[SCSI] aacraid: resolve compiler warnings using ptrdiff_t

Unsigned long is not always the same size as a pointer, namely on 32 bit
systems with 64 bit address space. Ptrdiff_t is the same size as a
pointer in all configurations. By using ptrdiff_t we can mitigate the
warning messages on these configurations. There should be no side
effects of this patch.
Signed-off-by: Mark Salyzyn <aacraid@adaptec.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

drivers/scsi/aacraid/commctrl.c

@@ -391,10 +391,8 @@ static int close_getadapter_fib(struct aac_dev * dev, void __user *arg)
 		/*
 		 *	Extract the fibctx from the input parameters
 		 */
-		if (fibctx->unique == (u32)(unsigned long)arg) {   
-			/* We found a winner */
+		if (fibctx->unique == (u32)(ptrdiff_t)arg) /* We found a winner */
 			break;
-		}
 		entry = entry->next;
 		fibctx = NULL;
 	}

drivers/scsi/aacraid/comminit.c

@@ -5,7 +5,7 @@
  * based on the old aacraid driver that is..
  * Adaptec aacraid device driver for Linux.
  *
- * Copyright (c) 2000 Adaptec, Inc. (aacraid@adaptec.com)
+ * Copyright (c) 2000-2007 Adaptec, Inc. (aacraid@adaptec.com)
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -110,7 +110,7 @@ static int aac_alloc_comm(struct aac_dev *dev, void **commaddr, unsigned long co
 	/*
 	 *	Align the beginning of Headers to commalign
 	 */
-	align = (commalign - ((unsigned long)(base) & (commalign - 1)));
+	align = (commalign - ((ptrdiff_t)(base) & (commalign - 1)));
 	base = base + align;
 	phys = phys + align;
 	/*

drivers/scsi/aacraid/dpcsup.c

@@ -256,7 +256,8 @@ unsigned int aac_intr_normal(struct aac_dev * dev, u32 Index)
 			return 1;
 		}
 		memset(hw_fib, 0, sizeof(struct hw_fib));
-		memcpy(hw_fib, (struct hw_fib *)(((unsigned long)(dev->regs.sa)) + (index & ~0x00000002L)), sizeof(struct hw_fib));
+		memcpy(hw_fib, (struct hw_fib *)(((ptrdiff_t)(dev->regs.sa)) +
+		  (index & ~0x00000002L)), sizeof(struct hw_fib));
 		memset(fib, 0, sizeof(struct fib));
 		INIT_LIST_HEAD(&fib->fiblink);
 		fib->type = FSAFS_NTC_FIB_CONTEXT;