default_file_splice_read goes through great lenght to create an iovec array and iov_iter for all the reads, but is a helper only useful for files not implementing ->read_iter as we have the much better generic_file_splice_read version available for those. Remove the iters and just call __kernel_read in a loop instead.
Signed-off-by: Christoph Hellwig <[email protected]> --- fs/read_write.c | 2 +- fs/splice.c | 53 +++++++++++++--------------------------------- include/linux/fs.h | 2 -- 3 files changed, 16 insertions(+), 41 deletions(-) diff --git a/fs/read_write.c b/fs/read_write.c index 6a2170eaee64f9..1c41c25e548d8c 100644 --- a/fs/read_write.c +++ b/fs/read_write.c @@ -1070,7 +1070,7 @@ ssize_t vfs_iter_write(struct file *file, struct iov_iter *iter, loff_t *ppos, } EXPORT_SYMBOL(vfs_iter_write); -ssize_t vfs_readv(struct file *file, const struct iovec __user *vec, +static ssize_t vfs_readv(struct file *file, const struct iovec __user *vec, unsigned long vlen, loff_t *pos, rwf_t flags) { struct iovec iovstack[UIO_FASTIOV]; diff --git a/fs/splice.c b/fs/splice.c index d7c8a7c4db07ff..d1efc53875bd93 100644 --- a/fs/splice.c +++ b/fs/splice.c @@ -342,38 +342,26 @@ const struct pipe_buf_operations nosteal_pipe_buf_ops = { }; EXPORT_SYMBOL(nosteal_pipe_buf_ops); -static ssize_t kernel_readv(struct file *file, const struct kvec *vec, - unsigned long vlen, loff_t offset) -{ - mm_segment_t old_fs; - loff_t pos = offset; - ssize_t res; - - old_fs = get_fs(); - set_fs(KERNEL_DS); - /* The cast to a user pointer is valid due to the set_fs() */ - res = vfs_readv(file, (const struct iovec __user *)vec, vlen, &pos, 0); - set_fs(old_fs); - - return res; -} - static ssize_t default_file_splice_read(struct file *in, loff_t *ppos, struct pipe_inode_info *pipe, size_t len, unsigned int flags) { - struct kvec *vec, __vec[PIPE_DEF_BUFFERS]; struct iov_iter to; struct page **pages; unsigned int nr_pages; unsigned int mask; size_t offset, base, copied = 0; + loff_t pos; ssize_t res; int i; if (pipe_full(pipe->head, pipe->tail, pipe->max_usage)) return -EAGAIN; + res = rw_verify_area(READ, in, ppos, len); + if (res < 0) + return res; + /* * Try to keep page boundaries matching to source pagecache ones - * it probably won't be much help, but... @@ -386,37 +374,26 @@ static ssize_t default_file_splice_read(struct file *in, loff_t *ppos, if (res <= 0) return -ENOMEM; - nr_pages = DIV_ROUND_UP(res + base, PAGE_SIZE); - - vec = __vec; - if (nr_pages > PIPE_DEF_BUFFERS) { - vec = kmalloc_array(nr_pages, sizeof(struct kvec), GFP_KERNEL); - if (unlikely(!vec)) { - res = -ENOMEM; - goto out; - } - } - mask = pipe->ring_size - 1; pipe->bufs[to.head & mask].offset = offset; pipe->bufs[to.head & mask].len -= offset; + nr_pages = DIV_ROUND_UP(res + base, PAGE_SIZE); + + pos = *ppos; for (i = 0; i < nr_pages; i++) { size_t this_len = min_t(size_t, len, PAGE_SIZE - offset); - vec[i].iov_base = page_address(pages[i]) + offset; - vec[i].iov_len = this_len; + + res = __kernel_read(in, page_address(pages[i]) + offset, + this_len, &pos); + if (res < 0) + goto out; len -= this_len; offset = 0; } + copied = pos - *ppos; + *ppos = pos; - res = kernel_readv(in, vec, nr_pages, *ppos); - if (res > 0) { - copied = res; - *ppos += res; - } - - if (vec != __vec) - kfree(vec); out: for (i = 0; i < nr_pages; i++) put_page(pages[i]); diff --git a/include/linux/fs.h b/include/linux/fs.h index 0c0ec76b600b50..fac6aead402a98 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1919,8 +1919,6 @@ ssize_t rw_copy_check_uvector(int type, const struct iovec __user * uvector, extern ssize_t vfs_read(struct file *, char __user *, size_t, loff_t *); extern ssize_t vfs_write(struct file *, const char __user *, size_t, loff_t *); -extern ssize_t vfs_readv(struct file *, const struct iovec __user *, - unsigned long, loff_t *, rwf_t); extern ssize_t vfs_copy_file_range(struct file *, loff_t , struct file *, loff_t, size_t, unsigned int); extern ssize_t generic_copy_file_range(struct file *file_in, loff_t pos_in, -- 2.26.2
