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From: Rusty Russell <rusty@rustcorp.com.au>
To: lkml - Kernel Mailing List <linux-kernel@vger.kernel.org>
Cc: Andrew Morton <akpm@osdl.org>, Andi Kleen <ak@muc.de>,
	virtualization <virtualization@lists.osdl.org>
Subject: [PATCH 3/10] lguest: Expose get_futex_key, get_key_refs and drop_key_refs.
Date: Fri, 09 Feb 2007 20:17:18 +1100	[thread overview]
Message-ID: <1171012638.2718.36.camel@localhost.localdomain> (raw)
In-Reply-To: <1171012458.2718.30.camel@localhost.localdomain>

Name: Expose get_futex_key, get_key_refs and drop_key_refs.

lguest uses the convenient futex infrastructure for inter-domain I/O,
so expose get_futex_key, get_key_refs (renamed get_futex_key_refs) and
drop_key_refs (renamed drop_futex_key_refs).  Also means we need to
expose the union that these use.

No code changes.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

===================================================================
--- a/include/linux/futex.h
+++ b/include/linux/futex.h
@@ -100,6 +100,35 @@ extern int
 extern int
 handle_futex_death(u32 __user *uaddr, struct task_struct *curr, int pi);
 
+/*
+ * Futexes are matched on equal values of this key.
+ * The key type depends on whether it's a shared or private mapping.
+ * Don't rearrange members without looking at hash_futex().
+ *
+ * offset is aligned to a multiple of sizeof(u32) (== 4) by definition.
+ * We set bit 0 to indicate if it's an inode-based key.
+ */
+union futex_key {
+	struct {
+		unsigned long pgoff;
+		struct inode *inode;
+		int offset;
+	} shared;
+	struct {
+		unsigned long address;
+		struct mm_struct *mm;
+		int offset;
+	} private;
+	struct {
+		unsigned long word;
+		void *ptr;
+		int offset;
+	} both;
+};
+int get_futex_key(u32 __user *uaddr, union futex_key *key);
+void get_futex_key_refs(union futex_key *key);
+void drop_futex_key_refs(union futex_key *key);
+
 #ifdef CONFIG_FUTEX
 extern void exit_robust_list(struct task_struct *curr);
 extern void exit_pi_state_list(struct task_struct *curr);
===================================================================
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -48,37 +48,12 @@
 #include <linux/pagemap.h>
 #include <linux/syscalls.h>
 #include <linux/signal.h>
+#include <linux/module.h>
 #include <asm/futex.h>
 
 #include "rtmutex_common.h"
 
 #define FUTEX_HASHBITS (CONFIG_BASE_SMALL ? 4 : 8)
-
-/*
- * Futexes are matched on equal values of this key.
- * The key type depends on whether it's a shared or private mapping.
- * Don't rearrange members without looking at hash_futex().
- *
- * offset is aligned to a multiple of sizeof(u32) (== 4) by definition.
- * We set bit 0 to indicate if it's an inode-based key.
- */
-union futex_key {
-	struct {
-		unsigned long pgoff;
-		struct inode *inode;
-		int offset;
-	} shared;
-	struct {
-		unsigned long address;
-		struct mm_struct *mm;
-		int offset;
-	} private;
-	struct {
-		unsigned long word;
-		void *ptr;
-		int offset;
-	} both;
-};
 
 /*
  * Priority Inheritance state:
@@ -175,7 +150,7 @@ static inline int match_futex(union fute
  *
  * Should be called with &current->mm->mmap_sem but NOT any spinlocks.
  */
-static int get_futex_key(u32 __user *uaddr, union futex_key *key)
+int get_futex_key(u32 __user *uaddr, union futex_key *key)
 {
 	unsigned long address = (unsigned long)uaddr;
 	struct mm_struct *mm = current->mm;
@@ -246,6 +221,7 @@ static int get_futex_key(u32 __user *uad
 	}
 	return err;
 }
+EXPORT_SYMBOL_GPL(get_futex_key);
 
