diff mbox series

[23/35] media: dvb-frontends: tda10048: Use the right div

Message ID 20240415-fix-cocci-v1-23-477afb23728b@chromium.org (mailing list archive)
State New, archived
Headers show
Series media: Fix coccinelle warning/errors | expand

Commit Message

Ricardo Ribalda April 15, 2024, 7:34 p.m. UTC 
z does not fit in 32 bits.

Found by cocci:
drivers/media/dvb-frontends/tda10048.c:345:1-7: WARNING: do_div() does a 64-by-32 division, please consider using div64_u64 instead.

Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
---
 drivers/media/dvb-frontends/tda10048.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

Comments

Dan Carpenter April 16, 2024, 10:10 a.m. UTC | #1 
On Mon, Apr 15, 2024 at 07:34:40PM +0000, Ricardo Ribalda wrote:
> z does not fit in 32 bits.
> 

z has to fit in 32 bits otherwise there is a different bug.

> Found by cocci:
> drivers/media/dvb-frontends/tda10048.c:345:1-7: WARNING: do_div() does a 64-by-32 division, please consider using div64_u64 instead.
> 
> Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
> ---
>  drivers/media/dvb-frontends/tda10048.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/drivers/media/dvb-frontends/tda10048.c b/drivers/media/dvb-frontends/tda10048.c
> index 5d5e4e9e4422..b176e7803e5b 100644
> --- a/drivers/media/dvb-frontends/tda10048.c
> +++ b/drivers/media/dvb-frontends/tda10048.c
> @@ -342,8 +342,7 @@ static int tda10048_set_wref(struct dvb_frontend *fe, u32 sample_freq_hz,
>  	t *= (2048 * 1024);
>  	t *= 1024;
>  	z = 7 * sample_freq_hz;

sample_freq_hz is a u32 so z can't be more than U32_MAX.  Perhaps there
is an integer overflow bug on this line.

The sample frequency is set in tda10048_set_if().

	state->sample_freq = state->xtal_hz * (state->pll_mfactor + 45);

->xtal_hz is set earlier in tda10048_set_if() and it goes up to
16,000,000.  So if ->pll_mfactor is non-zero this line will have an
integer overflow.  16million * 46 > U32_MAX.  Maybe when .clk_freq_khz
is TDA10048_CLK_16000 then ->pll_mfactor is zero?  Ugh...

> -	do_div(t, z);
> -	t += 5;
> +	t = div64_u64(t, z) + 5;
>  	do_div(t, 10);

regards,
dan carpenter
Dan Carpenter April 16, 2024, 10:27 a.m. UTC | #2 
I have created a Smatch check to warn about code like this:

drivers/media/dvb-frontends/tda10048.c:345 tda10048_set_wref() warn: unnecessary div64_u64(): divisor = '0-u32max'

regards,
dan carpenter

/*
 * Copyright 2024 Linaro Ltd.
 *
 * 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 the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, see http://www.gnu.org/copyleft/gpl.txt
 */

#include "smatch.h"
#include "smatch_extra.h"

static int my_id;

static const sval_t uint_max  = { .type = &uint_ctype, .value = UINT_MAX };

static void match_div64_u64(struct expression *expr)
{
	struct range_list *rl;

	get_real_absolute_rl(expr, &rl);
	if (sval_cmp(rl_max(rl), uint_max) > 0)
		return;
	sm_warning("unnecessary div64_u64(): divisor = '%s'", show_rl(rl));
}

void check_unnecessary_div64_u64(int id)
{
	my_id = id;

	if (option_project != PROJ_KERNEL)
		return;

	add_param_key_expr_hook("div64_u64", match_div64_u64, 1, "$", NULL);
}
Ricardo Ribalda April 16, 2024, 10:39 a.m. UTC | #3 
Hi Dan

What about going the safe way?

