From: Paul Menage Currently read_counter_write() is a raw file handler even though it's ultimately taking a number, since in some cases it wants to pre-process the string when converting it to a number. This patch converts res_counter_write() from a raw file handler to a write_string() handler; this allows some of the boilerplate copying/locking/checking to be removed, and simplies the cleanup path, since these functions are now performed by the cgroups framework. Signed-off-by: Paul Menage Cc: Paul Jackson Cc: Pavel Emelyanov Cc: Balbir Singh Cc: Serge Hallyn Cc: KAMEZAWA Hiroyuki Signed-off-by: Andrew Morton --- include/linux/res_counter.h | 11 +++++-- kernel/res_counter.c | 47 ++++++++++++++-------------------- mm/memcontrol.c | 24 +++-------------- 3 files changed, 33 insertions(+), 49 deletions(-) diff -puN include/linux/res_counter.h~cgroup-files-convert-res_counter_write-to-be-a-cgroups-write_string-handler include/linux/res_counter.h --- a/include/linux/res_counter.h~cgroup-files-convert-res_counter_write-to-be-a-cgroups-write_string-handler +++ a/include/linux/res_counter.h @@ -63,9 +63,14 @@ u64 res_counter_read_u64(struct res_coun ssize_t res_counter_read(struct res_counter *counter, int member, const char __user *buf, size_t nbytes, loff_t *pos, int (*read_strategy)(unsigned long long val, char *s)); -ssize_t res_counter_write(struct res_counter *counter, int member, - const char __user *buf, size_t nbytes, loff_t *pos, - int (*write_strategy)(char *buf, unsigned long long *val)); + +typedef int (*write_strategy_fn)(const char *buf, unsigned long long *val); + +int res_counter_memparse_write_strategy(const char *buf, + unsigned long long *res); + +int res_counter_write(struct res_counter *counter, int member, + const char *buffer, write_strategy_fn write_strategy); /* * the field descriptors. one for each member of res_counter diff -puN kernel/res_counter.c~cgroup-files-convert-res_counter_write-to-be-a-cgroups-write_string-handler kernel/res_counter.c --- a/kernel/res_counter.c~cgroup-files-convert-res_counter_write-to-be-a-cgroups-write_string-handler +++ a/kernel/res_counter.c @@ -102,44 +102,37 @@ u64 res_counter_read_u64(struct res_coun return *res_counter_member(counter, member); } -ssize_t res_counter_write(struct res_counter *counter, int member, - const char __user *userbuf, size_t nbytes, loff_t *pos, - int (*write_strategy)(char *st_buf, unsigned long long *val)) +int res_counter_memparse_write_strategy(const char *buf, + unsigned long long *res) { - int ret; - char *buf, *end; - unsigned long flags; - unsigned long long tmp, *val; + char *end; + /* FIXME - make memparse() take const char* args */ + *res = memparse((char *)buf, &end); + if (*end != '\0') + return -EINVAL; - buf = kmalloc(nbytes + 1, GFP_KERNEL); - ret = -ENOMEM; - if (buf == NULL) - goto out; - - buf[nbytes] = '\0'; - ret = -EFAULT; - if (copy_from_user(buf, userbuf, nbytes)) - goto out_free; + *res = PAGE_ALIGN(*res); + return 0; +} - ret = -EINVAL; +int res_counter_write(struct res_counter *counter, int member, + const char *buf, write_strategy_fn write_strategy) +{ + char *end; + unsigned long flags; + unsigned long long tmp, *val; - strstrip(buf); if (write_strategy) { - if (write_strategy(buf, &tmp)) { - goto out_free; - } + if (write_strategy(buf, &tmp)) + return -EINVAL; } else { tmp = simple_strtoull(buf, &end, 10); if (*end != '\0') - goto out_free; + return -EINVAL; } spin_lock_irqsave(&counter->lock, flags); val = res_counter_member(counter, member); *val = tmp; spin_unlock_irqrestore(&counter->lock, flags); - ret = nbytes; -out_free: - kfree(buf); -out: - return ret; + return 0; } diff -puN mm/memcontrol.c~cgroup-files-convert-res_counter_write-to-be-a-cgroups-write_string-handler mm/memcontrol.c --- a/mm/memcontrol.c~cgroup-files-convert-res_counter_write-to-be-a-cgroups-write_string-handler +++ a/mm/memcontrol.c @@ -838,32 +838,18 @@ out: return ret; } -static int mem_cgroup_write_strategy(char *buf, unsigned long long *tmp) -{ - *tmp = memparse(buf, &buf); - if (*buf != '\0') - return -EINVAL; - - /* - * Round up the value to the closest page size - */ - *tmp = ((*tmp + PAGE_SIZE - 1) >> PAGE_SHIFT) << PAGE_SHIFT; - return 0; -} - static u64 mem_cgroup_read(struct cgroup *cont, struct cftype *cft) { return res_counter_read_u64(&mem_cgroup_from_cont(cont)->res, cft->private); } -static ssize_t mem_cgroup_write(struct cgroup *cont, struct cftype *cft, - struct file *file, const char __user *userbuf, - size_t nbytes, loff_t *ppos) +static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft, + const char *buffer) { return res_counter_write(&mem_cgroup_from_cont(cont)->res, - cft->private, userbuf, nbytes, ppos, - mem_cgroup_write_strategy); + cft->private, buffer, + res_counter_memparse_write_strategy); } static int mem_cgroup_reset(struct cgroup *cont, unsigned int event) @@ -940,7 +926,7 @@ static struct cftype mem_cgroup_files[] { .name = "limit_in_bytes", .private = RES_LIMIT, - .write = mem_cgroup_write, + .write_string = mem_cgroup_write, .read_u64 = mem_cgroup_read, }, { _