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Subject[PATCH V8 19/33] fs: use read_iter and write_iter rather than aio_read and aio_write
Date
File systems implementing read_iter & write_iter should not be required
to keep aio_read and aio_write as well. The vfs should always call
read/write_iter if they exist. This will make it easier to remove the
aio_read/write operation in the future.

Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com>
Cc: Zach Brown <zab@zabbo.net>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
---
fs/aio.c | 4 ++--
fs/bad_inode.c | 14 ++++++++++++
fs/internal.h | 4 ++++
fs/read_write.c | 64 ++++++++++++++++++++++++++++++++++++++++++++++++------
include/linux/fs.h | 6 +++--
5 files changed, 81 insertions(+), 11 deletions(-)

diff --git a/fs/aio.c b/fs/aio.c
index 0da82c0..9fa03a1 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -1051,14 +1051,14 @@ static ssize_t aio_run_iocb(struct kiocb *req, bool compat)
case IOCB_CMD_PREADV:
mode = FMODE_READ;
rw = READ;
- rw_op = file->f_op->aio_read;
+ rw_op = do_aio_read;
goto rw_common;

case IOCB_CMD_PWRITE:
case IOCB_CMD_PWRITEV:
mode = FMODE_WRITE;
rw = WRITE;
- rw_op = file->f_op->aio_write;
+ rw_op = do_aio_write;
goto rw_common;
rw_common:
if (unlikely(!(file->f_mode & mode)))
diff --git a/fs/bad_inode.c b/fs/bad_inode.c
index 7c93953..38651e5 100644
--- a/fs/bad_inode.c
+++ b/fs/bad_inode.c
@@ -39,12 +39,24 @@ static ssize_t bad_file_aio_read(struct kiocb *iocb, const struct iovec *iov,
return -EIO;
}

+static ssize_t bad_file_read_iter(struct kiocb *iocb, struct iov_iter *iter,
+ loff_t pos)
+{
+ return -EIO;
+}
+
static ssize_t bad_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
unsigned long nr_segs, loff_t pos)
{
return -EIO;
}

+static ssize_t bad_file_write_iter(struct kiocb *iocb, struct iov_iter *iter,
+ loff_t pos)
+{
+ return -EIO;
+}
+
static int bad_file_readdir(struct file *file, struct dir_context *ctx)
{
return -EIO;
@@ -151,7 +163,9 @@ static const struct file_operations bad_file_ops =
.read = bad_file_read,
.write = bad_file_write,
.aio_read = bad_file_aio_read,
+ .read_iter = bad_file_read_iter,
.aio_write = bad_file_aio_write,
+ .write_iter = bad_file_write_iter,
.iterate = bad_file_readdir,
.poll = bad_file_poll,
.unlocked_ioctl = bad_file_unlocked_ioctl,
diff --git a/fs/internal.h b/fs/internal.h
index 7c5f01c..143a903 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -132,6 +132,10 @@ extern struct dentry *__d_alloc(struct super_block *, const struct qstr *);
*/
extern ssize_t __kernel_write(struct file *, const char *, size_t, loff_t *);
extern int rw_verify_area(int, struct file *, const loff_t *, size_t);
+extern ssize_t do_aio_read(struct kiocb *kiocb, const struct iovec *iov,
+ unsigned long nr_segs, loff_t pos);
+extern ssize_t do_aio_write(struct kiocb *kiocb, const struct iovec *iov,
+ unsigned long nr_segs, loff_t pos);

/*
* splice.c
diff --git a/fs/read_write.c b/fs/read_write.c
index 022929c..c3579a9 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -29,7 +29,7 @@ typedef ssize_t (*iov_fn_t)(struct kiocb *, const struct iovec *,
const struct file_operations generic_ro_fops = {
.llseek = generic_file_llseek,
.read = do_sync_read,
- .aio_read = generic_file_aio_read,
+ .read_iter = generic_file_read_iter,
.mmap = generic_file_readonly_mmap,
.splice_read = generic_file_splice_read,
};
@@ -359,6 +359,29 @@ int rw_verify_area(int read_write, struct file *file, const loff_t *ppos, size_t
return count > MAX_RW_COUNT ? MAX_RW_COUNT : count;
}

