[PATCH] pidspace: is_init()

This is an updated version of Eric Biederman's is_init() patch.
(http://lkml.org/lkml/2006/2/6/280).  It applies cleanly to 2.6.18-rc3 and
replaces a few more instances of ->pid == 1 with is_init().

Further, is_init() checks pid and thus removes dependency on Eric's other
patches for now.

Eric's original description:

	There are a lot of places in the kernel where we test for init
	because we give it special properties.  Most  significantly init
	must not die.  This results in code all over the kernel test
	->pid == 1.

	Introduce is_init to capture this case.

	With multiple pid spaces for all of the cases affected we are
	looking for only the first process on the system, not some other
	process that has pid == 1.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Cc: Serge Hallyn <serue@us.ibm.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Cc: <lxc-devel@lists.sourceforge.net>
Acked-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

19 files changed, 22 insertions, 22 deletions

diff --git a/arch/alpha/mm/fault.c b/arch/alpha/mm/fault.c
index 622dabd8468..8871529a34e 100644
--- a/arch/alpha/mm/fault.c
+++ b/arch/alpha/mm/fault.c
@@ -193,7 +193,7 @@ do_page_fault(unsigned long address, unsigned long mmcsr,
 	/* We ran out of memory, or some other thing happened to us that
 	   made us unable to handle the page fault gracefully.  */
  out_of_memory:
-	if (current->pid == 1) {
+	if (is_init(current)) {
 		yield();
 		down_read(&mm->mmap_sem);
 		goto survive;
diff --git a/arch/arm/mm/fault.c b/arch/arm/mm/fault.c
index a5b33ff3924..5e658a87449 100644
--- a/arch/arm/mm/fault.c
+++ b/arch/arm/mm/fault.c
@@ -198,7 +198,7 @@ survive:
 		return fault;
 	}
 
-	if (tsk->pid != 1)
+	if (!is_init(tsk))
 		goto out;
 
 	/*
diff --git a/arch/arm26/mm/fault.c b/arch/arm26/mm/fault.c
index a7c4cc92209..a1f6d8a9cc3 100644
--- a/arch/arm26/mm/fault.c
+++ b/arch/arm26/mm/fault.c
@@ -185,7 +185,7 @@ survive:
 	}
 
 	fault = -3; /* out of memory */
-	if (tsk->pid != 1)
+	if (!is_init(tsk))
 		goto out;
 
 	/*
diff --git a/arch/i386/lib/usercopy.c b/arch/i386/lib/usercopy.c
index efc7e7d5f4d..08502fc6d0c 100644
--- a/arch/i386/lib/usercopy.c
+++ b/arch/i386/lib/usercopy.c
@@ -739,7 +739,7 @@ survive:
 			retval = get_user_pages(current, current->mm,
 					(unsigned long )to, 1, 1, 0, &pg, NULL);
 
-			if (retval == -ENOMEM && current->pid == 1) {
+			if (retval == -ENOMEM && is_init(current)) {
 				up_read(&current->mm->mmap_sem);
 				blk_congestion_wait(WRITE, HZ/50);
 				goto survive;
diff --git a/arch/i386/mm/fault.c b/arch/i386/mm/fault.c
index 50d8617391d..2581575786c 100644
--- a/arch/i386/mm/fault.c
+++ b/arch/i386/mm/fault.c
@@ -589,7 +589,7 @@ no_context:
  */
 out_of_memory:
 	up_read(&mm->mmap_sem);
-	if (tsk->pid == 1) {
+	if (is_init(tsk)) {
 		yield();
 		down_read(&mm->mmap_sem);
 		goto survive;
diff --git a/arch/ia64/mm/fault.c b/arch/ia64/mm/fault.c
index d8b1b4ac7f2..59f3ab93761 100644
--- a/arch/ia64/mm/fault.c
+++ b/arch/ia64/mm/fault.c
@@ -280,7 +280,7 @@ ia64_do_page_fault (unsigned long address, unsigned long isr, struct pt_regs *re
 
