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kernfs: implement ->write_iter

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Switch kernfs to implement the write_iter method instead of plain old
write to prepare to supporting splice and sendfile again.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20210120204631.274206-3-hch@lst.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Christoph Hellwig
2021-01-20 21:46:30 +01:00
committed by Greg Kroah-Hartman
parent 4eaad21a6a
commit cc099e0b39
1 changed files with 10 additions and 18 deletions
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28
fs/kernfs/file.c
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@@ -242,13 +242,7 @@ static ssize_t kernfs_fop_read_iter(struct kiocb *iocb, struct iov_iter *iter)
return kernfs_file_read_iter(iocb, iter); return kernfs_file_read_iter(iocb, iter);
} }
/** /*
* kernfs_fop_write - kernfs vfs write callback
* @file: file pointer
* @user_buf: data to write
* @count: number of bytes
* @ppos: starting offset
*
* Copy data in from userland and pass it to the matching kernfs write * Copy data in from userland and pass it to the matching kernfs write
* operation. * operation.
* *
@@ -258,20 +252,18 @@ static ssize_t kernfs_fop_read_iter(struct kiocb *iocb, struct iov_iter *iter)
* modify only the the value you're changing, then write entire buffer * modify only the the value you're changing, then write entire buffer
* back. * back.
*/ */
static ssize_t kernfs_fop_write(struct file *file, const char __user *user_buf, static ssize_t kernfs_fop_write_iter(struct kiocb *iocb, struct iov_iter *iter)
size_t count, loff_t *ppos)
{ {
struct kernfs_open_file *of = kernfs_of(file); struct kernfs_open_file *of = kernfs_of(iocb->ki_filp);
ssize_t len = iov_iter_count(iter);
const struct kernfs_ops *ops; const struct kernfs_ops *ops;
ssize_t len;
char *buf; char *buf;
if (of->atomic_write_len) { if (of->atomic_write_len) {
len = count;
if (len > of->atomic_write_len) if (len > of->atomic_write_len)
return -E2BIG; return -E2BIG;
} else { } else {
len = min_t(size_t, count, PAGE_SIZE); len = min_t(size_t, len, PAGE_SIZE);
} }
buf = of->prealloc_buf; buf = of->prealloc_buf;
@@ -282,7 +274,7 @@ static ssize_t kernfs_fop_write(struct file *file, const char __user *user_buf,
if (!buf) if (!buf)
return -ENOMEM; return -ENOMEM;
if (copy_from_user(buf, user_buf, len)) { if (copy_from_iter(buf, len, iter) != len) {
len = -EFAULT; len = -EFAULT;
goto out_free; goto out_free;
} }
@@ -301,7 +293,7 @@ static ssize_t kernfs_fop_write(struct file *file, const char __user *user_buf,
ops = kernfs_ops(of->kn); ops = kernfs_ops(of->kn);
if (ops->write) if (ops->write)
len = ops->write(of, buf, len, *ppos); len = ops->write(of, buf, len, iocb->ki_pos);
else else
len = -EINVAL; len = -EINVAL;
@@ -309,7 +301,7 @@ static ssize_t kernfs_fop_write(struct file *file, const char __user *user_buf,
mutex_unlock(&of->mutex); mutex_unlock(&of->mutex);
if (len > 0) if (len > 0)
*ppos += len; iocb->ki_pos += len;
out_free: out_free:
if (buf == of->prealloc_buf) if (buf == of->prealloc_buf)
@@ -662,7 +654,7 @@ static int kernfs_fop_open(struct inode *inode, struct file *file)
/* /*
* Write path needs to atomic_write_len outside active reference. * Write path needs to atomic_write_len outside active reference.
* Cache it in open_file. See kernfs_fop_write() for details. * Cache it in open_file. See kernfs_fop_write_iter() for details.
*/ */
of->atomic_write_len = ops->atomic_write_len; of->atomic_write_len = ops->atomic_write_len;
@@ -950,7 +942,7 @@ EXPORT_SYMBOL_GPL(kernfs_notify);
const struct file_operations kernfs_file_fops = { const struct file_operations kernfs_file_fops = {
.read_iter = kernfs_fop_read_iter, .read_iter = kernfs_fop_read_iter,
.write = kernfs_fop_write, .write_iter = kernfs_fop_write_iter,
.llseek = generic_file_llseek, .llseek = generic_file_llseek,
.mmap = kernfs_fop_mmap, .mmap = kernfs_fop_mmap,
.open = kernfs_fop_open, .open = kernfs_fop_open,