+ssize_t do_aio_read(struct kiocb *kiocb, const struct iovec *iov,
+ unsigned long nr_segs, loff_t pos)
+{
+ struct file *file = kiocb->ki_filp;
+
+ if (file->f_op->read_iter) {
+ size_t count;
+ struct iov_iter iter;
+ int ret;
+
+ count = 0;
+ ret = generic_segment_checks(iov, &nr_segs, &count,
+ VERIFY_WRITE);
+ if (ret)
+ return ret;
+
+ iov_iter_init(&iter, iov, nr_segs, count, 0);
+ return file->f_op->read_iter(kiocb, &iter, pos);
+ }
+
+ return file->f_op->aio_read(kiocb, iov, nr_segs, pos);
+}
+
ssize_t do_sync_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos)
{
struct iovec iov = { .iov_base = buf, .iov_len = len };
@@ -370,7 +393,7 @@ ssize_t do_sync_read(struct file *filp, char __user *buf, size_t len, loff_t *pp
kiocb.ki_left = len;
kiocb.ki_nbytes = len;

- ret = filp->f_op->aio_read(&kiocb, &iov, 1, kiocb.ki_pos);
+ ret = do_aio_read(&kiocb, &iov, 1, kiocb.ki_pos);
if (-EIOCBQUEUED == ret)
ret = wait_on_sync_kiocb(&kiocb);
*ppos = kiocb.ki_pos;
@@ -409,6 +432,29 @@ ssize_t vfs_read(struct file *file, char __user *buf, size_t count, loff_t *pos)

EXPORT_SYMBOL(vfs_read);

+ssize_t do_aio_write(struct kiocb *kiocb, const struct iovec *iov,
+ unsigned long nr_segs, loff_t pos)
+{
+ struct file *file = kiocb->ki_filp;
+
+ if (file->f_op->write_iter) {
+ size_t count;
+ struct iov_iter iter;
+ int ret;
+
+ count = 0;
+ ret = generic_segment_checks(iov, &nr_segs, &count,
+ VERIFY_READ);
+ if (ret)
+ return ret;
+
+ iov_iter_init(&iter, iov, nr_segs, count, 0);
+ return file->f_op->write_iter(kiocb, &iter, pos);
+ }
+
+ return file->f_op->aio_write(kiocb, iov, nr_segs, pos);
+}
+
ssize_t do_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 };
@@ -420,7 +466,7 @@ ssize_t do_sync_write(struct file *filp, const char __user *buf, size_t len, lof
kiocb.ki_left = len;
kiocb.ki_nbytes = len;

- ret = filp->f_op->aio_write(&kiocb, &iov, 1, kiocb.ki_pos);
+ ret = do_aio_write(&kiocb, &iov, 1, kiocb.ki_pos);
if (-EIOCBQUEUED == ret)
ret = wait_on_sync_kiocb(&kiocb);
*ppos = kiocb.ki_pos;
@@ -748,10 +794,12 @@ static ssize_t do_readv_writev(int type, struct file *file,
fnv = NULL;
if (type == READ) {
fn = file->f_op->read;
- fnv = file->f_op->aio_read;
+ if (file->f_op->aio_read || file->f_op->read_iter)
+ fnv = do_aio_read;
} else {
fn = (io_fn_t)file->f_op->write;
- fnv = file->f_op->aio_write;
+ if (file->f_op->aio_write || file->f_op->write_iter)
+ fnv = do_aio_write;
file_start_write(file);
}

@@ -930,10 +978,12 @@ static ssize_t compat_do_readv_writev(int type, struct file *file,
fnv = NULL;
if (type == READ) {
fn = file->f_op->read;
- fnv = file->f_op->aio_read;
+ if (file->f_op->aio_read || file->f_op->read_iter)
+ fnv = do_aio_read;
} else {
fn = (io_fn_t)file->f_op->write;
- fnv = file->f_op->aio_write;
+ if (file->f_op->aio_write || file->f_op->write_iter)
+ fnv = do_aio_write;
file_start_write(file);
}

diff --git a/include/linux/fs.h b/include/linux/fs.h
index fc1e2a8..26d9d8d4 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1654,12 +1654,14 @@ struct file_operations {

static inline int file_readable(struct file *filp)
{
- return filp && (filp->f_op->read || filp->f_op->aio_read);
+ return filp && (filp->f_op->read || filp->f_op->aio_read ||
+ filp->f_op->read_iter);
}

static inline int file_writable(struct file *filp)
{
- return filp && (filp->f_op->write || filp->f_op->aio_write);
+ return filp && (filp->f_op->write || filp->f_op->aio_write ||
+ filp->f_op->write_iter);
}

struct inode_operations {
--
1.8.3.4


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