treewide: Use fallthrough pseudo-keyword

Replace the existing /* fall through */ comments and its variants with
the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
fall-through markings when it is the case.

[1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through

Signed-off-by: Gustavo A. R. Silva <[email protected]>

Author: GustavoARSilva

arch/alpha/kernel/module.c

@@ -212,7 +212,7 @@ apply_relocate_add(Elf64_Shdr *sechdrs, const char *strtab,
 			    STO_ALPHA_STD_GPLOAD)
 				/* Omit the prologue. */
 				value += 8;
-			/* FALLTHRU */
+			fallthrough;
 		case R_ALPHA_BRADDR:
 			value -= (u64)location + 4;
 			if (value & 3)

arch/alpha/kernel/signal.c

@@ -453,7 +453,7 @@ syscall_restart(unsigned long r0, unsigned long r19,
 			regs->r0 = EINTR;
 			break;
 		}
-		/* fallthrough */
+		fallthrough;
 	case ERESTARTNOINTR:
 		regs->r0 = r0;	/* reset v0 and a3 and replay syscall */
 		regs->r19 = r19;

arch/alpha/kernel/traps.c

@@ -883,7 +883,7 @@ do_entUnaUser(void __user * va, unsigned long opcode,
 
 	case 0x26: /* sts */
 		fake_reg = s_reg_to_mem(alpha_read_fp_reg(reg));
-		/* FALLTHRU */
+		fallthrough;
 
 	case 0x2c: /* stl */
 		__asm__ __volatile__(
@@ -911,7 +911,7 @@ do_entUnaUser(void __user * va, unsigned long opcode,
 
 	case 0x27: /* stt */
 		fake_reg = alpha_read_fp_reg(reg);
-		/* FALLTHRU */
+		fallthrough;
 
 	case 0x2d: /* stq */
 		__asm__ __volatile__(

arch/arc/kernel/disasm.c

@@ -339,7 +339,7 @@ void __kprobes disasm_instr(unsigned long addr, struct disasm_state *state,
 
 	case op_LDWX_S:	/* LDWX_S c, [b, u6] */
 		state->x = 1;
-		/* intentional fall-through */
+		fallthrough;
 
 	case op_LDW_S:	/* LDW_S c, [b, u6] */
 		state->zz = 2;

arch/arc/kernel/signal.c

@@ -321,7 +321,7 @@ static void arc_restart_syscall(struct k_sigaction *ka, struct pt_regs *regs)
 			regs->r0 = -EINTR;
 			break;
 		}
-		/* fallthrough */
+		fallthrough;
 
 	case -ERESTARTNOINTR:
 		/*

arch/arc/kernel/unwind.c

@@ -572,7 +572,7 @@ static unsigned long read_pointer(const u8 **pLoc, const void *end,
 #else
 		BUILD_BUG_ON(sizeof(u32) != sizeof(value));
 #endif
-		/* Fall through */
+		fallthrough;
 	case DW_EH_PE_native:
 		if (end < (const void *)(ptr.pul + 1))
 			return 0;
@@ -827,15 +827,15 @@ static int processCFI(const u8 *start, const u8 *end, unsigned long targetLoc,
 			case DW_CFA_def_cfa:
 				state->cfa.reg = get_uleb128(&ptr.p8, end);
 				unw_debug("cfa_def_cfa: r%lu ", state->cfa.reg);
-				/* fall through */
+				fallthrough;
 			case DW_CFA_def_cfa_offset:
 				state->cfa.offs = get_uleb128(&ptr.p8, end);
 				unw_debug("cfa_def_cfa_offset: 0x%lx ",
 					  state->cfa.offs);
 				break;
 			case DW_CFA_def_cfa_sf:
 				state->cfa.reg = get_uleb128(&ptr.p8, end);
-				/* fall through */
+				fallthrough;
 			case DW_CFA_def_cfa_offset_sf:
 				state->cfa.offs = get_sleb128(&ptr.p8, end)
 				    * state->dataAlign;

