s390/dasd: add ioctl to perform a swap of the drivers copy pair

The newly defined ioctl BIODASDCOPYPAIRSWAP takes a structure that
specifies a copy pair that should be swapped. It will call the device
discipline function to perform the swap operation.

The structure looks as followed:

struct dasd_copypair_swap_data_t {
       char primary[20];
       char secondary[20];
       __u8 reserved[64];
};

where primary is the old primary device that will be replaced by the
secondary device. The old primary will become a secondary device
afterwards.

Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Reviewed-by: Jan Hoeppner <hoeppner@linux.ibm.com>
Link: https://lore.kernel.org/r/20220920192616.808070-6-sth@linux.ibm.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/arch/s390/include/uapi/asm/dasd.h b/arch/s390/include/uapi/asm/dasd.h
index 9ec86fae998050881dfcf56b760be156b5ca6384..93d1ccd3304c706f591d98932090eb994f200d4c 100644 (file)
--- a/arch/s390/include/uapi/asm/dasd.h
+++ b/arch/s390/include/uapi/asm/dasd.h
@@ -182,6 +182,18 @@ typedef struct format_data_t {
        unsigned int intensity;
 } format_data_t;
 
+/*
+ * struct dasd_copypair_swap_data_t
+ * represents all data necessary to issue a swap of the copy pair relation
+ */
+struct dasd_copypair_swap_data_t {
+       char primary[20]; /* BUSID of primary */
+       char secondary[20]; /* BUSID of secondary */
+
+       /* Reserved for future updates. */
+       __u8 reserved[64];
+};
+
 /*
  * values to be used for format_data_t.intensity
  * 0/8: normal format
@@ -326,6 +338,8 @@ struct dasd_snid_ioctl_data {
 #define BIODASDSATTR   _IOW(DASD_IOCTL_LETTER,2,attrib_data_t)
 /* Release Allocated Space */
 #define BIODASDRAS     _IOW(DASD_IOCTL_LETTER, 3, format_data_t)
+/* Swap copy pair relation */
+#define BIODASDCOPYPAIRSWAP _IOW(DASD_IOCTL_LETTER, 4, struct dasd_copypair_swap_data_t)
 
 /* Get Sense Path Group ID (SNID) data */
 #define BIODASDSNID    _IOWR(DASD_IOCTL_LETTER, 1, struct dasd_snid_ioctl_data)

diff --git a/drivers/s390/block/dasd_ioctl.c b/drivers/s390/block/dasd_ioctl.c
index 95349f95758c48726985fa429036afde8e553503..d0ddf2cc97861345252bd38fd0a274a852c98506 100644 (file)
--- a/drivers/s390/block/dasd_ioctl.c
+++ b/drivers/s390/block/dasd_ioctl.c
@@ -379,6 +379,56 @@ static int dasd_ioctl_release_space(struct block_device *bdev, void __user *argp
        return rc;
 }
 
+/*
+ * Swap driver iternal copy relation.
+ */
+static int
+dasd_ioctl_copy_pair_swap(struct block_device *bdev, void __user *argp)
+{
+       struct dasd_copypair_swap_data_t data;
+       struct dasd_device *device;
+       int rc;
+
+       if (!capable(CAP_SYS_ADMIN))
+               return -EACCES;
+
+       device = dasd_device_from_gendisk(bdev->bd_disk);
+       if (!device)
+               return -ENODEV;
+
+       if (copy_from_user(&data, argp, sizeof(struct dasd_copypair_swap_data_t))) {
+               dasd_put_device(device);
+               return -EFAULT;
+       }
+       if (memchr_inv(data.reserved, 0, sizeof(data.reserved))) {
+               pr_warn("%s: Ivalid swap data specified.\n",
+                       dev_name(&device->cdev->dev));
+               dasd_put_device(device);
+               return DASD_COPYPAIRSWAP_INVALID;
+       }
+       if (bdev_is_partition(bdev)) {
+               pr_warn("%s: The specified DASD is a partition and cannot be swapped\n",
+                       dev_name(&device->cdev->dev));
+               dasd_put_device(device);
+               return DASD_COPYPAIRSWAP_INVALID;
+       }
+       if (!device->copy) {
+               pr_warn("%s: The specified DASD has no copy pair set up\n",
+                       dev_name(&device->cdev->dev));
+               dasd_put_device(device);
+               return -ENODEV;
+       }
+       if (!device->discipline->copy_pair_swap) {
+               dasd_put_device(device);
+               return -EOPNOTSUPP;
+       }
+       rc = device->discipline->copy_pair_swap(device, data.primary,
+                                               data.secondary);
+       dasd_put_device(device);
+
+       return rc;
+}
+
 #ifdef CONFIG_DASD_PROFILE
 /*
  * Reset device profile information
@@ -637,6 +687,9 @@ int dasd_ioctl(struct block_device *bdev, fmode_t mode,
        case BIODASDRAS:
                rc = dasd_ioctl_release_space(bdev, argp);
                break;
+       case BIODASDCOPYPAIRSWAP:
+               rc = dasd_ioctl_copy_pair_swap(bdev, argp);
+               break;
        default:
                /* if the discipline has an ioctl method try it. */
                rc = -ENOTTY;