2020-12-02 21:18:41

by Axel Rasmussen

[permalink] [raw]
Subject: [PATCH] userfaultfd: selftests: make __{s,u}64 format specifiers portable

On certain platforms (powerpcle is the one on which I ran into this),
"%Ld" and "%Lu" are unsuitable for printing __s64 and __u64,
respectively, resulting in a build warning. Cast to {u,}int64_t, and
use the PRI{d,u}64 macros defined in inttypes.h to print them. This
ought to be portable to all platforms.

Splitting this off into a separate function lets us remove some lines,
and get rid of some (I would argue) stylistically odd cases where we
joined printf() and exit() into a single statement with a ,.

Finally, this also fixes a "missing braces around initializer" warning
when we initialize prms in wp_range().

Signed-off-by: Axel Rasmussen <[email protected]>
---
tools/testing/selftests/vm/userfaultfd.c | 77 +++++++++++-------------
1 file changed, 36 insertions(+), 41 deletions(-)

diff --git a/tools/testing/selftests/vm/userfaultfd.c b/tools/testing/selftests/vm/userfaultfd.c
index 9b0912a01777..31e1ff887e4b 100644
--- a/tools/testing/selftests/vm/userfaultfd.c
+++ b/tools/testing/selftests/vm/userfaultfd.c
@@ -55,6 +55,8 @@
#include <setjmp.h>
#include <stdbool.h>
#include <assert.h>
+#include <inttypes.h>
+#include <stdint.h>

#include "../kselftest.h"

@@ -135,6 +137,12 @@ static void usage(void)
exit(1);
}

+static void uffd_error(const char *message, __s64 code)
+{
+ fprintf(stderr, "%s: %" PRId64 "\n", message, (int64_t)code);
+ exit(1);
+}
+
static void uffd_stats_reset(struct uffd_stats *uffd_stats,
unsigned long n_cpus)
{
@@ -331,7 +339,7 @@ static int my_bcmp(char *str1, char *str2, size_t n)

static void wp_range(int ufd, __u64 start, __u64 len, bool wp)
{
- struct uffdio_writeprotect prms = { 0 };
+ struct uffdio_writeprotect prms;

/* Write protection page faults */
prms.range.start = start;
@@ -340,7 +348,8 @@ static void wp_range(int ufd, __u64 start, __u64 len, bool wp)
prms.mode = wp ? UFFDIO_WRITEPROTECT_MODE_WP : 0;

if (ioctl(ufd, UFFDIO_WRITEPROTECT, &prms)) {
- fprintf(stderr, "clear WP failed for address 0x%Lx\n", start);
+ fprintf(stderr, "clear WP failed for address 0x%" PRIx64 "\n",
+ (uint64_t)start);
exit(1);
}
}
@@ -474,14 +483,11 @@ static void retry_copy_page(int ufd, struct uffdio_copy *uffdio_copy,
if (ioctl(ufd, UFFDIO_COPY, uffdio_copy)) {
/* real retval in ufdio_copy.copy */
if (uffdio_copy->copy != -EEXIST) {
- fprintf(stderr, "UFFDIO_COPY retry error %Ld\n",
- uffdio_copy->copy);
- exit(1);
+ uffd_error("UFFDIO_COPY retry error",
+ uffdio_copy->copy);
}
- } else {
- fprintf(stderr, "UFFDIO_COPY retry unexpected %Ld\n",
- uffdio_copy->copy); exit(1);
- }
+ } else
+ uffd_error("UFFDIO_COPY retry unexpected", uffdio_copy->copy);
}

static int __copy_page(int ufd, unsigned long offset, bool retry)
@@ -502,15 +508,11 @@ static int __copy_page(int ufd, unsigned long offset, bool retry)
uffdio_copy.copy = 0;
if (ioctl(ufd, UFFDIO_COPY, &uffdio_copy)) {
/* real retval in ufdio_copy.copy */
- if (uffdio_copy.copy != -EEXIST) {
- fprintf(stderr, "UFFDIO_COPY error %Ld\n",
- uffdio_copy.copy);
- exit(1);
- }
- } else if (uffdio_copy.copy != page_size) {
- fprintf(stderr, "UFFDIO_COPY unexpected copy %Ld\n",
- uffdio_copy.copy); exit(1);
- } else {
+ if (uffdio_copy.copy != -EEXIST)
+ uffd_error("UFFDIO_COPY error", uffdio_copy.copy);
+ } else if (uffdio_copy.copy != page_size)
+ uffd_error("UFFDIO_COPY unexpected copy", uffdio_copy.copy);
+ else {
if (test_uffdio_copy_eexist && retry) {
test_uffdio_copy_eexist = false;
retry_copy_page(ufd, &uffdio_copy, offset);
@@ -788,7 +790,8 @@ static int userfaultfd_open(int features)
return 1;
}
if (uffdio_api.api != UFFD_API) {
- fprintf(stderr, "UFFDIO_API error %Lu\n", uffdio_api.api);
+ fprintf(stderr, "UFFDIO_API error: %" PRIu64 "\n",
+ (uint64_t)uffdio_api.api);
return 1;
}

