fuse: use kvmalloc to allocate array of pipe_buffer structs. (d6d931ad) · Commits · 戴 / test

The amount of pipe->buffers is basically controlled by userspace by fcntl(... F_SETPIPE_SZ ...) so it could be large. High order allocations could be slow (if memory is heavily fragmented) or may fail if the order is larger than PAGE_ALLOC_COSTLY_ORDER. Since the 'bufs' doesn't need to be physically contiguous, use the kvmalloc_array() to allocate memory. If high order page isn't available, the kvamalloc*() will fallback to 0-order. Signed-off-by:

Andrey Ryabinin <aryabinin@virtuozzo.com> Signed-off-by:

Miklos Szeredi <mszeredi@redhat.com>

fs/fuse/dev.c

+6 −6

Original line number	Diff line number	Diff line
		@@ -1373,7 +1373,7 @@ static ssize_t fuse_dev_splice_read(struct file in, loff_t ppos,
		if (!fud)
		return -EPERM;

		bufs = kmalloc_array(pipe->buffers, sizeof(struct pipe_buffer),
		bufs = kvmalloc_array(pipe->buffers, sizeof(struct pipe_buffer),
		GFP_KERNEL);
		if (!bufs)
		return -ENOMEM;
		@@ -1407,7 +1407,7 @@ out:
		for (; page_nr < cs.nr_segs; page_nr++)
		put_page(bufs[page_nr].page);

		kfree(bufs);
		kvfree(bufs);
		return ret;
		}

		@@ -1957,7 +1957,7 @@ static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe,

		pipe_lock(pipe);

		bufs = kmalloc_array(pipe->buffers, sizeof(struct pipe_buffer),
		bufs = kvmalloc_array(pipe->buffers, sizeof(struct pipe_buffer),
		GFP_KERNEL);
		if (!bufs) {
		pipe_unlock(pipe);
		@@ -2017,7 +2017,7 @@ static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe,
		pipe_buf_release(pipe, &bufs[idx]);

		out:
		kfree(bufs);
		kvfree(bufs);
		return ret;
		}

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