[PATCH] s390: use normal switch statement for ioctls in dasd_ioctlc

Add an ->ioctl method to the dasd_discipline structure.  This allows to apply
the same kind of cleanups the last patch applied to dasd_ioctl.c to
dasd_eckd.c (the only dasd discipline with special ioctls) aswell.

Again lots of code removed.  During auditing the ioctls I found two fishy
return value propagations from copy_{from,to}_user, maintainers please check
those, I've marked them with XXX comments.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

3 files changed, 55 insertions, 97 deletions

diff --git a/drivers/s390/block/dasd_eckd.c b/drivers/s390/block/dasd_eckd.c
index 822e2a265578..ee09ef33d08d 100644
--- a/drivers/s390/block/dasd_eckd.c
+++ b/drivers/s390/block/dasd_eckd.c
@@ -1227,19 +1227,14 @@ dasd_eckd_fill_info(struct dasd_device * device,
  * (see dasd_eckd_reserve) device.
  */
 static int
-dasd_eckd_release(struct block_device *bdev, int no, long args)
+dasd_eckd_release(struct dasd_device *device)
 {
-        struct dasd_device *device;
         struct dasd_ccw_req *cqr;
         int rc;
 
         if (!capable(CAP_SYS_ADMIN))
                 return -EACCES;
 
-        device = bdev->bd_disk->private_data;
-        if (device == NULL)
-                return -ENODEV;
-
         cqr = dasd_smalloc_request(dasd_eckd_discipline.name,
                                    1, 32, device);
         if (IS_ERR(cqr)) {
@@ -1272,19 +1267,14 @@ dasd_eckd_release(struct block_device *bdev, int no, long args)
  * the interrupt is outstanding for a certain time. 
  */
 static int
-dasd_eckd_reserve(struct block_device *bdev, int no, long args)
+dasd_eckd_reserve(struct dasd_device *device)
 {
-        struct dasd_device *device;
         struct dasd_ccw_req *cqr;
         int rc;
 
         if (!capable(CAP_SYS_ADMIN))
                 return -EACCES;
 
-        device = bdev->bd_disk->private_data;
-        if (device == NULL)
-                return -ENODEV;
-
         cqr = dasd_smalloc_request(dasd_eckd_discipline.name,
                                    1, 32, device);
         if (IS_ERR(cqr)) {
@@ -1316,19 +1306,14 @@ dasd_eckd_reserve(struct block_device *bdev, int no, long args)
  * (unconditional reserve)
  */
 static int
-dasd_eckd_steal_lock(struct block_device *bdev, int no, long args)
+dasd_eckd_steal_lock(struct dasd_device *device)
 {
-        struct dasd_device *device;
         struct dasd_ccw_req *cqr;
         int rc;
 
         if (!capable(CAP_SYS_ADMIN))
                 return -EACCES;
 
-        device = bdev->bd_disk->private_data;
-        if (device == NULL)
-                return -ENODEV;
-
         cqr = dasd_smalloc_request(dasd_eckd_discipline.name,
                                    1, 32, device);
         if (IS_ERR(cqr)) {
@@ -1358,19 +1343,14 @@ dasd_eckd_steal_lock(struct block_device *bdev, int no, long args)
  * Read performance statistics
  */
 static int
-dasd_eckd_performance(struct block_device *bdev, int no, long args)
+dasd_eckd_performance(struct dasd_device *device, void __user *argp)
 {
-        struct dasd_device *device;
         struct dasd_psf_prssd_data *prssdp;
         struct dasd_rssd_perf_stats_t *stats;
         struct dasd_ccw_req *cqr;
         struct ccw1 *ccw;
         int rc;
 
-        device = bdev->bd_disk->private_data;
-        if (device == NULL)
-                return -ENODEV;
-
         cqr = dasd_smalloc_request(dasd_eckd_discipline.name,
                                    1 /* PSF */  + 1 /* RSSD */ ,
                                    (sizeof (struct dasd_psf_prssd_data) +
@@ -1414,8 +1394,9 @@ dasd_eckd_performance(struct block_device *bdev, int no, long args)
                 /* Prepare for Read Subsystem Data */
                 prssdp = (struct dasd_psf_prssd_data *) cqr->data;
                 stats = (struct dasd_rssd_perf_stats_t *) (prssdp + 1);
-                rc = copy_to_user((long __user *) args, (long *) stats,
-                                  sizeof(struct dasd_rssd_perf_stats_t));
+                if (copy_to_user(argp, stats,
+                                 sizeof(struct dasd_rssd_perf_stats_t)))
+                        rc = -EFAULT;
         }
         dasd_sfree_request(cqr, cqr->device);
         return rc;
@@ -1426,27 +1407,22 @@ dasd_eckd_performance(struct block_device *bdev, int no, long args)
  * Returnes the cache attributes used in Define Extend (DE).
  */
 static int
-dasd_eckd_get_attrib (struct block_device *bdev, int no, long args)
+dasd_eckd_get_attrib(struct dasd_device *device, void __user *argp)
 {
-        struct dasd_device *device;
-        struct dasd_eckd_private *private;
-        struct attrib_data_t attrib;
+        struct dasd_eckd_private *private =
+                (struct dasd_eckd_private *)device->private;
+        struct attrib_data_t attrib = private->attrib;
         int rc;
 
