Cc: LKML
Sukadev Bhattiprolu [[email protected]] wrote: | | Subject: [v12][PATCH 3/9] Define set_pidmap() function | | Define a set_pidmap() interface which is like alloc_pidmap() only that | caller specifies the pid number to be assigned. | | Changelog[v9]: | - Completely rewrote this patch based on Eric Biederman's code. | Changelog[v7]: | - [Eric Biederman] Generalize alloc_pidmap() to take a range of pids. | Changelog[v6]: | - Separate target_pid > 0 case to minimize the number of checks needed. | Changelog[v3]: | - (Eric Biederman): Avoid set_pidmap() function. Added couple of | checks for target_pid in alloc_pidmap() itself. | Changelog[v2]: | - (Serge Hallyn) Check for 'pid < 0' in set_pidmap().(Code | actually checks for 'pid <= 0' for completeness). | | Signed-off-by: Sukadev Bhattiprolu <[email protected]> | Acked-by: Oren Laadan <[email protected]> | --- | kernel/pid.c | 41 +++++++++++++++++++++++++++++++++-------- | 1 files changed, 33 insertions(+), 8 deletions(-) | | diff --git a/kernel/pid.c b/kernel/pid.c | index c4d9914..afef766 100644 | --- a/kernel/pid.c | +++ b/kernel/pid.c | @@ -147,18 +147,19 @@ static int alloc_pidmap_page(struct pidmap *map) | return 0; | } | | -static int alloc_pidmap(struct pid_namespace *pid_ns) | +static int do_alloc_pidmap(struct pid_namespace *pid_ns, int last, int min, | + int max) | { | - int i, offset, max_scan, pid, last = pid_ns->last_pid; | + int i, offset, max_scan, pid; | int rc = -EAGAIN; | struct pidmap *map; | | pid = last + 1; | if (pid >= pid_max) | - pid = RESERVED_PIDS; | + pid = min; | offset = pid & BITS_PER_PAGE_MASK; | map = &pid_ns->pidmap[pid/BITS_PER_PAGE]; | - max_scan = (pid_max + BITS_PER_PAGE - 1)/BITS_PER_PAGE - !offset; | + max_scan = (max + BITS_PER_PAGE - 1)/BITS_PER_PAGE - !offset; | for (i = 0; i <= max_scan; ++i) { | rc = alloc_pidmap_page(map); | if (rc) | @@ -168,7 +169,6 @@ static int alloc_pidmap(struct pid_namespace *pid_ns) | do { | if (!test_and_set_bit(offset, map->page)) { | atomic_dec(&map->nr_free); | - pid_ns->last_pid = pid; | return pid; | } | offset = find_next_offset(map, offset); | @@ -179,16 +179,16 @@ static int alloc_pidmap(struct pid_namespace *pid_ns) | * bitmap block and the final block was the same | * as the starting point, pid is before last_pid. | */ | - } while (offset < BITS_PER_PAGE && pid < pid_max && | + } while (offset < BITS_PER_PAGE && pid < max && | (i != max_scan || pid < last || | !((last+1) & BITS_PER_PAGE_MASK))); | } | - if (map < &pid_ns->pidmap[(pid_max-1)/BITS_PER_PAGE]) { | + if (map < &pid_ns->pidmap[(max-1)/BITS_PER_PAGE]) { | ++map; | offset = 0; | } else { | map = &pid_ns->pidmap[0]; | - offset = RESERVED_PIDS; | + offset = min; | if (unlikely(last == offset)) { | rc = -EAGAIN; | break; | @@ -199,6 +199,31 @@ static int alloc_pidmap(struct pid_namespace *pid_ns) | return rc; | } | | +static int alloc_pidmap(struct pid_namespace *pid_ns) | +{ | + int nr; | + | + nr = do_alloc_pidmap(pid_ns, pid_ns->last_pid, RESERVED_PIDS, pid_max); | + if (nr >= 0) | + pid_ns->last_pid = nr; | + return nr; | +} | + | +static int set_pidmap(struct pid_namespace *pid_ns, int target) | +{ | + if (!target) | + return alloc_pidmap(pid_ns); | + | + if (target >= pid_max) | + return -EINVAL; | + | + if ((target < 0) || (target < RESERVED_PIDS && | + pid_ns->last_pid >= RESERVED_PIDS)) | + return -EINVAL; | + | + return do_alloc_pidmap(pid_ns, target - 1, target, target + 1); | +} | + | int next_pidmap(struct pid_namespace *pid_ns, int last) | { | int offset; | -- | 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