--- a/drivers/media/dvb-frontends/tda10048.c
+++ b/drivers/media/dvb-frontends/tda10048.c
@@ -341,7 +341,7 @@ static int tda10048_set_wref(struct dvb_frontend
*fe, u32 sample_freq_hz,
        /* t *= 2147483648 on 32bit platforms */
        t *= (2048 * 1024);
        t *= 1024;
-       z = 7 * sample_freq_hz;
+       z = (u64)7 * sample_freq_hz;
        t = div64_u64(t, z) + 5;
        do_div(t, 10);

@@ -409,6 +409,7 @@ static int tda10048_set_if(struct dvb_frontend *fe, u32 bw)
        struct tda10048_config *config = &state->config;
        int i;
        u32 if_freq_khz;
+       u64 sample_freq;

        dprintk(1, "%s(bw = %d)\n", __func__, bw);

@@ -450,9 +451,10 @@ static int tda10048_set_if(struct dvb_frontend *fe, u32 bw)
        dprintk(1, "- pll_pfactor = %d\n", state->pll_pfactor);

        /* Calculate the sample frequency */
-       state->sample_freq = state->xtal_hz * (state->pll_mfactor + 45);
-       state->sample_freq /= (state->pll_nfactor + 1);
-       state->sample_freq /= (state->pll_pfactor + 4);
+       sample_freq = (u64)state->xtal_hz * (state->pll_mfactor + 45);
+       do_div(sample_freq, state->pll_nfactor + 1);
+       do_div(sample_freq, state->pll_pfactor + 4);
+       state->sample_freq = sample_freq;
        dprintk(1, "- sample_freq = %d\n", state->sample_freq);

        /* Update the I/F */

I will add a extra patch to fix tda10048_set_if

Thanks

PS: Thanks a lot for your reviews, really appreciate! I have a v2 with
your changes, I am giving it a couple of days before re-submitting

On Tue, 16 Apr 2024 at 12:10, Dan Carpenter <dan.carpenter@linaro.org> wrote:
>
> On Mon, Apr 15, 2024 at 07:34:40PM +0000, Ricardo Ribalda wrote:
> > z does not fit in 32 bits.
> >
>
> z has to fit in 32 bits otherwise there is a different bug.
>
> > Found by cocci:
> > drivers/media/dvb-frontends/tda10048.c:345:1-7: WARNING: do_div() does a 64-by-32 division, please consider using div64_u64 instead.
> >
> > Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
> > ---
> >  drivers/media/dvb-frontends/tda10048.c | 3 +--
> >  1 file changed, 1 insertion(+), 2 deletions(-)
> >
> > diff --git a/drivers/media/dvb-frontends/tda10048.c b/drivers/media/dvb-frontends/tda10048.c
> > index 5d5e4e9e4422..b176e7803e5b 100644
> > --- a/drivers/media/dvb-frontends/tda10048.c
> > +++ b/drivers/media/dvb-frontends/tda10048.c
> > @@ -342,8 +342,7 @@ static int tda10048_set_wref(struct dvb_frontend *fe, u32 sample_freq_hz,
> >       t *= (2048 * 1024);
> >       t *= 1024;
> >       z = 7 * sample_freq_hz;
>
> sample_freq_hz is a u32 so z can't be more than U32_MAX.  Perhaps there
> is an integer overflow bug on this line.
>
> The sample frequency is set in tda10048_set_if().
>
>         state->sample_freq = state->xtal_hz * (state->pll_mfactor + 45);
>
> ->xtal_hz is set earlier in tda10048_set_if() and it goes up to
> 16,000,000.  So if ->pll_mfactor is non-zero this line will have an
> integer overflow.  16million * 46 > U32_MAX.  Maybe when .clk_freq_khz
> is TDA10048_CLK_16000 then ->pll_mfactor is zero?  Ugh...
>
> > -     do_div(t, z);
> > -     t += 5;
> > +     t = div64_u64(t, z) + 5;
> >       do_div(t, 10);
>
> regards,
> dan carpenter
>
Dan Carpenter April 16, 2024, 10:56 a.m. UTC | #4 
On Tue, Apr 16, 2024 at 12:39:33PM +0200, Ricardo Ribalda wrote:
> Hi Dan
> 
> What about going the safe way?
> 
> --- a/drivers/media/dvb-frontends/tda10048.c
> +++ b/drivers/media/dvb-frontends/tda10048.c
> @@ -341,7 +341,7 @@ static int tda10048_set_wref(struct dvb_frontend
> *fe, u32 sample_freq_hz,
>         /* t *= 2147483648 on 32bit platforms */
>         t *= (2048 * 1024);
>         t *= 1024;
> -       z = 7 * sample_freq_hz;
> +       z = (u64)7 * sample_freq_hz;

