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Subject[PATCH v21 002/100] eclone (2/11): Have alloc_pidmap() return actual error code
Date
From: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>

alloc_pidmap() can fail either because all pid numbers are in use or
because memory allocation failed. With support for setting a specific
pid number, alloc_pidmap() would also fail if either the given pid
number is invalid or in use.

Rather than have callers assume -ENOMEM, have alloc_pidmap() return
the actual error.

Changelog[v1]:
- [Oren Laadan] Rebase to kernel 2.6.33

Cc: linux-api@vger.kernel.org
Cc: x86@kernel.org
Cc: linux-s390@vger.kernel.org
Cc: linuxppc-dev@ozlabs.org
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Acked-by: Serge E. Hallyn <serue@us.ibm.com>
Tested-by: Serge E. Hallyn <serue@us.ibm.com>
Reviewed-by: Oren Laadan <orenl@cs.columbia.edu>
---
kernel/fork.c | 5 +++--
kernel/pid.c | 10 ++++++----
2 files changed, 9 insertions(+), 6 deletions(-)
diff --git a/kernel/fork.c b/kernel/fork.c
index 44b0791..afdfb08 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1147,10 +1147,11 @@ static struct task_struct *copy_process(unsigned long clone_flags,
goto bad_fork_cleanup_io;

if (pid != &init_struct_pid) {
- retval = -ENOMEM;
pid = alloc_pid(p->nsproxy->pid_ns);
- if (!pid)
+ if (IS_ERR(pid)) {
+ retval = PTR_ERR(pid);
goto bad_fork_cleanup_io;
+ }

if (clone_flags & CLONE_NEWPID) {
retval = pid_ns_prepare_proc(p->nsproxy->pid_ns);
diff --git a/kernel/pid.c b/kernel/pid.c
index 52a371a..8330488 100644
--- a/kernel/pid.c
+++ b/kernel/pid.c
@@ -160,7 +160,7 @@ static int alloc_pidmap(struct pid_namespace *pid_ns)
for (i = 0; i <= max_scan; ++i) {
if (unlikely(!map->page))
if (alloc_pidmap_page(map) < 0)
- break;
+ return -ENOMEM;
if (likely(atomic_read(&map->nr_free))) {
do {
if (!test_and_set_bit(offset, map->page)) {
@@ -191,7 +191,7 @@ static int alloc_pidmap(struct pid_namespace *pid_ns)
}
pid = mk_pid(pid_ns, map, offset);
}
- return -1;
+ return -EBUSY;
}

int next_pidmap(struct pid_namespace *pid_ns, int last)
@@ -260,8 +260,10 @@ struct pid *alloc_pid(struct pid_namespace *ns)
struct upid *upid;

pid = kmem_cache_alloc(ns->pid_cachep, GFP_KERNEL);
- if (!pid)
+ if (!pid) {
+ pid = ERR_PTR(-ENOMEM);
goto out;
+ }

tmp = ns;
for (i = ns->level; i >= 0; i--) {
@@ -295,7 +297,7 @@ out_free:
free_pidmap(pid->numbers + i);

kmem_cache_free(ns->pid_cachep, pid);
- pid = NULL;
+ pid = ERR_PTR(nr);
goto out;
}

--
1.6.3.3


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