   out_of_memory:
 	up_read(&mm->mmap_sem);
-	if (current->pid == 1) {
+	if (is_init(current)) {
 		yield();
 		down_read(&mm->mmap_sem);
 		goto survive;
diff --git a/arch/m32r/mm/fault.c b/arch/m32r/mm/fault.c
index dc18a33eefe..8d5f551b575 100644
--- a/arch/m32r/mm/fault.c
+++ b/arch/m32r/mm/fault.c
@@ -299,7 +299,7 @@ no_context:
  */
 out_of_memory:
 	up_read(&mm->mmap_sem);
-	if (tsk->pid == 1) {
+	if (is_init(tsk)) {
 		yield();
 		down_read(&mm->mmap_sem);
 		goto survive;
diff --git a/arch/m68k/mm/fault.c b/arch/m68k/mm/fault.c
index 5e2d87c10c8..911f2ce3f53 100644
--- a/arch/m68k/mm/fault.c
+++ b/arch/m68k/mm/fault.c
@@ -181,7 +181,7 @@ good_area:
  */
 out_of_memory:
 	up_read(&mm->mmap_sem);
-	if (current->pid == 1) {
+	if (is_init(current)) {
 		yield();
 		down_read(&mm->mmap_sem);
 		goto survive;
diff --git a/arch/mips/mm/fault.c b/arch/mips/mm/fault.c
index a4f8c45c4e8..8423d859077 100644
--- a/arch/mips/mm/fault.c
+++ b/arch/mips/mm/fault.c
@@ -171,7 +171,7 @@ no_context:
  */
 out_of_memory:
 	up_read(&mm->mmap_sem);
-	if (tsk->pid == 1) {
+	if (is_init(tsk)) {
 		yield();
 		down_read(&mm->mmap_sem);
 		goto survive;
diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c
index 77953f41d75..e8fa50624b7 100644
--- a/arch/powerpc/mm/fault.c
+++ b/arch/powerpc/mm/fault.c
@@ -386,7 +386,7 @@ bad_area_nosemaphore:
  */
 out_of_memory:
 	up_read(&mm->mmap_sem);
-	if (current->pid == 1) {
+	if (is_init(current)) {
 		yield();
 		down_read(&mm->mmap_sem);
 		goto survive;
diff --git a/arch/powerpc/platforms/pseries/ras.c b/arch/powerpc/platforms/pseries/ras.c
index 903115d67fd..311ed1993fc 100644
--- a/arch/powerpc/platforms/pseries/ras.c
+++ b/arch/powerpc/platforms/pseries/ras.c
@@ -337,7 +337,7 @@ static int recover_mce(struct pt_regs *regs, struct rtas_error_log * err)
 		   err->disposition == RTAS_DISP_NOT_RECOVERED &&
 		   err->target == RTAS_TARGET_MEMORY &&
 		   err->type == RTAS_TYPE_ECC_UNCORR &&
-		   !(current->pid == 0 || current->pid == 1)) {
+		   !(current->pid == 0 || is_init(current))) {
 		/* Kill off a user process with an ECC error */
 		printk(KERN_ERR "MCE: uncorrectable ecc error for pid %d\n",
 		       current->pid);
diff --git a/arch/ppc/kernel/traps.c b/arch/ppc/kernel/traps.c
index d7a433049b4..aafc8e8893d 100644
--- a/arch/ppc/kernel/traps.c
+++ b/arch/ppc/kernel/traps.c
@@ -119,7 +119,7 @@ void _exception(int signr, struct pt_regs *regs, int code, unsigned long addr)
 	 * generate the same exception over and over again and we get
 	 * nowhere.  Better to kill it and let the kernel panic.
 	 */
-	if (current->pid == 1) {
+	if (is_init(current)) {
 		__sighandler_t handler;
 