I think your patch works, but it might be nicer without the casts.  We
end up having the discussion where it's like "Can this hz be above 4GHz?"
And, here, I think we're safe but a lot of stuff is pushing up against
that limit these days...

regards,
dan carpenter
Dan Carpenter April 23, 2024, 9:55 a.m. UTC | #5 
Btw, here is the output from my check (based on linux next from a few
days ago).  There are some false positives because Smatch parses
__pow10() incorrectly etc but it's mostly correct.

regards,
dan carpenter

drivers/mtd/spi-nor/core.c:2896 spi_nor_late_init_params() warn: unnecessary div64_u64(): divisor = '2-255'
drivers/mtd/spi-nor/core.c:3409 spi_nor_set_mtd_eraseregions() warn: unnecessary div64_u64(): divisor = '1-u32max'
drivers/hwmon/occ/common.c:467 occ_get_powr_avg() warn: unnecessary div64_u64(): divisor = '1-u32max'
drivers/hwmon/occ/common.c:702 occ_store_caps_user() warn: unnecessary div64_u64(): divisor = '1000000'
drivers/hwmon/scmi-hwmon.c:67 scmi_hwmon_scale() warn: unnecessary div64_u64(): divisor = '1,10'
drivers/infiniband/hw/cxgb4/device.c:160 wr_log_show() warn: unnecessary div64_u64(): divisor = '1000'
drivers/infiniband/hw/cxgb4/device.c:161 wr_log_show() warn: unnecessary div64_u64(): divisor = '1000'
drivers/clk/clk-versaclock7.c:743 vc7_get_apll_rate() warn: unnecessary div64_u64(): divisor = '2-31'
drivers/clk/clk-versaclock7.c:794 vc7_calc_fod_1st_stage_rate() warn: unnecessary div64_u64(): divisor = '0-u32max'
drivers/clk/clk-versaclock7.c:812 vc7_calc_fod_2nd_stage_rate() warn: unnecessary div64_u64(): divisor = '2-u32max'
drivers/clk/clk-versaclock7.c:973 vc7_iod_recalc_rate() warn: unnecessary div64_u64(): divisor = '0-u32max'
drivers/clk/clk-versaclock7.c:990 vc7_iod_round_rate() warn: unnecessary div64_u64(): divisor = '14-33554431'
drivers/clk/clk-versaclock7.c:1016 vc7_iod_set_rate() warn: unnecessary div64_u64(): divisor = '0-u32max'
drivers/clk/clk-si570.c:263 si570_round_rate() warn: unnecessary div64_u64(): divisor = '2'
drivers/pci/setup-bus.c:1909 pci_bus_distribute_available_resources() warn: unnecessary div64_u64(): divisor = '1-u32max'
drivers/pci/setup-bus.c:1910 pci_bus_distribute_available_resources() warn: unnecessary div64_u64(): divisor = '1-u32max'
drivers/pci/setup-bus.c:1911 pci_bus_distribute_available_resources() warn: unnecessary div64_u64(): divisor = '1-u32max'
drivers/pci/setup-bus.c:1914 pci_bus_distribute_available_resources() warn: unnecessary div64_u64(): divisor = '0-u32max'
drivers/pci/setup-bus.c:1915 pci_bus_distribute_available_resources() warn: unnecessary div64_u64(): divisor = '0-u32max'
drivers/pci/setup-bus.c:1916 pci_bus_distribute_available_resources() warn: unnecessary div64_u64(): divisor = '0-u32max'
drivers/tty/serial/serial_core.c:431 uart_update_timeout() warn: unnecessary div64_u64(): divisor = '0-u32max'
drivers/ptp/ptp_qoriq.c:224 ptp_qoriq_adjfine() warn: unnecessary div64_u64(): divisor = '2'
