[PATCH 3/8] cdrom: factor out a cdrom_read_tocentry helper

[Christoph Hellwig]

Factor out a version of the CDROMREADTOCENTRY ioctl handler that can
be called directly from kernel space.

Signed-off-by: Christoph Hellwig <h...@lst.de>
Reviewed-by: Damien Le Moal <damien.lem...@wdc.com>
Reviewed-by: Hannes Reinecke <h...@suse.de
---
 drivers/cdrom/cdrom.c | 39 ++++++++++++++++++++++-----------------
 include/linux/cdrom.h |  3 +++
 2 files changed, 25 insertions(+), 17 deletions(-)

diff --git a/drivers/cdrom/cdrom.c b/drivers/cdrom/cdrom.c
index a1d2112fd283f..c91d1e1382142 100644
--- a/drivers/cdrom/cdrom.c
+++ b/drivers/cdrom/cdrom.c
@@ -2666,32 +2666,37 @@ static int cdrom_ioctl_read_tochdr(struct 
cdrom_device_info *cdi,
        return 0;
 }
 
+int cdrom_read_tocentry(struct cdrom_device_info *cdi,
+               struct cdrom_tocentry *entry)
+{
+       u8 requested_format = entry->cdte_format;
+       int ret;
+
+       if (requested_format != CDROM_MSF && requested_format != CDROM_LBA)
+               return -EINVAL;
+
+       /* make interface to low-level uniform */
+       entry->cdte_format = CDROM_MSF;
+       ret = cdi->ops->audio_ioctl(cdi, CDROMREADTOCENTRY, entry);
+       if (!ret)
+               sanitize_format(&entry->cdte_addr, &entry->cdte_format,
+                               requested_format);
+       return ret;
+}
+EXPORT_SYMBOL_GPL(cdrom_read_tocentry);
+
 static int cdrom_ioctl_read_tocentry(struct cdrom_device_info *cdi,
                void __user *argp)
 {
        struct cdrom_tocentry entry;
-       u8 requested_format;
        int ret;
 
-       /* cd_dbg(CD_DO_IOCTL, "entering CDROMREADTOCENTRY\n"); */
-
        if (copy_from_user(&entry, argp, sizeof(entry)))
                return -EFAULT;
-
-       requested_format = entry.cdte_format;
-       if (requested_format != CDROM_MSF && requested_format != CDROM_LBA)
-               return -EINVAL;
-       /* make interface to low-level uniform */
-       entry.cdte_format = CDROM_MSF;
-       ret = cdi->ops->audio_ioctl(cdi, CDROMREADTOCENTRY, &entry);
-       if (ret)
-               return ret;
-       sanitize_format(&entry.cdte_addr, &entry.cdte_format, requested_format);
-
-       if (copy_to_user(argp, &entry, sizeof(entry)))
+       ret = cdrom_read_tocentry(cdi, &entry);
+       if (!ret && copy_to_user(argp, &entry, sizeof(entry)))
                return -EFAULT;
-       /* cd_dbg(CD_DO_IOCTL, "CDROMREADTOCENTRY successful\n"); */
-       return 0;
+       return ret;
 }
 
 static int cdrom_ioctl_play_msf(struct cdrom_device_info *cdi,
diff --git a/include/linux/cdrom.h b/include/linux/cdrom.h
index 4f74ce050253d..008c4d79fa332 100644
--- a/include/linux/cdrom.h
+++ b/include/linux/cdrom.h
@@ -94,6 +94,9 @@ struct cdrom_device_ops {
                               struct packet_command *);
 };
 
+int cdrom_read_tocentry(struct cdrom_device_info *cdi,
+               struct cdrom_tocentry *entry);
+
 /* the general block_device operations structure: */
 extern int cdrom_open(struct cdrom_device_info *cdi, struct block_device *bdev,
                        fmode_t mode);
-- 
2.26.2