On 03/02/10 16:00, imun...@au1.ibm.com wrote:
> From: Ian Munsie <imun...@au.ibm.com>
> 
> Compiling these drivers results in the following compiler warnings on
> PowerPC 64 bit:
> 
> drivers/media/dvb/frontends/dib3000mc.c:853: warning: the frame size of 2208 
> bytes is larger than 2048 bytes
> drivers/media/dvb/frontends/dib7000p.c:1367: warning: the frame size of 2288 
> bytes is larger than 2048 bytes
> 
> The <driver>_i2c_enumeration functions use a large struct to hold the
> state, which is stored on the stack.
> 
> This patch allocates that structure dynamically instead, thereby
> conserving the driver's use of the stack.

Is this the same as the already-submitted patches?

Please see http://patchwork.kernel.org/patch/77892/
and http://patchwork.kernel.org/patch/77891/

and in general, use http://patchwork.kernel.org/ and
http://patchwork.ozlabs.org/ and/or mailing lists to see if patches
have already been submitted so that you don't waste time.
Or you could comments on my patches. ;)


> There is now the possibility that these functions will return -ENOMEM in
> case the dynamic memory allocation fails and while a useful message will
> show up in dmesg, at the moment the -ENOMEM condition is not relayed
> all the way back to userspace and it will receive an -ENODEV instead.
> Is it worth pursuing returning the correct error all the way up to
> userspace?
> 
> Signed-off-by: Ian Munsie <imun...@au.ibm.com>
> ---
>  drivers/media/dvb/frontends/dib3000mc.c |   43 +++++++++++++++++++-----------
>  drivers/media/dvb/frontends/dib7000p.c  |   44 +++++++++++++++++++-----------
>  2 files changed, 55 insertions(+), 32 deletions(-)
> 
> diff --git a/drivers/media/dvb/frontends/dib3000mc.c 
> b/drivers/media/dvb/frontends/dib3000mc.c
> index fa85160..78c2813 100644
> --- a/drivers/media/dvb/frontends/dib3000mc.c
> +++ b/drivers/media/dvb/frontends/dib3000mc.c
> @@ -13,6 +13,7 @@
>  
>  #include <linux/kernel.h>
>  #include <linux/i2c.h>
> +#include <linux/slab.h>
>  
>  #include "dvb_frontend.h"
>  
> @@ -813,43 +814,53 @@ EXPORT_SYMBOL(dib3000mc_set_config);
>  
>  int dib3000mc_i2c_enumeration(struct i2c_adapter *i2c, int no_of_demods, u8 
> default_addr, struct dib3000mc_config cfg[])
>  {
> -     struct dib3000mc_state st = { .i2c_adap = i2c };
> +     struct dib3000mc_state *st;
>       int k;
>       u8 new_addr;
> -
>       static u8 DIB3000MC_I2C_ADDRESS[] = {20,22,24,26};
> +     int ret = 0;
> +
> +     st = kzalloc(sizeof(struct dib3000mc_state), GFP_KERNEL);
> +     if (!st) {
> +             dprintk(KERN_ERR "Out of memory allocating dib3000mc_state in 
> %s", __func__);
> +             return -ENOMEM;
> +     }
> +     st->i2c_adap = i2c;
>  
>       for (k = no_of_demods-1; k >= 0; k--) {
> -             st.cfg = &cfg[k];
> +             st->cfg = &cfg[k];
>  
>               /* designated i2c address */
>               new_addr          = DIB3000MC_I2C_ADDRESS[k];
> -             st.i2c_addr = new_addr;
> -             if (dib3000mc_identify(&st) != 0) {
> -                     st.i2c_addr = default_addr;
> -                     if (dib3000mc_identify(&st) != 0) {
> +             st->i2c_addr = new_addr;
> +             if (dib3000mc_identify(st) != 0) {
> +                     st->i2c_addr = default_addr;
> +                     if (dib3000mc_identify(st) != 0) {
>                               dprintk("-E-  DiB3000P/MC #%d: not 
> identified\n", k);
> -                             return -ENODEV;
> +                             ret = -ENODEV;
> +                             goto out;