@@ -950,13 +953,12 @@ static void retry_uffdio_zeropage(int ufd,
offset);
if (ioctl(ufd, UFFDIO_ZEROPAGE, uffdio_zeropage)) {
if (uffdio_zeropage->zeropage != -EEXIST) {
- fprintf(stderr, "UFFDIO_ZEROPAGE retry error %Ld\n",
- uffdio_zeropage->zeropage);
- exit(1);
+ uffd_error("UFFDIO_ZEROPAGE retry error",
+ uffdio_zeropage->zeropage);
}
} else {
- fprintf(stderr, "UFFDIO_ZEROPAGE retry unexpected %Ld\n",
- uffdio_zeropage->zeropage); exit(1);
+ uffd_error("UFFDIO_ZEROPAGE retry unexpected",
+ uffdio_zeropage->zeropage);
}
}

@@ -979,26 +981,20 @@ static int __uffdio_zeropage(int ufd, unsigned long offset, bool retry)
if (ret) {
/* real retval in ufdio_zeropage.zeropage */
if (has_zeropage) {
- if (uffdio_zeropage.zeropage == -EEXIST) {
- fprintf(stderr, "UFFDIO_ZEROPAGE -EEXIST\n");
- exit(1);
- } else {
- fprintf(stderr, "UFFDIO_ZEROPAGE error %Ld\n",
- uffdio_zeropage.zeropage);
- exit(1);
- }
+ uffd_error(uffdio_zeropage.zeropage == -EEXIST ?
+ "UFFDIO_ZEROPAGE -EEXIST" :
+ "UFFDIO_ZEROPAGE error",
+ uffdio_zeropage.zeropage);
} else {
if (uffdio_zeropage.zeropage != -EINVAL) {
- fprintf(stderr,
- "UFFDIO_ZEROPAGE not -EINVAL %Ld\n",
- uffdio_zeropage.zeropage);
- exit(1);
+ uffd_error("UFFDIO_ZEROPAGE not -EINVAL",
+ uffdio_zeropage.zeropage);
}
}
} else if (has_zeropage) {
if (uffdio_zeropage.zeropage != page_size) {
- fprintf(stderr, "UFFDIO_ZEROPAGE unexpected %Ld\n",
- uffdio_zeropage.zeropage); exit(1);
+ uffd_error("UFFDIO_ZEROPAGE unexpected",
+ uffdio_zeropage.zeropage);
} else {
if (test_uffdio_zeropage_eexist && retry) {
test_uffdio_zeropage_eexist = false;
@@ -1008,9 +1004,8 @@ static int __uffdio_zeropage(int ufd, unsigned long offset, bool retry)
return 1;
}
} else {
- fprintf(stderr,
- "UFFDIO_ZEROPAGE succeeded %Ld\n",
- uffdio_zeropage.zeropage); exit(1);
+ uffd_error("UFFDIO_ZEROPAGE succeeded",
+ uffdio_zeropage.zeropage);
}

return 0;
--
2.29.2.454.gaff20da3a2-goog


2020-12-02 23:15:17

by Peter Xu

[permalink] [raw]
Subject: Re: [PATCH] userfaultfd: selftests: make __{s,u}64 format specifiers portable

Hi, Axel,

Looks mostly good to me, but a few nitpickings below.

On Wed, Dec 02, 2020 at 01:15:42PM -0800, Axel Rasmussen wrote:

[...]

> +static void uffd_error(const char *message, __s64 code)
> +{
> + fprintf(stderr, "%s: %" PRId64 "\n", message, (int64_t)code);
> + exit(1);
> +}

IMHO a macro that can take arbitrary parameters would be nicer, but if it
satisfy our need, definitely ok too.

[...]

