From 5e8e45c5dd03cf9830aad0b15fce26eab4a73c23 Mon Sep 17 00:00:00 2001
From: "Yoshinori K. Okuji" <okuji@gnu.org>
Date: Thu, 17 Aug 2000 00:23:28 +0000
Subject: Mask minor device numbers using MINOR_SHIFT when accessing to
 partitions.

---
 linux/dev/glue/block.c | 41 +++++++++++++++++++++++++++--------------
 1 file changed, 27 insertions(+), 14 deletions(-)

(limited to 'linux/dev/glue')

diff --git a/linux/dev/glue/block.c b/linux/dev/glue/block.c
index c450ea4..5ca4456 100644
--- a/linux/dev/glue/block.c
+++ b/linux/dev/glue/block.c
@@ -531,7 +531,9 @@ rdwr_partial (int rw, kdev_t dev, loff_t *off,
   for (gd = gendisk_head, nsect = -1; gd; gd = gd->next)
     if (gd->major == MAJOR (dev))
       {
-	nsect = gd->part[MINOR (dev)].nr_sects;
+	unsigned mask = (1 << gd->minor_shift) - 1;
+
+	nsect = gd->part[MINOR (dev) & mask].nr_sects;
 	break;
       }
   if (nsect > 0)
@@ -935,7 +937,8 @@ init_partition (struct name_map *np, kdev_t *dev,
   struct gendisk *gd = ds->gd;
   struct partition *p;
   struct temp_data *d = current_thread ()->pcb->data;
-
+  unsigned mask = (1 << gd->minor_shift) - 1;
+  
   if (! gd)
     {
       *part = -1;
@@ -951,9 +954,12 @@ init_partition (struct name_map *np, kdev_t *dev,
 	  sizeof (struct disklabel *) * gd->max_nr * gd->max_p);
   for (i = 1; i < gd->max_p; i++)
     {
+      unsigned part;
+      
       d->inode.i_rdev = *dev | i;
-      if (gd->part[MINOR (d->inode.i_rdev)].nr_sects <= 0
-	  || gd->part[MINOR (d->inode.i_rdev)].start_sect < 0)
+      part = MINOR (d->inode.i_rdev) & mask;
+      if (gd->part[part].nr_sects <= 0
+	  || gd->part[part].start_sect < 0)
 	continue;
       linux_intr_pri = SPL5;
       d->file.f_flags = 0;
@@ -975,11 +981,11 @@ init_partition (struct name_map *np, kdev_t *dev,
 		continue;
 
 	      /* Sanity check.  */
-	      if (p->p_size > gd->part[MINOR (d->inode.i_rdev)].nr_sects)
-		p->p_size = gd->part[MINOR (d->inode.i_rdev)].nr_sects;
+	      if (p->p_size > gd->part[part].nr_sects)
+		p->p_size = gd->part[part].nr_sects;
 	    }
 	}
-      ds->labels[MINOR (d->inode.i_rdev)] = lp;
+      ds->labels[part] = lp;
     }
 
 check:
@@ -989,8 +995,8 @@ check:
     return D_NO_SUCH_DEVICE;
   *dev = MKDEV (MAJOR (*dev), MINOR (*dev) | slice);
   if (slice >= gd->max_p
-      || gd->part[MINOR (*dev)].start_sect < 0
-      || gd->part[MINOR (*dev)].nr_sects <= 0)
+      || gd->part[MINOR (*dev) & mask].start_sect < 0
+      || gd->part[MINOR (*dev) & mask].nr_sects <= 0)
     return D_NO_SUCH_DEVICE;
   if (*part >= 0)
     {
@@ -1264,7 +1270,8 @@ check_limit (struct block_data *bd, loff_t *off, long bn, int count)
   int major, minor;
   long maxsz, sz;
   struct disklabel *lp = NULL;
-
+  unsigned mask;
+  
   if (count <= 0)
     return count;
 
@@ -1273,6 +1280,8 @@ check_limit (struct block_data *bd, loff_t *off, long bn, int count)
 
   if (bd->ds->gd)
     {
+      mask = (1 << bd->ds->gd->minor_shift) - 1;
+      
       if (bd->part >= 0)
 	{
 	  assert (bd->ds->labels);
@@ -1281,7 +1290,7 @@ check_limit (struct block_data *bd, loff_t *off, long bn, int count)
 	  maxsz = lp->d_partitions[bd->part].p_size;
 	}
       else
-	maxsz = bd->ds->gd->part[minor].nr_sects;
+	maxsz = bd->ds->gd->part[minor & mask].nr_sects;
     }
   else
     {
@@ -1296,7 +1305,7 @@ check_limit (struct block_data *bd, loff_t *off, long bn, int count)
     count = sz << 9;
   if (lp)
     bn += (lp->d_partitions[bd->part].p_offset
-	   - bd->ds->gd->part[minor].start_sect);
+	   - bd->ds->gd->part[minor & mask].start_sect);
   *off = (loff_t) bn << 9;
   bd->iocount++;
   return count;
@@ -1610,8 +1619,12 @@ device_get_status (void *d, dev_flavor_t flavor, dev_status_t status,
 	       = lp->d_partitions[bd->part].p_size << 9);
 	    }
 	  else
-	    (status[DEV_GET_SIZE_DEVICE_SIZE]
-	     = bd->ds->gd->part[MINOR (bd->dev)].nr_sects << 9);
+	    {
+	      unsigned mask = (1 << bd->ds->gd->minor_shift) - 1;
+	      
+	      (status[DEV_GET_SIZE_DEVICE_SIZE]
+	       = bd->ds->gd->part[MINOR (bd->dev) & mask].nr_sects << 9);
+	    }
 	}
       else
 	{
-- 
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