svn commit: r209683 - head/sys/dev/ata

[Warner Losh]

Author: imp
Date: Sun Jul  4 07:42:52 2010
New Revision: 209683
URL: http://svn.freebsd.org/changeset/base/209683

Log:
  Add a safety-belt.  If the identified disk has 0 blocks, don't attach
  it.  This can happen in some cases when plugging in SD/SmartCard PC
  Cards with empty slots.  It is better to detect this bogosity, and
  refuse to attach rather than panic with a division by zero (in one of
  many places) down stream.

Modified:
  head/sys/dev/ata/ata-disk.c

Modified: head/sys/dev/ata/ata-disk.c
==============================================================================
--- head/sys/dev/ata/ata-disk.c	Sun Jul  4 05:58:17 2010	(r209682)
+++ head/sys/dev/ata/ata-disk.c	Sun Jul  4 07:42:52 2010	(r209683)
@@ -54,7 +54,7 @@ __FBSDID("$FreeBSD$");
 
 /* prototypes */
 static void ad_init(device_t dev);
-static void ad_get_geometry(device_t dev);
+static int ad_get_geometry(device_t dev);
 static void ad_set_geometry(device_t dev);
 static void ad_done(struct ata_request *request);
 static void ad_describe(device_t dev);
@@ -106,7 +106,8 @@ ad_attach(device_t dev)
     device_set_ivars(dev, adp);
 
     /* get device geometry into internal structs */
-    ad_get_geometry(dev);
+    if (ad_get_geometry(dev))
+	return ENXIO;
 
     /* set the max size if configured */
     if (ata_setmax)
@@ -410,7 +411,7 @@ ad_init(device_t dev)
 	atadev->max_iosize = DEV_BSIZE;
 }
 
-static void
+static int
 ad_get_geometry(device_t dev)
 {
     struct ata_device *atadev = device_get_softc(dev);
@@ -432,6 +433,9 @@ ad_get_geometry(device_t dev)
     }
     lbasize = (u_int32_t)atadev->param.lba_size_1 |
 	      ((u_int32_t)atadev->param.lba_size_2 << 16);
+    /* This device exists, but has no size.  Filter out this bogus device. */
+    if (!lbasize && !adp->total_secs)
+	return ENXIO;
 
     /* does this device need oldstyle CHS addressing */
     if (!ad_version(atadev->param.version_major) || !lbasize)
@@ -449,6 +453,7 @@ ad_get_geometry(device_t dev)
     if ((atadev->param.support.command2 & ATA_SUPPORT_ADDRESS48) &&
 	lbasize48 > ATA_MAX_28BIT_LBA)
 	adp->total_secs = lbasize48;
+    return 0;
 }
 
 static void