drivers/ptp/ptp_dte.c:150 ptp_dte_adjfine() warn: unnecessary div64_u64(): divisor = '125000000'
drivers/ptp/ptp_dte.c:152 ptp_dte_adjfine() warn: unnecessary div64_u64(): divisor = '125000000'
drivers/gpu/drm/radeon/si_dpm.c:2200 si_calculate_power_efficiency_ratio() warn: unnecessary div64_u64(): divisor = '1000'
drivers/gpu/drm/radeon/si_dpm.c:2202 si_calculate_power_efficiency_ratio() warn: unnecessary div64_u64(): divisor = '1-4294836225'
drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi.c:356 rcar_mipi_dsi_pll_calc() warn: unnecessary div64_u64(): divisor = '0-255'
drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi.c:361 rcar_mipi_dsi_pll_calc() warn: unnecessary div64_u64(): divisor = '0-u16max'
drivers/gpu/drm/amd/amdgpu/../pm/legacy-dpm/si_dpm.c:2351 si_calculate_power_efficiency_ratio() warn: unnecessary div64_u64(): divisor = '1000'
drivers/gpu/drm/amd/amdgpu/../pm/legacy-dpm/si_dpm.c:2353 si_calculate_power_efficiency_ratio() warn: unnecessary div64_u64(): divisor = '1-4294836225'
drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c:1673 amdgpu_ras_sysfs_badpages_read() warn: unnecessary div64_u64(): divisor = '28'
drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c:1674 amdgpu_ras_sysfs_badpages_read() warn: unnecessary div64_u64(): divisor = '28'
drivers/gpu/drm/amd/amdgpu/../display/dc/dc_dmub_srv.c:592 populate_subvp_cmd_drr_info() warn: unnecessary div64_u64(): divisor = '2'
drivers/gpu/drm/amd/amdgpu/../display/dc/hwss/dce110/dce110_hwseq.c:807 dce110_edp_power_control() warn: unnecessary div64_u64(): divisor = '1000000'
drivers/gpu/drm/amd/amdgpu/../display/dc/hwss/dce110/dce110_hwseq.c:812 dce110_edp_power_control() warn: unnecessary div64_u64(): divisor = '1000000'
drivers/gpu/drm/amd/amdgpu/../display/dc/hwss/dce110/dce110_hwseq.c:935 dce110_edp_wait_for_T12() warn: unnecessary div64_u64(): divisor = '1000000'
drivers/gpu/drm/amd/amdgpu/../display/dc/link/protocols/link_edp_panel_control.c:765 edp_setup_psr() warn: unnecessary div64_u64(): divisor = '0-u32max'
drivers/gpu/drm/amd/amdgpu/../display/dc/link/protocols/link_edp_panel_control.c:765 edp_setup_psr() warn: unnecessary div64_u64(): divisor = '0-u32max'
drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm_mst_types.c:800 kbps_to_peak_pbn() warn: unnecessary div64_u64(): divisor = '432000'
drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm_psr.c:160 amdgpu_dm_psr_enable() warn: unnecessary div64_u64(): divisor = '0-u32max'
drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm_psr.c:160 amdgpu_dm_psr_enable() warn: unnecessary div64_u64(): divisor = '0-u32max'
drivers/gpu/drm/amd/amdgpu/../display/modules/freesync/freesync.c:106 calc_duration_in_us_from_refresh_in_uhz() warn: unnecessary div64_u64(): divisor = '0-u32max'
drivers/gpu/drm/amd/amdgpu/../display/modules/freesync/freesync.c:117 calc_duration_in_us_from_v_total() warn: unnecessary div64_u64(): divisor = '0-u32max'
