[PATCH] Support up to 256 SCSI disks on Linux

[PATCH] Support up to 256 SCSI disks on Linux

[Colin Watson]

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Linux's Documentation/devices.txt file says that up to 256 SCSI disks
are supported. GRUB currently only supports the first 16. Wikimedia
filed an Ubuntu bug report about this
(https://bugs.launchpad.net/bugs/335174), so here's a patch to extend
this. (I really haven't been able to test this much at all beyond
compile-testing as I don't have a suitable system myself ...)

I suppose it might be nice to macroify the stuff in
grub_util_getdiskname, but TBH I'm not sure it would shorten it all that
much or make it much more readable, so I didn't bother.

Thanks,

-- 
Colin Watson                                       [cjwatson@ubuntu.com]

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Index: util/raid.c
===================================================================
--- util/raid.c	(revision 2016)
+++ util/raid.c	(working copy)
@@ -32,6 +32,16 @@
 #include <linux/raid/md_p.h>
 #include <linux/raid/md_u.h>
 
+static void
+grub_util_getdiskname_scsi (char *name, int scsi_major, int scsi_minor)
+{
+  int unit = scsi_major * 16 + scsi_minor;
+  if (unit < 26)
+    sprintf (name, "/dev/sd%c", 'a' + unit);
+  else
+    sprintf (name, "/dev/sd%c%c", 'a' + unit / 26 - 1, 'a' + unit % 26);
+}
+
 static char *
 grub_util_getdiskname (int major, int minor)
 {
@@ -48,7 +58,37 @@ grub_util_getdiskname (int major, int minor)
   else if (major == IDE3_MAJOR)
     sprintf (name, "/dev/hd%c", 'g' + minor / 64);
   else if (major == SCSI_DISK0_MAJOR)
-    sprintf (name, "/dev/sd%c", 'a' + minor / 16);
+    grub_util_getdiskname_scsi (name, 0, minor / 16);
+  else if (major == SCSI_DISK1_MAJOR)
+    grub_util_getdiskname_scsi (name, 1, minor / 16);
+  else if (major == SCSI_DISK2_MAJOR)
+    grub_util_getdiskname_scsi (name, 2, minor / 16);
+  else if (major == SCSI_DISK3_MAJOR)
+    grub_util_getdiskname_scsi (name, 3, minor / 16);
+  else if (major == SCSI_DISK4_MAJOR)
+    grub_util_getdiskname_scsi (name, 4, minor / 16);
+  else if (major == SCSI_DISK5_MAJOR)
+    grub_util_getdiskname_scsi (name, 5, minor / 16);
+  else if (major == SCSI_DISK6_MAJOR)
+    grub_util_getdiskname_scsi (name, 6, minor / 16);
+  else if (major == SCSI_DISK7_MAJOR)
+    grub_util_getdiskname_scsi (name, 7, minor / 16);
+  else if (major == SCSI_DISK8_MAJOR)
+    grub_util_getdiskname_scsi (name, 8, minor / 16);
+  else if (major == SCSI_DISK9_MAJOR)
+    grub_util_getdiskname_scsi (name, 9, minor / 16);
+  else if (major == SCSI_DISK10_MAJOR)
+    grub_util_getdiskname_scsi (name, 10, minor / 16);
+  else if (major == SCSI_DISK11_MAJOR)
+    grub_util_getdiskname_scsi (name, 11, minor / 16);
+  else if (major == SCSI_DISK12_MAJOR)
+    grub_util_getdiskname_scsi (name, 12, minor / 16);
+  else if (major == SCSI_DISK13_MAJOR)
+    grub_util_getdiskname_scsi (name, 13, minor / 16);
+  else if (major == SCSI_DISK14_MAJOR)
+    grub_util_getdiskname_scsi (name, 14, minor / 16);
+  else if (major == SCSI_DISK15_MAJOR)
+    grub_util_getdiskname_scsi (name, 15, minor / 16);
   else
     grub_util_error ("Unknown device number: %d, %d", major, minor);
     
Index: util/grub-mkdevicemap.c
===================================================================
--- util/grub-mkdevicemap.c	(revision 2016)
+++ util/grub-mkdevicemap.c	(working copy)
@@ -231,7 +231,10 @@ get_scsi_disk_name (char *name, int unit)
 {
 #if defined(__linux__)
   /* GNU/Linux */
-  sprintf (name, "/dev/sd%c", unit + 'a');
+  if (unit < 26)
+    sprintf (name, "/dev/sd%c", unit + 'a');
+  else
+    sprintf (name, "/dev/sd%c%c", unit / 26 - 1 + 'a', unit % 26 + 'a');
 #elif defined(__GNU__)
   /* GNU/Hurd */
   sprintf (name, "/dev/sd%d", unit);
@@ -516,7 +519,11 @@ make_device_map (const char *device_map, int flopp
 #endif /* __linux__ */
 
   /* The rest is SCSI disks.  */
+#ifdef __linux__
+  for (i = 0; i < 256; i++)
+#else
   for (i = 0; i < 16; i++)
+#endif /* __linux__ */
     {
       char name[16];
       
