new methods: ->read_iter() and ->write_iter()
Beginning to introduce those. Just the callers for now, and it's
clumsier than it'll eventually become; once we finish converting
aio_read and aio_write instances, the things will get nicer.
For now, these guys are in parallel to ->aio_read() and ->aio_write();
they take iocb and iov_iter, with everything in iov_iter already
validated. File offset is passed in iocb->ki_pos, iov/nr_segs -
in iov_iter.
Main concerns in that series are stack footprint and ability to
split the damn thing cleanly.
[fix from Peter Ujfalusi <peter.ujfalusi@ti.com> folded]
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/read_write.c b/fs/read_write.c
index d29d2a3..fe2f9d5 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -25,6 +25,7 @@
typedef ssize_t (*io_fn_t)(struct file *, char __user *, size_t, loff_t *);
typedef ssize_t (*iov_fn_t)(struct kiocb *, const struct iovec *,
unsigned long, loff_t);
+typedef ssize_t (*iter_fn_t)(struct kiocb *, struct iov_iter *);
const struct file_operations generic_ro_fops = {
.llseek = generic_file_llseek,
@@ -390,6 +391,27 @@
EXPORT_SYMBOL(do_sync_read);
+ssize_t new_sync_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos)
+{
+ struct iovec iov = { .iov_base = buf, .iov_len = len };
+ struct kiocb kiocb;
+ struct iov_iter iter;
+ ssize_t ret;
+
+ init_sync_kiocb(&kiocb, filp);
+ kiocb.ki_pos = *ppos;
+ kiocb.ki_nbytes = len;
+ iov_iter_init(&iter, READ, &iov, 1, len);
+
+ ret = filp->f_op->read_iter(&kiocb, &iter);
+ if (-EIOCBQUEUED == ret)
+ ret = wait_on_sync_kiocb(&kiocb);
+ *ppos = kiocb.ki_pos;
+ return ret;
+}
+
+EXPORT_SYMBOL(new_sync_read);
+
ssize_t vfs_read(struct file *file, char __user *buf, size_t count, loff_t *pos)
{
ssize_t ret;
@@ -406,8 +428,10 @@
count = ret;
if (file->f_op->read)
ret = file->f_op->read(file, buf, count, pos);
- else
+ else if (file->f_op->aio_read)
ret = do_sync_read(file, buf, count, pos);
+ else
+ ret = new_sync_read(file, buf, count, pos);
if (ret > 0) {
fsnotify_access(file);
add_rchar(current, ret);
@@ -439,6 +463,27 @@
EXPORT_SYMBOL(do_sync_write);
+ssize_t new_sync_write(struct file *filp, const char __user *buf, size_t len, loff_t *ppos)
+{
+ struct iovec iov = { .iov_base = (void __user *)buf, .iov_len = len };
+ struct kiocb kiocb;
+ struct iov_iter iter;
+ ssize_t ret;
+
+ init_sync_kiocb(&kiocb, filp);
+ kiocb.ki_pos = *ppos;
+ kiocb.ki_nbytes = len;
+ iov_iter_init(&iter, WRITE, &iov, 1, len);
+
+ ret = filp->f_op->write_iter(&kiocb, &iter);
+ if (-EIOCBQUEUED == ret)
+ ret = wait_on_sync_kiocb(&kiocb);
+ *ppos = kiocb.ki_pos;
+ return ret;
+}
+
+EXPORT_SYMBOL(new_sync_write);
+
ssize_t __kernel_write(struct file *file, const char *buf, size_t count, loff_t *pos)
{
mm_segment_t old_fs;
@@ -455,8 +500,10 @@
count = MAX_RW_COUNT;
if (file->f_op->write)
ret = file->f_op->write(file, p, count, pos);
- else
+ else if (file->f_op->aio_write)
ret = do_sync_write(file, p, count, pos);
+ else
+ ret = new_sync_write(file, p, count, pos);
set_fs(old_fs);
if (ret > 0) {
fsnotify_modify(file);
@@ -483,8 +530,10 @@
file_start_write(file);
if (file->f_op->write)
ret = file->f_op->write(file, buf, count, pos);
- else
+ else if (file->f_op->aio_write)
ret = do_sync_write(file, buf, count, pos);
+ else
+ ret = new_sync_write(file, buf, count, pos);
if (ret > 0) {
fsnotify_modify(file);
add_wchar(current, ret);
@@ -601,6 +650,25 @@
}
EXPORT_SYMBOL(iov_shorten);
+static ssize_t do_iter_readv_writev(struct file *filp, int rw, const struct iovec *iov,
+ unsigned long nr_segs, size_t len, loff_t *ppos, iter_fn_t fn)
+{
+ struct kiocb kiocb;
+ struct iov_iter iter;
+ ssize_t ret;
+
+ init_sync_kiocb(&kiocb, filp);
+ kiocb.ki_pos = *ppos;
+ kiocb.ki_nbytes = len;
+
+ iov_iter_init(&iter, rw, iov, nr_segs, len);
+ ret = fn(&kiocb, &iter);
+ if (ret == -EIOCBQUEUED)
+ ret = wait_on_sync_kiocb(&kiocb);
+ *ppos = kiocb.ki_pos;
+ return ret;
+}
+
static ssize_t do_sync_readv_writev(struct file *filp, const struct iovec *iov,
unsigned long nr_segs, size_t len, loff_t *ppos, iov_fn_t fn)
{
@@ -738,6 +806,7 @@
ssize_t ret;
io_fn_t fn;
iov_fn_t fnv;
+ iter_fn_t iter_fn;
ret = rw_copy_check_uvector(type, uvector, nr_segs,
ARRAY_SIZE(iovstack), iovstack, &iov);
@@ -753,13 +822,18 @@
if (type == READ) {
fn = file->f_op->read;
fnv = file->f_op->aio_read;
+ iter_fn = file->f_op->read_iter;
} else {
fn = (io_fn_t)file->f_op->write;
fnv = file->f_op->aio_write;
+ iter_fn = file->f_op->write_iter;
file_start_write(file);
}
- if (fnv)
+ if (iter_fn)
+ ret = do_iter_readv_writev(file, type, iov, nr_segs, tot_len,
+ pos, iter_fn);
+ else if (fnv)
ret = do_sync_readv_writev(file, iov, nr_segs, tot_len,
pos, fnv);
else
@@ -912,6 +986,7 @@
ssize_t ret;
io_fn_t fn;
iov_fn_t fnv;
+ iter_fn_t iter_fn;
ret = compat_rw_copy_check_uvector(type, uvector, nr_segs,
UIO_FASTIOV, iovstack, &iov);
@@ -927,13 +1002,18 @@
if (type == READ) {
fn = file->f_op->read;
fnv = file->f_op->aio_read;
+ iter_fn = file->f_op->read_iter;
} else {
fn = (io_fn_t)file->f_op->write;
fnv = file->f_op->aio_write;
+ iter_fn = file->f_op->write_iter;
file_start_write(file);
}
- if (fnv)
+ if (iter_fn)
+ ret = do_iter_readv_writev(file, type, iov, nr_segs, tot_len,
+ pos, iter_fn);
+ else if (fnv)
ret = do_sync_readv_writev(file, iov, nr_segs, tot_len,
pos, fnv);
else