 /*
  * Take a reference to the resource addressed by a key.
@@ -254,7 +230,7 @@ static int get_futex_key(u32 __user *uad
  * NOTE: mmap_sem MUST be held between get_futex_key() and calling this
  * function, if it is called at all.  mmap_sem keeps key->shared.inode valid.
  */
-static inline void get_key_refs(union futex_key *key)
+inline void get_futex_key_refs(union futex_key *key)
 {
 	if (key->both.ptr != 0) {
 		if (key->both.offset & 1)
@@ -263,12 +239,13 @@ static inline void get_key_refs(union fu
 			atomic_inc(&key->private.mm->mm_count);
 	}
 }
+EXPORT_SYMBOL_GPL(get_futex_key_refs);
 
 /*
  * Drop a reference to the resource addressed by a key.
  * The hash bucket spinlock must not be held.
  */
-static void drop_key_refs(union futex_key *key)
+void drop_futex_key_refs(union futex_key *key)
 {
 	if (key->both.ptr != 0) {
 		if (key->both.offset & 1)
@@ -277,6 +254,7 @@ static void drop_key_refs(union futex_ke
 			mmdrop(key->private.mm);
 	}
 }
+EXPORT_SYMBOL_GPL(drop_futex_key_refs);
 
 static inline int get_futex_value_locked(u32 *dest, u32 __user *from)
 {
@@ -871,7 +849,7 @@ static int futex_requeue(u32 __user *uad
 				this->lock_ptr = &hb2->lock;
 			}
 			this->key = key2;
-			get_key_refs(&key2);
+			get_futex_key_refs(&key2);
 			drop_count++;
 
 			if (ret - nr_wake >= nr_requeue)
@@ -884,9 +862,9 @@ out_unlock:
 	if (hb1 != hb2)
 		spin_unlock(&hb2->lock);
 
-	/* drop_key_refs() must be called outside the spinlocks. */
+	/* drop_futex_key_refs() must be called outside the spinlocks. */
 	while (--drop_count >= 0)
-		drop_key_refs(&key1);
+		drop_futex_key_refs(&key1);
 
 out:
 	up_read(&current->mm->mmap_sem);
@@ -904,7 +882,7 @@ queue_lock(struct futex_q *q, int fd, st
 
 	init_waitqueue_head(&q->waiters);
 
-	get_key_refs(&q->key);
+	get_futex_key_refs(&q->key);
 	hb = hash_futex(&q->key);
 	q->lock_ptr = &hb->lock;
 
@@ -923,7 +901,7 @@ queue_unlock(struct futex_q *q, struct f
 queue_unlock(struct futex_q *q, struct futex_hash_bucket *hb)
 {
 	spin_unlock(&hb->lock);
-	drop_key_refs(&q->key);
+	drop_futex_key_refs(&q->key);
 }
 
 /*
@@ -978,7 +956,7 @@ static int unqueue_me(struct futex_q *q)
 		ret = 1;
 	}
 
-	drop_key_refs(&q->key);
+	drop_futex_key_refs(&q->key);
 	return ret;
 }
 
@@ -997,7 +975,7 @@ static void unqueue_me_pi(struct futex_q
 
 	spin_unlock(&hb->lock);
 
-	drop_key_refs(&q->key);
+	drop_futex_key_refs(&q->key);
 }
 
 static int futex_wait(u32 __user *uaddr, u32 val, unsigned long time)




  parent reply	other threads:[~2007-02-09  9:18 UTC|newest]