drivers/gpu/drm/amd/amdgpu/../display/modules/freesync/freesync.c:132 mod_freesync_calc_v_total_from_refresh() warn: unnecessary div64_u64(): divisor = '0-u32max'
drivers/gpu/drm/amd/amdgpu/../display/modules/freesync/freesync.c:135 mod_freesync_calc_v_total_from_refresh() warn: unnecessary div64_u64(): divisor = '0-u32max'
drivers/gpu/drm/amd/amdgpu/../display/modules/freesync/freesync.c:135 mod_freesync_calc_v_total_from_refresh() warn: unnecessary div64_u64(): divisor = '1000000'
drivers/gpu/drm/amd/amdgpu/../display/modules/freesync/freesync.c:169 calc_v_total_from_duration() warn: unnecessary div64_u64(): divisor = '0-u32max'
drivers/gpu/drm/amd/amdgpu/../display/modules/freesync/freesync.c:169 calc_v_total_from_duration() warn: unnecessary div64_u64(): divisor = '1000'
drivers/gpu/drm/amd/amdgpu/../display/modules/freesync/freesync.c:201 update_v_total_for_static_ramp() warn: unnecessary div64_u64(): divisor = '1000000'
drivers/gpu/drm/amd/amdgpu/../display/modules/freesync/freesync.c:200 update_v_total_for_static_ramp() warn: unnecessary div64_u64(): divisor = '1000-4467765'
drivers/gpu/drm/amd/amdgpu/../display/modules/freesync/freesync.c:207 update_v_total_for_static_ramp() warn: unnecessary div64_u64(): divisor = '1000'
drivers/gpu/drm/amd/amdgpu/../display/modules/freesync/freesync.c:214 update_v_total_for_static_ramp() warn: unnecessary div64_u64(): divisor = '16666'
drivers/gpu/drm/amd/amdgpu/../display/modules/freesync/freesync.c:245 update_v_total_for_static_ramp() warn: unnecessary div64_u64(): divisor = '0-u32max'
drivers/gpu/drm/amd/amdgpu/../display/modules/freesync/freesync.c:245 update_v_total_for_static_ramp() warn: unnecessary div64_u64(): divisor = '1000'
drivers/gpu/drm/amd/amdgpu/../display/modules/freesync/freesync.c:1004 mod_freesync_build_vrr_params() warn: unnecessary div64_u64(): divisor = '0-u32max'
drivers/acpi/cppc_acpi.c:1855 cppc_perf_to_khz() warn: unnecessary div64_u64(): divisor = '0-u32max'
drivers/acpi/cppc_acpi.c:1863 cppc_perf_to_khz() warn: unnecessary div64_u64(): divisor = '0-u32max'
drivers/acpi/cppc_acpi.c:1885 cppc_khz_to_perf() warn: unnecessary div64_u64(): divisor = '0-u32max'
drivers/leds/rgb/leds-qcom-lpg.c:458 lpg_calc_freq() warn: unnecessary div64_u64(): divisor = '0-u32max'
drivers/leds/rgb/leds-qcom-lpg.c:464 lpg_calc_freq() warn: unnecessary div64_u64(): divisor = '1024'
drivers/md/dm-cache-policy-smq.c:1750 __smq_create() warn: unnecessary div64_u64(): divisor = '64-2097152'
drivers/md/dm-verity-fec.c:764 verity_fec_ctr() warn: unnecessary div64_u64(): divisor = '512-130560'
drivers/pwm/pwm-lpc32xx.c:48 lpc32xx_pwm_config() warn: unnecessary div64_u64(): divisor = 's32min-s32max'
drivers/pwm/pwm-bcm-iproc.c:138 iproc_pwmc_apply() warn: unnecessary div64_u64(): divisor = '1000000000'
drivers/pwm/pwm-bcm-iproc.c:140 iproc_pwmc_apply() warn: unnecessary div64_u64(): divisor = '1000000000'
drivers/pwm/pwm-sifive.c:95 pwm_sifive_update_clock() warn: unnecessary div64_u64(): divisor = '1000000000'
