From 102a0743326a03cd1a1202ceda21e175b7d3575c Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Tue, 20 Feb 2024 01:20:52 +0000
Subject: [PATCH] add new system file

---
 kernel/block/bsg.c |  213 +++++++++++++++++++++--------------------------------
 1 files changed, 85 insertions(+), 128 deletions(-)

diff --git a/kernel/block/bsg.c b/kernel/block/bsg.c
index 9a442c2..62707c7 100644
--- a/kernel/block/bsg.c
+++ b/kernel/block/bsg.c
@@ -1,13 +1,6 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * bsg.c - block layer implementation of the sg v4 interface
- *
- * Copyright (C) 2004 Jens Axboe <axboe@suse.de> SUSE Labs
- * Copyright (C) 2004 Peter M. Jones <pjones@redhat.com>
- *
- *  This file is subject to the terms and conditions of the GNU General Public
- *  License version 2.  See the file "COPYING" in the main directory of this
- *  archive for more details.
- *
  */
 #include <linux/module.h>
 #include <linux/init.h>
@@ -19,6 +12,7 @@
 #include <linux/idr.h>
 #include <linux/bsg.h>
 #include <linux/slab.h>
+#include <linux/pm_runtime.h>
 
 #include <scsi/scsi.h>
 #include <scsi/scsi_ioctl.h>
@@ -74,6 +68,11 @@
 {
 	struct scsi_request *sreq = scsi_req(rq);
 
+	if (hdr->dout_xfer_len && hdr->din_xfer_len) {
+		pr_warn_once("BIDI support in bsg has been removed.\n");
+		return -EOPNOTSUPP;
+	}
+
 	sreq->cmd_len = hdr->request_len;
 	if (sreq->cmd_len > BLK_MAX_CDB) {
 		sreq->cmd = kzalloc(sreq->cmd_len, GFP_KERNEL);
@@ -114,14 +113,10 @@
 			hdr->response_len = len;
 	}
 
-	if (rq->next_rq) {
-		hdr->dout_resid = sreq->resid_len;
-		hdr->din_resid = scsi_req(rq->next_rq)->resid_len;
-	} else if (rq_data_dir(rq) == READ) {
+	if (rq_data_dir(rq) == READ)
 		hdr->din_resid = sreq->resid_len;
-	} else {
+	else
 		hdr->dout_resid = sreq->resid_len;
-	}
 
 	return ret;
 }
@@ -138,32 +133,37 @@
 	.free_rq		= bsg_scsi_free_rq,
 };
 
-static struct request *
-bsg_map_hdr(struct request_queue *q, struct sg_io_v4 *hdr, fmode_t mode)
+static int bsg_sg_io(struct request_queue *q, fmode_t mode, void __user *uarg)
 {
-	struct request *rq, *next_rq = NULL;
+	struct request *rq;
+	struct bio *bio;
+	struct sg_io_v4 hdr;
 	int ret;
 
+	if (copy_from_user(&hdr, uarg, sizeof(hdr)))
+		return -EFAULT;
+
 	if (!q->bsg_dev.class_dev)
-		return ERR_PTR(-ENXIO);
+		return -ENXIO;
 
-	if (hdr->guard != 'Q')
-		return ERR_PTR(-EINVAL);
-
-	ret = q->bsg_dev.ops->check_proto(hdr);
+	if (hdr.guard != 'Q')
+		return -EINVAL;
+	ret = q->bsg_dev.ops->check_proto(&hdr);
 	if (ret)
-		return ERR_PTR(ret);
+		return ret;
 
-	rq = blk_get_request(q, hdr->dout_xfer_len ?
+	rq = blk_get_request(q, hdr.dout_xfer_len ?
 			REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN, 0);
 	if (IS_ERR(rq))
-		return rq;
+		return PTR_ERR(rq);
 
-	ret = q->bsg_dev.ops->fill_hdr(rq, hdr, mode);
-	if (ret)
-		goto out;
+	ret = q->bsg_dev.ops->fill_hdr(rq, &hdr, mode);
+	if (ret) {
+		blk_put_request(rq);
+		return ret;
+	}
 
