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From: Tejun Heo <tj@kernel.org>
To: akpm@linux-foundation.org
Cc: linux-kernel@vger.kernel.org, Tejun Heo <tj@kernel.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Rusty Russell <rusty@rustcorp.com.au>
Subject: [PATCH 01/32] cpumask: always use nr_cpu_ids in formatting and parsing functions
Date: Sat, 24 Jan 2015 09:03:07 -0500	[thread overview]
Message-ID: <1422108218-25398-2-git-send-email-tj@kernel.org> (raw)
In-Reply-To: <1422108218-25398-1-git-send-email-tj@kernel.org>

Currently, the formatting and parsing functions in cpumask.h use
nr_cpumask_bits like other cpumask functions; however, nr_cpumask_bits
is either NR_CPUS or nr_cpu_ids depending on CONFIG_CPUMASK_OFFSTACK.
This leads to inconsistent behaviors.

With CONFIG_NR_CPUS=512 and !CONFIG_CPUMASK_OFFSTACK

  # cat /sys/devices/virtual/net/lo/queues/rx-0/rps_cpus
  00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000
  # cat /proc/self/status | grep Cpus_allowed:
  Cpus_allowed:   f

With CONFIG_NR_CPUS=1024 and CONFIG_CPUMASK_OFFSTACK (fedora default)

  # cat /sys/devices/virtual/net/lo/queues/rx-0/rps_cpus
  0
  # cat /proc/self/status | grep Cpus_allowed:
  Cpus_allowed:   f

Note that /proc/self/status is always using nr_cpu_ids regardless of
config.  This is because seq cpumask formattings functions always use
nr_cpu_ids.

Given that the same output fields may switch between the two forms,
converging on nr_cpu_ids always isn't too likely to surprise userland.
This patch updates the formatting and parsing functions in cpumask.h
to always use nr_cpu_ids.  There's no point in dealing with CPUs which
aren't even possible on the machine.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
---
Hello,

Linus, this is the first of the three pre-requisite patches to convert
the users of the dedicated bitmap formatting functions over to
'%*pb[l]' formatting.

If this approach is agreed upon, I think it'd be best to route these
three patches through mainline soon so that subsystem conversion
patches can pull these in and apply per-subsystem conversion patches.

Thanks.

 include/linux/cpumask.h | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h
index b950e9d..98939d1 100644
--- a/include/linux/cpumask.h
+++ b/include/linux/cpumask.h
@@ -550,7 +550,7 @@ static inline void cpumask_copy(struct cpumask *dstp,
 static inline int cpumask_scnprintf(char *buf, int len,
 				    const struct cpumask *srcp)
 {
-	return bitmap_scnprintf(buf, len, cpumask_bits(srcp), nr_cpumask_bits);
+	return bitmap_scnprintf(buf, len, cpumask_bits(srcp), nr_cpu_ids);
 }
 
 /**
@@ -564,7 +564,7 @@ static inline int cpumask_scnprintf(char *buf, int len,
 static inline int cpumask_parse_user(const char __user *buf, int len,
 				     struct cpumask *dstp)
 {
-	return bitmap_parse_user(buf, len, cpumask_bits(dstp), nr_cpumask_bits);
+	return bitmap_parse_user(buf, len, cpumask_bits(dstp), nr_cpu_ids);
 }
 
 /**
@@ -579,7 +579,7 @@ static inline int cpumask_parselist_user(const char __user *buf, int len,
 				     struct cpumask *dstp)
 {
 	return bitmap_parselist_user(buf, len, cpumask_bits(dstp),
-							nr_cpumask_bits);
+				     nr_cpu_ids);
 }
 
 /**
@@ -595,7 +595,7 @@ static inline int cpulist_scnprintf(char *buf, int len,
 				    const struct cpumask *srcp)
 {
 	return bitmap_scnlistprintf(buf, len, cpumask_bits(srcp),
-				    nr_cpumask_bits);
+				    nr_cpu_ids);
 }
 
 /**
@@ -610,7 +610,7 @@ static inline int cpumask_parse(const char *buf, struct cpumask *dstp)
 	char *nl = strchr(buf, '\n');
 	unsigned int len = nl ? (unsigned int)(nl - buf) : strlen(buf);
 
-	return bitmap_parse(buf, len, cpumask_bits(dstp), nr_cpumask_bits);
+	return bitmap_parse(buf, len, cpumask_bits(dstp), nr_cpu_ids);
 }
 