drivers/pwm/pwm-spear.c:98 spear_pwm_config() warn: unnecessary div64_u64(): divisor = '1000000000'
drivers/pwm/pwm-spear.c:100 spear_pwm_config() warn: unnecessary div64_u64(): divisor = '1000000000'
drivers/media/i2c/st-vgxy61.c:482 get_pixel_rate() warn: unnecessary div64_u64(): divisor = '0-255'
drivers/media/i2c/st-vgxy61.c:569 vgxy61_check_bw() warn: unnecessary div64_u64(): divisor = '0-u32max'
drivers/media/i2c/ds90ub913.c:642 ub913_i2c_master_init() warn: unnecessary div64_u64(): divisor = '1000000000'
drivers/media/i2c/ds90ub913.c:643 ub913_i2c_master_init() warn: unnecessary div64_u64(): divisor = '1000000000'
drivers/media/i2c/ds90ub953.c:832 ub953_i2c_master_init() warn: unnecessary div64_u64(): divisor = '1000000000'
drivers/media/i2c/ds90ub953.c:833 ub953_i2c_master_init() warn: unnecessary div64_u64(): divisor = '1000000000'
drivers/media/platform/ti/vpe/sc.c:202 sc_config_scaler() warn: unnecessary div64_u64(): divisor = '0-u32max'
drivers/media/dvb-core/dvb_demux.c:425 dvb_dmx_swfilter_packet() warn: unnecessary div64_u64(): divisor = '1024'
drivers/scsi/sym53c8xx_2/sym_hipd.c:749 sym_prepare_setting() warn: unnecessary div64_u64(): divisor = '40000-2560000'
drivers/video/fbdev/omap2/omapfb/dss/dsi.c:4773 dsi_vm_calc() warn: unnecessary div64_u64(): divisor = 's32min-s32max'
drivers/video/fbdev/omap2/omapfb/dss/dsi.c:4780 dsi_vm_calc() warn: unnecessary div64_u64(): divisor = 's32min-s32max'
drivers/cpufreq/cppc_cpufreq.c:124 cppc_scale_freq_workfn() warn: unnecessary div64_u64(): divisor = '0-u32max'
drivers/pinctrl/ti/pinctrl-ti-iodelay.c:192 ti_iodelay_compute_dpe() warn: unnecessary div64_u64(): divisor = '176-34602480'
drivers/net/wireless/intel/iwlwifi/mvm/ptp.c:55 iwl_mvm_ptp_get_adj_time() warn: unnecessary div64_u64(): divisor = '1000'
drivers/net/ethernet/xilinx/xilinx_axienet_main.c:240 axienet_usec_to_timer() warn: unnecessary div64_u64(): divisor = '125000000'
drivers/net/ethernet/broadcom/bnxt/bnxt_ptp.c:407 bnxt_get_target_cycles() warn: unnecessary div64_u64(): divisor = '0-u32max'
drivers/net/ethernet/aquantia/atlantic/hw_atl/hw_atl_b0.c:1262 hw_atl_b0_adj_params_get() warn: unnecessary div64_u64(): divisor = '1000000000'
drivers/net/ethernet/engleder/tsnep_selftests.c:164 delay_base_time() warn: unnecessary div64_u64(): divisor = '62500,100000,200000,333333,400000,411854,500000,1000000,1500000,1700000,2000000,6000000'
drivers/net/ethernet/mellanox/mlxsw/spectrum_ptp.c:301 mlxsw_sp1_ptp_clock_init() warn: unnecessary div64_u64(): divisor = '3435819912'
drivers/net/ethernet/mellanox/mlx5/core/en/htb.c:263 mlx5e_htb_convert_rate() warn: unnecessary div64_u64(): divisor = '1-u32max'
drivers/net/ethernet/mellanox/mlx5/core/lib/clock.c:519 find_target_cycles() warn: unnecessary div64_u64(): divisor = '0-u32max'
drivers/net/ethernet/mellanox/mlx5/core/lib/clock.c:966 mlx5_init_overflow_period() warn: unnecessary div64_u64(): divisor = '0-u32max'
