diff options
| author |   David Howells <dhowells@redhat.com> | 2019-10-16 16:47:32 +0100 |
|---|---|---|
| committer | David Howells <dhowells@redhat.com> | 2019-11-15 16:22:54 +0000 |
| commit | 6718b6f855a0b4962d54bd625be2718cb820cec6 (patch) | |
| tree | 39d5e543cf914b26bdf4937b15d167c66c615f45 /fs/fuse | |
| parent | pipe: Use head and tail pointers for the ring, not cursor and length (diff) | |
| download | linux-dev-6718b6f855a0b4962d54bd625be2718cb820cec6.tar.xz linux-dev-6718b6f855a0b4962d54bd625be2718cb820cec6.zip | |
pipe: Allow pipes to have kernel-reserved slots
Split pipe->ring_size into two numbers:
(1) pipe->ring_size - indicates the hard size of the pipe ring.
(2) pipe->max_usage - indicates the maximum number of pipe ring slots that
userspace orchestrated events can fill.
This allows for a pipe that is both writable by the general kernel
notification facility and by userspace, allowing plenty of ring space for
notifications to be added whilst preventing userspace from being able to
pin too much unswappable kernel space.
Signed-off-by: David Howells <dhowells@redhat.com>
Diffstat (limited to 'fs/fuse')
| -rw-r--r-- | fs/fuse/dev.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c index c56011f95a87..423b6c657bf0 100644 --- a/fs/fuse/dev.c +++ b/fs/fuse/dev.c @@ -703,7 +703,7 @@ static int fuse_copy_fill(struct fuse_copy_state *cs) cs->pipebufs++; cs->nr_segs--; } else { - if (cs->nr_segs >= cs->pipe->ring_size) + if (cs->nr_segs >= cs->pipe->max_usage) return -EIO; page = alloc_page(GFP_HIGHUSER); @@ -879,7 +879,7 @@ static int fuse_ref_page(struct fuse_copy_state *cs, struct page *page, struct pipe_buffer *buf; int err; - if (cs->nr_segs >= cs->pipe->ring_size) + if (cs->nr_segs >= cs->pipe->max_usage) return -EIO; err = unlock_request(cs->req); @@ -1341,7 +1341,7 @@ static ssize_t fuse_dev_splice_read(struct file *in, loff_t *ppos, if (!fud) return -EPERM; - bufs = kvmalloc_array(pipe->ring_size, sizeof(struct pipe_buffer), + bufs = kvmalloc_array(pipe->max_usage, sizeof(struct pipe_buffer), GFP_KERNEL); if (!bufs) return -ENOMEM; @@ -1353,7 +1353,7 @@ static ssize_t fuse_dev_splice_read(struct file *in, loff_t *ppos, if (ret < 0) goto out; - if (pipe_occupancy(pipe->head, pipe->tail) + cs.nr_segs > pipe->ring_size) { + if (pipe_occupancy(pipe->head, pipe->tail) + cs.nr_segs > pipe->max_usage) { ret = -EIO; goto out; } |