diff options
Diffstat (limited to 'fs/splice.c')
-rw-r--r-- | fs/splice.c | 193 |
1 files changed, 64 insertions, 129 deletions
diff --git a/fs/splice.c b/fs/splice.c index 70cc52af780b..866d5c2367b2 100644 --- a/fs/splice.c +++ b/fs/splice.c @@ -341,89 +341,6 @@ 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; - ssize_t res; - int i; - - if (pipe_full(pipe->head, pipe->tail, pipe->max_usage)) - return -EAGAIN; - - /* - * Try to keep page boundaries matching to source pagecache ones - - * it probably won't be much help, but... - */ - offset = *ppos & ~PAGE_MASK; - - iov_iter_pipe(&to, READ, pipe, len + offset); - - res = iov_iter_get_pages_alloc(&to, &pages, len + offset, &base); - 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; - - 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; - len -= this_len; - offset = 0; - } - - 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]); - kvfree(pages); - iov_iter_advance(&to, copied); /* truncates and discards */ - return res; -} - /* * Send 'sd->len' bytes to socket from 'sd->file' at position 'sd->pos' * using sendpage(). Return the number of bytes sent. @@ -807,33 +724,6 @@ done: EXPORT_SYMBOL(iter_file_splice_write); -static int write_pipe_buf(struct pipe_inode_info *pipe, struct pipe_buffer *buf, - struct splice_desc *sd) -{ - int ret; - void *data; - loff_t tmp = sd->pos; - - data = kmap(buf->page); - ret = __kernel_write(sd->u.file, data + buf->offset, sd->len, &tmp); - kunmap(buf->page); - - return ret; -} - -static ssize_t default_file_splice_write(struct pipe_inode_info *pipe, - struct file *out, loff_t *ppos, - size_t len, unsigned int flags) -{ - ssize_t ret; - - ret = splice_from_pipe(pipe, out, ppos, len, flags, write_pipe_buf); - if (ret > 0) - *ppos += ret; - - return ret; -} - /** * generic_splice_sendpage - splice data from a pipe to a socket * @pipe: pipe to splice from @@ -855,15 +745,23 @@ ssize_t generic_splice_sendpage(struct pipe_inode_info *pipe, struct file *out, EXPORT_SYMBOL(generic_splice_sendpage); +static int warn_unsupported(struct file *file, const char *op) +{ + pr_debug_ratelimited( + "splice %s not supported for file %pD4 (pid: %d comm: %.20s)\n", + op, file, current->pid, current->comm); + return -EINVAL; +} + /* * Attempt to initiate a splice from pipe to file. */ static long do_splice_from(struct pipe_inode_info *pipe, struct file *out, loff_t *ppos, size_t len, unsigned int flags) { - if (out->f_op->splice_write) - return out->f_op->splice_write(pipe, out, ppos, len, flags); - return default_file_splice_write(pipe, out, ppos, len, flags); + if (unlikely(!out->f_op->splice_write)) + return warn_unsupported(out, "write"); + return out->f_op->splice_write(pipe, out, ppos, len, flags); } /* @@ -885,9 +783,9 @@ static long do_splice_to(struct file *in, loff_t *ppos, if (unlikely(len > MAX_RW_COUNT)) len = MAX_RW_COUNT; - if (in->f_op->splice_read) - return in->f_op->splice_read(in, ppos, pipe, len, flags); - return default_file_splice_read(in, ppos, pipe, len, flags); + if (unlikely(!in->f_op->splice_read)) + return warn_unsupported(in, "read"); + return in->f_op->splice_read(in, ppos, pipe, len, flags); } /** @@ -1107,9 +1005,8 @@ static int splice_pipe_to_pipe(struct pipe_inode_info *ipipe, /* * Determine where to splice to/from. */ -long do_splice(struct file *in, loff_t __user *off_in, - struct file *out, loff_t __user *off_out, - size_t len, unsigned int flags) +long do_splice(struct file *in, loff_t *off_in, struct file *out, + loff_t *off_out, size_t len, unsigned int flags) { struct pipe_inode_info *ipipe; struct pipe_inode_info *opipe; @@ -1143,8 +1040,7 @@ long do_splice(struct file *in, loff_t __user *off_in, if (off_out) { if (!(out->f_mode & FMODE_PWRITE)) return -EINVAL; - if (copy_from_user(&offset, off_out, sizeof(loff_t))) - return -EFAULT; + offset = *off_out; } else { offset = out->f_pos; } @@ -1165,8 +1061,8 @@ long do_splice(struct file *in, loff_t __user *off_in, if (!off_out) out->f_pos = offset; - else if (copy_to_user(off_out, &offset, sizeof(loff_t))) - ret = -EFAULT; + else + *off_out = offset; return ret; } @@ -1177,8 +1073,7 @@ long do_splice(struct file *in, loff_t __user *off_in, if (off_in) { if (!(in->f_mode & FMODE_PREAD)) return -EINVAL; - if (copy_from_user(&offset, off_in, sizeof(loff_t))) - return -EFAULT; + offset = *off_in; } else { offset = in->f_pos; } @@ -1202,8 +1097,8 @@ long do_splice(struct file *in, loff_t __user *off_in, wakeup_pipe_readers(opipe); if (!off_in) in->f_pos = offset; - else if (copy_to_user(off_in, &offset, sizeof(loff_t))) - ret = -EFAULT; + else + *off_in = offset; return ret; } @@ -1211,6 +1106,46 @@ long do_splice(struct file *in, loff_t __user *off_in, return -EINVAL; } +static long __do_splice(struct file *in, loff_t __user *off_in, + struct file *out, loff_t __user *off_out, + size_t len, unsigned int flags) +{ + struct pipe_inode_info *ipipe; + struct pipe_inode_info *opipe; + loff_t offset, *__off_in = NULL, *__off_out = NULL; + long ret; + + ipipe = get_pipe_info(in, true); + opipe = get_pipe_info(out, true); + + if (ipipe && off_in) + return -ESPIPE; + if (opipe && off_out) + return -ESPIPE; + + if (off_out) { + if (copy_from_user(&offset, off_out, sizeof(loff_t))) + return -EFAULT; + __off_out = &offset; + } + if (off_in) { + if (copy_from_user(&offset, off_in, sizeof(loff_t))) + return -EFAULT; + __off_in = &offset; + } + + ret = do_splice(in, __off_in, out, __off_out, len, flags); + if (ret < 0) + return ret; + + if (__off_out && copy_to_user(off_out, __off_out, sizeof(loff_t))) + return -EFAULT; + if (__off_in && copy_to_user(off_in, __off_in, sizeof(loff_t))) + return -EFAULT; + + return ret; +} + static int iter_to_pipe(struct iov_iter *from, struct pipe_inode_info *pipe, unsigned flags) @@ -1405,8 +1340,8 @@ SYSCALL_DEFINE6(splice, int, fd_in, loff_t __user *, off_in, if (in.file) { out = fdget(fd_out); if (out.file) { - error = do_splice(in.file, off_in, out.file, off_out, - len, flags); + error = __do_splice(in.file, off_in, out.file, off_out, + len, flags); fdput(out); } fdput(in); |