LKML Archive on lore.kernel.org
 help / color / Atom feed
From: "Joel Fernandes (Google)" <joel@joelfernandes.org>
To: linux-kernel@vger.kernel.org
Cc: Vineeth Pillai <viremana@linux.microsoft.com>,
	Joel Fernandes <joel@joelfernandes.org>,
	Aaron Lu <aaron.lwe@gmail.com>,
	Aubrey Li <aubrey.li@linux.intel.com>,
	Julien Desfossez <jdesfossez@digitalocean.com>,
	Kees Cook <keescook@chromium.org>,
	"Paul E. McKenney" <paulmck@kernel.org>,
	Paul Turner <pjt@google.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Steven Rostedt <rostedt@goodmis.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Tim Chen <tim.c.chen@intel.com>,
	Tim Chen <tim.c.chen@linux.intel.com>,
	Vincent Guittot <vincent.guittot@linaro.org>,
	x86@kernel.org (maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)),
	fweisbec@gmail.com, kerrnel@google.com,
	Phil Auld <pauld@redhat.com>,
	Valentin Schneider <valentin.schneider@arm.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Chen Yu <yu.c.chen@intel.com>,
	Christian Brauner <christian.brauner@ubuntu.com>
Subject: [PATCH RFC 07/12] bitops: Introduce find_next_or_bit
Date: Fri, 14 Aug 2020 23:19:03 -0400
Message-ID: <20200815031908.1015049-8-joel@joelfernandes.org> (raw)
In-Reply-To: <20200815031908.1015049-1-joel@joelfernandes.org>

From: Vineeth Pillai <viremana@linux.microsoft.com>

Hotplug fixes to core-scheduling require a new bitops API.

Introduce a new API find_next_or_bit() which returns the bit number of
the next set bit in OR-ed bit masks of the given bit masks.

Signed-off-by: Vineeth Pillai <viremana@linux.microsoft.com>
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
---
 include/asm-generic/bitops/find.h | 16 +++++++++
 lib/find_bit.c                    | 56 +++++++++++++++++++++++++------
 2 files changed, 61 insertions(+), 11 deletions(-)

diff --git a/include/asm-generic/bitops/find.h b/include/asm-generic/bitops/find.h
index 9fdf21302fdf..0b476ca0d665 100644
--- a/include/asm-generic/bitops/find.h
+++ b/include/asm-generic/bitops/find.h
@@ -32,6 +32,22 @@ extern unsigned long find_next_and_bit(const unsigned long *addr1,
 		unsigned long offset);
 #endif
 
+#ifndef find_next_or_bit
+/**
+ * find_next_or_bit - find the next set bit in any memory regions
+ * @addr1: The first address to base the search on
+ * @addr2: The second address to base the search on
+ * @offset: The bitnumber to start searching at
+ * @size: The bitmap size in bits
+ *
+ * Returns the bit number for the next set bit
+ * If no bits are set, returns @size.
+ */
+extern unsigned long find_next_or_bit(const unsigned long *addr1,
+		const unsigned long *addr2, unsigned long size,
+		unsigned long offset);
+#endif
+
 #ifndef find_next_zero_bit
 /**
  * find_next_zero_bit - find the next cleared bit in a memory region
diff --git a/lib/find_bit.c b/lib/find_bit.c
index 49f875f1baf7..2eca8e2b16b1 100644
--- a/lib/find_bit.c
+++ b/lib/find_bit.c
@@ -19,7 +19,14 @@
 
 #if !defined(find_next_bit) || !defined(find_next_zero_bit) ||			\
 	!defined(find_next_bit_le) || !defined(find_next_zero_bit_le) ||	\
-	!defined(find_next_and_bit)
+	!defined(find_next_and_bit) || !defined(find_next_or_bit)
+
+typedef enum {
+	FNB_AND = 0,
+	FNB_OR  = 1,
+	FNB_MAX = 2
+} fnb_bwops_t;
+
 /*
  * This is a common helper function for find_next_bit, find_next_zero_bit, and
  * find_next_and_bit. The differences are:
@@ -29,7 +36,8 @@
  */
 static unsigned long _find_next_bit(const unsigned long *addr1,
 		const unsigned long *addr2, unsigned long nbits,
-		unsigned long start, unsigned long invert, unsigned long le)
+		unsigned long start, unsigned long invert,
+		fnb_bwops_t type, unsigned long le)
 {
 	unsigned long tmp, mask;
 