-	rq->timeout = msecs_to_jiffies(hdr->timeout);
+	rq->timeout = msecs_to_jiffies(hdr.timeout);
 	if (!rq->timeout)
 		rq->timeout = q->sg_timeout;
 	if (!rq->timeout)
@@ -171,64 +171,28 @@
 	if (rq->timeout < BLK_MIN_SG_TIMEOUT)
 		rq->timeout = BLK_MIN_SG_TIMEOUT;
 
-	if (hdr->dout_xfer_len && hdr->din_xfer_len) {
-		if (!test_bit(QUEUE_FLAG_BIDI, &q->queue_flags)) {
-			ret = -EOPNOTSUPP;
-			goto out;
-		}
-
-		next_rq = blk_get_request(q, REQ_OP_SCSI_IN, 0);
-		if (IS_ERR(next_rq)) {
-			ret = PTR_ERR(next_rq);
-			goto out;
-		}
-
-		rq->next_rq = next_rq;
-		ret = blk_rq_map_user(q, next_rq, NULL, uptr64(hdr->din_xferp),
-				       hdr->din_xfer_len, GFP_KERNEL);
-		if (ret)
-			goto out_free_nextrq;
-	}
-
-	if (hdr->dout_xfer_len) {
-		ret = blk_rq_map_user(q, rq, NULL, uptr64(hdr->dout_xferp),
-				hdr->dout_xfer_len, GFP_KERNEL);
-	} else if (hdr->din_xfer_len) {
-		ret = blk_rq_map_user(q, rq, NULL, uptr64(hdr->din_xferp),
-				hdr->din_xfer_len, GFP_KERNEL);
+	if (hdr.dout_xfer_len) {
+		ret = blk_rq_map_user(q, rq, NULL, uptr64(hdr.dout_xferp),
+				hdr.dout_xfer_len, GFP_KERNEL);
+	} else if (hdr.din_xfer_len) {
+		ret = blk_rq_map_user(q, rq, NULL, uptr64(hdr.din_xferp),
+				hdr.din_xfer_len, GFP_KERNEL);
 	}
 
 	if (ret)
-		goto out_unmap_nextrq;
-	return rq;
+		goto out_free_rq;
 
-out_unmap_nextrq:
-	if (rq->next_rq)
-		blk_rq_unmap_user(rq->next_rq->bio);
-out_free_nextrq:
-	if (rq->next_rq)
-		blk_put_request(rq->next_rq);
-out:
-	q->bsg_dev.ops->free_rq(rq);
-	blk_put_request(rq);
-	return ERR_PTR(ret);
-}
+	bio = rq->bio;
 
-static int blk_complete_sgv4_hdr_rq(struct request *rq, struct sg_io_v4 *hdr,
-				    struct bio *bio, struct bio *bidi_bio)
-{
-	int ret;
-
-	ret = rq->q->bsg_dev.ops->complete_rq(rq, hdr);
-
-	if (rq->next_rq) {
-		blk_rq_unmap_user(bidi_bio);
-		blk_put_request(rq->next_rq);
-	}
-
+	blk_execute_rq(q, NULL, rq, !(hdr.flags & BSG_FLAG_Q_AT_TAIL));
+	ret = rq->q->bsg_dev.ops->complete_rq(rq, &hdr);
 	blk_rq_unmap_user(bio);
+
+out_free_rq:
 	rq->q->bsg_dev.ops->free_rq(rq);
 	blk_put_request(rq);
+	if (!ret && copy_to_user(uarg, &hdr, sizeof(hdr)))
+		return -EFAULT;
 	return ret;
 }
 
@@ -345,12 +309,15 @@
 static int bsg_open(struct inode *inode, struct file *file)
 {
 	struct bsg_device *bd;
+	struct bsg_class_device *bcd;
 
 	bd = bsg_get_device(inode, file);
 
 	if (IS_ERR(bd))
 		return PTR_ERR(bd);
 
