On Mon, 24 Jun 2024 11:19:19 +0200 Mauro Carvalho Chehab <mchehab+huawei@xxxxxxxxxx> wrote: > Sometimes it is desired to produce a single log line for errors. This description is a bit cryptic. Maybe an example would make it easier for anyone coming across this in the future? > Add a new helper function for such purpose. > > Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@xxxxxxxxxx> Minor comment inline. > --- > drivers/firmware/efi/cper.c | 41 +++++++++++++++++++++++++++++++++++++ > include/linux/cper.h | 2 ++ > 2 files changed, 43 insertions(+) > > diff --git a/drivers/firmware/efi/cper.c b/drivers/firmware/efi/cper.c > index 7d2cdd9e2227..4cf56657afde 100644 > --- a/drivers/firmware/efi/cper.c > +++ b/drivers/firmware/efi/cper.c > @@ -106,6 +106,47 @@ void cper_print_bits(const char *pfx, unsigned int bits, > printk("%s\n", buf); > } > > +/* > + * cper_bits_to_str - return a string for set bits > + * @buf: buffer to store the output string > + * @buf_size: size of the output string buffer > + * @bits: bit mask > + * @strs: string array, indexed by bit position > + * @strs_size: size of the string array: @strs > + * @mask: a continuous bitmask used to detect the first valid bit of the > + * bitmap. > + * > + * Add to @buf the bitmask in hexadecimal. Then, for each set bit in @bits > + * mask, add the corresponding string describing the bit in @strs to @buf. > + */ > +char *cper_bits_to_str(char *buf, int buf_size, unsigned long bits, > + const char * const strs[], unsigned int strs_size) > +{ > + int len = buf_size; > + char *str = buf; > + int i, size; > + > + for_each_set_bit(i, &bits, strs_size) { > + if (!(bits & (1U << (i)))) > + continue; > + > + if (*buf && len > 0) { That first check on *buf is a bit esoteric. It's more than possible we get a non clear buffer passed in. I'd just use a bool first = true; ... if (!first && len > 0) { *str = '|'; len--; str++; } first = false; > + *str = '|'; > + len--; > + str++; > + } > + > + size = strscpy(str, strs[i], len); > + if (size < 0) > + break; > + > + len -= size; > + str += size; > + } > + return buf; Why return buf? You never use it and it's not entirely obvious that is the right thing to return (as opposed to length written for example). > +} > +EXPORT_SYMBOL_GPL(cper_bits_to_str); > + > static const char * const proc_type_strs[] = { > "IA32/X64", > "IA64", > diff --git a/include/linux/cper.h b/include/linux/cper.h > index 265b0f8fc0b3..c2f14b916bfb 100644 > --- a/include/linux/cper.h > +++ b/include/linux/cper.h > @@ -584,6 +584,8 @@ const char *cper_mem_err_type_str(unsigned int); > const char *cper_mem_err_status_str(u64 status); > void cper_print_bits(const char *prefix, unsigned int bits, > const char * const strs[], unsigned int strs_size); > +char *cper_bits_to_str(char *buf, int buf_size, unsigned long bits, > + const char * const strs[], unsigned int strs_size); > void cper_mem_err_pack(const struct cper_sec_mem_err *, > struct cper_mem_err_compact *); > const char *cper_mem_err_unpack(struct trace_seq *,