iov_iter_truncate()
Now It Can Be Done(tm) - we don't need to do iov_shorten() in
generic_file_direct_write() anymore, now that all ->direct_IO()
instances are converted to proper iov_iter methods and honour
iter->count and iter->iov_offset properly.
Get rid of count/ocount arguments of generic_file_direct_write(),
while we are at it.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index f8cee20..ea63a51c 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -1659,8 +1659,7 @@
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 @@
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 @@
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 @@
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 @@
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 7026014..66d2d5d 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -1188,8 +1188,7 @@
{
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 @@
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 @@
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 @@
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 @@
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 @@
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 9ce9ed7..06b6a16 100644
--- a/fs/ocfs2/file.c
+++ b/fs/ocfs2/file.c
@@ -2241,7 +2241,6 @@
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 @@
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 @@
/* 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 762bb3e..c997aa2 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -626,7 +626,7 @@
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 @@
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 @@
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 @@
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 @@
}
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 d096ebc..8153396 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2407,8 +2407,7 @@
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 4876e9f..532f59d 100644
--- a/include/linux/uio.h
+++ b/include/linux/uio.h
@@ -82,6 +82,12 @@
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 3aeaf2d..c0404b7 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2345,8 +2345,7 @@
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 @@
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 @@
{
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 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 @@
if (count == 0)
goto out;
+ iov_iter_truncate(&from, count);
+
err = file_remove_suid(file);
if (err)
goto out;
@@ -2596,14 +2594,11 @@
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;