From: Chris Down chris@chrisdown.name
mainline inclusion from mainline-5.1-rc1 commit 677dc9731b54dccaaadbdcea18f8eecc95cee832 category: bugfix bugzilla: 34611 CVE: NA
------------------------------------------------- memcg has a significant number of files exposed to kernfs where their value is either exposed directly or is "max" in the case of PAGE_COUNTER_MAX.
This patch makes this generic by providing a single function to do this work. In combination with the previous patch adding mem_cgroup_from_seq, this makes all of the seq_show feeder functions significantly more simple.
Link: http://lkml.kernel.org/r/20190124194100.GA31425@chrisdown.name Signed-off-by: Chris Down chris@chrisdown.name Acked-by: Johannes Weiner hannes@cmpxchg.org Acked-by: Michal Hocko mhocko@suse.com Cc: Tejun Heo tj@kernel.org Cc: Roman Gushchin guro@fb.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org (cherry picked from commit 677dc9731b54dccaaadbdcea18f8eecc95cee832) Signed-off-by: Kefeng Wang wangkefeng.wang@huawei.com Signed-off-by: Liu Shixin liushixin2@huawei.com Reviewed-by: Kefeng Wang wangkefeng.wang@huawei.com Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- mm/memcontrol.c | 64 +++++++++++++++---------------------------------- 1 file changed, 19 insertions(+), 45 deletions(-)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 265e47a7acfe..fb473b4738b1 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -5522,6 +5522,16 @@ static void mem_cgroup_bind(struct cgroup_subsys_state *root_css) root_mem_cgroup->use_hierarchy = false; }
+static int seq_puts_memcg_tunable(struct seq_file *m, unsigned long value) +{ + if (value == PAGE_COUNTER_MAX) + seq_puts(m, "max\n"); + else + seq_printf(m, "%llu\n", (u64)value * PAGE_SIZE); + + return 0; +} + static u64 memory_current_read(struct cgroup_subsys_state *css, struct cftype *cft) { @@ -5532,15 +5542,8 @@ static u64 memory_current_read(struct cgroup_subsys_state *css,
static int memory_min_show(struct seq_file *m, void *v) { - struct mem_cgroup *memcg = mem_cgroup_from_seq(m); - unsigned long min = READ_ONCE(memcg->memory.min); - - if (min == PAGE_COUNTER_MAX) - seq_puts(m, "max\n"); - else - seq_printf(m, "%llu\n", (u64)min * PAGE_SIZE); - - return 0; + return seq_puts_memcg_tunable(m, + READ_ONCE(mem_cgroup_from_seq(m)->memory.min)); }
static ssize_t memory_min_write(struct kernfs_open_file *of, @@ -5562,15 +5565,8 @@ static ssize_t memory_min_write(struct kernfs_open_file *of,
static int memory_low_show(struct seq_file *m, void *v) { - struct mem_cgroup *memcg = mem_cgroup_from_seq(m); - unsigned long low = READ_ONCE(memcg->memory.low); - - if (low == PAGE_COUNTER_MAX) - seq_puts(m, "max\n"); - else - seq_printf(m, "%llu\n", (u64)low * PAGE_SIZE); - - return 0; + return seq_puts_memcg_tunable(m, + READ_ONCE(mem_cgroup_from_seq(m)->memory.low)); }
static ssize_t memory_low_write(struct kernfs_open_file *of, @@ -5592,15 +5588,7 @@ static ssize_t memory_low_write(struct kernfs_open_file *of,
static int memory_high_show(struct seq_file *m, void *v) { - struct mem_cgroup *memcg = mem_cgroup_from_seq(m); - unsigned long high = READ_ONCE(memcg->high); - - if (high == PAGE_COUNTER_MAX) - seq_puts(m, "max\n"); - else - seq_printf(m, "%llu\n", (u64)high * PAGE_SIZE); - - return 0; + return seq_puts_memcg_tunable(m, READ_ONCE(mem_cgroup_from_seq(m)->high)); }
static ssize_t memory_high_write(struct kernfs_open_file *of, @@ -5629,15 +5617,8 @@ static ssize_t memory_high_write(struct kernfs_open_file *of,
static int memory_max_show(struct seq_file *m, void *v) { - struct mem_cgroup *memcg = mem_cgroup_from_seq(m); - unsigned long max = READ_ONCE(memcg->memory.max); - - if (max == PAGE_COUNTER_MAX) - seq_puts(m, "max\n"); - else - seq_printf(m, "%llu\n", (u64)max * PAGE_SIZE); - - return 0; + return seq_puts_memcg_tunable(m, + READ_ONCE(mem_cgroup_from_seq(m)->memory.max)); }
static ssize_t memory_max_write(struct kernfs_open_file *of, @@ -6767,15 +6748,8 @@ static u64 swap_current_read(struct cgroup_subsys_state *css,
static int swap_max_show(struct seq_file *m, void *v) { - struct mem_cgroup *memcg = mem_cgroup_from_seq(m); - unsigned long max = READ_ONCE(memcg->swap.max); - - if (max == PAGE_COUNTER_MAX) - seq_puts(m, "max\n"); - else - seq_printf(m, "%llu\n", (u64)max * PAGE_SIZE); - - return 0; + return seq_puts_memcg_tunable(m, + READ_ONCE(mem_cgroup_from_seq(m)->swap.max)); }
static ssize_t swap_max_write(struct kernfs_open_file *of,