>                       }
>               }
>  
> -             dib3000mc_set_output_mode(&st, OUTMODE_MPEG2_PAR_CONT_CLK);
> +             dib3000mc_set_output_mode(st, OUTMODE_MPEG2_PAR_CONT_CLK);
>  
>               // set new i2c address and force divstr (Bit 1) to value 0 (Bit 
> 0)
> -             dib3000mc_write_word(&st, 1024, (new_addr << 3) | 0x1);
> -             st.i2c_addr = new_addr;
> +             dib3000mc_write_word(st, 1024, (new_addr << 3) | 0x1);
> +             st->i2c_addr = new_addr;
>       }
>  
>       for (k = 0; k < no_of_demods; k++) {
> -             st.cfg = &cfg[k];
> -             st.i2c_addr = DIB3000MC_I2C_ADDRESS[k];
> +             st->cfg = &cfg[k];
> +             st->i2c_addr = DIB3000MC_I2C_ADDRESS[k];
>  
> -             dib3000mc_write_word(&st, 1024, st.i2c_addr << 3);
> +             dib3000mc_write_word(st, 1024, st->i2c_addr << 3);
>  
>               /* turn off data output */
> -             dib3000mc_set_output_mode(&st, OUTMODE_HIGH_Z);
> +             dib3000mc_set_output_mode(st, OUTMODE_HIGH_Z);
>       }
> -     return 0;
> +out:
> +     kfree(st);
> +     return ret;
>  }
>  EXPORT_SYMBOL(dib3000mc_i2c_enumeration);
>  
> diff --git a/drivers/media/dvb/frontends/dib7000p.c 
> b/drivers/media/dvb/frontends/dib7000p.c
> index 750ae61..08d47f2 100644
> --- a/drivers/media/dvb/frontends/dib7000p.c
> +++ b/drivers/media/dvb/frontends/dib7000p.c
> @@ -9,6 +9,7 @@
>   */
>  #include <linux/kernel.h>
>  #include <linux/i2c.h>
> +#include <linux/slab.h>
>  
>  #include "dvb_math.h"
>  #include "dvb_frontend.h"
> @@ -1323,47 +1324,58 @@ 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 *st;
>       int k = 0;
>       u8 new_addr = 0;
> +     int ret = 0;
> +
> +     st = kzalloc(sizeof(struct dib7000p_state), GFP_KERNEL);
> +     if (!st) {
> +             dprintk(KERN_ERR "Out of memory allocating dib7000p_state in 
> %s", __func__);
> +             return -ENOMEM;
> +     }
> +     st->i2c_adap = i2c;
>  
>       for (k = no_of_demods-1; k >= 0; k--) {
> -             st.cfg = cfg[k];
> +             st->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) {
> +             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) {
>                               dprintk("DiB7000P #%d: not identified\n", k);
> -                             return -EIO;
> +                             ret = -EIO;
> +                             goto out;
>                       }
>               }
>  
>               /* start diversity to pull_down div_str - just for 
> i2c-enumeration */
> -             dib7000p_set_output_mode(&st, OUTMODE_DIVERSITY);
> +             dib7000p_set_output_mode(st, OUTMODE_DIVERSITY);
>  
>               /* set new i2c address and force divstart */
> -             dib7000p_write_word(&st, 1285, (new_addr << 2) | 0x2);
> +             dib7000p_write_word(st, 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;
> +             st->cfg = cfg[k];
> +             st->i2c_addr = (0x40 + k) << 1;
>  
>               // unforce divstr
> -             dib7000p_write_word(&st, 1285, st.i2c_addr << 2);
> +             dib7000p_write_word(st, 1285, st->i2c_addr << 2);
>  
>               /* deactivate div - it was just for i2c-enumeration */
> -             dib7000p_set_output_mode(&st, OUTMODE_HIGH_Z);
> +             dib7000p_set_output_mode(st, OUTMODE_HIGH_Z);
>       }
>  
> -     return 0;
> +out:
> +     kfree(st);
> +     return ret;
>  }
>  EXPORT_SYMBOL(dib7000p_i2c_enumeration);
>  


-- 
~Randy
--
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