| Message ID | 20241018-cxl-pra-v1-2-7f49ba58208b@intel.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | printf: Add struct range print specifier | expand |
Ira Weiny wrote: > The use of struct range in the CXL subsystem is growing. In particular, > the addition of Dynamic Capacity devices uses struct range in a number > of places which are reported in debug and error messages. > > To wit requiring the printing of the start/end fields in each print > became cumbersome. Dan Williams mentions in [1] that it might be time > to have a print specifier for struct range similar to struct resource > > A few alternatives were considered including '%par', '%r', and '%pn'. > %pra follows that struct range is similar to struct resource (%p[rR]) > but needs to be different. Based on discussions with Petr and Andy > '%pra' was chosen.[2] > > Andy also suggested to keep the range prints similar to struct resource > though combined code. Add hex_range() to handle printing for both > pointer types. > > Finally introduce DEFINE_RANGE() as a parallel to DEFINE_RES_*() and use > it in the tests. > > Cc: Jonathan Corbet <corbet@lwn.net> (maintainer:DOCUMENTATION) > Cc: linux-doc@vger.kernel.org > Cc: linux-kernel@vger.kernel.org (open list) > Link: https://lore.kernel.org/all/663922b475e50_d54d72945b@dwillia2-xfh.jf.intel.com.notmuch/ [1] > Link: https://lore.kernel.org/all/66cea3bf3332f_f937b29424@iweiny-mobl.notmuch/ [2] > Suggested-by: "Dan Williams" <dan.j.williams@intel.com> > Signed-off-by: Ira Weiny <ira.weiny@intel.com> > > --- > Changes: > [iweiny: split from CXL patch set] > [Andy: Define DEFINE_RANGE()] > [Andy: rework hex_range() logic] > [Andy: Don't use fallthrough] > [Andy: clean up help comment] > [Fan: clean up printk comment] > [Rasmus: fix buf processing in hex_range()] > [Rasmus: simplify buffer sizing] > [Rasmus: add '[' to string] > [Bagas: Clarify the start == end print behavior] > --- > Documentation/core-api/printk-formats.rst | 13 +++++++ > include/linux/range.h | 6 ++++ > lib/test_printf.c | 17 +++++++++ > lib/vsprintf.c | 57 +++++++++++++++++++++++++++---- > 4 files changed, 87 insertions(+), 6 deletions(-) > > diff --git a/Documentation/core-api/printk-formats.rst b/Documentation/core-api/printk-formats.rst > index 14e093da3ccd..e1ebf0376154 100644 > --- a/Documentation/core-api/printk-formats.rst > +++ b/Documentation/core-api/printk-formats.rst > @@ -231,6 +231,19 @@ width of the CPU data path. > > Passed by reference. > > +Struct Range > +------------ > + > +:: > + > + %pra [range 0x0000000060000000-0x000000006fffffff] > + %pra [range 0x0000000060000000] > + > +For printing struct range. struct range holds an arbitrary range of u64 > +values. If start is equal to end only print the start value. I was going to say "why this special case that does not exist for the %pr case?", but then checked the code and found it *does* do this for %pr. So if you're going to document this special case for %pra might as well update the documentation for %pr too. Alternatively, drop the new %pra documentation for this corner case as accommodating the U64_MAX size range case is arguably a mistake in the caller. Either way, just make it consistent.
Dan Williams wrote: > Ira Weiny wrote: [snip] > > diff --git a/Documentation/core-api/printk-formats.rst b/Documentation/core-api/printk-formats.rst > > index 14e093da3ccd..e1ebf0376154 100644 > > --- a/Documentation/core-api/printk-formats.rst > > +++ b/Documentation/core-api/printk-formats.rst > > @@ -231,6 +231,19 @@ width of the CPU data path. > > > > Passed by reference. > > > > +Struct Range > > +------------ > > + > > +:: > > + > > + %pra [range 0x0000000060000000-0x000000006fffffff] > > + %pra [range 0x0000000060000000] > > + > > +For printing struct range. struct range holds an arbitrary range of u64 > > +values. If start is equal to end only print the start value. > > I was going to say "why this special case that does not exist for the > %pr case?", but then checked the code and found it *does* do this for %pr. > So if you're going to document this special case for %pra might as well > update the documentation for %pr too. > > Alternatively, drop the new %pra documentation for this corner case as > accommodating the U64_MAX size range case is arguably a mistake in the > caller. > > Either way, just make it consistent. I've dropped the special case in the documentation. Ira
On Fri, Oct 18, 2024 at 01:05:22PM -0700, Dan Williams wrote: > Ira Weiny wrote: ... > > + %pra [range 0x0000000060000000] > > + > > +For printing struct range. struct range holds an arbitrary range of u64 > > +values. If start is equal to end only print the start value. > > I was going to say "why this special case that does not exist for the > %pr case?", but then checked the code and found it *does* do this for %pr. > So if you're going to document this special case for %pra might as well > update the documentation for %pr too. > > Alternatively, drop the new %pra documentation for this corner case as > accommodating the U64_MAX size range case is arguably a mistake in the > caller. You probably meant "...(U64_MAX + 1) size..." as we end up with the same value. But yeah, I also noticed the same.
