Just a sampling of a few fallthrough comments still in the tree in -next as of today.
Done using: $ git grep -i -10 -P '(?:/\*|//).*fall' -- '*.[ch]' and visual inspection til I got tired of looking for more --- drivers/net/usb/usbnet.c- case -EPIPE: drivers/net/usb/usbnet.c- dev->net->stats.rx_errors++; drivers/net/usb/usbnet.c- usbnet_defer_kevent (dev, EVENT_RX_HALT); drivers/net/usb/usbnet.c: // FALLTHROUGH drivers/net/usb/usbnet.c- drivers/net/usb/usbnet.c- /* software-driven interface shutdown */ drivers/net/usb/usbnet.c- case -ECONNRESET: /* async unlink */ arch/powerpc/perf/hv-24x7.c-static bool domain_is_valid(unsigned domain) arch/powerpc/perf/hv-24x7.c-{ arch/powerpc/perf/hv-24x7.c- switch (domain) { arch/powerpc/perf/hv-24x7.c-#define DOMAIN(n, v, x, c) \ arch/powerpc/perf/hv-24x7.c- case HV_PERF_DOMAIN_##n: \ arch/powerpc/perf/hv-24x7.c: /* fall through */ arch/powerpc/perf/hv-24x7.c-#include "hv-24x7-domains.h" arch/powerpc/perf/hv-24x7.c-#undef DOMAIN arch/powerpc/platforms/52xx/mpc52xx_gpt.c- case WDIOC_SETTIMEOUT: arch/powerpc/platforms/52xx/mpc52xx_gpt.c- ret = get_user(timeout, data); arch/powerpc/platforms/52xx/mpc52xx_gpt.c- if (ret) arch/powerpc/platforms/52xx/mpc52xx_gpt.c- break; arch/powerpc/platforms/52xx/mpc52xx_gpt.c- real_timeout = (u64) timeout * 1000000000ULL; arch/powerpc/platforms/52xx/mpc52xx_gpt.c- ret = mpc52xx_gpt_do_start(gpt_wdt, real_timeout, 0, 1); arch/powerpc/platforms/52xx/mpc52xx_gpt.c- if (ret) arch/powerpc/platforms/52xx/mpc52xx_gpt.c- break; arch/powerpc/platforms/52xx/mpc52xx_gpt.c: /* fall through and return the timeout */ arch/powerpc/platforms/52xx/mpc52xx_gpt.c- arch/powerpc/platforms/52xx/mpc52xx_gpt.c- case WDIOC_GETTIMEOUT: arch/x86/events/core.c- case INTEL_PMC_IDX_METRIC_BASE ... INTEL_PMC_IDX_METRIC_END: arch/x86/events/core.c- /* All the metric events are mapped onto the fixed counter 3. */ arch/x86/events/core.c- idx = INTEL_PMC_IDX_FIXED_SLOTS; arch/x86/events/core.c: /* fall through */ arch/x86/events/core.c- case INTEL_PMC_IDX_FIXED ... INTEL_PMC_IDX_FIXED_BTS-1: arch/x86/kernel/e820.c- switch (type) { arch/x86/kernel/e820.c: case E820_TYPE_RAM: /* Fall through: */ arch/x86/kernel/e820.c- case E820_TYPE_RESERVED_KERN: pr_cont("usable"); break; arch/x86/kernel/e820.c- case E820_TYPE_RESERVED: pr_cont("reserved"); break; arch/x86/kernel/e820.c- case E820_TYPE_SOFT_RESERVED: pr_cont("soft reserved"); break; arch/x86/kernel/e820.c- case E820_TYPE_ACPI: pr_cont("ACPI data"); break; arch/x86/kernel/e820.c- case E820_TYPE_NVS: pr_cont("ACPI NVS"); break; arch/x86/kernel/e820.c- case E820_TYPE_UNUSABLE: pr_cont("unusable"); break; arch/x86/kernel/e820.c: case E820_TYPE_PMEM: /* Fall through: */ arch/x86/kernel/e820.c- case E820_TYPE_PRAM: pr_cont("persistent (type %u)", type); break; arch/x86/kernel/e820.c- default: pr_cont("type %u", type); break; arch/x86/kernel/e820.c- switch (entry->type) { arch/x86/kernel/e820.c: case E820_TYPE_RESERVED_KERN: /* Fall-through: */ arch/x86/kernel/e820.c- case E820_TYPE_RAM: return "System RAM"; arch/x86/kernel/e820.c- case E820_TYPE_ACPI: return "ACPI Tables"; arch/x86/kernel/e820.c- case E820_TYPE_NVS: return "ACPI Non-volatile Storage"; arch/x86/kernel/e820.c- case E820_TYPE_UNUSABLE: return "Unusable memory"; arch/x86/kernel/e820.c- case E820_TYPE_PRAM: return "Persistent Memory (legacy)"; arch/x86/kernel/e820.c- case E820_TYPE_PMEM: return "Persistent Memory"; arch/x86/kernel/e820.c- case E820_TYPE_RESERVED: return "Reserved"; arch/x86/kernel/e820.c- case E820_TYPE_SOFT_RESERVED: return "Soft Reserved"; arch/x86/kernel/e820.c- switch (entry->type) { arch/x86/kernel/e820.c: case E820_TYPE_RESERVED_KERN: /* Fall-through: */ arch/x86/kernel/e820.c- case E820_TYPE_RAM: return IORESOURCE_SYSTEM_RAM; arch/x86/kernel/e820.c: case E820_TYPE_ACPI: /* Fall-through: */ arch/x86/kernel/e820.c: case E820_TYPE_NVS: /* Fall-through: */ arch/x86/kernel/e820.c: case E820_TYPE_UNUSABLE: /* Fall-through: */ arch/x86/kernel/e820.c: case E820_TYPE_PRAM: /* Fall-through: */ arch/x86/kernel/e820.c: case E820_TYPE_PMEM: /* Fall-through: */ arch/x86/kernel/e820.c: case E820_TYPE_RESERVED: /* Fall-through: */ arch/x86/kernel/e820.c: case E820_TYPE_SOFT_RESERVED: /* Fall-through: */ arch/x86/kernel/e820.c- default: return IORESOURCE_MEM; drivers/acpi/acpica/dswexec.c- } drivers/acpi/acpica/dswexec.c- drivers/acpi/acpica/dswexec.c: /* Fall through */ drivers/acpi/acpica/dswexec.c: /*lint -fallthrough */ drivers/acpi/acpica/dswexec.c- drivers/acpi/acpica/dswexec.c- case AML_INT_EVAL_SUBTREE_OP: drivers/acpi/acpica/dswexec.c- drivers/acpi/acpica/dswload.c- (walk_state-> drivers/acpi/acpica/dswload.c- parse_flags & ACPI_PARSE_MODULE_LEVEL)) { drivers/acpi/acpica/dswload.c- break; drivers/acpi/acpica/dswload.c- } drivers/acpi/acpica/dswload.c- drivers/acpi/acpica/dswload.c: /*lint -fallthrough */ drivers/acpi/acpica/dswload.c- drivers/acpi/acpica/dswload.c- default: (other acpica files exist, but acpica is autogenerated) drivers/ata/pata_cmd64x.c- case 1: drivers/ata/pata_cmd64x.c- ppi[0] = &cmd_info[4]; drivers/ata/pata_cmd64x.c- ppi[1] = &cmd_info[4]; drivers/ata/pata_cmd64x.c: /* FALL THRU */ drivers/ata/pata_cmd64x.c- /* Early revs have no CNTRL_CH0 */ drivers/ata/pata_cmd64x.c- case 2: drivers/atm/firestream.c- switch (STATUS_CODE (qe)) { drivers/atm/firestream.c- case 0x1: drivers/atm/firestream.c: /* Fall through for streaming mode */ drivers/atm/firestream.c- case 0x2:/* Packet received OK.... */ drivers/atm/firestream.c- if (atm_vcc) { drivers/atm/firestream.c- skb = pe->skb; drivers/atm/firestream.c- pe->fp->n--; drivers/block/rsxx/core.c- case CARD_STATE_FAULT: drivers/block/rsxx/core.c- dev_crit(CARD_TO_DEV(card), drivers/block/rsxx/core.c- "Hardware Fault reported!\n"); drivers/block/rsxx/core.c: /* Fall through. */ drivers/block/rsxx/core.c- drivers/block/rsxx/core.c- /* Everything else, detach DMA interface if it's attached. */ drivers/block/rsxx/core.c- case CARD_STATE_SHUTDOWN: etc...