block: scsi_ioctl: Avoid the use of one-element arrays

One-element arrays are being deprecated[1]. Replace the one-element array
with a simple object of type compat_caddr_t: 'compat_caddr_t unused'[2],
once it seems this field is actually never used.

Also, update struct cdrom_generic_command in UAPI by adding an
anonimous union to avoid using the one-element array _reserved_.

[1] https://www.kernel.org/doc/html/v5.9-rc1/process/deprecated.html#zero-length-and-one-element-arrays
[2] https://github.com/KSPP/linux/issues/86

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Link: https://lore.kernel.org/lkml/5f76f5d0.qJ4t%2FHWuRzSW7bTa%25lkp@intel.com/
Build-tested-by: kernel test robot <lkp@intel.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/block/scsi_ioctl.c b/block/scsi_ioctl.c
index 4421e61..227f489 100644 (file)
--- a/block/scsi_ioctl.c
+++ b/block/scsi_ioctl.c
@@ -651,7 +651,7 @@ struct compat_cdrom_generic_command {
        unsigned char   data_direction;
        compat_int_t    quiet;
        compat_int_t    timeout;
-       compat_caddr_t  reserved[1];
+       compat_caddr_t  unused;
 };
 #endif
 
@@ -673,7 +673,7 @@ static int scsi_get_cdrom_generic_arg(struct cdrom_generic_command *cgc,
                        .data_direction = cgc32.data_direction,
                        .quiet          = cgc32.quiet,
                        .timeout        = cgc32.timeout,
-                       .reserved[0]    = compat_ptr(cgc32.reserved[0]),
+                       .unused         = compat_ptr(cgc32.unused),
                };
                memcpy(&cgc->cmd, &cgc32.cmd, CDROM_PACKET_SIZE);
                return 0;
@@ -698,7 +698,7 @@ static int scsi_put_cdrom_generic_arg(const struct cdrom_generic_command *cgc,
                        .data_direction = cgc->data_direction,
                        .quiet          = cgc->quiet,
                        .timeout        = cgc->timeout,
-                       .reserved[0]    = (uintptr_t)(cgc->reserved[0]),
+                       .unused         = (uintptr_t)(cgc->unused),
                };
                memcpy(&cgc32.cmd, &cgc->cmd, CDROM_PACKET_SIZE);
 

diff --git a/include/uapi/linux/cdrom.h b/include/uapi/linux/cdrom.h
index 2817230..6c34f6e 100644 (file)
--- a/include/uapi/linux/cdrom.h
+++ b/include/uapi/linux/cdrom.h
@@ -289,7 +289,10 @@ struct cdrom_generic_command
        unsigned char           data_direction;
        int                     quiet;
        int                     timeout;
-       void                    __user *reserved[1];    /* unused, actually */
+       union {
+               void            __user *reserved[1];    /* unused, actually */
+               void            __user *unused;
+       };
 };
 
 /*