@@ -37,8 +45,16 @@ static unsigned long _find_next_bit(const unsigned long *addr1,
 		return nbits;
 
 	tmp = addr1[start / BITS_PER_LONG];
-	if (addr2)
-		tmp &= addr2[start / BITS_PER_LONG];
+	if (addr2) {
+		switch (type) {
+		case FNB_AND:
+			tmp &= addr2[start / BITS_PER_LONG];
+			break;
+		case FNB_OR:
+			tmp |= addr2[start / BITS_PER_LONG];
+			break;
+		}
+	}
 	tmp ^= invert;
 
 	/* Handle 1st word. */
@@ -56,8 +72,16 @@ static unsigned long _find_next_bit(const unsigned long *addr1,
 			return nbits;
 
 		tmp = addr1[start / BITS_PER_LONG];
-		if (addr2)
-			tmp &= addr2[start / BITS_PER_LONG];
+		if (addr2) {
+			switch (type) {
+			case FNB_AND:
+				tmp &= addr2[start / BITS_PER_LONG];
+				break;
+			case FNB_OR:
+				tmp |= addr2[start / BITS_PER_LONG];
+				break;
+			}
+		}
 		tmp ^= invert;
 	}
 
@@ -75,7 +99,7 @@ static unsigned long _find_next_bit(const unsigned long *addr1,
 unsigned long find_next_bit(const unsigned long *addr, unsigned long size,
 			    unsigned long offset)
 {
-	return _find_next_bit(addr, NULL, size, offset, 0UL, 0);
+	return _find_next_bit(addr, NULL, size, offset, 0UL, FNB_AND, 0);
 }
 EXPORT_SYMBOL(find_next_bit);
 #endif
@@ -84,7 +108,7 @@ EXPORT_SYMBOL(find_next_bit);
 unsigned long find_next_zero_bit(const unsigned long *addr, unsigned long size,
 				 unsigned long offset)
 {
-	return _find_next_bit(addr, NULL, size, offset, ~0UL, 0);
+	return _find_next_bit(addr, NULL, size, offset, ~0UL, FNB_AND, 0);
 }
 EXPORT_SYMBOL(find_next_zero_bit);
 #endif
@@ -94,11 +118,21 @@ unsigned long find_next_and_bit(const unsigned long *addr1,
 		const unsigned long *addr2, unsigned long size,
 		unsigned long offset)
 {
-	return _find_next_bit(addr1, addr2, size, offset, 0UL, 0);
+	return _find_next_bit(addr1, addr2, size, offset, 0UL, FNB_AND, 0);
 }
 EXPORT_SYMBOL(find_next_and_bit);
 #endif
 
+#if !defined(find_next_or_bit)
+unsigned long find_next_or_bit(const unsigned long *addr1,
+		const unsigned long *addr2, unsigned long size,
+		unsigned long offset)
+{
+	return _find_next_bit(addr1, addr2, size, offset, 0UL, FNB_OR, 0);
+}
+EXPORT_SYMBOL(find_next_or_bit);
+#endif
+
 #ifndef find_first_bit
 /*
  * Find the first set bit in a memory region.
@@ -161,7 +195,7 @@ EXPORT_SYMBOL(find_last_bit);
 unsigned long find_next_zero_bit_le(const void *addr, unsigned
 		long size, unsigned long offset)
 {
-	return _find_next_bit(addr, NULL, size, offset, ~0UL, 1);
+	return _find_next_bit(addr, NULL, size, offset, ~0UL, FNB_AND, 1);
 }
 EXPORT_SYMBOL(find_next_zero_bit_le);
 #endif
@@ -170,7 +204,7 @@ EXPORT_SYMBOL(find_next_zero_bit_le);
 unsigned long find_next_bit_le(const void *addr, unsigned
 		long size, unsigned long offset)
 {
-	return _find_next_bit(addr, NULL, size, offset, 0UL, 1);
+	return _find_next_bit(addr, NULL, size, offset, 0UL, FNB_AND, 1);
 }
 EXPORT_SYMBOL(find_next_bit_le);
 #endif
-- 
2.28.0.220.ged08abb693-goog


