Merge tag 'for-5.8/block-2020-06-01' of git://git.kernel.dk/linux-block

Pull block updates from Jens Axboe:
 "Core block changes that have been queued up for this release:

   - Remove dead blk-throttle and blk-wbt code (Guoqing)

   - Include pid in blktrace note traces (Jan)

   - Don't spew I/O errors on wouldblock termination (me)

   - Zone append addition (Johannes, Keith, Damien)

   - IO accounting improvements (Konstantin, Christoph)

   - blk-mq hardware map update improvements (Ming)

   - Scheduler dispatch improvement (Salman)

   - Inline block encryption support (Satya)

   - Request map fixes and improvements (Weiping)

   - blk-iocost tweaks (Tejun)

   - Fix for timeout failing with error injection (Keith)

   - Queue re-run fixes (Douglas)

   - CPU hotplug improvements (Christoph)

   - Queue entry/exit improvements (Christoph)

   - Move DMA drain handling to the few drivers that use it (Christoph)

   - Partition handling cleanups (Christoph)"

* tag 'for-5.8/block-2020-06-01' of git://git.kernel.dk/linux-block: (127 commits)
  block: mark bio_wouldblock_error() bio with BIO_QUIET
  blk-wbt: rename __wbt_update_limits to wbt_update_limits
  blk-wbt: remove wbt_update_limits
  blk-throttle: remove tg_drain_bios
  blk-throttle: remove blk_throtl_drain
  null_blk: force complete for timeout request
  blk-mq: drain I/O when all CPUs in a hctx are offline
  blk-mq: add blk_mq_all_tag_iter
  blk-mq: open code __blk_mq_alloc_request in blk_mq_alloc_request_hctx
  blk-mq: use BLK_MQ_NO_TAG in more places
  blk-mq: rename BLK_MQ_TAG_FAIL to BLK_MQ_NO_TAG
  blk-mq: move more request initialization to blk_mq_rq_ctx_init
  blk-mq: simplify the blk_mq_get_request calling convention
  blk-mq: remove the bio argument to ->prepare_request
  nvme: force complete cancelled requests
  blk-mq: blk-mq: provide forced completion method
  block: fix a warning when blkdev.h is included for !CONFIG_BLOCK builds
  block: blk-crypto-fallback: remove redundant initialization of variable err
  block: reduce part_stat_lock() scope
  block: use __this_cpu_add() instead of access by smp_processor_id()
  ...

1 files changed, 27 insertions, 1 deletions

diff --git a/drivers/block/null_blk_main.c b/drivers/block/null_blk_main.c
index ce9e33603a4d..87b31f9ca362 100644
--- a/drivers/block/null_blk_main.c
+++ b/drivers/block/null_blk_main.c
@@ -1250,8 +1250,34 @@ static inline blk_status_t null_handle_memory_backed(struct nullb_cmd *cmd,
 	return errno_to_blk_status(err);
 }
 
+static void nullb_zero_read_cmd_buffer(struct nullb_cmd *cmd)
+{
+	struct nullb_device *dev = cmd->nq->dev;
+	struct bio *bio;
+
+	if (dev->memory_backed)
+		return;
+
+	if (dev->queue_mode == NULL_Q_BIO && bio_op(cmd->bio) == REQ_OP_READ) {
+		zero_fill_bio(cmd->bio);
+	} else if (req_op(cmd->rq) == REQ_OP_READ) {
+		__rq_for_each_bio(bio, cmd->rq)
+			zero_fill_bio(bio);
+	}
+}
+
 static inline void nullb_complete_cmd(struct nullb_cmd *cmd)
 {
+	/*
+	 * Since root privileges are required to configure the null_blk
+	 * driver, it is fine that this driver does not initialize the
+	 * data buffers of read commands. Zero-initialize these buffers
+	 * anyway if KMSAN is enabled to prevent that KMSAN complains
+	 * about null_blk not initializing read data buffers.
+	 */
+	if (IS_ENABLED(CONFIG_KMSAN))
+		nullb_zero_read_cmd_buffer(cmd);
+
 	/* Complete IO by inline, softirq or timer */
 	switch (cmd->nq->dev->irqmode) {
 	case NULL_IRQ_SOFTIRQ:
@@ -1397,7 +1423,7 @@ static bool should_requeue_request(struct request *rq)
 static enum blk_eh_timer_return null_timeout_rq(struct request *rq, bool res)
 {
 	pr_info("rq %p timed out\n", rq);
-	blk_mq_complete_request(rq);
+	blk_mq_force_complete_rq(rq);
 	return BLK_EH_DONE;
 }