Cc LKML
Sukadev Bhattiprolu [[email protected]] wrote: | | Subject: [v12][PATCH 1/9] Factor out code to allocate pidmap page | | To simplify alloc_pidmap(), move code to allocate a pid map page to a | separate function. | | Changelog[v3]: | - Earlier version of patchset called alloc_pidmap_page() from two | places. But now its called from only one place. Even so, moving | this code out into a separate function simplifies alloc_pidmap(). | Changelog[v2]: | - (Matt Helsley, Dave Hansen) Have alloc_pidmap_page() return | -ENOMEM on error instead of -1. | | Signed-off-by: Sukadev Bhattiprolu <[email protected]> | Acked-by: Serge Hallyn <[email protected]> | Reviewed-by: Oren Laadan <[email protected]> | --- | kernel/pid.c | 45 ++++++++++++++++++++++++++++++--------------- | 1 files changed, 30 insertions(+), 15 deletions(-) | | diff --git a/kernel/pid.c b/kernel/pid.c | index d3f722d..7d4bb6e 100644 | --- a/kernel/pid.c | +++ b/kernel/pid.c | @@ -122,9 +122,35 @@ static void free_pidmap(struct upid *upid) | atomic_inc(&map->nr_free); | } | | +static int alloc_pidmap_page(struct pidmap *map) | +{ | + void *page; | + | + if (likely(map->page)) | + return 0; | + | + page = kzalloc(PAGE_SIZE, GFP_KERNEL); | + | + /* | + * Free the page if someone raced with us installing it: | + */ | + spin_lock_irq(&pidmap_lock); | + if (map->page) | + kfree(page); | + else | + map->page = page; | + spin_unlock_irq(&pidmap_lock); | + | + if (unlikely(!map->page)) | + return -ENOMEM; | + | + return 0; | +} | + | static int alloc_pidmap(struct pid_namespace *pid_ns) | { | int i, offset, max_scan, pid, last = pid_ns->last_pid; | + int rc; | struct pidmap *map; | | pid = last + 1; | @@ -134,21 +160,10 @@ static int alloc_pidmap(struct pid_namespace *pid_ns) | map = &pid_ns->pidmap[pid/BITS_PER_PAGE]; | max_scan = (pid_max + BITS_PER_PAGE - 1)/BITS_PER_PAGE - !offset; | for (i = 0; i <= max_scan; ++i) { | - if (unlikely(!map->page)) { | - void *page = kzalloc(PAGE_SIZE, GFP_KERNEL); | - /* | - * Free the page if someone raced with us | - * installing it: | - */ | - spin_lock_irq(&pidmap_lock); | - if (map->page) | - kfree(page); | - else | - map->page = page; | - spin_unlock_irq(&pidmap_lock); | - if (unlikely(!map->page)) | - break; | - } | + rc = alloc_pidmap_page(map); | + if (rc) | + break; | + | if (likely(atomic_read(&map->nr_free))) { | do { | if (!test_and_set_bit(offset, map->page)) { | -- | 1.6.0.4 | | _______________________________________________ | Containers mailing list | [email protected] | https://lists.linux-foundation.org/mailman/listinfo/containers -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