Thread overview: 53+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-02-09  9:11 [PATCH 0/10] lguest Rusty Russell
2007-02-09  9:14 ` [PATCH 1/10] lguest: Don't rely on last-linked fallthru when no paravirt handler Rusty Russell
2007-02-09  9:15   ` [PATCH 2/10] lguest: Export symbols for lguest as a module Rusty Russell
2007-02-09  9:32     ` Andi Kleen
2007-02-09 12:06       ` Rusty Russell
2007-02-09 13:58         ` Andi Kleen
2007-02-10 11:39           ` Rusty Russell
2007-02-09  9:17   ` Rusty Russell [this message]
2007-02-09  9:18   ` [PATCH 4/10] lguest: Initialize esp0 properly all the time Rusty Russell
2007-02-09  9:19     ` [PATCH 5/10] Make hvc_console.c compile on non-PowerPC Rusty Russell
     [not found]       ` <1171012827.2718.42.camel@localhost.localdomain>
2007-02-09  9:22         ` [PATCH 7/10] lguest: Simple lguest network driver Rusty Russell
2007-02-09  9:23           ` [PATCH 8/10] lguest: console driver Rusty Russell
2007-02-09  9:24             ` [PATCH 9/10] lguest: block driver Rusty Russell
2007-02-09  9:25               ` [PATCH 10/10] lguest: documentatation including example launcher Rusty Russell
2007-02-09  9:35         ` [PATCH 6/10] lguest code: the little linux hypervisor Andrew Morton
2007-02-09 11:00           ` Rusty Russell
2007-02-09 11:13             ` Zachary Amsden
2007-02-09 11:50               ` Andi Kleen
2007-02-09 11:54                 ` Zachary Amsden
2007-02-09 11:57                   ` Andi Kleen
2007-02-09 12:08                     ` Zachary Amsden
2007-02-09 22:29                 ` David Miller
2007-02-09 10:09         ` Andi Kleen
2007-02-09 12:39           ` Rusty Russell
2007-02-09 13:57             ` Andi Kleen
2007-02-09 15:01               ` Rusty Russell
2007-02-09 14:17             ` Sam Ravnborg
2007-02-09 15:23               ` Rusty Russell
2007-02-12 13:34                 ` [q] kbuild for private asm-offsets (Re: [PATCH 6/10] lguest code: the little linux hypervisor.) Oleg Verych
2007-02-12 17:24                   ` Andi Kleen
2007-02-12 21:41                   ` Sam Ravnborg
2007-02-12 23:41                   ` Rusty Russell
2007-02-13  3:10                     ` Oleg Verych
2007-02-16 15:55                       ` [pp] kbuild: lguest with private asm-offsets (and some bloat) Oleg Verych
2007-02-16 15:59                         ` [pp] kbuild: asm-offsets generalized Oleg Verych
2007-02-16 18:56                           ` Sam Ravnborg
2007-02-16 21:56                             ` Oleg Verych
2007-02-17  4:43                               ` Rusty Russell
2007-02-17  5:33                                 ` Oleg Verych
2007-04-01 20:42                           ` Sam Ravnborg
2007-04-01 21:08                             ` Oleg Verych
2007-04-01 21:03                               ` Sam Ravnborg
2007-02-09 10:55       ` [PATCH 6a/10] lguest: Config and headers Rusty Russell
2007-02-09 10:56         ` [PATCH 6b/10] lguest: the host code (lg.ko) Rusty Russell
2007-02-09 10:57           ` [PATCH 6c/10] lguest: the guest code Rusty Russell
2007-02-09 10:58             ` [PATCH 6d/10] lguest: the Makefiles Rusty Russell
2007-02-09 17:06             ` [PATCH 6c/10] lguest: the guest code Len Brown
2007-02-09 17:14               ` James Morris
2007-02-09 17:49                 ` Len Brown
2007-02-09 23:48                   ` [PATCH 11/10] lguest: use disable_acpi() Rusty Russell
2007-02-09  9:31   ` [PATCH 1/10] lguest: Don't rely on last-linked fallthru when no paravirt handler Andi Kleen
2007-02-09 11:52     ` Rusty Russell
2007-02-09 20:49       ` Jeremy Fitzhardinge

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