scsi: bfa: document overflow of io_profile_start_time

io_profile_start_time() gets read using do_gettimeofday() and passed
down as a 32-bit value through multiple functions. This will overflow in
y2038 or y2106, depending on whether it gets interpreted as unsigned in
the end.

This changes do_gettimeofday() to ktime_get_real_seconds() and pushes
the point at which it overflows to where we actually assign it to the
bfa_fcpim_del_itn_stats_s structure, with an appropriate comment.

Signed-off-by: Arnd Bergmann <[e-mail]>
Acked-by: Anil Gurumurthy <[e-mail]>
Signed-off-by: Martin K. Petersen <[e-mail]>

drivers/scsi/bfa/bfa_fcpim.c

···
 }
 
 bfa_status_t
-bfa_fcpim_profile_on(struct bfa_s *bfa, u32 time)
+bfa_fcpim_profile_on(struct bfa_s *bfa, time64_t time)
 {
 	struct bfa_itnim_s *itnim;
 	struct bfa_fcpim_s *fcpim = BFA_FCPIM(bfa);
···
 		return BFA_STATUS_IOPROFILE_OFF;
 
 	itnim->ioprofile.index = BFA_IOBUCKET_MAX;
+	/* unsigned 32-bit time_t overflow here in y2106 */
 	itnim->ioprofile.io_profile_start_time =
 				bfa_io_profile_start_time(itnim->bfa);
 	itnim->ioprofile.clock_res_mul = bfa_io_lat_clock_res_mul;

drivers/scsi/bfa/bfa_fcpim.h

···
 	struct bfa_fcpim_del_itn_stats_s del_itn_stats;
 	bfa_boolean_t		ioredirect;
 	bfa_boolean_t		io_profile;
-	u32			io_profile_start_time;
+	time64_t		io_profile_start_time;
 	bfa_fcpim_profile_t     profile_comp;
 	bfa_fcpim_profile_t     profile_start;
 };
···
 			struct bfa_itnim_iostats_s *stats, u8 lp_tag);
 void bfa_fcpim_add_stats(struct bfa_itnim_iostats_s *fcpim_stats,
 			struct bfa_itnim_iostats_s *itnim_stats);
-bfa_status_t bfa_fcpim_profile_on(struct bfa_s *bfa, u32 time);
+bfa_status_t bfa_fcpim_profile_on(struct bfa_s *bfa, time64_t time);
 bfa_status_t bfa_fcpim_profile_off(struct bfa_s *bfa);
 
 #define bfa_fcpim_ioredirect_enabled(__bfa)				\

drivers/scsi/bfa/bfad_bsg.c

···
 {
 	struct bfa_bsg_fcpim_profile_s *iocmd =
 				(struct bfa_bsg_fcpim_profile_s *)cmd;
-	struct timeval  tv;
 	unsigned long	flags;
 
-	do_gettimeofday(&tv);
 	spin_lock_irqsave(&bfad->bfad_lock, flags);
 	if (v_cmd == IOCMD_FCPIM_PROFILE_ON)
-		iocmd->status = bfa_fcpim_profile_on(&bfad->bfa, tv.tv_sec);
+		iocmd->status = bfa_fcpim_profile_on(&bfad->bfa, ktime_get_real_seconds());
 	else if (v_cmd == IOCMD_FCPIM_PROFILE_OFF)
 		iocmd->status = bfa_fcpim_profile_off(&bfad->bfa);
 	spin_unlock_irqrestore(&bfad->bfad_lock, flags);