         if (!capable(CAP_SYS_ADMIN))
                 return -EACCES;
-        if (!args)
+        if (!argp)
                 return -EINVAL;
 
-        device = bdev->bd_disk->private_data;
-        if (device == NULL)
-                return -ENODEV;
-
-        private = (struct dasd_eckd_private *) device->private;
-        attrib = private->attrib;
-
-        rc = copy_to_user((long __user *) args, (long *) &attrib,
-                          sizeof (struct attrib_data_t));
+        rc = 0;
+        if (copy_to_user(argp, (long *) &attrib,
+                         sizeof (struct attrib_data_t)))
+                rc = -EFAULT;
 
         return rc;
 }
@@ -1456,26 +1432,19 @@ dasd_eckd_get_attrib (struct block_device *bdev, int no, long args)
  * Stores the attributes for cache operation to be used in Define Extend (DE).
  */
 static int
-dasd_eckd_set_attrib(struct block_device *bdev, int no, long args)
+dasd_eckd_set_attrib(struct dasd_device *device, void __user *argp)
 {
-        struct dasd_device *device;
-        struct dasd_eckd_private *private;
+        struct dasd_eckd_private *private =
+                (struct dasd_eckd_private *)device->private;
         struct attrib_data_t attrib;
 
         if (!capable(CAP_SYS_ADMIN))
                 return -EACCES;
-        if (!args)
+        if (!argp)
                 return -EINVAL;
 
-        device = bdev->bd_disk->private_data;
-        if (device == NULL)
-                return -ENODEV;
-
-        if (copy_from_user(&attrib, (void __user *) args,
-                           sizeof (struct attrib_data_t))) {
+        if (copy_from_user(&attrib, argp, sizeof(struct attrib_data_t)))
                 return -EFAULT;
-        }
-        private = (struct dasd_eckd_private *) device->private;
         private->attrib = attrib;
 
         DEV_MESSAGE(KERN_INFO, device,
@@ -1484,6 +1453,27 @@ dasd_eckd_set_attrib(struct block_device *bdev, int no, long args)
         return 0;
 }
 
+static int
+dasd_eckd_ioctl(struct dasd_device *device, unsigned int cmd, void __user *argp)
+{
+        switch (cmd) {
+        case BIODASDGATTR:
+                return dasd_eckd_get_attrib(device, argp);
+        case BIODASDSATTR:
+                return dasd_eckd_set_attrib(device, argp);
+        case BIODASDPSRD:
+                return dasd_eckd_performance(device, argp);
+        case BIODASDRLSE:
+                return dasd_eckd_release(device);
+        case BIODASDRSRV:
+                return dasd_eckd_reserve(device);
+        case BIODASDSLCK:
+                return dasd_eckd_steal_lock(device);
+        default:
+                return -ENOIOCTLCMD;
+        }
+}
+
 /*
  * Print sense data and related channel program.
  * Parts are printed because printk buffer is only 1024 bytes.
@@ -1642,6 +1632,7 @@ static struct dasd_discipline dasd_eckd_discipline = {
         .free_cp = dasd_eckd_free_cp,
         .dump_sense = dasd_eckd_dump_sense,
         .fill_info = dasd_eckd_fill_info,
+        .ioctl = dasd_eckd_ioctl,
 };
 
 static int __init
@@ -1649,59 +1640,18 @@ dasd_eckd_init(void)
 {
         int ret;
 
