Messages in this thread | | | Subject | Re: [PATCH v9] mmc: Export host capabilities to debugfs. | From | Harish Jenny K N <> | Date | Mon, 12 Mar 2018 19:04:17 +0530 |
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On Monday 12 March 2018 06:33 PM, Andy Shevchenko wrote: > On Mon, 2018-03-12 at 18:00 +0530, Harish Jenny K N wrote: > > >>>>>>> + for_each_set_bit(bit, (const unsigned long *)&caps, >>>>>>> BITS_PER_LONG) >>>>>>> + for_each_set_bit(bit, (const unsigned long >>>>>>> *)&caps2, >>>>>>> BITS_PER_LONG) >>>>>> Explicit casting is not needed anymore in both cases. >>>>> Also maybe use sizeof(mmc_host_capabilities) instead of >>>>> BITS_PER_LONG? >>>> You mean sizeof(caps) and not sizeof(mmc_host_capabilities) . >>>> Right ? >>> meant ARRAY_SIZE(mmc_host_capabilities) >> ARRAY_SIZE(mmc_host_capabilities) will be 32 and this will be my old >> change for which I got a comment from Andy Shevchenko asking me to >> replace u32 with unsigned long. >> >> This is the old comment: >> >>>> + int size = sizeof(u32) * BITS_PER_BYTE; >>> This is redundant. Use BITS_PER_LONG (why's that, see below) in the > There is nothing about ARRAY_SIZE(). > ARRAY_SIZE() will work quite good as well.
Yes. Definitely it works. I was only mentioning about changing u32 to unsigned long for caps and passing BITS_PER_LONG as size in for_each_set_bit. > >> for_each_set_bit(). >> >>>> + for_each_set_bit(bit, (const unsigned long *)&caps, size) >>>> + for_each_set_bit(bit, (const unsigned long *)&caps2, size) >>> These are UB cases. >>> Fix is simple, replace u32 by unsigned long in (1) above. >> Note: Without typecasting &caps to(const unsigned long *) will give >> compilation error in this case. > What kind of? >
Sorry for I was not clear that the compilation error is for the following case > u32 caps = host->caps; > for_each_set_bit(bit, &caps, ARRAY_SIZE(mmc_host_capabilities))
example: compilation for arm gives this error for the following lines:
drivers/mmc/core/debugfs.c: In function 'mmc_caps_show': ./include/linux/bitops.h:41:30: error: passing argument 1 of '_find_first_bit_le' from incompatible pointer type [-Werror=incompatible-pointer-types] for ((bit) = find_first_bit((addr), (size)); \ ^ ./arch/arm/include/asm/bitops.h:202:50: note: in definition of macro 'find_first_bit' #define find_first_bit(p,sz) _find_first_bit_le(p,sz) ^ drivers/mmc/core/debugfs.c:318:2: note: in expansion of macro 'for_each_set_bit' for_each_set_bit(bit, &caps, ARRAY_SIZE(mmc_host_capabilities)) ^ ./arch/arm/include/asm/bitops.h:165:12: note: expected 'const long unsigned int *' but argument is of type 'u32 * {aka unsigned int *}' extern int _find_first_bit_le(const unsigned long *p, unsigned size); ^
Thanks, Harish Jenny K N
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