Merge tag 'block-2023-01-06' of git://git.kernel.dk/linux

Pull block fixes from Jens Axboe:
 "The big change here is obviously the revert of the pktcdvd driver
  removal. Outside of that, just minor tweaks. In detail:

   - Re-instate the pktcdvd driver, which necessitates adding back
     bio_copy_data_iter() and the fops->devnode() hook for now (me)

   - Fix for splitting of a bio marked as NOWAIT, causing either nowait
     reads or writes to error with EAGAIN even if parts of the IO
     completed (me)

   - Fix for ublk, punting management commands to io-wq as they can all
     easily block for extended periods of time (Ming)

   - Removal of SRCU dependency for the block layer (Paul)"

* tag 'block-2023-01-06' of git://git.kernel.dk/linux:
  block: Remove "select SRCU"
  Revert "pktcdvd: remove driver."
  Revert "block: remove devnode callback from struct block_device_operations"
  Revert "block: bio_copy_data_iter"
  ublk: honor IO_URING_F_NONBLOCK for handling control command
  block: don't allow splitting of a REQ_NOWAIT bio
  block: handle bio_split_to_limits() NULL return

Documentation/ABI/testing/debugfs-pktcdvd

@@ -0,0 +1,18 @@
+What:           /sys/kernel/debug/pktcdvd/pktcdvd[0-7]
+Date:           Oct. 2006
+KernelVersion:  2.6.20
+Contact:        Thomas Maier <balagi@justmail.de>
+Description:
+
+The pktcdvd module (packet writing driver) creates
+these files in debugfs:
+
+/sys/kernel/debug/pktcdvd/pktcdvd[0-7]/
+
+    ====            ====== ====================================
+    info            0444   Lots of driver statistics and infos.
+    ====            ====== ====================================
+
+Example::
+
+    cat /sys/kernel/debug/pktcdvd/pktcdvd0/info

Documentation/ABI/testing/sysfs-class-pktcdvd

@@ -0,0 +1,97 @@
+sysfs interface
+---------------
+The pktcdvd module (packet writing driver) creates the following files in the
+sysfs: (<devid> is in the format major:minor)
+
+What:		/sys/class/pktcdvd/add
+What:		/sys/class/pktcdvd/remove
+What:		/sys/class/pktcdvd/device_map
+Date:		Oct. 2006
+KernelVersion:	2.6.20
+Contact:	Thomas Maier <balagi@justmail.de>
+Description:
+
+		==========	==============================================
+		add		(WO) Write a block device id (major:minor) to
+				create a new pktcdvd device and map it to the
+				block device.
+
+		remove		(WO) Write the pktcdvd device id (major:minor)
+				to remove the pktcdvd device.
+
+		device_map	(RO) Shows the device mapping in format:
+				pktcdvd[0-7] <pktdevid> <blkdevid>
+		==========	==============================================
+
+
+What:		/sys/class/pktcdvd/pktcdvd[0-7]/dev
+What:		/sys/class/pktcdvd/pktcdvd[0-7]/uevent
+Date:		Oct. 2006
+KernelVersion:	2.6.20
+Contact:	Thomas Maier <balagi@justmail.de>
+Description:
+		dev:	(RO) Device id
+
+		uevent:	(WO) To send a uevent
+
+
+What:		/sys/class/pktcdvd/pktcdvd[0-7]/stat/packets_started
+What:		/sys/class/pktcdvd/pktcdvd[0-7]/stat/packets_finished
+What:		/sys/class/pktcdvd/pktcdvd[0-7]/stat/kb_written
+What:		/sys/class/pktcdvd/pktcdvd[0-7]/stat/kb_read
+What:		/sys/class/pktcdvd/pktcdvd[0-7]/stat/kb_read_gather
+What:		/sys/class/pktcdvd/pktcdvd[0-7]/stat/reset
+Date:		Oct. 2006
+KernelVersion:	2.6.20
+Contact:	Thomas Maier <balagi@justmail.de>
+Description:
+		packets_started:	(RO) Number of started packets.
+
+		packets_finished:	(RO) Number of finished packets.
+
+		kb_written:		(RO) kBytes written.
+
+		kb_read:		(RO) kBytes read.
+
+		kb_read_gather:		(RO) kBytes read to fill write packets.
+
+		reset:			(WO) Write any value to it to reset
+					pktcdvd device statistic values, like
+					bytes read/written.
+
+
+What:		/sys/class/pktcdvd/pktcdvd[0-7]/write_queue/size
+What:		/sys/class/pktcdvd/pktcdvd[0-7]/write_queue/congestion_off
+What:		/sys/class/pktcdvd/pktcdvd[0-7]/write_queue/congestion_on
+Date:		Oct. 2006
+KernelVersion:	2.6.20
+Contact:	Thomas Maier <balagi@justmail.de>
+Description:
+		==============	================================================
+		size		(RO) Contains the size of the bio write queue.
+
+		congestion_off	(RW) If bio write queue size is below this mark,
+				accept new bio requests from the block layer.
+
+		congestion_on	(RW) If bio write queue size is higher as this
+				mark, do no longer accept bio write requests
+				from the block layer and wait till the pktcdvd
+				device has processed enough bio's so that bio
+				write queue size is below congestion off mark.
+				A value of <= 0 disables congestion control.
+		==============	================================================
+
+
+Example:
+--------
+To use the pktcdvd sysfs interface directly, you can do::
+
+    # create a new pktcdvd device mapped to /dev/hdc
+    echo "22:0" >/sys/class/pktcdvd/add
+    cat /sys/class/pktcdvd/device_map
+    # assuming device pktcdvd0 was created, look at stat's
+    cat /sys/class/pktcdvd/pktcdvd0/stat/kb_written
+    # print the device id of the mapped block device
+    fgrep pktcdvd0 /sys/class/pktcdvd/device_map
+    # remove device, using pktcdvd0 device id   253:0
+    echo "253:0" >/sys/class/pktcdvd/remove