On Fri, Oct 18, 2024 at 02:46:25PM -0500, Ira Weiny wrote: > The use of struct range in the CXL subsystem is growing. In particular, > the addition of Dynamic Capacity devices uses struct range in a number > of places which are reported in debug and error messages. > > To wit requiring the printing of the start/end fields in each print > became cumbersome. Dan Williams mentions in [1] that it might be time > to have a print specifier for struct range similar to struct resource > > A few alternatives were considered including '%par', '%r', and '%pn'. > %pra follows that struct range is similar to struct resource (%p[rR]) > but needs to be different. Based on discussions with Petr and Andy > '%pra' was chosen.[2] > > Andy also suggested to keep the range prints similar to struct resource > though combined code. Add hex_range() to handle printing for both > pointer types. > > Finally introduce DEFINE_RANGE() as a parallel to DEFINE_RES_*() and use > it in the tests. ... > case 'R': > case 'r': > - return resource_string(buf, end, ptr, spec, fmt); > + return resource_and_range(fmt, buf, end, ptr, spec); Since you are going to have a new version, I think this should be _or_ instead of _and_.
On Sun 2024-10-20 21:49:50, Ira Weiny wrote: > Dan Williams wrote: > > Ira Weiny wrote: > > [snip] > > > > diff --git a/Documentation/core-api/printk-formats.rst b/Documentation/core-api/printk-formats.rst > > > index 14e093da3ccd..e1ebf0376154 100644 > > > --- a/Documentation/core-api/printk-formats.rst > > > +++ b/Documentation/core-api/printk-formats.rst > > > @@ -231,6 +231,19 @@ width of the CPU data path. > > > > > > Passed by reference. > > > > > > +Struct Range > > > +------------ > > > + > > > +:: > > > + > > > + %pra [range 0x0000000060000000-0x000000006fffffff] > > > + %pra [range 0x0000000060000000] > > > + > > > +For printing struct range. struct range holds an arbitrary range of u64 > > > +values. If start is equal to end only print the start value. > > > > I was going to say "why this special case that does not exist for the > > %pr case?", but then checked the code and found it *does* do this for %pr. > > So if you're going to document this special case for %pra might as well > > update the documentation for %pr too. > > > > Alternatively, drop the new %pra documentation for this corner case as > > accommodating the U64_MAX size range case is arguably a mistake in the > > caller. > > > > Either way, just make it consistent. > > I've dropped the special case in the documentation. I would actually prefer the opposite and update the %pr documentation. The behavior might be surprising and people should beware of it, for example when writing a parser for the output. Best Regards, Petr
Petr Mladek wrote: > On Sun 2024-10-20 21:49:50, Ira Weiny wrote: > > Dan Williams wrote: > > > Ira Weiny wrote: > > > > [snip] > > > > > > diff --git a/Documentation/core-api/printk-formats.rst b/Documentation/core-api/printk-formats.rst > > > > index 14e093da3ccd..e1ebf0376154 100644 > > > > --- a/Documentation/core-api/printk-formats.rst > > > > +++ b/Documentation/core-api/printk-formats.rst > > > > @@ -231,6 +231,19 @@ width of the CPU data path. > > > > > > > > Passed by reference. > > > > > > > > +Struct Range > > > > +------------ > > > > + > > > > +:: > > > > + > > > > + %pra [range 0x0000000060000000-0x000000006fffffff] > > > > + %pra [range 0x0000000060000000] > > > > + > > > > +For printing struct range. struct range holds an arbitrary range of u64 > > > > +values. If start is equal to end only print the start value. > > > > > > I was going to say "why this special case that does not exist for the > > > %pr case?", but then checked the code and found it *does* do this for %pr. > > > So if you're going to document this special case for %pra might as well > > > update the documentation for %pr too. > > > > > > Alternatively, drop the new %pra documentation for this corner case as > > > accommodating the U64_MAX size range case is arguably a mistake in the > > > caller. > > > > > > Either way, just make it consistent. > > > > I've dropped the special case in the documentation. > > I would actually prefer the opposite and update the %pr documentation. > > The behavior might be surprising and people should beware of it, > for example when writing a parser for the output. Works for me. I added a patch to enhance %pr and left in the %pra doc. Ira
