[RFC v17][PATCH 13/60] pids 3/7: Add target_pid parameter to alloc_pidmap()
From: Oren Laadan <hidden>
Date: 2009-07-22 10:16:28
Also in:
linux-mm, lkml
Subsystem:
the rest · Maintainer:
Linus Torvalds
From: Sukadev Bhattiprolu <redacted> With support for setting a specific pid number for a process, alloc_pidmap() will need a paramter a 'target_pid' parameter. Changelog[v2]: - (Serge Hallyn) Check for 'pid < 0' in set_pidmap().(Code actually checks for 'pid <= 0' for completeness). Signed-off-by: Sukadev Bhattiprolu <redacted> Acked-by: Serge Hallyn <redacted> Reviewed-by: Oren Laadan <redacted> --- kernel/pid.c | 28 ++++++++++++++++++++++++++-- 1 files changed, 26 insertions(+), 2 deletions(-)
diff --git a/kernel/pid.c b/kernel/pid.c
index 9c678ce..29cf119 100644
--- a/kernel/pid.c
+++ b/kernel/pid.c@@ -147,11 +147,35 @@ static int alloc_pidmap_page(struct pidmap *map) return 0; } -static int alloc_pidmap(struct pid_namespace *pid_ns) +static int set_pidmap(struct pid_namespace *pid_ns, int pid) +{ + int offset; + struct pidmap *map; + + if (pid <= 0 || pid >= pid_max) + return -EINVAL; + + offset = pid & BITS_PER_PAGE_MASK; + map = &pid_ns->pidmap[pid/BITS_PER_PAGE]; + + if (alloc_pidmap_page(map)) + return -ENOMEM; + + if (test_and_set_bit(offset, map->page)) + return -EBUSY; + + atomic_dec(&map->nr_free); + return pid; +} + +static int alloc_pidmap(struct pid_namespace *pid_ns, int target_pid) { int i, rc, offset, max_scan, pid, last = pid_ns->last_pid; struct pidmap *map; + if (target_pid) + return set_pidmap(pid_ns, target_pid); + pid = last + 1; if (pid >= pid_max) pid = RESERVED_PIDS;
@@ -270,7 +294,7 @@ struct pid *alloc_pid(struct pid_namespace *ns) tmp = ns; for (i = ns->level; i >= 0; i--) { - nr = alloc_pidmap(tmp); + nr = alloc_pidmap(tmp, 0); if (nr < 0) goto out_free;
--
1.6.0.4
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