Re: git: f3f350c5c8e4 - stable/13 - cpuset: Add compat shim to the sched_affinity functions

In reply to: Konstantin Belousov : "Re: git: f3f350c5c8e4 - stable/13 - cpuset: Add compat shim to the sched_affinity functions"
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From: Dmitry Chagin <dchagin_at_heemeyer.club>
Date: Sun, 19 Feb 2023 18:31:45 UTC
On Sun, Feb 19, 2023 at 06:42:42PM +0200, Konstantin Belousov wrote:
> On Sun, Feb 19, 2023 at 07:26:18AM +0000, Dmitry Chagin wrote:
> > The branch stable/13 has been updated by dchagin:
> > 
> > URL: https://cgit.FreeBSD.org/src/commit/?id=f3f350c5c8e4f6b0d3ff9806881b8f042a9ca925
> > 
> > commit f3f350c5c8e4f6b0d3ff9806881b8f042a9ca925
> > Author:     Dmitry Chagin <dchagin@FreeBSD.org>
> > AuthorDate: 2023-02-15 09:23:15 +0000
> > Commit:     Dmitry Chagin <dchagin@FreeBSD.org>
> > CommitDate: 2023-02-19 07:26:06 +0000
> > 
> >     cpuset: Add compat shim to the sched_affinity functions
> >     
> >     To allow to run a newer world on a pre-1400079 kernel a compat shims to
> >     the sched_affinity functions has beed added.
> >     
> >     Reported by:            antoine
> >     Tested by:              antoine
> >     Reviewed by:            kib
> >     Differential revision:  https://reviews.freebsd.org/D38555
> >     MFC after:              3 days
> >     
> >     (cherry picked from commit cbc32e4c5e8427e0f1032d9d3aa5863dd1538c11)
> > ---
> >  lib/libc/gen/sched_getaffinity.c | 15 ++++++++++++++-
> >  lib/libc/gen/sched_setaffinity.c | 14 +++++++++++++-
> >  lib/libc/include/libc_private.h  |  6 ++++++
> >  sys/sys/param.h                  |  1 +
> >  4 files changed, 34 insertions(+), 2 deletions(-)
> > 
> > diff --git a/lib/libc/gen/sched_getaffinity.c b/lib/libc/gen/sched_getaffinity.c
> > index 95145a1eb019..fce47fbfc0d2 100644
> > --- a/lib/libc/gen/sched_getaffinity.c
> > +++ b/lib/libc/gen/sched_getaffinity.c
> > @@ -26,16 +26,29 @@
> >   * SUCH DAMAGE.
> >   */
> >  
> > +#define	_WANT_P_OSREL
> > +#include <sys/param.h>
> >  #include <errno.h>
> >  #include <sched.h>
> >  #include <string.h>
> >  
> > +#include "libc_private.h"
> > +
> >  int
> >  sched_getaffinity(pid_t pid, size_t cpusetsz, cpuset_t *cpuset)
> >  {
> > +	cpuwhich_t which;
> >  	int error;
> >  
> > -	error = cpuset_getaffinity(CPU_LEVEL_WHICH, CPU_WHICH_TIDPID,
> > +	if (__getosreldate() < P_OSREL_TIDPID) {
> > +		if (pid == 0 || pid > _PID_MAX)
> > +			which = CPU_WHICH_TID;
> > +		else
> > +			which = CPU_WHICH_PID;
> > +	} else
> > +		which = CPU_WHICH_TIDPID;
> > +
> > +	error = cpuset_getaffinity(CPU_LEVEL_WHICH, which,
> >  	    pid == 0 ? -1 : pid, cpusetsz, cpuset);
> >  	if (error == -1 && errno == ERANGE)
> >  		errno = EINVAL;
> > diff --git a/lib/libc/gen/sched_setaffinity.c b/lib/libc/gen/sched_setaffinity.c
> > index 36ed0f45d417..b878e1affc41 100644
> > --- a/lib/libc/gen/sched_setaffinity.c
> > +++ b/lib/libc/gen/sched_setaffinity.c
> > @@ -26,20 +26,32 @@
> >   * SUCH DAMAGE.
> >   */
> >  
> > +#define	_WANT_P_OSREL
> >  #include <sys/param.h>
> >  #include <sys/sysctl.h>
> >  #include <errno.h>
> >  #include <sched.h>
> >  #include <string.h>
> >  
> > +#include "libc_private.h"
> > +
> >  int
> >  sched_setaffinity(pid_t pid, size_t cpusetsz, const cpuset_t *cpuset)
> >  {
> >  	static int mp_maxid;
> > +	cpuwhich_t which;
> >  	cpuset_t c;
> >  	int error, lbs, cpu;
> >  	size_t len, sz;
> >  
> > +	if (__getosreldate() < P_OSREL_TIDPID) {
> > +		if (pid == 0 || pid > _PID_MAX)
> > +			which = CPU_WHICH_TID;
> > +		else
> > +			which = CPU_WHICH_PID;
> > +	} else
> > +		which = CPU_WHICH_TIDPID;
> > +
> >  	sz = cpusetsz > sizeof(cpuset_t) ? sizeof(cpuset_t) : cpusetsz;
> >  	memset(&c, 0, sizeof(c));
> >  	memcpy(&c, cpuset, sz);
> > @@ -58,7 +70,7 @@ sched_setaffinity(pid_t pid, size_t cpusetsz, const cpuset_t *cpuset)
> >  			if (cpu > mp_maxid)
> >  				CPU_CLR(cpu, &c);
> >  	}
> > -	error = cpuset_setaffinity(CPU_LEVEL_WHICH, CPU_WHICH_TIDPID,
> > +	error = cpuset_setaffinity(CPU_LEVEL_WHICH, which,
> >  	    pid == 0 ? -1 : pid, sizeof(cpuset_t), &c);
> >  	if (error == -1 && errno == EDEADLK)
> >  		errno = EINVAL;
> > diff --git a/lib/libc/include/libc_private.h b/lib/libc/include/libc_private.h
> > index 61c1eb438142..78a75cc6284d 100644
> > --- a/lib/libc/include/libc_private.h
> > +++ b/lib/libc/include/libc_private.h
> > @@ -39,6 +39,12 @@
> >  #include <sys/_types.h>
> >  #include <sys/_pthreadtypes.h>
> >  
> > +/*
> > + * The kernel doesn't expose PID_MAX to the user space. Save it here
> > + * to allow to run a newer world on a pre-1400079 kernel.
> > + */
> > +#define	_PID_MAX	99999
> > +
> >  /*
> >   * This global flag is non-zero when a process has created one
> >   * or more threads. It is used to avoid calling locking functions
> > diff --git a/sys/sys/param.h b/sys/sys/param.h
> > index 909ff0ef1d8b..d2fbad6c127b 100644
> > --- a/sys/sys/param.h
> > +++ b/sys/sys/param.h
> > @@ -91,6 +91,7 @@
> >  #define	P_OSREL_CK_SUPERBLOCK		1300000
> >  #define	P_OSREL_CK_INODE		1300005
> >  #define	P_OSREL_POWERPC_NEW_AUX_ARGS	1300070
> > +#define	P_OSREL_TIDPID			1400079
> Does it work to have 14.x osrel value for P_OSREL_TIDPID as compat selector
> on 13.x?
> 