diff --git a/Documentation/core-api/printk-formats.rst b/Documentation/core-api/printk-formats.rst index 14e093da3ccd..e1ebf0376154 100644 --- a/Documentation/core-api/printk-formats.rst +++ b/Documentation/core-api/printk-formats.rst @@ -231,6 +231,19 @@ width of the CPU data path. Passed by reference. +Struct Range +------------ + +:: + + %pra [range 0x0000000060000000-0x000000006fffffff] + %pra [range 0x0000000060000000] + +For printing struct range. struct range holds an arbitrary range of u64 +values. If start is equal to end only print the start value. + +Passed by reference. + DMA address types dma_addr_t ---------------------------- diff --git a/include/linux/range.h b/include/linux/range.h index 6ad0b73cb7ad..1358d4b1807a 100644 --- a/include/linux/range.h +++ b/include/linux/range.h @@ -31,4 +31,10 @@ int clean_sort_range(struct range *range, int az); void sort_range(struct range *range, int nr_range); +#define DEFINE_RANGE(_start, _end) \ +(struct range) { \ + .start = (_start), \ + .end = (_end), \ + } + #endif diff --git a/lib/test_printf.c b/lib/test_printf.c index 5afdf5efc627..59dbe4f9a4cb 100644 --- a/lib/test_printf.c +++ b/lib/test_printf.c @@ -432,6 +432,22 @@ struct_resource(void) "%pR", &test_resource); } +static void __init +struct_range(void) +{ + struct range test_range = DEFINE_RANGE(0xc0ffee00ba5eba11, + 0xc0ffee00ba5eba11); + test("[range 0xc0ffee00ba5eba11]", "%pra", &test_range); + + test_range = DEFINE_RANGE(0xc0ffee, 0xba5eba11); + test("[range 0x0000000000c0ffee-0x00000000ba5eba11]", + "%pra", &test_range); + + test_range = DEFINE_RANGE(0xba5eba11, 0xc0ffee); + test("[range 0x00000000ba5eba11-0x0000000000c0ffee]", + "%pra", &test_range); +} + static void __init addr(void) { @@ -807,6 +823,7 @@ test_pointer(void) symbol_ptr(); kernel_ptr(); struct_resource(); + struct_range(); addr(); escaped_str(); hex_string(); diff --git a/lib/vsprintf.c b/lib/vsprintf.c index 09f022ba1c05..f6a62f273fad 100644 --- a/lib/vsprintf.c +++ b/lib/vsprintf.c @@ -1039,6 +1039,20 @@ static const struct printf_spec default_dec04_spec = { .flags = ZEROPAD, }; +static noinline_for_stack +char *hex_range(char *buf, char *end, u64 start_val, u64 end_val, + struct printf_spec spec) +{ + buf = number(buf, end, start_val, spec); + if (start_val == end_val) + return buf; + + if (buf < end) + *buf = '-'; + ++buf; + return number(buf, end, end_val, spec); +} + static noinline_for_stack char *resource_string(char *buf, char *end, struct resource *res, struct printf_spec spec, const char *fmt) @@ -1115,11 +1129,7 @@ char *resource_string(char *buf, char *end, struct resource *res, p = string_nocheck(p, pend, "size ", str_spec); p = number(p, pend, resource_size(res), *specp); } else { - p = number(p, pend, res->start, *specp); - if (res->start != res->end) { - *p++ = '-'; - p = number(p, pend, res->end, *specp); - } + p = hex_range(p, pend, res->start, res->end, *specp); } if (decode) { if (res->flags & IORESOURCE_MEM_64) @@ -1140,6 +1150,31 @@ char *resource_string(char *buf, char *end, struct resource *res, return string_nocheck(buf, end, sym, spec); } +static noinline_for_stack +char *range_string(char *buf, char *end, const struct range *range, + struct printf_spec spec, const char *fmt) +{ + char sym[sizeof("[range 0x0123456789abcdef-0x0123456789abcdef]")]; + char *p = sym, *pend = sym + sizeof(sym); + + struct printf_spec range_spec = { + .field_width = 2 + 2 * sizeof(range->start), /* 0x + 2 * 8 */ + .flags = SPECIAL | SMALL | ZEROPAD, + .base = 16, + .precision = -1, + }; + + if (check_pointer(&buf, end, range, spec)) + return buf; + + p = string_nocheck(p, pend, "[range ", default_str_spec); + p = hex_range(p, pend, range->start, range->end, range_spec); + *p++ = ']'; + *p = '\0'; + + return string_nocheck(buf, end, sym, spec); +} + static noinline_for_stack char *hex_string(char *buf, char *end, u8 *addr, struct printf_spec spec, const char *fmt) @@ -2229,6 +2264,15 @@ char *fwnode_string(char *buf, char *end, struct fwnode_handle *fwnode, return widen_string(buf, buf - buf_start, end, spec); } +static noinline_for_stack +char *resource_and_range(const char *fmt, char *buf, char *end, void *ptr, + struct printf_spec spec) +{ + if (*fmt == 'r' && fmt[1] == 'a') + return range_string(buf, end, ptr, spec, fmt); + return resource_string(buf, end, ptr, spec, fmt); +} + int __init no_hash_pointers_enable(char *str) { if (no_hash_pointers) @@ -2277,6 +2321,7 @@ char *rust_fmt_argument(char *buf, char *end, void *ptr); * - 'Bb' as above with module build ID (for use in backtraces) * - 'R' For decoded struct resource, e.g., [mem 0x0-0x1f 64bit pref] * - 'r' For raw struct resource, e.g., [mem 0x0-0x1f flags 0x201] + * - 'ra' For struct ranges, e.g., [range 0x0000000000000000 - 0x00000000000000ff] * - 'b[l]' For a bitmap, the number of bits is determined by the field * width which must be explicitly specified either as part of the * format string '%32b[l]' or through '%*b[l]', [l] selects @@ -2401,7 +2446,7 @@ char *pointer(const char *fmt, char *buf, char *end, void *ptr, return symbol_string(buf, end, ptr, spec, fmt); case 'R': case 'r': - return resource_string(buf, end, ptr, spec, fmt); + return resource_and_range(fmt, buf, end, ptr, spec); case 'h': return hex_string(buf, end, ptr, spec, fmt); case 'b':
The use of struct range in the CXL subsystem is growing. In particular, the addition of Dynamic Capacity devices uses struct range in a number of places which are reported in debug and error messages. To wit requiring the printing of the start/end fields in each print became cumbersome. Dan Williams mentions in [1] that it might be time to have a print specifier for struct range similar to struct resource A few alternatives were considered including '%par', '%r', and '%pn'. %pra follows that struct range is similar to struct resource (%p[rR]) but needs to be different. Based on discussions with Petr and Andy '%pra' was chosen.[2] Andy also suggested to keep the range prints similar to struct resource though combined code. Add hex_range() to handle printing for both pointer types. Finally introduce DEFINE_RANGE() as a parallel to DEFINE_RES_*() and use it in the tests. Cc: Jonathan Corbet <corbet@lwn.net> (maintainer:DOCUMENTATION) Cc: linux-doc@vger.kernel.org Cc: linux-kernel@vger.kernel.org (open list) Link: https://lore.kernel.org/all/663922b475e50_d54d72945b@dwillia2-xfh.jf.intel.com.notmuch/ [1] Link: https://lore.kernel.org/all/66cea3bf3332f_f937b29424@iweiny-mobl.notmuch/ [2] Suggested-by: "Dan Williams" <dan.j.williams@intel.com> Signed-off-by: Ira Weiny <ira.weiny@intel.com> --- Changes: [iweiny: split from CXL patch set] [Andy: Define DEFINE_RANGE()] [Andy: rework hex_range() logic] [Andy: Don't use fallthrough] [Andy: clean up help comment] [Fan: clean up printk comment] [Rasmus: fix buf processing in hex_range()] [Rasmus: simplify buffer sizing] [Rasmus: add '[' to string] [Bagas: Clarify the start == end print behavior] --- Documentation/core-api/printk-formats.rst | 13 +++++++ include/linux/range.h | 6 ++++ lib/test_printf.c | 17 +++++++++ lib/vsprintf.c | 57 +++++++++++++++++++++++++++---- 4 files changed, 87 insertions(+), 6 deletions(-)