 /**
@@ -622,7 +622,7 @@ static inline int cpumask_parse(const char *buf, struct cpumask *dstp)
  */
 static inline int cpulist_parse(const char *buf, struct cpumask *dstp)
 {
-	return bitmap_parselist(buf, cpumask_bits(dstp), nr_cpumask_bits);
+	return bitmap_parselist(buf, cpumask_bits(dstp), nr_cpu_ids);
 }
 
 /**
@@ -817,7 +817,7 @@ static inline ssize_t
 cpumap_print_to_pagebuf(bool list, char *buf, const struct cpumask *mask)
 {
 	return bitmap_print_to_pagebuf(list, buf, cpumask_bits(mask),
-				      nr_cpumask_bits);
+				      nr_cpu_ids);
 }
 
 /*
-- 
2.1.0


  reply	other threads:[~2015-01-24 14:03 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-01-24 14:03 [PATCHSET] bitmap, cpumask, nodemask: implement %*pb[l] to format bitmaps directly from printf family of functions Tejun Heo
2015-01-24 14:03 ` Tejun Heo [this message]
2015-01-26 23:42   ` [PATCH 01/32] cpumask: always use nr_cpu_ids in formatting and parsing functions Rusty Russell
2015-01-24 14:03 ` [PATCH 02/32] lib/vsprintf: implement bitmap printing through '%*pb[l]' Tejun Heo
2015-01-26 13:50   ` Peter Zijlstra
2015-01-24 14:03 ` [PATCH 03/32] cpumask, nodemask: implement cpumask/nodemask_pr_args() Tejun Heo
2015-01-24 14:03 ` [PATCH 04/32] bitmap: use %*pb[l] to print bitmaps including cpumasks and nodemasks Tejun Heo
2015-01-24 14:03 ` [PATCH 05/32] mips: " Tejun Heo
2015-01-24 14:03 ` [PATCH 06/32] powerpc: " Tejun Heo
2015-01-24 14:03 ` [PATCH 07/32] s390: " Tejun Heo
2015-01-26  9:17   ` Heiko Carstens
2015-01-24 14:03 ` [PATCH 08/32] tile: " Tejun Heo
2015-01-24 14:03 ` [PATCH 09/32] x86: " Tejun Heo
2015-01-24 14:03 ` [PATCH 10/32] ia64: " Tejun Heo
2015-01-24 14:03 ` [PATCH 11/32] xtensa: " Tejun Heo
2015-01-24 14:03 ` [PATCH 12/32] arm: " Tejun Heo
2015-01-24 14:03 ` [PATCH 13/32] cpuset: " Tejun Heo
2015-01-24 14:03 ` [PATCH 14/32] rcu: " Tejun Heo
2015-01-24 21:16   ` Paul E. McKenney
2015-01-24 14:03 ` [PATCH 15/32] sched: " Tejun Heo
2015-01-24 14:03 ` [PATCH 16/32] time: " Tejun Heo
2015-01-24 14:03 ` [PATCH 17/32] percpu: " Tejun Heo
2015-01-24 14:03 ` [PATCH 18/32] workqueue: use %*pb[l] to format " Tejun Heo
2015-01-24 14:03 ` [PATCH 19/32] tracing: use %*pb[l] to print " Tejun Heo
2015-01-24 14:03 ` [PATCH 20/32] net: " Tejun Heo
2015-01-27  8:07   ` David Miller
2015-01-24 14:03 ` [PATCH 21/32] wireless: " Tejun Heo
2015-03-02 15:14   ` Kalle Valo
2015-01-24 14:03 ` [PATCH 22/32] input: " Tejun Heo
2015-01-24 14:03 ` [PATCH 23/32] scsi: " Tejun Heo
2015-01-24 14:03 ` [PATCH 24/32] usb: " Tejun Heo
2015-01-25 12:45   ` Greg Kroah-Hartman
2015-01-24 14:03 ` [PATCH 25/32] drivers/base: " Tejun Heo
2015-01-25 13:22   ` Greg Kroah-Hartman
2015-01-24 14:03 ` [PATCH 26/32] slub: " Tejun Heo
2015-01-24 17:48   ` Christoph Lameter
2015-01-24 14:03 ` [PATCH 27/32] mm: " Tejun Heo
2015-01-24 14:03 ` [PATCH 28/32] padata: " Tejun Heo
2015-01-24 14:03 ` [PATCH 29/32] proc: " Tejun Heo
2015-01-24 14:03 ` [PATCH 30/32] irq: " Tejun Heo
2015-01-24 14:03 ` [PATCH 31/32] profile: " Tejun Heo
2015-01-24 14:03 ` [PATCH 32/32] bitmap, cpumask, nodemask: remove dedicated formatting functions Tejun Heo

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