[02/11] dib7000p: reduce large stack usage
Commit Message
From: Randy Dunlap <randy.dunlap@oracle.com>
Reduce the static stack usage of one of the 2 top offenders as listed by
'make checkstack':
Building with CONFIG_FRAME_WARN=2048 produces:
drivers/media/dvb/frontends/dib7000p.c:1367: warning: the frame size of 2320 bytes is larger than 2048 bytes
and in 'make checkstack', the stack usage goes from:
0x00002409 dib7000p_i2c_enumeration [dib7000p]: 2328
to unlisted with this patch.
Also change one caller of dib7000p_i2c_enumeration() to check its
return value.
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Patrick Boettcher <pboettcher@dibcom.fr>
Cc: Mauro Carvalho Chehab <mchehab@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
drivers/media/dvb/dvb-usb/cxusb.c | 5 +--
drivers/media/dvb/frontends/dib7000p.c | 36 ++++++++++++++---------
2 files changed, 25 insertions(+), 16 deletions(-)
Comments
akpm@linux-foundation.org wrote:
> diff -puN drivers/media/dvb/frontends/dib7000p.c~dib7000p-reduce-large-stack-usage drivers/media/dvb/frontends/dib7000p.c
> --- a/drivers/media/dvb/frontends/dib7000p.c~dib7000p-reduce-large-stack-usage
> +++ a/drivers/media/dvb/frontends/dib7000p.c
> @@ -1324,46 +1324,54 @@ EXPORT_SYMBOL(dib7000p_pid_filter);
>
> int dib7000p_i2c_enumeration(struct i2c_adapter *i2c, int no_of_demods, u8 default_addr, struct dib7000p_config cfg[])
> {
> - struct dib7000p_state st = { .i2c_adap = i2c };
> + struct dib7000p_state *dpst;
> int k = 0;
> u8 new_addr = 0;
>
> + dpst = kzalloc(sizeof(struct dib7000p_state), GFP_KERNEL);
> + if (!dpst)
> + return -ENODEV;
I think ENOMEM would be appropriate here.
The same applies to patch 01/11.
Regards,
Andreas
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@@ -1025,8 +1025,9 @@ static int cxusb_dualdig4_rev2_frontend_
cxusb_bluebird_gpio_pulse(adap->dev, 0x02, 1);
- dib7000p_i2c_enumeration(&adap->dev->i2c_adap, 1, 18,
- &cxusb_dualdig4_rev2_config);
+ if (dib7000p_i2c_enumeration(&adap->dev->i2c_adap, 1, 18,
+ &cxusb_dualdig4_rev2_config) < 0)
+ return -ENODEV;
adap->fe = dvb_attach(dib7000p_attach, &adap->dev->i2c_adap, 0x80,
&cxusb_dualdig4_rev2_config);
@@ -1324,46 +1324,54 @@ EXPORT_SYMBOL(dib7000p_pid_filter);
int dib7000p_i2c_enumeration(struct i2c_adapter *i2c, int no_of_demods, u8 default_addr, struct dib7000p_config cfg[])
{
- struct dib7000p_state st = { .i2c_adap = i2c };
+ struct dib7000p_state *dpst;
int k = 0;
u8 new_addr = 0;
+ dpst = kzalloc(sizeof(struct dib7000p_state), GFP_KERNEL);
+ if (!dpst)
+ return -ENODEV;
+
+ dpst->i2c_adap = i2c;
+
for (k = no_of_demods-1; k >= 0; k--) {
- st.cfg = cfg[k];
+ dpst->cfg = cfg[k];
/* designated i2c address */
new_addr = (0x40 + k) << 1;
- st.i2c_addr = new_addr;
- dib7000p_write_word(&st, 1287, 0x0003); /* sram lead in, rdy */
- if (dib7000p_identify(&st) != 0) {
- st.i2c_addr = default_addr;
- dib7000p_write_word(&st, 1287, 0x0003); /* sram lead in, rdy */
- if (dib7000p_identify(&st) != 0) {
+ dpst->i2c_addr = new_addr;
+ dib7000p_write_word(dpst, 1287, 0x0003); /* sram lead in, rdy */
+ if (dib7000p_identify(dpst) != 0) {
+ dpst->i2c_addr = default_addr;
+ dib7000p_write_word(dpst, 1287, 0x0003); /* sram lead in, rdy */
+ if (dib7000p_identify(dpst) != 0) {
dprintk("DiB7000P #%d: not identified\n", k);
+ kfree(dpst);
return -EIO;
}
}
/* start diversity to pull_down div_str - just for i2c-enumeration */
- dib7000p_set_output_mode(&st, OUTMODE_DIVERSITY);
+ dib7000p_set_output_mode(dpst, OUTMODE_DIVERSITY);
/* set new i2c address and force divstart */
- dib7000p_write_word(&st, 1285, (new_addr << 2) | 0x2);
+ dib7000p_write_word(dpst, 1285, (new_addr << 2) | 0x2);
dprintk("IC %d initialized (to i2c_address 0x%x)", k, new_addr);
}
for (k = 0; k < no_of_demods; k++) {
- st.cfg = cfg[k];
- st.i2c_addr = (0x40 + k) << 1;
+ dpst->cfg = cfg[k];
+ dpst->i2c_addr = (0x40 + k) << 1;
// unforce divstr
- dib7000p_write_word(&st, 1285, st.i2c_addr << 2);
+ dib7000p_write_word(dpst, 1285, dpst->i2c_addr << 2);
/* deactivate div - it was just for i2c-enumeration */
- dib7000p_set_output_mode(&st, OUTMODE_HIGH_Z);
+ dib7000p_set_output_mode(dpst, OUTMODE_HIGH_Z);
}
+ kfree(dpst);
return 0;
}
EXPORT_SYMBOL(dib7000p_i2c_enumeration);