-        dasd_ioctl_no_register(THIS_MODULE, BIODASDGATTR,
-                               dasd_eckd_get_attrib);
-        dasd_ioctl_no_register(THIS_MODULE, BIODASDSATTR,
-                               dasd_eckd_set_attrib);
-        dasd_ioctl_no_register(THIS_MODULE, BIODASDPSRD,
-                               dasd_eckd_performance);
-        dasd_ioctl_no_register(THIS_MODULE, BIODASDRLSE,
-                               dasd_eckd_release);
-        dasd_ioctl_no_register(THIS_MODULE, BIODASDRSRV,
-                               dasd_eckd_reserve);
-        dasd_ioctl_no_register(THIS_MODULE, BIODASDSLCK,
-                               dasd_eckd_steal_lock);
-
         ASCEBC(dasd_eckd_discipline.ebcname, 4);
 
         ret = ccw_driver_register(&dasd_eckd_driver);
-        if (ret) {
-                dasd_ioctl_no_unregister(THIS_MODULE, BIODASDGATTR,
-                                         dasd_eckd_get_attrib);
-                dasd_ioctl_no_unregister(THIS_MODULE, BIODASDSATTR,
-                                         dasd_eckd_set_attrib);
-                dasd_ioctl_no_unregister(THIS_MODULE, BIODASDPSRD,
-                                         dasd_eckd_performance);
-                dasd_ioctl_no_unregister(THIS_MODULE, BIODASDRLSE,
-                                         dasd_eckd_release);
-                dasd_ioctl_no_unregister(THIS_MODULE, BIODASDRSRV,
-                                         dasd_eckd_reserve);
-                dasd_ioctl_no_unregister(THIS_MODULE, BIODASDSLCK,
-                                         dasd_eckd_steal_lock);
-                return ret;
-        }
-
-        dasd_generic_auto_online(&dasd_eckd_driver);
-        return 0;
+        if (!ret)
+                dasd_generic_auto_online(&dasd_eckd_driver);
+        return ret;
 }
 
 static void __exit
 dasd_eckd_cleanup(void)
 {
         ccw_driver_unregister(&dasd_eckd_driver);
-
-        dasd_ioctl_no_unregister(THIS_MODULE, BIODASDGATTR,
-                                 dasd_eckd_get_attrib);
-        dasd_ioctl_no_unregister(THIS_MODULE, BIODASDSATTR,
-                                 dasd_eckd_set_attrib);
-        dasd_ioctl_no_unregister(THIS_MODULE, BIODASDPSRD,
-                                 dasd_eckd_performance);
-        dasd_ioctl_no_unregister(THIS_MODULE, BIODASDRLSE,
-                                 dasd_eckd_release);
-        dasd_ioctl_no_unregister(THIS_MODULE, BIODASDRSRV,
-                                 dasd_eckd_reserve);
-        dasd_ioctl_no_unregister(THIS_MODULE, BIODASDSLCK,
-                                 dasd_eckd_steal_lock);
 }
 
 module_init(dasd_eckd_init);
diff --git a/drivers/s390/block/dasd_int.h b/drivers/s390/block/dasd_int.h
index 6010ecf76b4c..e9485559e22e 100644
--- a/drivers/s390/block/dasd_int.h
+++ b/drivers/s390/block/dasd_int.h
@@ -272,6 +272,7 @@ struct dasd_discipline {
         /* i/o control functions. */
         int (*fill_geometry) (struct dasd_device *, struct hd_geometry *);
         int (*fill_info) (struct dasd_device *, struct dasd_information2_t *);
+        int (*ioctl) (struct dasd_device *, unsigned int, void __user *);
 };
 
 extern struct dasd_discipline *dasd_diag_discipline_pointer;
diff --git a/drivers/s390/block/dasd_ioctl.c b/drivers/s390/block/dasd_ioctl.c
index e3ad34686444..bb6caf46bbd9 100644
--- a/drivers/s390/block/dasd_ioctl.c
+++ b/drivers/s390/block/dasd_ioctl.c
@@ -448,7 +448,14 @@ dasd_ioctl(struct inode *inode, struct file *file,
         case DASDAPIVER:
                 return dasd_ioctl_api_version(argp);
         default:
-                /* resort to the deprecated dynamic ioctl list */
+                /* if the discipline has an ioctl method try it. */
+                if (device->discipline->ioctl) {
+                        int rval = device->discipline->ioctl(device, cmd, argp);
+                        if (rval != -ENOIOCTLCMD)
+                                return rval;
+                }
+
+                /* else resort to the deprecated dynamic ioctl list */
                 list_for_each_entry(ioctl, &dasd_ioctl_list, list) {
                         if (ioctl->no == cmd) {
                                 /* Found a matching ioctl. Call it. */