mem_cgroup_resize_limit() and mem_cgroup_resize_memsw_limit() are almost
identical functions. Instead of having two of them, we could pass an
additional argument to mem_cgroup_resize_limit() and by using it,
consolidate all the code in a single function.

Signed-off-by: Andrey Ryabinin <aryabi...@virtuozzo.com>
---
 mm/memcontrol.c | 61 +++++++++++++--------------------------------------------
 1 file changed, 14 insertions(+), 47 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 0d26db9a665d..f6253c80a5c8 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2445,50 +2445,17 @@ static inline int 
mem_cgroup_move_swap_account(swp_entry_t entry,
 
 static DEFINE_MUTEX(memcg_limit_mutex);
 
-static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
-                                  unsigned long limit)
+static bool invalid_mem_limit(struct mem_cgroup *memcg, bool memsw,
+                             unsigned long limit)
 {
-       unsigned long usage;
-       bool enlarge = false;
-       int ret;
-
-       do {
-               if (signal_pending(current)) {
-                       ret = -EINTR;
-                       break;
-               }
-
-               mutex_lock(&memcg_limit_mutex);
-               if (limit > memcg->memsw.limit) {
-                       mutex_unlock(&memcg_limit_mutex);
-                       ret = -EINVAL;
-                       break;
-               }
-               if (limit > memcg->memory.limit)
-                       enlarge = true;
-               ret = page_counter_limit(&memcg->memory, limit);
-               mutex_unlock(&memcg_limit_mutex);
-
-               if (!ret)
-                       break;
-
-               usage = page_counter_read(&memcg->memory);
-               if (!try_to_free_mem_cgroup_pages(memcg, usage - limit,
-                                       GFP_KERNEL, true)) {
-                       ret = -EBUSY;
-                       break;
-               }
-       } while (true);
-
-       if (!ret && enlarge)
-               memcg_oom_recover(memcg);
-
-       return ret;
+       return (!memsw && limit > memcg->memsw.limit) ||
+               (memsw && limit < memcg->memory.limit);
 }
 
-static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
-                                        unsigned long limit)
+static int mem_cgroup_resize_limit(struct mem_cgroup *memcg, bool memsw,
+                                  unsigned long limit)
 {
+       struct page_counter *counter = memsw ? &memcg->memsw : &memcg->memory;
        unsigned long usage;
        bool enlarge = false;
        int ret;
@@ -2500,22 +2467,22 @@ static int mem_cgroup_resize_memsw_limit(struct 
mem_cgroup *memcg,
                }
 
                mutex_lock(&memcg_limit_mutex);
-               if (limit < memcg->memory.limit) {
+               if (invalid_mem_limit(memcg, memsw, limit)) {
                        mutex_unlock(&memcg_limit_mutex);
                        ret = -EINVAL;
                        break;
                }
-               if (limit > memcg->memsw.limit)
+               if (limit > counter->limit)
                        enlarge = true;
-               ret = page_counter_limit(&memcg->memsw, limit);
+               ret = page_counter_limit(counter, limit);
                mutex_unlock(&memcg_limit_mutex);
 
                if (!ret)
                        break;
 
-               usage = page_counter_read(&memcg->memsw);
+               usage = page_counter_read(counter);
                if (!try_to_free_mem_cgroup_pages(memcg, usage - limit,
-                                       GFP_KERNEL, false)) {
+                                       GFP_KERNEL, !memsw)) {
                        ret = -EBUSY;
                        break;
                }
@@ -3193,10 +3160,10 @@ static ssize_t mem_cgroup_write(struct kernfs_open_file 
*of,
                }
                switch (MEMFILE_TYPE(of_cft(of)->private)) {
                case _MEM:
-                       ret = mem_cgroup_resize_limit(memcg, nr_pages);
+                       ret = mem_cgroup_resize_limit(memcg, false, nr_pages);
                        break;
                case _MEMSWAP:
-                       ret = mem_cgroup_resize_memsw_limit(memcg, nr_pages);
+                       ret = mem_cgroup_resize_limit(memcg, true, nr_pages);
                        break;
                case _KMEM:
                        ret = memcg_update_kmem_limit(memcg, nr_pages);
-- 
2.13.6

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