Add timeout handler, so that we can provide forward progress guarantee for
unprivileged ublk, which can't be trusted.
One thing is that sync() calls sync_bdevs(wait) for all block devices after
running sync_bdevs(no_wait), and if one device can't move on, the sync() won't
return any more.
Add timeout for unprivileged ublk to avoid such affect for other users which call
sync() syscall.
Fixes: 4093cb5a0634 ("ublk_drv: add mechanism for supporting unprivileged ublk device")
Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx>
---
drivers/block/ublk_drv.c | 18 ++++++++++++++++++
1 file changed, 18 insertions(+)
diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
index afbef182820b..50f5e5abd721 100644
--- a/drivers/block/ublk_drv.c
+++ b/drivers/block/ublk_drv.c
@@ -129,6 +129,7 @@ struct ublk_queue {
unsigned long io_addr; /* mapped vm address */
unsigned int max_io_sz;
bool force_abort;
+ bool timeout;
unsigned short nr_io_ready; /* how many ios setup */
struct ublk_device *dev;
struct ublk_io ios[];
@@ -898,6 +899,22 @@ static void ublk_queue_cmd(struct ublk_queue *ubq, struct request *rq)
}
}
+static enum blk_eh_timer_return ublk_timeout(struct request *rq)
+{
+ struct ublk_queue *ubq = rq->mq_hctx->driver_data;
+
+ if (ubq->flags & UBLK_F_UNPRIVILEGED_DEV) {
+ if (!ubq->timeout) {
+ send_sig(SIGKILL, ubq->ubq_daemon, 0);
+ ubq->timeout = true;
+ }
+
+ return BLK_EH_DONE;
+ }
+
+ return BLK_EH_RESET_TIMER;
+}
+
static blk_status_t ublk_queue_rq(struct blk_mq_hw_ctx *hctx,
const struct blk_mq_queue_data *bd)
{
@@ -957,6 +974,7 @@ static const struct blk_mq_ops ublk_mq_ops = {
.queue_rq = ublk_queue_rq,
.init_hctx = ublk_init_hctx,
.init_request = ublk_init_rq,
+ .timeout = ublk_timeout,
};
static int ublk_ch_open(struct inode *inode, struct file *filp)
--
2.38.1
