block: expose 'read_keys' and 'read_reservation' PR callbacks

.github/workflows/kernel_build.yml

@@ -0,0 +1,28 @@
+name: blktests-ci
+
+on:
+  pull_request:
+
+jobs:
+  build-kernel:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Configure git
+        run: |
+          git config --global --add safe.directory '*'
+      - name: Checkout git
+        run: |
+          sudo apt-get install -y libelf-dev
+          mkdir -p linux
+          cd linux
+          git init
+          git remote add origin https://github.com/${{ github.repository }}
+          git fetch origin --depth=5 ${{ github.event.pull_request.head.sha }}
+          git reset --hard ${{ github.event.pull_request.head.sha }}
+          git log -1
+      - name: Build kernel
+        run: |
+          cd linux
+          make defconfig
+          make -j 8
+

block/ioctl.c

@@ -422,6 +422,63 @@ static int blkdev_pr_clear(struct block_device *bdev, blk_mode_t mode,
 	return ops->pr_clear(bdev, c.key);
 }
 
+static int blkdev_pr_read_keys(struct block_device *bdev, blk_mode_t mode,
+		struct pr_keys __user *arg)
+{
+	const struct pr_ops *ops = bdev->bd_disk->fops->pr_ops;
+	struct pr_keys k_in, *k_out;
+	size_t k_len;
+	int ret, num_keys;
+
+	if (!blkdev_pr_allowed(bdev, mode))
+		return -EPERM;
+	if (!ops || !ops->pr_read_keys)
+		return -EOPNOTSUPP;
+
+	if (copy_from_user(&k_in, arg, sizeof(k_in)))
+		return -EFAULT;
+
+	num_keys = k_in.num_keys;
+	k_out = kzalloc(sizeof(struct pr_keys) + num_keys * sizeof(u64),
+			GFP_KERNEL);
+	if (!k_out)
+		return -ENOMEM;
+
+	k_out->num_keys = num_keys;
+	ret = ops->pr_read_keys(bdev, k_out);
+	if (ret) {
+		kfree(k_out);
+		return ret;
+	}
+
+	k_len = sizeof(k_in) + num_keys * sizeof(u64);
+	if (copy_to_user(arg, k_out, k_len))
+		ret = -EFAULT;
+
+	kfree(k_out);
+	return ret;
+}
+
+static int blkdev_pr_read_reservation(struct block_device *bdev,
+		blk_mode_t mode, struct pr_held_reservation __user *arg)
+{
+	const struct pr_ops *ops = bdev->bd_disk->fops->pr_ops;
+	struct pr_held_reservation r;
+	int ret;
+
+	if (!blkdev_pr_allowed(bdev, mode))
+		return -EPERM;
+	if (!ops || !ops->pr_read_reservation)
+		return -EOPNOTSUPP;
+
+	ret = ops->pr_read_reservation(bdev, &r);
+	if (ret)
+		return ret;
+	if (copy_to_user(arg, &r, sizeof(r)))
+		return -EFAULT;
+	return 0;
+}
+
 static int blkdev_flushbuf(struct block_device *bdev, unsigned cmd,
 		unsigned long arg)
 {
@@ -643,6 +700,10 @@ static int blkdev_common_ioctl(struct block_device *bdev, blk_mode_t mode,
 		return blkdev_pr_preempt(bdev, mode, argp, true);
 	case IOC_PR_CLEAR:
 		return blkdev_pr_clear(bdev, mode, argp);
+	case IOC_PR_READ_KEYS:
+		return blkdev_pr_read_keys(bdev, mode, argp);
+	case IOC_PR_READ_RESV:
+		return blkdev_pr_read_reservation(bdev, mode, argp);
 	default:
 		return -ENOIOCTLCMD;
 	}

drivers/scsi/sd.c

@@ -2008,9 +2008,13 @@ static int sd_pr_read_reservation(struct block_device *bdev,
 	if (result)
 		return result;
 
+	rsv->generation = get_unaligned_be32(&data[0]);
+	rsv->type = 0;
 	len = get_unaligned_be32(&data[4]);
-	if (!len)
+	if (!len) {
+		rsv->key = 0;
 		return 0;
+	}
 
 	/* Make sure we have at least the key and type */
 	if (len < 14) {
@@ -2020,9 +2024,9 @@ static int sd_pr_read_reservation(struct block_device *bdev,
 		return -EINVAL;
 	}
 
-	rsv->generation = get_unaligned_be32(&data[0]);
 	rsv->key = get_unaligned_be64(&data[8]);
-	rsv->type = scsi_pr_type_to_block(data[21] & 0x0f);
+	if (len == 16)
+		rsv->type = scsi_pr_type_to_block(data[21] & 0x0f);
 	return 0;
 }
 

include/linux/pr.h

@@ -4,18 +4,6 @@
 
 #include <uapi/linux/pr.h>
 
-struct pr_keys {
-	u32	generation;
-	u32	num_keys;
-	u64	keys[];
-};
-
-struct pr_held_reservation {
-	u64		key;
-	u32		generation;
-	enum pr_type	type;
-};
-
 struct pr_ops {
 	int (*pr_register)(struct block_device *bdev, u64 old_key, u64 new_key,
 			u32 flags);

include/uapi/linux/pr.h

@@ -56,6 +56,18 @@ struct pr_clear {
 	__u32	__pad;
 };
 
+struct pr_keys {
+	__u32	generation;
+	__u32	num_keys;
+	__u64	keys[];
+};
+
+struct pr_held_reservation {
+	__u64		key;
+	__u32		generation;
+	__u32		type;
+};
+
 #define PR_FL_IGNORE_KEY	(1 << 0)	/* ignore existing key */
 
 #define IOC_PR_REGISTER		_IOW('p', 200, struct pr_registration)
@@ -64,5 +76,7 @@ struct pr_clear {
 #define IOC_PR_PREEMPT		_IOW('p', 203, struct pr_preempt)
 #define IOC_PR_PREEMPT_ABORT	_IOW('p', 204, struct pr_preempt)
 #define IOC_PR_CLEAR		_IOW('p', 205, struct pr_clear)
+#define IOC_PR_READ_KEYS	_IOWR('p', 206, struct pr_keys)
+#define IOC_PR_READ_RESV	_IOWR('p', 207, struct pr_held_reservation)
 
 #endif /* _UAPI_PR_H */