[undi] Allocate base memory before calling UNDI loader entry point

Allocate base memory (by decreasing the free base memory counter)
before calling the UNDI loader entry point, to minimise surprises for
the UNDI loader code.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/arch/x86/drivers/net/undiload.c

 	/* Only one UNDI instance may be loaded at any given time */
 	if ( undi_loader_entry.segment ) {
 		DBG ( "UNDI %p cannot load multiple instances\n", undi );
-		return -EBUSY;
+		rc = -EBUSY;
+		goto err_multiple;
 	}
 
 	/* Set up START_UNDI parameters */
 	undi_loader.UNDI_CS = fbms_seg;
 	fbms_seg -= ( ( undirom->data_size + 0x0f ) >> 4 );
 	undi_loader.UNDI_DS = fbms_seg;
+	undi->fbms = ( fbms_seg >> 6 );
+	set_fbms ( undi->fbms );
+	DBGC ( undi, "UNDI %p allocated [%d,%d) kB of base memory\n",
+	       undi, undi->fbms, undi->restore_fbms );
 
 	/* Debug info */
-	DBGC ( undi, "UNDI %p loading UNDI ROM %p to CS %04x DS %04x for ",
-	       undi, undirom, undi_loader.UNDI_CS, undi_loader.UNDI_DS );
+	DBGC ( undi, "UNDI %p loading ROM %p to CS %04x:%04zx DS %04x:%04zx "
+	       "for ", undi, undirom, undi_loader.UNDI_CS, undirom->code_size,
+	       undi_loader.UNDI_DS, undirom->data_size );
 	if ( undi->pci_busdevfn != UNDI_NO_PCI_BUSDEVFN ) {
 		unsigned int bus = ( undi->pci_busdevfn >> 8 );
 		unsigned int devfn = ( undi->pci_busdevfn & 0xff );
 			       : "=a" ( exit )
 			       : "a" ( __from_data16 ( &undi_loader ) )
 			       : "ebx", "ecx", "edx", "esi", "edi" );
-
 	if ( exit != PXENV_EXIT_SUCCESS ) {
-		/* Clear entry point */
-		memset ( &undi_loader_entry, 0, sizeof ( undi_loader_entry ) );
-
 		rc = -EUNDILOAD ( undi_loader.Status );
 		DBGC ( undi, "UNDI %p loader failed: %s\n",
 		       undi, strerror ( rc ) );
-		return rc;
+		goto err_loader;
 	}
 
 	/* Populate PXE device structure */
 	       undi->pxenv.offset, undi->ppxe.segment, undi->ppxe.offset,
 	       undi->entry.segment, undi->entry.offset );
 
-	/* Update free base memory counter */
-	undi->fbms = ( fbms_seg >> 6 );
-	set_fbms ( undi->fbms );
-	DBGC ( undi, "UNDI %p using [%d,%d) kB of base memory\n",
-	       undi, undi->fbms, undi->restore_fbms );
-
 	return 0;
+
+ err_loader:
+	set_fbms ( undi->restore_fbms );
+	memset ( &undi_loader_entry, 0, sizeof ( undi_loader_entry ) );
+ err_multiple:
+	return rc;
 }
 
 /**