drivers/net/ethernet/intel/ice/ice_ptp.c:1717 ice_ptp_cfg_clkout() warn: unnecessary div64_u64(): divisor = '1000000000'
drivers/base/arch_topology.c:406 topology_init_cpu_capacity_cppc() warn: unnecessary div64_u64(): divisor = '0-u32max'
block/blk-iolatency.c:441 check_scale_change() warn: unnecessary div64_u64(): divisor = '100'
block/blk-iolatency.c:266 iolat_update_total_lat_avg() warn: unnecessary div64_u64(): divisor = '250000000'
block/blk-iolatency.c:236 latency_sum_ok() warn: unnecessary div64_u64(): divisor = '10'
block/blk-iolatency.c:955 iolatency_pd_stat() warn: unnecessary div64_u64(): divisor = '1000'
block/blk-iolatency.c:956 iolatency_pd_stat() warn: unnecessary div64_u64(): divisor = '1000000'
block/blk-iocost.c:706 abs_cost_to_cost() warn: unnecessary div64_u64(): divisor = '0-u32max'
block/blk-iocost.c:714 cost_to_abs_cost() warn: unnecessary div64_u64(): divisor = '65536'
block/blk-iocost.c:797 ioc_refresh_period_us() warn: unnecessary div64_u64(): divisor = '100'
block/blk-iocost.c:831 ioc_autop_idx() warn: unnecessary div64_u64(): divisor = '137438'
block/blk-iocost.c:943 ioc_refresh_params_disk() warn: unnecessary div64_u64(): divisor = '1000000'
block/blk-iocost.c:945 ioc_refresh_params_disk() warn: unnecessary div64_u64(): divisor = '1000000'
block/blk-iocost.c:1015 ioc_adjust_base_vrate() warn: unnecessary div64_u64(): divisor = '100'
block/blk-iocost.c:1018 ioc_adjust_base_vrate() warn: unnecessary div64_u64(): divisor = '100'
block/blk-iocost.c:1030 ioc_adjust_base_vrate() warn: unnecessary div64_u64(): divisor = '100'
block/blk-iocost.c:1365 iocg_kick_delay() warn: unnecessary div64_u64(): divisor = '1000000'
block/blk-iocost.c:1618 ioc_lat_stat() warn: unnecessary div64_u64(): divisor = '0-u32max'
block/blk-iocost.c:1762 hweight_after_donation() warn: unnecessary div64_u64(): divisor = '65536'
block/blk-iocost.c:1990 transfer_surpluses() warn: unnecessary div64_u64(): divisor = '0-65536'
block/blk-iocost.c:1999 transfer_surpluses() warn: unnecessary div64_u64(): divisor = '65536'
block/blk-iocost.c:2004 transfer_surpluses() warn: unnecessary div64_u64(): divisor = '0-u32max'
block/blk-iocost.c:2009 transfer_surpluses() warn: unnecessary div64_u64(): divisor = '0-u32max'
block/blk-iocost.c:2013 transfer_surpluses() warn: unnecessary div64_u64(): divisor = '0-u32max'
block/blk-iocost.c:2016 transfer_surpluses() warn: unnecessary div64_u64(): divisor = '0-u32max'
block/blk-iocost.c:2020 transfer_surpluses() warn: unnecessary div64_u64(): divisor = '0-u32max'
block/blk-iocost.c:2044 transfer_surpluses() warn: unnecessary div64_u64(): divisor = '0-u32max'
block/blk-iocost.c:2213 ioc_check_iocgs() warn: unnecessary div64_u64(): divisor = '65536'
block/blk-iocost.c:2823 ioc_rqos_done() warn: unnecessary div64_u64(): divisor = '137'
block/blk-iocost.c:3047 ioc_pd_stat() warn: unnecessary div64_u64(): divisor = '137438'