  parent reply index

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-15  3:18 [PATCH RFC 00/12] Core-sched v6+: kernel protection and hotplug fixes Joel Fernandes (Google)
2020-08-15  3:18 ` [PATCH RFC 01/12] irq_work: Add support to detect if work is pending Joel Fernandes (Google)
2020-08-15  8:13   ` peterz
2020-08-17  2:04     ` Joel Fernandes
2020-08-15  3:18 ` [PATCH RFC 02/12] entry/idle: Add a common function for activites during idle entry/exit Joel Fernandes (Google)
2020-08-15  8:14   ` peterz
2020-08-17  2:17     ` Joel Fernandes
2020-08-15  3:18 ` [PATCH RFC 03/12] arch/x86: Add a new TIF flag for untrusted tasks Joel Fernandes (Google)
2020-08-15  3:19 ` [PATCH RFC 04/12] kernel/entry: Add support for core-wide protection of kernel-mode Joel Fernandes (Google)
2020-08-15  3:19 ` [PATCH RFC 05/12] entry/idle: Enter and exit kernel protection during idle entry and exit Joel Fernandes (Google)
2020-08-15  3:19 ` [PATCH RFC 06/12] entry/kvm: Protect the kernel when entering from guest Joel Fernandes (Google)
2020-08-15  3:19 ` Joel Fernandes (Google) [this message]
2020-08-15  3:19 ` [PATCH RFC 08/12] cpumask: Introduce a new iterator for_each_cpu_wrap_or Joel Fernandes (Google)
2020-08-15  3:19 ` [PATCH RFC 09/12] sched/coresched: Use for_each_cpu(_wrap)_or for pick_next_task Joel Fernandes (Google)
2020-08-15  3:19 ` [PATCH RFC 10/12] sched/coresched: Make core_pick_seq per run-queue Joel Fernandes (Google)
2020-08-15  3:19 ` [PATCH RFC 11/12] sched/coresched: Check for dynamic changes in smt_mask Joel Fernandes (Google)
2020-08-15  3:19 ` [PATCH RFC 12/12] sched/coresched: rq->core should be set only if not previously set Joel Fernandes (Google)
2020-08-19 18:26 ` [PATCH RFC 00/12] Core-sched v6+: kernel protection and hotplug fixes Kees Cook
2020-08-20  1:44   ` Joel Fernandes
2020-08-22 20:22 ` Joel Fernandes

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20200815031908.1015049-8-joel@joelfernandes.org \
    --to=joel@joelfernandes.org \
    --cc=aaron.lwe@gmail.com \
    --cc=aubrey.li@linux.intel.com \
    --cc=christian.brauner@ubuntu.com \
    --cc=fweisbec@gmail.com \
    --cc=jdesfossez@digitalocean.com \
    --cc=keescook@chromium.org \
    --cc=kerrnel@google.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=pauld@redhat.com \
    --cc=paulmck@kernel.org \
    --cc=pbonzini@redhat.com \
    --cc=peterz@infradead.org \
    --cc=pjt@google.com \
    --cc=rostedt@goodmis.org \
    --cc=tglx@linutronix.de \
    --cc=tim.c.chen@intel.com \
    --cc=tim.c.chen@linux.intel.com \
    --cc=valentin.schneider@arm.com \
    --cc=vincent.guittot@linaro.org \
    --cc=viremana@linux.microsoft.com \
    --cc=x86@kernel.org \
    --cc=yu.c.chen@intel.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

LKML Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/lkml/0 lkml/git/0.git
	git clone --mirror https://lore.kernel.org/lkml/1 lkml/git/1.git
	git clone --mirror https://lore.kernel.org/lkml/2 lkml/git/2.git
	git clone --mirror https://lore.kernel.org/lkml/3 lkml/git/3.git
	git clone --mirror https://lore.kernel.org/lkml/4 lkml/git/4.git
	git clone --mirror https://lore.kernel.org/lkml/5 lkml/git/5.git
	git clone --mirror https://lore.kernel.org/lkml/6 lkml/git/6.git
	git clone --mirror https://lore.kernel.org/lkml/7 lkml/git/7.git
	git clone --mirror https://lore.kernel.org/lkml/8 lkml/git/8.git
	git clone --mirror https://lore.kernel.org/lkml/9 lkml/git/9.git
	git clone --mirror https://lore.kernel.org/lkml/10 lkml/git/10.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 lkml lkml/ https://lore.kernel.org/lkml \
		linux-kernel@vger.kernel.org
	public-inbox-index lkml

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-kernel


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git