 		spin_lock_irq(&current->sighand->siglock);
diff --git a/arch/ppc/mm/fault.c b/arch/ppc/mm/fault.c
index bc776beb313..465f451f3bc 100644
--- a/arch/ppc/mm/fault.c
+++ b/arch/ppc/mm/fault.c
@@ -291,7 +291,7 @@ bad_area:
  */
 out_of_memory:
 	up_read(&mm->mmap_sem);
-	if (current->pid == 1) {
+	if (is_init(current)) {
 		yield();
 		down_read(&mm->mmap_sem);
 		goto survive;
diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c
index f2b9a84dc2b..9c3c19fe62f 100644
--- a/arch/s390/mm/fault.c
+++ b/arch/s390/mm/fault.c
@@ -353,7 +353,7 @@ no_context:
 */
 out_of_memory:
 	up_read(&mm->mmap_sem);
-	if (tsk->pid == 1) {
+	if (is_init(tsk)) {
 		yield();
 		down_read(&mm->mmap_sem);
 		goto survive;
diff --git a/arch/sh/mm/fault.c b/arch/sh/mm/fault.c
index 507f2891470..68663b8f99a 100644
--- a/arch/sh/mm/fault.c
+++ b/arch/sh/mm/fault.c
@@ -149,7 +149,7 @@ no_context:
  */
 out_of_memory:
 	up_read(&mm->mmap_sem);
-	if (current->pid == 1) {
+	if (is_init(current)) {
 		yield();
 		down_read(&mm->mmap_sem);
 		goto survive;
diff --git a/arch/sh64/mm/fault.c b/arch/sh64/mm/fault.c
index f08d0eaf649..8e2f6c28b73 100644
--- a/arch/sh64/mm/fault.c
+++ b/arch/sh64/mm/fault.c
@@ -277,7 +277,7 @@ bad_area:
 			show_regs(regs);
 #endif
 		}
-		if (tsk->pid == 1) {
+		if (is_init(tsk)) {
 			panic("INIT had user mode bad_area\n");
 		}
 		tsk->thread.address = address;
@@ -319,14 +319,14 @@ no_context:
  * us unable to handle the page fault gracefully.
  */
 out_of_memory:
-	if (current->pid == 1) {
+	if (is_init(current)) {
 		panic("INIT out of memory\n");
 		yield();
 		goto survive;
 	}
 	printk("fault:Out of memory\n");
 	up_read(&mm->mmap_sem);
-	if (current->pid == 1) {
+	if (is_init(current)) {
 		yield();
 		down_read(&mm->mmap_sem);
 		goto survive;
diff --git a/arch/um/kernel/trap.c b/arch/um/kernel/trap.c
index 61a23fff439..c7b195c7e51 100644
--- a/arch/um/kernel/trap.c
+++ b/arch/um/kernel/trap.c
@@ -120,7 +120,7 @@ out_nosemaphore:
  * us unable to handle the page fault gracefully.
  */
 out_of_memory:
-	if (current->pid == 1) {
+	if (is_init(current)) {
 		up_read(&mm->mmap_sem);
 		yield();
 		down_read(&mm->mmap_sem);
diff --git a/arch/x86_64/mm/fault.c b/arch/x86_64/mm/fault.c
index 9ba54cc2b5f..3751b4788e2 100644
--- a/arch/x86_64/mm/fault.c
+++ b/arch/x86_64/mm/fault.c
@@ -244,7 +244,7 @@ static int is_errata93(struct pt_regs *regs, unsigned long address)
 
 int unhandled_signal(struct task_struct *tsk, int sig)
 {
-	if (tsk->pid == 1)
+	if (is_init(tsk))
 		return 1;
 	if (tsk->ptrace & PT_PTRACED)
 		return 0;
@@ -580,7 +580,7 @@ no_context:
  */
 out_of_memory:
 	up_read(&mm->mmap_sem);
-	if (current->pid == 1) { 
+	if (is_init(current)) {
 		yield();
 		goto again;
 	}
diff --git a/arch/xtensa/mm/fault.c b/arch/xtensa/mm/fault.c
index a945a33e85a..dd0dbec2e57 100644
--- a/arch/xtensa/mm/fault.c
+++ b/arch/xtensa/mm/fault.c
@@ -144,7 +144,7 @@ bad_area:
 	 */
 out_of_memory:
 	up_read(&mm->mmap_sem);
-	if (current->pid == 1) {
+	if (is_init(current)) {
 		yield();
 		down_read(&mm->mmap_sem);
 		goto survive;