MAINTAINERS

@@ -16610,6 +16610,13 @@ S:	Supported
 F:	Documentation/devicetree/bindings/input/pine64,pinephone-keyboard.yaml
 F:	drivers/input/keyboard/pinephone-keyboard.c
 
+PKTCDVD DRIVER
+M:	linux-block@vger.kernel.org
+S:	Orphan
+F:	drivers/block/pktcdvd.c
+F:	include/linux/pktcdvd.h
+F:	include/uapi/linux/pktcdvd.h
+
 PLANTOWER PMS7003 AIR POLLUTION SENSOR DRIVER
 M:	Tomasz Duszynski <tduszyns@gmail.com>
 S:	Maintained

block/Kconfig

@@ -6,7 +6,6 @@ menuconfig BLOCK
        bool "Enable the block layer" if EXPERT
        default y
        select SBITMAP
-       select SRCU
        help
 	 Provide block layer support for the kernel.
 

block/bio.c

@@ -1401,6 +1401,27 @@ void __bio_advance(struct bio *bio, unsigned bytes)
 }
 EXPORT_SYMBOL(__bio_advance);
 
+void bio_copy_data_iter(struct bio *dst, struct bvec_iter *dst_iter,
+			struct bio *src, struct bvec_iter *src_iter)
+{
+	while (src_iter->bi_size && dst_iter->bi_size) {
+		struct bio_vec src_bv = bio_iter_iovec(src, *src_iter);
+		struct bio_vec dst_bv = bio_iter_iovec(dst, *dst_iter);
+		unsigned int bytes = min(src_bv.bv_len, dst_bv.bv_len);
+		void *src_buf = bvec_kmap_local(&src_bv);
+		void *dst_buf = bvec_kmap_local(&dst_bv);
+
+		memcpy(dst_buf, src_buf, bytes);
+
+		kunmap_local(dst_buf);
+		kunmap_local(src_buf);
+
+		bio_advance_iter_single(src, src_iter, bytes);
+		bio_advance_iter_single(dst, dst_iter, bytes);
+	}
+}
+EXPORT_SYMBOL(bio_copy_data_iter);
+
 /**
  * bio_copy_data - copy contents of data buffers from one bio to another
  * @src: source bio
@@ -1414,21 +1435,7 @@ void bio_copy_data(struct bio *dst, struct bio *src)
 	struct bvec_iter src_iter = src->bi_iter;
 	struct bvec_iter dst_iter = dst->bi_iter;
 
-	while (src_iter.bi_size && dst_iter.bi_size) {
-		struct bio_vec src_bv = bio_iter_iovec(src, src_iter);
-		struct bio_vec dst_bv = bio_iter_iovec(dst, dst_iter);
-		unsigned int bytes = min(src_bv.bv_len, dst_bv.bv_len);
-		void *src_buf = bvec_kmap_local(&src_bv);
-		void *dst_buf = bvec_kmap_local(&dst_bv);
-
-		memcpy(dst_buf, src_buf, bytes);
-
-		kunmap_local(dst_buf);
-		kunmap_local(src_buf);
-
-		bio_advance_iter_single(src, &src_iter, bytes);
-		bio_advance_iter_single(dst, &dst_iter, bytes);
-	}
+	bio_copy_data_iter(dst, &dst_iter, src, &src_iter);
 }
 EXPORT_SYMBOL(bio_copy_data);
 

block/blk-merge.c

@@ -309,6 +309,16 @@ static struct bio *bio_split_rw(struct bio *bio, const struct queue_limits *lim,
 	*segs = nsegs;
 	return NULL;
 split:
+	/*
+	 * We can't sanely support splitting for a REQ_NOWAIT bio. End it
+	 * with EAGAIN if splitting is required and return an error pointer.
+	 */
+	if (bio->bi_opf & REQ_NOWAIT) {
+		bio->bi_status = BLK_STS_AGAIN;
+		bio_endio(bio);
+		return ERR_PTR(-EAGAIN);
+	}
+
 	*segs = nsegs;
 