> @@ -340,7 +348,8 @@ static void wp_range(int ufd, __u64 start, __u64 len, bool wp)
> prms.mode = wp ? UFFDIO_WRITEPROTECT_MODE_WP : 0;
>
> if (ioctl(ufd, UFFDIO_WRITEPROTECT, &prms)) {
> - fprintf(stderr, "clear WP failed for address 0x%Lx\n", start);
> + fprintf(stderr, "clear WP failed for address 0x%" PRIx64 "\n",
> + (uint64_t)start);
> exit(1);

Is it intended to not use uffd_error() here?

> }
> }

[...]

> @@ -979,26 +981,20 @@ static int __uffdio_zeropage(int ufd, unsigned long offset, bool retry)
> if (ret) {
> /* real retval in ufdio_zeropage.zeropage */
> if (has_zeropage) {
> - if (uffdio_zeropage.zeropage == -EEXIST) {
> - fprintf(stderr, "UFFDIO_ZEROPAGE -EEXIST\n");
> - exit(1);
> - } else {
> - fprintf(stderr, "UFFDIO_ZEROPAGE error %Ld\n",
> - uffdio_zeropage.zeropage);
> - exit(1);
> - }
> + uffd_error(uffdio_zeropage.zeropage == -EEXIST ?
> + "UFFDIO_ZEROPAGE -EEXIST" :
> + "UFFDIO_ZEROPAGE error",

Nit: The indents here are a bit odd..

Thanks,

--
Peter Xu

2020-12-02 23:59:33

by Axel Rasmussen

[permalink] [raw]
Subject: Re: [PATCH] userfaultfd: selftests: make __{s,u}64 format specifiers portable

On Wed, Dec 2, 2020 at 3:10 PM Peter Xu <[email protected]> wrote:
>
> Hi, Axel,
>
> Looks mostly good to me, but a few nitpickings below.
>
> On Wed, Dec 02, 2020 at 01:15:42PM -0800, Axel Rasmussen wrote:
>
> [...]
>
> > +static void uffd_error(const char *message, __s64 code)
> > +{
> > + fprintf(stderr, "%s: %" PRId64 "\n", message, (int64_t)code);
> > + exit(1);
> > +}
>
> IMHO a macro that can take arbitrary parameters would be nicer, but if it
> satisfy our need, definitely ok too.
>
> [...]
>
> > @@ -340,7 +348,8 @@ static void wp_range(int ufd, __u64 start, __u64 len, bool wp)
> > prms.mode = wp ? UFFDIO_WRITEPROTECT_MODE_WP : 0;
> >
> > if (ioctl(ufd, UFFDIO_WRITEPROTECT, &prms)) {
> > - fprintf(stderr, "clear WP failed for address 0x%Lx\n", start);
> > + fprintf(stderr, "clear WP failed for address 0x%" PRIx64 "\n",
> > + (uint64_t)start);
> > exit(1);
>
> Is it intended to not use uffd_error() here?

Yes, this is intentional. This particular case prints the value in
hexadecimal, rather than decimal.

(Agree that uffd_error() could be made more general to cover cases
like this. I opted for the simplest thing which covers all but two
cases - this one, and one where we "return 1;" instead of "exit(1);" -
but I don't feel strongly.)

>
> > }
> > }
>
> [...]
>
> > @@ -979,26 +981,20 @@ static int __uffdio_zeropage(int ufd, unsigned long offset, bool retry)
> > if (ret) {
> > /* real retval in ufdio_zeropage.zeropage */
> > if (has_zeropage) {
> > - if (uffdio_zeropage.zeropage == -EEXIST) {
> > - fprintf(stderr, "UFFDIO_ZEROPAGE -EEXIST\n");
> > - exit(1);
> > - } else {
> > - fprintf(stderr, "UFFDIO_ZEROPAGE error %Ld\n",
> > - uffdio_zeropage.zeropage);
> > - exit(1);
> > - }
> > + uffd_error(uffdio_zeropage.zeropage == -EEXIST ?
> > + "UFFDIO_ZEROPAGE -EEXIST" :
> > + "UFFDIO_ZEROPAGE error",
>
> Nit: The indents here are a bit odd..

This is what clang-format yields. Are you thinking it would be better
to line everything up with the ( in uffd_error( ?

Or, perhaps this case is a good reason to make uffd_error() a variadic
macro so we can insert "-EEXIST" || "error" with a "%s".

>
> Thanks,
>
> --
> Peter Xu
>

2020-12-03 00:12:46

by Miguel Ojeda

[permalink] [raw]
Subject: Re: [PATCH] userfaultfd: selftests: make __{s,u}64 format specifiers portable

On Thu, Dec 3, 2020 at 12:55 AM Axel Rasmussen <[email protected]> wrote:
>
> This is what clang-format yields. Are you thinking it would be better
> to line everything up with the ( in uffd_error( ?

