From 11167454e9cbfa95856fea3f8e5428b4215a534c Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Wed, 20 Jan 2021 21:46:30 +0100 Subject: [PATCH] kernfs: implement ->write_iter commit cc099e0b399889c6485c88368b19824b087c9f8c upstream. 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 Link: https://lore.kernel.org/r/20210120204631.274206-3-hch@lst.de Signed-off-by: Greg Kroah-Hartman --- fs/kernfs/file.c | 28 ++++++++++------------------ 1 file changed, 10 insertions(+), 18 deletions(-) diff --git a/fs/kernfs/file.c b/fs/kernfs/file.c index 8276e4c8722d8..b1a5cccf189ec 100644 --- a/fs/kernfs/file.c +++ b/fs/kernfs/file.c @@ -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); } -/** - * 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 * 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 * back. */ -static ssize_t kernfs_fop_write(struct file *file, const char __user *user_buf, - size_t count, loff_t *ppos) +static ssize_t kernfs_fop_write_iter(struct kiocb *iocb, struct iov_iter *iter) { - 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; - ssize_t len; char *buf; if (of->atomic_write_len) { - len = count; if (len > of->atomic_write_len) return -E2BIG; } else { - len = min_t(size_t, count, PAGE_SIZE); + len = min_t(size_t, len, PAGE_SIZE); } buf = of->prealloc_buf; @@ -282,7 +274,7 @@ static ssize_t kernfs_fop_write(struct file *file, const char __user *user_buf, if (!buf) return -ENOMEM; - if (copy_from_user(buf, user_buf, len)) { + if (copy_from_iter(buf, len, iter) != len) { len = -EFAULT; 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); if (ops->write) - len = ops->write(of, buf, len, *ppos); + len = ops->write(of, buf, len, iocb->ki_pos); else len = -EINVAL; @@ -309,7 +301,7 @@ static ssize_t kernfs_fop_write(struct file *file, const char __user *user_buf, mutex_unlock(&of->mutex); if (len > 0) - *ppos += len; + iocb->ki_pos += len; out_free: 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. - * 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; @@ -950,7 +942,7 @@ EXPORT_SYMBOL_GPL(kernfs_notify); const struct file_operations kernfs_file_fops = { .read_iter = kernfs_fop_read_iter, - .write = kernfs_fop_write, + .write_iter = kernfs_fop_write_iter, .llseek = generic_file_llseek, .mmap = kernfs_fop_mmap, .open = kernfs_fop_open,