Re: [PATCH 07/12] vhost-scsi: convert put_page() to put_user_page*()
From: "Michael S. Tsirkin" <mst@redhat.com>
Date: 2019-07-24 08:08:16
Also in:
ceph-devel, kvm, linux-block, linux-cifs, linux-fsdevel, linux-mm, linux-nfs, linux-rdma, lkml, virtualization
On Tue, Jul 23, 2019 at 09:25:13PM -0700, john.hubbard@gmail.com wrote:
From: Jérôme Glisse <redacted>
For pages that were retained via get_user_pages*(), release those pages
via the new put_user_page*() routines, instead of via put_page().
This is part a tree-wide conversion, as described in commit fc1d8e7cca2d
("mm: introduce put_user_page*(), placeholder versions").
Changes from Jérôme's original patch:
* Changed a WARN_ON to a BUG_ON.
Signed-off-by: Jérôme Glisse <redacted>
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Cc: virtualization@lists.linux-foundation.org
Cc: linux-fsdevel@vger.kernel.org
Cc: linux-block@vger.kernel.org
Cc: linux-mm@kvack.org
Cc: Jan Kara <jack@suse.cz>
Cc: Dan Williams <redacted>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Johannes Thumshirn <redacted>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Ming Lei <redacted>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Boaz Harrosh <redacted>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Jason Wang <redacted>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Stefan Hajnoczi <stefanha@redhat.com>Acked-by: Michael S. Tsirkin <mst@redhat.com>
quoted hunk ↗ jump to hunk
--- drivers/vhost/scsi.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-)diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c index a9caf1bc3c3e..282565ab5e3f 100644 --- a/drivers/vhost/scsi.c +++ b/drivers/vhost/scsi.c@@ -329,11 +329,11 @@ static void vhost_scsi_release_cmd(struct se_cmd *se_cmd) if (tv_cmd->tvc_sgl_count) { for (i = 0; i < tv_cmd->tvc_sgl_count; i++) - put_page(sg_page(&tv_cmd->tvc_sgl[i])); + put_user_page(sg_page(&tv_cmd->tvc_sgl[i])); } if (tv_cmd->tvc_prot_sgl_count) { for (i = 0; i < tv_cmd->tvc_prot_sgl_count; i++) - put_page(sg_page(&tv_cmd->tvc_prot_sgl[i])); + put_user_page(sg_page(&tv_cmd->tvc_prot_sgl[i])); } vhost_scsi_put_inflight(tv_cmd->inflight);@@ -630,6 +630,13 @@ vhost_scsi_map_to_sgl(struct vhost_scsi_cmd *cmd, size_t offset; unsigned int npages = 0; + /* + * Here in all cases we should have an IOVEC which use GUP. If that is + * not the case then we will wrongly call put_user_page() and the page + * refcount will go wrong (this is in vhost_scsi_release_cmd()) + */ + WARN_ON(!iov_iter_get_pages_use_gup(iter)); + bytes = iov_iter_get_pages(iter, pages, LONG_MAX, VHOST_SCSI_PREALLOC_UPAGES, &offset); /* No pages were pinned */@@ -681,7 +688,7 @@ vhost_scsi_iov_to_sgl(struct vhost_scsi_cmd *cmd, bool write, while (p < sg) { struct page *page = sg_page(p++); if (page) - put_page(page); + put_user_page(page); } return ret; }-- 2.22.0