+	bcd = &bd->queue->bsg_dev;
+	pm_runtime_get_sync(bcd->class_dev->parent);
 	file->private_data = bd;
 	return 0;
 }
@@ -358,36 +325,48 @@
 static int bsg_release(struct inode *inode, struct file *file)
 {
 	struct bsg_device *bd = file->private_data;
+	struct bsg_class_device *bcd;
 
 	file->private_data = NULL;
+
+	bcd = &bd->queue->bsg_dev;
+	pm_runtime_put_sync(bcd->class_dev->parent);
 	return bsg_put_device(bd);
+}
+
+static int bsg_get_command_q(struct bsg_device *bd, int __user *uarg)
+{
+	return put_user(bd->max_queue, uarg);
+}
+
+static int bsg_set_command_q(struct bsg_device *bd, int __user *uarg)
+{
+	int queue;
+
+	if (get_user(queue, uarg))
+		return -EFAULT;
+	if (queue < 1)
+		return -EINVAL;
+
+	spin_lock_irq(&bd->lock);
+	bd->max_queue = queue;
+	spin_unlock_irq(&bd->lock);
+	return 0;
 }
 
 static long bsg_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 {
 	struct bsg_device *bd = file->private_data;
-	int __user *uarg = (int __user *) arg;
-	int ret;
+	void __user *uarg = (void __user *) arg;
 
 	switch (cmd) {
-		/*
-		 * our own ioctls
-		 */
+	/*
+	 * Our own ioctls
+	 */
 	case SG_GET_COMMAND_Q:
-		return put_user(bd->max_queue, uarg);
-	case SG_SET_COMMAND_Q: {
-		int queue;
-
-		if (get_user(queue, uarg))
-			return -EFAULT;
-		if (queue < 1)
-			return -EINVAL;
-
-		spin_lock_irq(&bd->lock);
-		bd->max_queue = queue;
-		spin_unlock_irq(&bd->lock);
-		return 0;
-	}
+		return bsg_get_command_q(bd, uarg);
+	case SG_SET_COMMAND_Q:
+		return bsg_set_command_q(bd, uarg);
 
 	/*
 	 * SCSI/sg ioctls
@@ -400,36 +379,13 @@
 	case SG_GET_RESERVED_SIZE:
 	case SG_SET_RESERVED_SIZE:
 	case SG_EMULATED_HOST:
-	case SCSI_IOCTL_SEND_COMMAND: {
-		void __user *uarg = (void __user *) arg;
 		return scsi_cmd_ioctl(bd->queue, NULL, file->f_mode, cmd, uarg);
-	}
-	case SG_IO: {
-		struct request *rq;
-		struct bio *bio, *bidi_bio = NULL;
-		struct sg_io_v4 hdr;
-		int at_head;
-
-		if (copy_from_user(&hdr, uarg, sizeof(hdr)))
-			return -EFAULT;
-
-		rq = bsg_map_hdr(bd->queue, &hdr, file->f_mode);
-		if (IS_ERR(rq))
-			return PTR_ERR(rq);
-
-		bio = rq->bio;
-		if (rq->next_rq)
-			bidi_bio = rq->next_rq->bio;
-
-		at_head = (0 == (hdr.flags & BSG_FLAG_Q_AT_TAIL));
-		blk_execute_rq(bd->queue, NULL, rq, at_head);
-		ret = blk_complete_sgv4_hdr_rq(rq, &hdr, bio, bidi_bio);
-
-		if (copy_to_user(uarg, &hdr, sizeof(hdr)))
-			return -EFAULT;
-
-		return ret;
-	}
+	case SG_IO:
+		return bsg_sg_io(bd->queue, file->f_mode, uarg);
+	case SCSI_IOCTL_SEND_COMMAND:
+		pr_warn_ratelimited("%s: calling unsupported SCSI_IOCTL_SEND_COMMAND\n",
+				current->comm);
+		return -EINVAL;
 	default:
 		return -ENOTTY;
 	}
@@ -439,6 +395,7 @@
 	.open		=	bsg_open,
 	.release	=	bsg_release,
 	.unlocked_ioctl	=	bsg_ioctl,
+	.compat_ioctl	=	compat_ptr_ioctl,
 	.owner		=	THIS_MODULE,
 	.llseek		=	default_llseek,
 };
@@ -471,7 +428,7 @@
 	/*
 	 * we need a proper transport to send commands, not a stacked device
 	 */
-	if (!queue_is_rq_based(q))
+	if (!queue_is_mq(q))
 		return 0;
 
 	bcd = &q->bsg_dev;

--
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