Hi,
在 2023/07/11 10:02, Yu Kuai 写道:
+static bool submit_bio_filter(struct bio *bio)
+{
+ if (bio_flagged(bio, BIO_FILTERED))
+ return false;
+
+ bio_set_flag(bio, BIO_FILTERED);
+ return bio->bi_bdev->bd_filter->ops->submit_bio(bio);
+}
+
static void __submit_bio(struct bio *bio)
{
+ /*
+ * If there is a filter driver attached, check if the BIO needs
to go to
+ * the filter driver first, which can then pass on the bio or
consume it.
+ */
+ if (bio->bi_bdev->bd_filter && submit_bio_filter(bio))
+ return;
+
if (unlikely(!blk_crypto_bio_prep(&bio)))
return;
...
+static void __blkfilter_detach(struct block_device *bdev)
+{
+ struct blkfilter *flt = bdev->bd_filter;
+ const struct blkfilter_operations *ops = flt->ops;
+
+ bdev->bd_filter = NULL;
+ ops->detach(flt);
+ module_put(ops->owner);
+}
+
+void blkfilter_detach(struct block_device *bdev)
+{
+ if (bdev->bd_filter) {
+ blk_mq_freeze_queue(bdev->bd_queue);
And this is not sate as well, for bio-based device, q_usage_counter is
not grabbed while submit_bio_filter() is called, hence there is a risk
of uaf from submit_bio_filter().
Thanks,
Kuai