sure, not perfect, but it will, ideally it should be something like
below, being testing now, I'll post it on phab later:


diff --git a/lib/libc/gen/sched_getaffinity.c b/lib/libc/gen/sched_getaffinity.c
index fce47fbfc0d2..7c8f37a8cb64 100644
--- a/lib/libc/gen/sched_getaffinity.c
+++ b/lib/libc/gen/sched_getaffinity.c
@@ -38,9 +38,11 @@ int
 sched_getaffinity(pid_t pid, size_t cpusetsz, cpuset_t *cpuset)
 {
 	cpuwhich_t which;
-	int error;
+	int error, osrel;
 
-	if (__getosreldate() < P_OSREL_TIDPID) {
+	osrel = __getosreldate();
+	if (osrel < P_OSREL_TIDPID ||
+	    (P_OSREL_MAJOR(osrel) == 14 && osrel < 1400079)) {
 		if (pid == 0 || pid > _PID_MAX)
 			which = CPU_WHICH_TID;
 		else
diff --git a/lib/libc/gen/sched_setaffinity.c b/lib/libc/gen/sched_setaffinity.c
index b878e1affc41..622021bab3cd 100644
--- a/lib/libc/gen/sched_setaffinity.c
+++ b/lib/libc/gen/sched_setaffinity.c
@@ -41,10 +41,12 @@ sched_setaffinity(pid_t pid, size_t cpusetsz, const cpuset_t *cpuset)
 	static int mp_maxid;
 	cpuwhich_t which;
 	cpuset_t c;
-	int error, lbs, cpu;
+	int error, lbs, cpu, osrel;
 	size_t len, sz;
 
-	if (__getosreldate() < P_OSREL_TIDPID) {
+        osrel = __getosreldate();
+	if (osrel < P_OSREL_TIDPID ||
+	    (P_OSREL_MAJOR(osrel) == 14 && osrel < 1400079)) {
 		if (pid == 0 || pid > _PID_MAX)
 			which = CPU_WHICH_TID;
 		else
diff --git a/sys/sys/param.h b/sys/sys/param.h
index d2fbad6c127b..714c6cff5c90 100644
--- a/sys/sys/param.h
+++ b/sys/sys/param.h
@@ -91,7 +91,7 @@
 #define	P_OSREL_CK_SUPERBLOCK		1300000
 #define	P_OSREL_CK_INODE		1300005
 #define	P_OSREL_POWERPC_NEW_AUX_ARGS	1300070
-#define	P_OSREL_TIDPID			1400079
+#define	P_OSREL_TIDPID			1302501
 
 #define	P_OSREL_MAJOR(x)		((x) / 100000)
 #endif






> >  
> >  #define	P_OSREL_MAJOR(x)		((x) / 100000)
> >  #endif