_truncate(&from, count);
 
         if (mapping->nrpages) {
                 ret = filemap_write_and_wait_range(VFS_I(ip)->i_mapping,
@@ -697,8 +699,7 @@ xfs_file_dio_aio_write(
         }
 
         trace_xfs_file_direct_write(ip, count, iocb->ki_pos, 0);
-        iov_iter_init(&from, WRITE, iovp, nr_segs, count);
-        ret = generic_file_direct_write(iocb, &from, pos, count, ocount);
+        ret = generic_file_direct_write(iocb, &from, pos);
 
 out:
         xfs_rw_iunlock(ip, iolock);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index d096ebc7f348..8153396d19b4 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2407,8 +2407,7 @@ extern ssize_t generic_file_aio_read(struct kiocb *, const struct iovec *, unsig
 extern ssize_t generic_file_read_iter(struct kiocb *, struct iov_iter *);
 extern ssize_t __generic_file_aio_write(struct kiocb *, const struct iovec *, unsigned long);
 extern ssize_t generic_file_aio_write(struct kiocb *, const struct iovec *, unsigned long, loff_t);
-extern ssize_t generic_file_direct_write(struct kiocb *, struct iov_iter *,
-                loff_t, size_t, size_t);
+extern ssize_t generic_file_direct_write(struct kiocb *, struct iov_iter *, loff_t);
 extern ssize_t generic_perform_write(struct file *, struct iov_iter *, loff_t);
 extern ssize_t do_sync_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos);
 extern ssize_t do_sync_write(struct file *filp, const char __user *buf, size_t len, loff_t *ppos);
diff --git a/include/linux/uio.h b/include/linux/uio.h
index 4876e9f2a58f..532f59d0adbb 100644
--- a/include/linux/uio.h
+++ b/include/linux/uio.h
@@ -82,6 +82,12 @@ static inline size_t iov_iter_count(struct iov_iter *i)
         return i->count;
 }
 
+static inline void iov_iter_truncate(struct iov_iter *i, size_t count)
+{
+        if (i->count > count)
+                i->count = count;
+}
+
 int memcpy_fromiovec(unsigned char *kdata, struct iovec *iov, int len);
 int memcpy_toiovec(struct iovec *iov, unsigned char *kdata, int len);
 
diff --git a/mm/filemap.c b/mm/filemap.c
index 3aeaf2df4135..c0404b763a17 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2345,8 +2345,7 @@ int pagecache_write_end(struct file *file, struct address_space *mapping,
 EXPORT_SYMBOL(pagecache_write_end);
 
 ssize_t
-generic_file_direct_write(struct kiocb *iocb, struct iov_iter *from,
-                loff_t pos, size_t count, size_t ocount)
+generic_file_direct_write(struct kiocb *iocb, struct iov_iter *from, loff_t pos)
 {
         struct file     *file = iocb->ki_filp;
         struct address_space *mapping = file->f_mapping;
@@ -2356,10 +2355,7 @@ generic_file_direct_write(struct kiocb *iocb, struct iov_iter *from,
         pgoff_t         end;
         struct iov_iter data;
 
-        if (count != ocount)
-                from->nr_segs = iov_shorten((struct iovec *)from->iov, from->nr_segs, count);
-
-        write_len = iov_length(from->iov, from->nr_segs);
+        write_len = iov_iter_count(from);
         end = (pos + write_len - 1) >> PAGE_CACHE_SHIFT;
 
         written = filemap_write_and_wait_range(mapping, pos, pos + write_len - 1);
@@ -2568,7 +2564,6 @@ ssize_t __generic_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
 {
         struct file *file = iocb->ki_filp;
         struct address_space * mapping = file->f_mapping;
-        size_t ocount;          /* original count */
         size_t count;           /* after file limit checks */
         struct inode    *inode = mapping->host;
         loff_t          pos = iocb->ki_pos;
@@ -2577,7 +2572,8 @@ ssize_t __generic_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
         ssize_t         status;
         struct iov_iter from;
 
-        count = ocount = iov_length(iov, nr_segs);
+        count = iov_length(iov, nr_segs);
+        iov_iter_init(&from, WRITE, iov, nr_segs, count);
 
         /* We can write back this queue in page reclaim */
         current->backing_dev_info = mapping->backing_dev_info;
@@ -2588,6 +2584,8 @@ ssize_t __generic_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
         if (count == 0)
                 goto out;
 
+        iov_iter_truncate(&from, count);
+
         err = file_remove_suid(file);
         if (err)
                 goto out;
@@ -2596,14 +2594,11 @@ ssize_t __generic_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
         if (err)
                 goto out;
 
-        iov_iter_init(&from, WRITE, iov, nr_segs, count);
-
         /* coalesce the iovecs and go direct-to-BIO for O_DIRECT */
         if (unlikely(file->f_flags & O_DIRECT)) {
                 loff_t endbyte;
 
-                written = generic_file_direct_write(iocb, &from, pos,
-                                                        count, ocount);
+                written = generic_file_direct_write(iocb, &from, pos);
                 if (written < 0 || written == count)
                         goto out;