fs/bcachefs/tests.c:788 btree_perf_test_thread() warn: unnecessary div64_u64(): divisor = '0-u32max'
fs/bcachefs/alloc_background.c:2261 bch2_recalc_capacity() warn: unnecessary div64_u64(): divisor = '100'
fs/btrfs/block-group.c:2793 calculate_global_root_id() warn: unnecessary div64_u64(): divisor = '134217728,1073741824'
fs/nilfs2/the_nilfs.c:416 nilfs_max_segment_count() warn: unnecessary div64_u64(): divisor = '16-u32max'
fs/f2fs/gc.c:568 atgc_lookup_victim() warn: unnecessary div64_u64(): divisor = '0-u32max'
fs/f2fs/iostat.c:23 iostat_get_avg_bytes() warn: unnecessary div64_u64(): divisor = '0'
kernel/trace/trace_benchmark.c:107 trace_do_benchmark() warn: unnecessary div64_u64(): divisor = '0,2-u32max'
kernel/trace/trace_benchmark.c:129 trace_do_benchmark() warn: unnecessary div64_u64(): divisor = '1-u32max'
kernel/trace/trace_events_hist.c:701 hist_field_get_div_fn() warn: unnecessary div64_u64(): divisor = '1-1048576'
kernel/trace/trace_events_hist.c:5430 __get_percentage() warn: unnecessary div64_u64(): divisor = '10000'
kernel/dma/map_benchmark.c:82 map_benchmark_thread() warn: unnecessary div64_u64(): divisor = '100'
kernel/dma/map_benchmark.c:83 map_benchmark_thread() warn: unnecessary div64_u64(): divisor = '100'
kernel/fork.c:1011 set_max_threads() warn: unnecessary div64_u64(): divisor = '131072'
sound/usb/mixer_quirks.c:2353 snd_rme_current_freq_get() warn: unnecessary div64_u64(): divisor = '1-u32max'
sound/soc/sof/ipc4-mtrace.c:432 ipc4_mtrace_enable() warn: unnecessary div64_u64(): divisor = '1000'
sound/soc/sti/uniperif_player.c:182 uni_player_clk_set_rate() warn: unnecessary div64_u64(): divisor = '1000000'
net/netfilter/xt_hashlimit.c:498 user2credits() warn: unnecessary div64_u64(): divisor = '32000'
net/netfilter/xt_hashlimit.c:498 user2credits() warn: unnecessary div64_u64(): divisor = '31'
net/netfilter/xt_hashlimit.c:500 user2credits() warn: unnecessary div64_u64(): divisor = '10000,1000000'
net/ipv4/inetpeer.c:79 inet_initpeers() warn: unnecessary div64_u64(): divisor = '19200'
Ricardo Ribalda April 29, 2024, 11:39 a.m. UTC | #6 
Hi Dan

On Tue, 23 Apr 2024 at 11:55, Dan Carpenter <dan.carpenter@linaro.org> wrote:
>
> Btw, here is the output from my check (based on linux next from a few
> days ago).  There are some false positives because Smatch parses
> __pow10() incorrectly etc but it's mostly correct.

This looks pretty cool :)

Are you planning to add this to smatch soon?

Thanks!
diff mbox series

Patch

diff --git a/drivers/media/dvb-frontends/tda10048.c b/drivers/media/dvb-frontends/tda10048.c
index 5d5e4e9e4422..b176e7803e5b 100644
--- a/drivers/media/dvb-frontends/tda10048.c
+++ b/drivers/media/dvb-frontends/tda10048.c
@@ -342,8 +342,7 @@  static int tda10048_set_wref(struct dvb_frontend *fe, u32 sample_freq_hz,
 	t *= (2048 * 1024);
 	t *= 1024;
 	z = 7 * sample_freq_hz;
-	do_div(t, z);
-	t += 5;
+	t = div64_u64(t, z) + 5;
 	do_div(t, 10);
 
 	tda10048_writereg(state, TDA10048_TIME_WREF_LSB, (u8)t);