Yeah, sometimes clang-format cannot do a good job with the 80 column
limit + 8 tabs.

You are definitely not forced to follow clang-format output by any
means. Subsystem maintainers decide what style they prefer anyway,
which could range from a manual approach to following clang-format
strictly. Clang-format implements the general kernel style as closely
as we could get it so far (it will improve more in the future when we
raise the minimum clang-format version required). See
Doc/process/clang-format.rst.

> Or, perhaps this case is a good reason to make uffd_error() a variadic
> macro so we can insert "-EEXIST" || "error" with a "%s".

...and indeed, sometimes it is a hint that simplifying things could help :-)

Cheers,
Miguel

2020-12-03 01:35:35

by Peter Xu

[permalink] [raw]
Subject: Re: [PATCH] userfaultfd: selftests: make __{s,u}64 format specifiers portable

On Wed, Dec 02, 2020 at 03:52:56PM -0800, Axel Rasmussen wrote:
> On Wed, Dec 2, 2020 at 3:10 PM Peter Xu <[email protected]> wrote:
> >
> > Hi, Axel,
> >
> > Looks mostly good to me, but a few nitpickings below.
> >
> > On Wed, Dec 02, 2020 at 01:15:42PM -0800, Axel Rasmussen wrote:
> >
> > [...]
> >
> > > +static void uffd_error(const char *message, __s64 code)
> > > +{
> > > + fprintf(stderr, "%s: %" PRId64 "\n", message, (int64_t)code);
> > > + exit(1);
> > > +}
> >
> > IMHO a macro that can take arbitrary parameters would be nicer, but if it
> > satisfy our need, definitely ok too.
> >
> > [...]
> >
> > > @@ -340,7 +348,8 @@ static void wp_range(int ufd, __u64 start, __u64 len, bool wp)
> > > prms.mode = wp ? UFFDIO_WRITEPROTECT_MODE_WP : 0;
> > >
> > > if (ioctl(ufd, UFFDIO_WRITEPROTECT, &prms)) {
> > > - fprintf(stderr, "clear WP failed for address 0x%Lx\n", start);
> > > + fprintf(stderr, "clear WP failed for address 0x%" PRIx64 "\n",
> > > + (uint64_t)start);
> > > exit(1);
> >
> > Is it intended to not use uffd_error() here?
>
> Yes, this is intentional. This particular case prints the value in
> hexadecimal, rather than decimal.
>
> (Agree that uffd_error() could be made more general to cover cases
> like this. I opted for the simplest thing which covers all but two
> cases - this one, and one where we "return 1;" instead of "exit(1);" -
> but I don't feel strongly.)

Actually it's as simple as:

#define uffd_error(...) do { \
fprintf(stderr, __VA_ARGS__); \
fprintf(stderr, "\n"); \
exit(1); \
} while (0)

But it's okay, I think.

>
> >
> > > }
> > > }
> >
> > [...]
> >
> > > @@ -979,26 +981,20 @@ static int __uffdio_zeropage(int ufd, unsigned long offset, bool retry)
> > > if (ret) {
> > > /* real retval in ufdio_zeropage.zeropage */
> > > if (has_zeropage) {
> > > - if (uffdio_zeropage.zeropage == -EEXIST) {
> > > - fprintf(stderr, "UFFDIO_ZEROPAGE -EEXIST\n");
> > > - exit(1);
> > > - } else {
> > > - fprintf(stderr, "UFFDIO_ZEROPAGE error %Ld\n",
> > > - uffdio_zeropage.zeropage);
> > > - exit(1);
> > > - }
> > > + uffd_error(uffdio_zeropage.zeropage == -EEXIST ?
> > > + "UFFDIO_ZEROPAGE -EEXIST" :
> > > + "UFFDIO_ZEROPAGE error",
> >
> > Nit: The indents here are a bit odd..
>
> This is what clang-format yields. Are you thinking it would be better
> to line everything up with the ( in uffd_error( ?
>
> Or, perhaps this case is a good reason to make uffd_error() a variadic
> macro so we can insert "-EEXIST" || "error" with a "%s".

Yes. It fixes a build warning, so I think current patch is fine too.

No matter whether you'd like a v2, please feel free to take:

Acked-by: Peter Xu <[email protected]>

Thanks,

--
Peter Xu