 	/*
@@ -358,11 +368,13 @@ struct bio *__bio_split_to_limits(struct bio *bio,
 	default:
 		split = bio_split_rw(bio, lim, nr_segs, bs,
 				get_max_io_size(bio, lim) << SECTOR_SHIFT);
+		if (IS_ERR(split))
+			return NULL;
 		break;
 	}
 
 	if (split) {
-		/* there isn't chance to merge the splitted bio */
+		/* there isn't chance to merge the split bio */
 		split->bi_opf |= REQ_NOMERGE;
 
 		blkcg_bio_issue_init(split);

block/blk-mq.c

@@ -2951,8 +2951,11 @@ void blk_mq_submit_bio(struct bio *bio)
 	blk_status_t ret;
 
 	bio = blk_queue_bounce(bio, q);
-	if (bio_may_exceed_limits(bio, &q->limits))
+	if (bio_may_exceed_limits(bio, &q->limits)) {
 		bio = __bio_split_to_limits(bio, &q->limits, &nr_segs);
+		if (!bio)
+			return;
+	}
 
 	if (!bio_integrity_prep(bio))
 		return;

block/genhd.c

@@ -1201,10 +1201,21 @@ struct class block_class = {
 	.dev_uevent	= block_uevent,
 };
 
+static char *block_devnode(struct device *dev, umode_t *mode,
+			   kuid_t *uid, kgid_t *gid)
+{
+	struct gendisk *disk = dev_to_disk(dev);
+
+	if (disk->fops->devnode)
+		return disk->fops->devnode(disk, mode);
+	return NULL;
+}
+
 const struct device_type disk_type = {
 	.name		= "disk",
 	.groups		= disk_attr_groups,
 	.release	= disk_release,
+	.devnode	= block_devnode,
 };
 
 #ifdef CONFIG_PROC_FS

drivers/block/Kconfig

@@ -285,6 +285,49 @@ config BLK_DEV_RAM_SIZE
 	  The default value is 4096 kilobytes. Only change this if you know
 	  what you are doing.
 
+config CDROM_PKTCDVD
+	tristate "Packet writing on CD/DVD media (DEPRECATED)"
+	depends on !UML
+	depends on SCSI
+	select CDROM
+	help
+	  Note: This driver is deprecated and will be removed from the
+	  kernel in the near future!
+
+	  If you have a CDROM/DVD drive that supports packet writing, say
+	  Y to include support. It should work with any MMC/Mt Fuji
+	  compliant ATAPI or SCSI drive, which is just about any newer
+	  DVD/CD writer.
+
+	  Currently only writing to CD-RW, DVD-RW, DVD+RW and DVDRAM discs
+	  is possible.
+	  DVD-RW disks must be in restricted overwrite mode.
+
+	  See the file <file:Documentation/cdrom/packet-writing.rst>
+	  for further information on the use of this driver.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called pktcdvd.
+
+config CDROM_PKTCDVD_BUFFERS
+	int "Free buffers for data gathering"
+	depends on CDROM_PKTCDVD
+	default "8"
+	help
+	  This controls the maximum number of active concurrent packets. More
+	  concurrent packets can increase write performance, but also require
+	  more memory. Each concurrent packet will require approximately 64Kb
+	  of non-swappable kernel memory, memory which will be allocated when
+	  a disc is opened for writing.
+
+config CDROM_PKTCDVD_WCACHE
+	bool "Enable write caching"
+	depends on CDROM_PKTCDVD
+	help
+	  If enabled, write caching will be set for the CD-R/W device. For now
+	  this option is dangerous unless the CD-RW media is known good, as we
+	  don't do deferred write error handling yet.
+
 config ATA_OVER_ETH
 	tristate "ATA over Ethernet support"
 	depends on NET

drivers/block/Makefile

@@ -20,6 +20,7 @@ obj-$(CONFIG_AMIGA_Z2RAM)	+= z2ram.o
 obj-$(CONFIG_N64CART)		+= n64cart.o
 obj-$(CONFIG_BLK_DEV_RAM)	+= brd.o
 obj-$(CONFIG_BLK_DEV_LOOP)	+= loop.o
+obj-$(CONFIG_CDROM_PKTCDVD)	+= pktcdvd.o
 obj-$(CONFIG_SUNVDC)		+= sunvdc.o
 
 obj-$(CONFIG_BLK_DEV_NBD)	+= nbd.o

drivers/block/drbd/drbd_req.c

@@ -1607,6 +1607,8 @@ void drbd_submit_bio(struct bio *bio)
 	struct drbd_device *device = bio->bi_bdev->bd_disk->private_data;
 
 	bio = bio_split_to_limits(bio);
+	if (!bio)
+		return;
 
 	/*
 	 * what we "blindly" assume: