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
author: Linus Torvalds <torvalds@linux-foundation.org> 2023-01-06 13:12:42 -0800
committer: Linus Torvalds <torvalds@linux-foundation.org> 2023-01-06 13:12:42 -0800
commit: a689b938df39ab513026c53fb7011fd7cd594943 (patch)
tree: 190d683bba2d6e6f9e769d232cc2412dcbd0541e
parent: ef1a4a770994b97a86988fd86f5a2784b87449f7 (diff)
parent: b2b50d572135c5c6e10c2ff79cd828d5a8141ef6 (diff)
download: linux-a689b938df39ab513026c53fb7011fd7cd594943.tar.gz
linux-a689b938df39ab513026c53fb7011fd7cd594943.tar.bz2
linux-a689b938df39ab513026c53fb7011fd7cd594943.zip
22 files changed, 3487 insertions, 18 deletions
diff --git a/Documentation/ABI/testing/debugfs-pktcdvd b/Documentation/ABI/testing/debugfs-pktcdvd
new file mode 100644
index 000000000000..f6f65a4faea0
--- /dev/null
+++ b/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
diff --git a/Documentation/ABI/testing/sysfs-class-pktcdvd b/Documentation/ABI/testing/sysfs-class-pktcdvd
new file mode 100644
index 000000000000..ba1ce626591d
--- /dev/null
+++ b/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
diff --git a/MAINTAINERS b/MAINTAINERS
index ea941dc469fa..a36df9ed283d 100644
--- a/MAINTAINERS
+++ b/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
diff --git a/block/Kconfig b/block/Kconfig
index 444c5ab3b67e..5d9d9c84d516 100644
--- a/block/Kconfig
+++ b/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.
 
diff --git a/block/bio.c b/block/bio.c
index 5f96fcae3f75..ab59a491a883 100644
--- a/block/bio.c
+++ b/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);
 
diff --git a/block/blk-merge.c b/block/blk-merge.c
index 35a8f75cc45d..b7c193d67185 100644
--- a/block/blk-merge.c
+++ b/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);
diff --git a/block/blk-mq.c b/block/blk-mq.c
index c5cf0dbca1db..2c49b4151da1 100644
--- a/block/blk-mq.c
+++ b/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;
diff --git a/block/genhd.c b/block/genhd.c
index ab3cbe44196f..23cf83b3331c 100644
--- a/block/genhd.c
+++ b/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
diff --git a/drivers/block/Kconfig b/drivers/block/Kconfig
index a2184b428493..a41145d52de9 100644
--- a/drivers/block/Kconfig
+++ b/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
diff --git a/drivers/block/Makefile b/drivers/block/Makefile
index 962ee65d8ca3..101612cba303 100644
--- a/drivers/block/Makefile
+++ b/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
diff --git a/drivers/block/drbd/drbd_req.c b/drivers/block/drbd/drbd_req.c
index eb14ec8ec04c..e36216d50753 100644
--- a/drivers/block/drbd/drbd_req.c
+++ b/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:
diff --git a/drivers/block/pktcdvd.c b/drivers/block/pktcdvd.c
new file mode 100644
index 000000000000..4cea3b08087e
--- /dev/null
+++ b/drivers/block/pktcdvd.c
@@ -0,0 +1,2944 @@
+/*
+ * Copyright (C) 2000 Jens Axboe <axboe@suse.de>
+ * Copyright (C) 2001-2004 Peter Osterlund <petero2@telia.com>
+ * Copyright (C) 2006 Thomas Maier <balagi@justmail.de>
+ *
+ * May be copied or modified under the terms of the GNU General Public
+ * License.  See linux/COPYING for more information.
+ *
+ * Packet writing layer for ATAPI and SCSI CD-RW, DVD+RW, DVD-RW and
+ * DVD-RAM devices.
+ *
+ * Theory of operation:
+ *
+ * At the lowest level, there is the standard driver for the CD/DVD device,
+ * such as drivers/scsi/sr.c. This driver can handle read and write requests,
+ * but it doesn't know anything about the special restrictions that apply to
+ * packet writing. One restriction is that write requests must be aligned to
+ * packet boundaries on the physical media, and the size of a write request
+ * must be equal to the packet size. Another restriction is that a
+ * GPCMD_FLUSH_CACHE command has to be issued to the drive before a read
+ * command, if the previous command was a write.
+ *
+ * The purpose of the packet writing driver is to hide these restrictions from
+ * higher layers, such as file systems, and present a block device that can be
+ * randomly read and written using 2kB-sized blocks.
+ *
+ * The lowest layer in the packet writing driver is the packet I/O scheduler.
+ * Its data is defined by the struct packet_iosched and includes two bio
+ * queues with pending read and write requests. These queues are processed
+ * by the pkt_iosched_process_queue() function. The write requests in this
+ * queue are already properly aligned and sized. This layer is responsible for
+ * issuing the flush cache commands and scheduling the I/O in a good order.
+ *
+ * The next layer transforms unaligned write requests to aligned writes. This
+ * transformation requires reading missing pieces of data from the underlying
+ * block device, assembling the pieces to full packets and queuing them to the
+ * packet I/O scheduler.
+ *
+ * At the top layer there is a custom ->submit_bio function that forwards
+ * read requests directly to the iosched queue and puts write requests in the
+ * unaligned write queue. A kernel thread performs the necessary read
+ * gathering to convert the unaligned writes to aligned writes and then feeds
+ * them to the packet I/O scheduler.
+ *
+ *************************************************************************/
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/pktcdvd.h>
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/compat.h>
+#include <linux/kthread.h>
+#include <linux/errno.h>
+#include <linux/spinlock.h>
+#include <linux/file.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <linux/miscdevice.h>
+#include <linux/freezer.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/backing-dev.h>
+#include <scsi/scsi_cmnd.h>
+#include <scsi/scsi_ioctl.h>
+#include <scsi/scsi.h>
+#include <linux/debugfs.h>
+#include <linux/device.h>
+#include <linux/nospec.h>
+#include <linux/uaccess.h>
+
+#define DRIVER_NAME	"pktcdvd"
+
+#define pkt_err(pd, fmt, ...)						\
+	pr_err("%s: " fmt, pd->name, ##__VA_ARGS__)
+#define pkt_notice(pd, fmt, ...)					\
+	pr_notice("%s: " fmt, pd->name, ##__VA_ARGS__)
+#define pkt_info(pd, fmt, ...)						\
+	pr_info("%s: " fmt, pd->name, ##__VA_ARGS__)
+
+#define pkt_dbg(level, pd, fmt, ...)					\
+do {									\
+	if (level == 2 && PACKET_DEBUG >= 2)				\
+		pr_notice("%s: %s():" fmt,				\
+			  pd->name, __func__, ##__VA_ARGS__);		\
+	else if (level == 1 && PACKET_DEBUG >= 1)			\
+		pr_notice("%s: " fmt, pd->name, ##__VA_ARGS__);		\
+} while (0)
+
+#define MAX_SPEED 0xffff
+
+static DEFINE_MUTEX(pktcdvd_mutex);
+static struct pktcdvd_device *pkt_devs[MAX_WRITERS];
+static struct proc_dir_entry *pkt_proc;
+static int pktdev_major;
+static int write_congestion_on  = PKT_WRITE_CONGESTION_ON;
+static int write_congestion_off = PKT_WRITE_CONGESTION_OFF;
+static struct mutex ctl_mutex;	/* Serialize open/close/setup/teardown */
+static mempool_t psd_pool;
+static struct bio_set pkt_bio_set;
+
+static struct class	*class_pktcdvd = NULL;    /* /sys/class/pktcdvd */
+static struct dentry	*pkt_debugfs_root = NULL; /* /sys/kernel/debug/pktcdvd */
+
+/* forward declaration */
+static int pkt_setup_dev(dev_t dev, dev_t* pkt_dev);
+static int pkt_remove_dev(dev_t pkt_dev);
+static int pkt_seq_show(struct seq_file *m, void *p);
+
+static sector_t get_zone(sector_t sector, struct pktcdvd_device *pd)
+{
+	return (sector + pd->offset) & ~(sector_t)(pd->settings.size - 1);
+}
+
+/**********************************************************
+ * sysfs interface for pktcdvd
+ * by (C) 2006  Thomas Maier <balagi@justmail.de>
+ 
+  /sys/class/pktcdvd/pktcdvd[0-7]/
+                     stat/reset
+                     stat/packets_started
+                     stat/packets_finished
+                     stat/kb_written
+                     stat/kb_read
+                     stat/kb_read_gather
+                     write_queue/size
+                     write_queue/congestion_off
+                     write_queue/congestion_on
+ **********************************************************/
+
+static ssize_t packets_started_show(struct device *dev,
+				    struct device_attribute *attr, char *buf)
+{
+	struct pktcdvd_device *pd = dev_get_drvdata(dev);
+
+	return sysfs_emit(buf, "%lu\n", pd->stats.pkt_started);
+}
+static DEVICE_ATTR_RO(packets_started);
+
+static ssize_t packets_finished_show(struct device *dev,
+				     struct device_attribute *attr, char *buf)
+{
+	struct pktcdvd_device *pd = dev_get_drvdata(dev);
+
+	return sysfs_emit(buf, "%lu\n", pd->stats.pkt_ended);
+}
+static DEVICE_ATTR_RO(packets_finished);
+
+static ssize_t kb_written_show(struct device *dev,
+			       struct device_attribute *attr, char *buf)
+{
+	struct pktcdvd_device *pd = dev_get_drvdata(dev);
+
+	return sysfs_emit(buf, "%lu\n", pd->stats.secs_w >> 1);
+}
+static DEVICE_ATTR_RO(kb_written);
+
+static ssize_t kb_read_show(struct device *dev,
+			    struct device_attribute *attr, char *buf)
+{
+	struct pktcdvd_device *pd = dev_get_drvdata(dev);
+
+	return sysfs_emit(buf, "%lu\n", pd->stats.secs_r >> 1);
+}
+static DEVICE_ATTR_RO(kb_read);
+
+static ssize_t kb_read_gather_show(struct device *dev,
+				   struct device_attribute *attr, char *buf)
+{
+	struct pktcdvd_device *pd = dev_get_drvdata(dev);
+
+	return sysfs_emit(buf, "%lu\n", pd->stats.secs_rg >> 1);
+}
+static DEVICE_ATTR_RO(kb_read_gather);
+
+static ssize_t reset_store(struct device *dev, struct device_attribute *attr,
+			   const char *buf, size_t len)
+{
+	struct pktcdvd_device *pd = dev_get_drvdata(dev);
+
+	if (len > 0) {
+		pd->stats.pkt_started = 0;
+		pd->stats.pkt_ended = 0;
+		pd->stats.secs_w = 0;
+		pd->stats.secs_rg = 0;
+		pd->stats.secs_r = 0;
+	}
+	return len;
+}
+static DEVICE_ATTR_WO(reset);
+
+static struct attribute *pkt_stat_attrs[] = {
+	&dev_attr_packets_finished.attr,
+	&dev_attr_packets_started.attr,
+	&dev_attr_kb_read.attr,
+	&dev_attr_kb_written.attr,
+	&dev_attr_kb_read_gather.attr,
+	&dev_attr_reset.attr,
+	NULL,
+};
+
+static const struct attribute_group pkt_stat_group = {
+	.name = "stat",
+	.attrs = pkt_stat_attrs,
+};
+
+static ssize_t size_show(struct device *dev,
+			 struct device_attribute *attr, char *buf)
+{
+	struct pktcdvd_device *pd = dev_get_drvdata(dev);
+	int n;
+
+	spin_lock(&pd->lock);
+	n = sysfs_emit(buf, "%d\n", pd->bio_queue_size);
+	spin_unlock(&pd->lock);
+	return n;
+}
+static DEVICE_ATTR_RO(size);
+
+static void init_write_congestion_marks(int* lo, int* hi)
+{
+	if (*hi > 0) {
+		*hi = max(*hi, 500);
+		*hi = min(*hi, 1000000);
+		if (*lo <= 0)
+			*lo = *hi - 100;
+		else {
+			*lo = min(*lo, *hi - 100);
+			*lo = max(*lo, 100);
+		}
+	} else {
+		*hi = -1;
+		*lo = -1;
+	}
+}
+
+static ssize_t congestion_off_show(struct device *dev,
+				   struct device_attribute *attr, char *buf)
+{
+	struct pktcdvd_device *pd = dev_get_drvdata(dev);
+	int n;
+
+	spin_lock(&pd->lock);
+	n = sysfs_emit(buf, "%d\n", pd->write_congestion_off);
+	spin_unlock(&pd->lock);
+	return n;
+}
+
+static ssize_t congestion_off_store(struct device *dev,
+				    struct device_attribute *attr,
+				    const char *buf, size_t len)
+{
+	struct pktcdvd_device *pd = dev_get_drvdata(dev);
+	int val;
+
+	if (sscanf(buf, "%d", &val) == 1) {
+		spin_lock(&pd->lock);
+		pd->write_congestion_off = val;
+		init_write_congestion_marks(&pd->write_congestion_off,
+					&pd->write_congestion_on);
+		spin_unlock(&pd->lock);
+	}
+	return len;
+}
+static DEVICE_ATTR_RW(congestion_off);
+
+static ssize_t congestion_on_show(struct device *dev,
+				  struct device_attribute *attr, char *buf)
+{
+	struct pktcdvd_device *pd = dev_get_drvdata(dev);
+	int n;
+
+	spin_lock(&pd->lock);
+	n = sysfs_emit(buf, "%d\n", pd->write_congestion_on);
+	spin_unlock(&pd->lock);
+	return n;
+}
+
+static ssize_t congestion_on_store(struct device *dev,
+				   struct device_attribute *attr,
+				   const char *buf, size_t len)
+{
+	struct pktcdvd_device *pd = dev_get_drvdata(dev);
+	int val;
+
+	if (sscanf(buf, "%d", &val) == 1) {
+		spin_lock(&pd->lock);
+		pd->write_congestion_on = val;
+		init_write_congestion_marks(&pd->write_congestion_off,
+					&pd->write_congestion_on);
+		spin_unlock(&pd->lock);
+	}
+	return len;
+}
+static DEVICE_ATTR_RW(congestion_on);
+
+static struct attribute *pkt_wq_attrs[] = {
+	&dev_attr_congestion_on.attr,
+	&dev_attr_congestion_off.attr,
+	&dev_attr_size.attr,
+	NULL,
+};
+
+static const struct attribute_group pkt_wq_group = {
+	.name = "write_queue",
+	.attrs = pkt_wq_attrs,
+};
+
+static const struct attribute_group *pkt_groups[] = {
+	&pkt_stat_group,
+	&pkt_wq_group,
+	NULL,
+};
+
+static void pkt_sysfs_dev_new(struct pktcdvd_device *pd)
+{
+	if (class_pktcdvd) {
+		pd->dev = device_create_with_groups(class_pktcdvd, NULL,
+						    MKDEV(0, 0), pd, pkt_groups,
+						    "%s", pd->name);
+		if (IS_ERR(pd->dev))
+			pd->dev = NULL;
+	}
+}
+
+static void pkt_sysfs_dev_remove(struct pktcdvd_device *pd)
+{
+	if (class_pktcdvd)
+		device_unregister(pd->dev);
+}
+
+
+/********************************************************************
+  /sys/class/pktcdvd/
+                     add            map block device
+                     remove         unmap packet dev
+                     device_map     show mappings
+ *******************************************************************/
+
+static void class_pktcdvd_release(struct class *cls)
+{
+	kfree(cls);
+}
+
+static ssize_t device_map_show(struct class *c, struct class_attribute *attr,
+			       char *data)
+{
+	int n = 0;
+	int idx;
+	mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING);
+	for (idx = 0; idx < MAX_WRITERS; idx++) {
+		struct pktcdvd_device *pd = pkt_devs[idx];
+		if (!pd)
+			continue;
+		n += sprintf(data+n, "%s %u:%u %u:%u\n",
+			pd->name,
+			MAJOR(pd->pkt_dev), MINOR(pd->pkt_dev),
+			MAJOR(pd->bdev->bd_dev),
+			MINOR(pd->bdev->bd_dev));
+	}
+	mutex_unlock(&ctl_mutex);
+	return n;
+}
+static CLASS_ATTR_RO(device_map);
+
+static ssize_t add_store(struct class *c, struct class_attribute *attr,
+			 const char *buf, size_t count)
+{
+	unsigned int major, minor;
+
+	if (sscanf(buf, "%u:%u", &major, &minor) == 2) {
+		/* pkt_setup_dev() expects caller to hold reference to self */
+		if (!try_module_get(THIS_MODULE))
+			return -ENODEV;
+
+		pkt_setup_dev(MKDEV(major, minor), NULL);
+
+		module_put(THIS_MODULE);
+
+		return count;
+	}
+
+	return -EINVAL;
+}
+static CLASS_ATTR_WO(add);
+
+static ssize_t remove_store(struct class *c, struct class_attribute *attr,
+			    const char *buf, size_t count)
+{
+	unsigned int major, minor;
+	if (sscanf(buf, "%u:%u", &major, &minor) == 2) {
+		pkt_remove_dev(MKDEV(major, minor));
+		return count;
+	}
+	return -EINVAL;
+}
+static CLASS_ATTR_WO(remove);
+
+static struct attribute *class_pktcdvd_attrs[] = {
+	&class_attr_add.attr,
+	&class_attr_remove.attr,
+	&class_attr_device_map.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(class_pktcdvd);
+
+static int pkt_sysfs_init(void)
+{
+	int ret = 0;
+
+	/*
+	 * create control files in sysfs
+	 * /sys/class/pktcdvd/...