arch/arm/kernel/hw_breakpoint.c

@@ -547,7 +547,7 @@ static int arch_build_bp_info(struct perf_event *bp,
 		if ((hw->ctrl.type != ARM_BREAKPOINT_EXECUTE)
 			&& max_watchpoint_len >= 8)
 			break;
-		/* Else, fall through */
+		fallthrough;
 	default:
 		return -EINVAL;
 	}
@@ -612,12 +612,12 @@ int hw_breakpoint_arch_parse(struct perf_event *bp,
 		/* Allow halfword watchpoints and breakpoints. */
 		if (hw->ctrl.len == ARM_BREAKPOINT_LEN_2)
 			break;
-		/* Else, fall through */
+		fallthrough;
 	case 3:
 		/* Allow single byte watchpoint. */
 		if (hw->ctrl.len == ARM_BREAKPOINT_LEN_1)
 			break;
-		/* Else, fall through */
+		fallthrough;
 	default:
 		ret = -EINVAL;
 		goto out;
@@ -884,7 +884,7 @@ static int hw_breakpoint_pending(unsigned long addr, unsigned int fsr,
 		break;
 	case ARM_ENTRY_ASYNC_WATCHPOINT:
 		WARN(1, "Asynchronous watchpoint exception taken. Debugging results may be unreliable\n");
-		/* Fall through */
+		fallthrough;
 	case ARM_ENTRY_SYNC_WATCHPOINT:
 		watchpoint_handler(addr, fsr, regs);
 		break;
@@ -933,7 +933,7 @@ static bool core_has_os_save_restore(void)
 		ARM_DBG_READ(c1, c1, 4, oslsr);
 		if (oslsr & ARM_OSLSR_OSLM0)
 			return true;
-		/* Else, fall through */
+		fallthrough;
 	default:
 		return false;
 	}

arch/arm/kernel/signal.c

@@ -596,7 +596,7 @@ static int do_signal(struct pt_regs *regs, int syscall)
 		switch (retval) {
 		case -ERESTART_RESTARTBLOCK:
 			restart -= 2;
-			/* Fall through */
+			fallthrough;
 		case -ERESTARTNOHAND:
 		case -ERESTARTSYS:
 		case -ERESTARTNOINTR:

arch/arm/mach-ep93xx/crunch.c

@@ -49,7 +49,7 @@ static int crunch_do(struct notifier_block *self, unsigned long cmd, void *t)
 		 * FALLTHROUGH: Ensure we don't try to overwrite our newly
 		 * initialised state information on the first fault.
 		 */
-		/* Fall through */
+		fallthrough;
 
 	case THREAD_NOTIFY_EXIT:
 		crunch_task_release(thread);

arch/arm/mach-mmp/pm-mmp2.c

@@ -123,19 +123,19 @@ void mmp2_pm_enter_lowpower_mode(int state)
 	case POWER_MODE_SYS_SLEEP:
 		apcr |= MPMU_PCR_PJ_SLPEN;		/* set the SLPEN bit */
 		apcr |= MPMU_PCR_PJ_VCTCXOSD;		/* set VCTCXOSD */
-		/* fall through */
+		fallthrough;
 	case POWER_MODE_CHIP_SLEEP:
 		apcr |= MPMU_PCR_PJ_SLPEN;
-		/* fall through */
+		fallthrough;
 	case POWER_MODE_APPS_SLEEP:
 		apcr |= MPMU_PCR_PJ_APBSD;		/* set APBSD */
-		/* fall through */
+		fallthrough;
 	case POWER_MODE_APPS_IDLE:
 		apcr |= MPMU_PCR_PJ_AXISD;		/* set AXISDD bit */
 		apcr |= MPMU_PCR_PJ_DDRCORSD;		/* set DDRCORSD bit */
 		idle_cfg |= APMU_PJ_IDLE_CFG_PJ_PWRDWN;	/* PJ power down */
 		apcr |= MPMU_PCR_PJ_SPSD;
-		/* fall through */
+		fallthrough;
 	case POWER_MODE_CORE_EXTIDLE:
 		idle_cfg |= APMU_PJ_IDLE_CFG_PJ_IDLE;	/* set the IDLE bit */
 		idle_cfg &= ~APMU_PJ_IDLE_CFG_ISO_MODE_CNTRL_MASK;