[PATCH] Warning fix in raid6_recover

[Pavel Roskin <proski@gnu.org>]

Hello!

This is an fix for this warning:

disk/raid6_recover.c: In function 'grub_raid6_recover':
disk/raid6_recover.c:95: warning: 'err[1]' may be used uninitialized in this function
disk/raid6_recover.c:95: warning: 'err[0]' may be used uninitialized in this function

The warning about err[0] appears to be legitimate.  For some values of
disknr err[0] will never be set.  Namely, it will happen if disknr is
equal p or p+1, for negative disknr and for disknr being more or equal
array->total_devs.  It's better to have a check for that case.

The warning about err[1] is incorrect and can be easily eliminated once
we realize that err[nerr++] is always err[1].

Since both err[0] and err[1] are only assigned positive values, we can
initialize them with -1.  This would also eliminate nerr, as we can
check err[1] instead.

It would be great to give better names to most variables.  err[0] and
err[1] could become separate variables.  There is no need for them to be
an array.  And they are not error codes, despite what their names imply.
Unfortunately, I'm not familiar enough with RAID6 to suggest better
names.

ChangeLog:
	* disk/raid6_recover.c (grub_raid6_recover): Fix warnings about
	uninitialized err[0] and err[1].  Initialize them with -1.  Add
	sanity check for err[0].  Eliminate nerr variable.

Index: disk/raid6_recover.c
===================================================================
--- disk/raid6_recover.c	(revision 2191)
+++ disk/raid6_recover.c	(working copy)
@@ -92,7 +92,7 @@
                     char *buf, grub_disk_addr_t sector, int size)
 {
   int i, q, pos;
-  int err[2], nerr;
+  int err[2] = { -1, -1 };
   char *pbuf = 0, *qbuf = 0;
 
   size <<= GRUB_DISK_SECTOR_BITS;
@@ -115,7 +115,6 @@
   if (pos == (int) array->total_devs)
     pos = 0;
 
-  nerr = 1;
   for (i = 0; i < (int) array->total_devs - 2; i++)
     {
       if (pos == disknr)
@@ -131,10 +130,11 @@
             }
           else
             {
-              if (nerr >= 2)
+              /* Too many bad devices */
+              if (err[1] >= 0)
                 goto quit;
 
-              err[nerr++] = i;
+              err[1] = i;
               grub_errno = GRUB_ERR_NONE;
             }
         }
@@ -144,8 +144,13 @@
         pos = 0;
     }
 
-  if (nerr == 1)
+  /* Invalid disknr or p */
+  if (err[0] < 0)
+    goto quit;
+
+  if (err[1] < 0)
     {
+      /* One bad device */
       if ((array->device[p]) &&
           (! grub_disk_read (array->device[p], sector, 0, size, buf)))
         {
@@ -169,6 +174,7 @@
     }
   else
     {
+      /* Two bad devices */
       grub_uint8_t c;
 
       if ((! array->device[p]) || (! array->device[q]))


-- 
Regards,
Pavel Roskin