Merge tag 'for-5.17/block-2022-01-11' of git://git.kernel.dk/linux-block

Pull block updates from Jens Axboe:

 - Unify where the struct request handling code is located in the blk-mq
   code (Christoph)

 - Header cleanups (Christoph)

 - Clean up the io_context handling code (Christoph, me)

 - Get rid of ->rq_disk in struct request (Christoph)

 - Error handling fix for add_disk() (Christoph)

 - request allocation cleanusp (Christoph)

 - Documentation updates (Eric, Matthew)

 - Remove trivial crypto unregister helper (Eric)

 - Reduce shared tag overhead (John)

 - Reduce poll_stats memory overhead (me)

 - Known indirect function call for dio (me)

 - Use atomic references for struct request (me)

 - Support request list issue for block and NVMe (me)

 - Improve queue dispatch pinning (Ming)

 - Improve the direct list issue code (Keith)

 - BFQ improvements (Jan)

 - Direct completion helper and use it in mmc block (Sebastian)

 - Use raw spinlock for the blktrace code (Wander)

 - fsync error handling fix (Ye)

 - Various fixes and cleanups (Lukas, Randy, Yang, Tetsuo, Ming, me)

* tag 'for-5.17/block-2022-01-11' of git://git.kernel.dk/linux-block: (132 commits)
  MAINTAINERS: add entries for block layer documentation
  docs: block: remove queue-sysfs.rst
  docs: sysfs-block: document virt_boundary_mask
  docs: sysfs-block: document stable_writes
  docs: sysfs-block: fill in missing documentation from queue-sysfs.rst
  docs: sysfs-block: add contact for nomerges
  docs: sysfs-block: sort alphabetically
  docs: sysfs-block: move to stable directory
  block: don't protect submit_bio_checks by q_usage_counter
  block: fix old-style declaration
  nvme-pci: fix queue_rqs list splitting
  block: introduce rq_list_move
  block: introduce rq_list_for_each_safe macro
  block: move rq_list macros to blk-mq.h
  block: drop needless assignment in set_task_ioprio()
  block: remove unnecessary trailing '\'
  bio.h: fix kernel-doc warnings
  block: check minor range in device_add_disk()
  block: use "unsigned long" for blk_validate_block_size().
  block: fix error unwinding in device_add_disk
  ...

1 files changed, 32 insertions, 5 deletions

diff --git a/block/fops.c b/block/fops.c
index 0da147edbd18..26bf15c770d2 100644
--- a/block/fops.c
+++ b/block/fops.c
@@ -566,21 +566,48 @@ static ssize_t blkdev_read_iter(struct kiocb *iocb, struct iov_iter *to)
 {
 	struct block_device *bdev = iocb->ki_filp->private_data;
 	loff_t size = bdev_nr_bytes(bdev);
+	size_t count = iov_iter_count(to);
 	loff_t pos = iocb->ki_pos;
 	size_t shorted = 0;
-	ssize_t ret;
+	ssize_t ret = 0;
 
-	if (unlikely(pos + iov_iter_count(to) > size)) {
+	if (unlikely(pos + count > size)) {
 		if (pos >= size)
 			return 0;
 		size -= pos;
-		if (iov_iter_count(to) > size) {
-			shorted = iov_iter_count(to) - size;
+		if (count > size) {
+			shorted = count - size;
 			iov_iter_truncate(to, size);
 		}
 	}
 
-	ret = generic_file_read_iter(iocb, to);
+	if (iocb->ki_flags & IOCB_DIRECT) {
+		struct address_space *mapping = iocb->ki_filp->f_mapping;
+
+		if (iocb->ki_flags & IOCB_NOWAIT) {
+			if (filemap_range_needs_writeback(mapping, iocb->ki_pos,
+						iocb->ki_pos + count - 1))
+				return -EAGAIN;
+		} else {
+			ret = filemap_write_and_wait_range(mapping,
+						iocb->ki_pos,
+					        iocb->ki_pos + count - 1);
+			if (ret < 0)
+				return ret;
+		}
+
+		file_accessed(iocb->ki_filp);
+
+		ret = blkdev_direct_IO(iocb, to);
+		if (ret >= 0) {
+			iocb->ki_pos += ret;
+			count -= ret;
+		}
+		if (ret < 0 || !count)
+			return ret;
+	}
+
+	ret = filemap_read(iocb, to, ret);
 
 	if (unlikely(shorted))
 		iov_iter_reexpand(to, iov_iter_count(to) + shorted);