Index: util/hostdisk.c
===================================================================
--- util/hostdisk.c	(revision 2016)
+++ util/hostdisk.c	(working copy)
@@ -709,8 +709,12 @@ convert_system_partition_to_system_disk (const cha
 	   || strncmp ("sd", p, 2) == 0)
 	  && p[2] >= 'a' && p[2] <= 'z')
 	{
-	  /* /dev/[hsv]d[a-z][0-9]* */
-	  p[3] = '\0';
+	  if (p[3] >= 'a' && p[3] <= 'z')
+	    /* /dev/[hsv]d[a-z][a-z][0-9]* */
+	    p[4] = '\0';
+	  else
+	    /* /dev/[hsv]d[a-z][0-9]* */
+	    p[3] = '\0';
 	  return path;
 	}
 

Re: [PATCH] Support up to 256 SCSI disks on Linux

[Robert Millan]

On Wed, Mar 04, 2009 at 04:35:09PM +0000, Colin Watson wrote:
> Linux's Documentation/devices.txt file says that up to 256 SCSI disks
> are supported. GRUB currently only supports the first 16. Wikimedia
> filed an Ubuntu bug report about this
> (https://bugs.launchpad.net/bugs/335174), so here's a patch to extend
> this. (I really haven't been able to test this much at all beyond
> compile-testing as I don't have a suitable system myself ...)
> 
> I suppose it might be nice to macroify the stuff in
> grub_util_getdiskname, but TBH I'm not sure it would shorten it all that
> much or make it much more readable, so I didn't bother.

Hi Colin,

I feel some dejavu.  I think this is not the first max disk limit you
find ;-)

>    else if (major == SCSI_DISK0_MAJOR)
> -    sprintf (name, "/dev/sd%c", 'a' + minor / 16);
> +    grub_util_getdiskname_scsi (name, 0, minor / 16);
> +  else if (major == SCSI_DISK1_MAJOR)
> +    grub_util_getdiskname_scsi (name, 1, minor / 16);
> [...]

Can this be factorized somehow?  Space in raid.mod is quite critical; when
used it usually ends up in core.img, which needs to fit in the embed area.

-- 
Robert Millan

  The DRM opt-in fallacy: "Your data belongs to us. We will decide when (and
  how) you may access your data; but nobody's threatening your freedom: we
  still allow you to remove your data and not access it at all."

Re: [PATCH] Support up to 256 SCSI disks on Linux

[Robert Millan]

On Wed, Mar 04, 2009 at 10:16:29PM +0100, Robert Millan wrote:
> >    else if (major == SCSI_DISK0_MAJOR)
> > -    sprintf (name, "/dev/sd%c", 'a' + minor / 16);
> > +    grub_util_getdiskname_scsi (name, 0, minor / 16);
> > +  else if (major == SCSI_DISK1_MAJOR)
> > +    grub_util_getdiskname_scsi (name, 1, minor / 16);
> > [...]
> 
> Can this be factorized somehow?  Space in raid.mod is quite critical; when
> used it usually ends up in core.img, which needs to fit in the embed area.

Oh, I'm sorry.  I thought you were editting disk/raid.c.  util/raid.c has no
size issues.  A macro would still be nice though.

-- 
Robert Millan

  The DRM opt-in fallacy: "Your data belongs to us. We will decide when (and
  how) you may access your data; but nobody's threatening your freedom: we
  still allow you to remove your data and not access it at all."

Re: [PATCH] Support up to 256 SCSI disks on Linux

[phcoder]

Robert Millan wrote:
> On Wed, Mar 04, 2009 at 10:16:29PM +0100, Robert Millan wrote:
>>>    else if (major == SCSI_DISK0_MAJOR)
>>> -    sprintf (name, "/dev/sd%c", 'a' + minor / 16);
>>> +    grub_util_getdiskname_scsi (name, 0, minor / 16);
>>> +  else if (major == SCSI_DISK1_MAJOR)
>>> +    grub_util_getdiskname_scsi (name, 1, minor / 16);
>>> [...]
>> Can this be factorized somehow?  Space in raid.mod is quite critical; when
>> used it usually ends up in core.img, which needs to fit in the embed area.
> 
> Oh, I'm sorry.  I thought you were editting disk/raid.c.  util/raid.c has no
> size issues.  A macro would still be nice though.
> 
What about making an array of SCSI_DISK?_MAJOR and then just go through it?

-- 

Regards
Vladimir 'phcoder' Serbinenko

Re: [PATCH] Support up to 256 SCSI disks on Linux

[Robert Millan]

On Sat, Apr 11, 2009 at 01:05:19AM +0200, phcoder wrote:
> Robert Millan wrote:
>> On Wed, Mar 04, 2009 at 10:16:29PM +0100, Robert Millan wrote:
>>>>    else if (major == SCSI_DISK0_MAJOR)
>>>> -    sprintf (name, "/dev/sd%c", 'a' + minor / 16);
>>>> +    grub_util_getdiskname_scsi (name, 0, minor / 16);
>>>> +  else if (major == SCSI_DISK1_MAJOR)
>>>> +    grub_util_getdiskname_scsi (name, 1, minor / 16);
>>>> [...]
>>> Can this be factorized somehow?  Space in raid.mod is quite critical; when
>>> used it usually ends up in core.img, which needs to fit in the embed area.
>>
>> Oh, I'm sorry.  I thought you were editting disk/raid.c.  util/raid.c has no
>> size issues.  A macro would still be nice though.
>>
> What about making an array of SCSI_DISK?_MAJOR and then just go through it?

Sounds good.

-- 
Robert Millan

  The DRM opt-in fallacy: "Your data belongs to us. We will decide when (and
  how) you may access your data; but nobody's threatening your freedom: we
  still allow you to remove your data and not access it at all."