+	 */
+	class_pktcdvd = kzalloc(sizeof(*class_pktcdvd), GFP_KERNEL);
+	if (!class_pktcdvd)
+		return -ENOMEM;
+	class_pktcdvd->name = DRIVER_NAME;
+	class_pktcdvd->owner = THIS_MODULE;
+	class_pktcdvd->class_release = class_pktcdvd_release;
+	class_pktcdvd->class_groups = class_pktcdvd_groups;
+	ret = class_register(class_pktcdvd);
+	if (ret) {
+		kfree(class_pktcdvd);
+		class_pktcdvd = NULL;
+		pr_err("failed to create class pktcdvd\n");
+		return ret;
+	}
+	return 0;
+}
+
+static void pkt_sysfs_cleanup(void)
+{
+	if (class_pktcdvd)
+		class_destroy(class_pktcdvd);
+	class_pktcdvd = NULL;
+}
+
+/********************************************************************
+  entries in debugfs
+
+  /sys/kernel/debug/pktcdvd[0-7]/
+			info
+
+ *******************************************************************/
+
+static int pkt_debugfs_seq_show(struct seq_file *m, void *p)
+{
+	return pkt_seq_show(m, p);
+}
+
+static int pkt_debugfs_fops_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, pkt_debugfs_seq_show, inode->i_private);
+}
+
+static const struct file_operations debug_fops = {
+	.open		= pkt_debugfs_fops_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+	.owner		= THIS_MODULE,
+};
+
+static void pkt_debugfs_dev_new(struct pktcdvd_device *pd)
+{
+	if (!pkt_debugfs_root)
+		return;
+	pd->dfs_d_root = debugfs_create_dir(pd->name, pkt_debugfs_root);
+	if (!pd->dfs_d_root)
+		return;
+
+	pd->dfs_f_info = debugfs_create_file("info", 0444,
+					     pd->dfs_d_root, pd, &debug_fops);
+}
+
+static void pkt_debugfs_dev_remove(struct pktcdvd_device *pd)
+{
+	if (!pkt_debugfs_root)
+		return;
+	debugfs_remove(pd->dfs_f_info);
+	debugfs_remove(pd->dfs_d_root);
+	pd->dfs_f_info = NULL;
+	pd->dfs_d_root = NULL;
+}
+
+static void pkt_debugfs_init(void)
+{
+	pkt_debugfs_root = debugfs_create_dir(DRIVER_NAME, NULL);
+}
+
+static void pkt_debugfs_cleanup(void)
+{
+	debugfs_remove(pkt_debugfs_root);
+	pkt_debugfs_root = NULL;
+}
+
+/* ----------------------------------------------------------*/
+
+
+static void pkt_bio_finished(struct pktcdvd_device *pd)
+{
+	BUG_ON(atomic_read(&pd->cdrw.pending_bios) <= 0);
+	if (atomic_dec_and_test(&a
author	Linus Torvalds <torvalds@linux-foundation.org>	2023-01-06 13:12:42 -0800
committer	Linus Torvalds <torvalds@linux-foundation.org>	2023-01-06 13:12:42 -0800
commit	a689b938df39ab513026c53fb7011fd7cd594943 (patch)
tree	190d683bba2d6e6f9e769d232cc2412dcbd0541e
parent	ef1a4a770994b97a86988fd86f5a2784b87449f7 (diff)
parent	b2b50d572135c5c6e10c2ff79cd828d5a8141ef6 (diff)
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