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Commit 856c13aa1ff6136c1968414fdea5938ea9d5ebf2

Authored by Paul Menage
Committed by Linus Torvalds
1 parent f92523e3a7
Exists in master and in 7 other branches imx_3.0.35_4.1.0, imx_3.10.17_1.0.1_ga, imx_3.10.53_1.1.0_ga, imx_3.14.28_1.0.0_ga, smarc-imx_3.10.53_1.1.0_ga, smarc-imx_3.14.28_1.0.0_ga, smarc-l5.0.0_1.0.0-ga

cgroup files: convert res_counter_write() to be a cgroups write_string() handler 

Currently res_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.

[lizf@cn.fujitsu.com: build fix]
Signed-off-by: Paul Menage <menage@google.com>
Cc: Paul Jackson <pj@sgi.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Serge Hallyn <serue@us.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Showing 3 changed files with 34 additions and 49 deletions Side-by-side Diff

include/linux/res_counter.h
Diff comments   View file @ 856c13a
... ... @@ -63,9 +63,14 @@
63 63 ssize_t res_counter_read(struct res_counter *counter, int member,
64 64 const char __user *buf, size_t nbytes, loff_t *pos,
65 65 int (*read_strategy)(unsigned long long val, char *s));
66   -ssize_t res_counter_write(struct res_counter *counter, int member,
67   - const char __user *buf, size_t nbytes, loff_t *pos,
68   - int (*write_strategy)(char *buf, unsigned long long *val));
  66 +
  67 +typedef int (*write_strategy_fn)(const char *buf, unsigned long long *val);
  68 +
  69 +int res_counter_memparse_write_strategy(const char *buf,
  70 + unsigned long long *res);
  71 +
  72 +int res_counter_write(struct res_counter *counter, int member,
  73 + const char *buffer, write_strategy_fn write_strategy);
69 74  
70 75 /*
71 76 * the field descriptors. one for each member of res_counter
kernel/res_counter.c
Diff comments   View file @ 856c13a
... ... @@ -13,6 +13,7 @@
13 13 #include <linux/slab.h>
14 14 #include <linux/res_counter.h>
15 15 #include <linux/uaccess.h>
  16 +#include <linux/mm.h>
16 17  
17 18 void res_counter_init(struct res_counter *counter)
18 19 {
19 20  
20 21  
21 22  
22 23  
23 24  
... ... @@ -102,45 +103,38 @@
102 103 return *res_counter_member(counter, member);
103 104 }
104 105  
105   -ssize_t res_counter_write(struct res_counter *counter, int member,
106   - const char __user *userbuf, size_t nbytes, loff_t *pos,
107   - int (*write_strategy)(char *st_buf, unsigned long long *val))
  106 +int res_counter_memparse_write_strategy(const char *buf,
  107 + unsigned long long *res)
108 108 {
109   - int ret;
110   - char *buf, *end;
  109 + char *end;
  110 + /* FIXME - make memparse() take const char* args */
  111 + *res = memparse((char *)buf, &end);
  112 + if (*end != '\0')
  113 + return -EINVAL;
  114 +
  115 + *res = PAGE_ALIGN(*res);
  116 + return 0;
  117 +}
  118 +
  119 +int res_counter_write(struct res_counter *counter, int member,
  120 + const char *buf, write_strategy_fn write_strategy)
  121 +{
  122 + char *end;
111 123 unsigned long flags;
112 124 unsigned long long tmp, *val;
113 125  
114   - buf = kmalloc(nbytes + 1, GFP_KERNEL);
115   - ret = -ENOMEM;
116   - if (buf == NULL)
117   - goto out;
118   -
119   - buf[nbytes] = '\0';
120   - ret = -EFAULT;
121   - if (copy_from_user(buf, userbuf, nbytes))
122   - goto out_free;
123   -
124   - ret = -EINVAL;
125   -
126   - strstrip(buf);
127 126 if (write_strategy) {
128   - if (write_strategy(buf, &tmp)) {
129   - goto out_free;
130   - }
  127 + if (write_strategy(buf, &tmp))
  128 + return -EINVAL;
131 129 } else {
132 130 tmp = simple_strtoull(buf, &end, 10);
133 131 if (*end != '\0')
134   - goto out_free;
  132 + return -EINVAL;
135 133 }
136 134 spin_lock_irqsave(&counter->lock, flags);
137 135 val = res_counter_member(counter, member);
138 136 *val = tmp;
139 137 spin_unlock_irqrestore(&counter->lock, flags);
140   - ret = nbytes;
141   -out_free:
142   - kfree(buf);
143   -out:
144   - return ret;
  138 + return 0;
145 139 }
... ... @@ -838,32 +838,18 @@
838 838 return ret;
839 839 }
840 840  
841   -static int mem_cgroup_write_strategy(char *buf, unsigned long long *tmp)
842   -{
843   - *tmp = memparse(buf, &buf);
844   - if (*buf != '\0')
845   - return -EINVAL;
846   -
847   - /*
848   - * Round up the value to the closest page size
849   - */
850   - *tmp = ((*tmp + PAGE_SIZE - 1) >> PAGE_SHIFT) << PAGE_SHIFT;
851   - return 0;
852   -}
853   -
854 841 static u64 mem_cgroup_read(struct cgroup *cont, struct cftype *cft)
855 842 {
856 843 return res_counter_read_u64(&mem_cgroup_from_cont(cont)->res,
857 844 cft->private);
858 845 }
859 846  
860   -static ssize_t mem_cgroup_write(struct cgroup *cont, struct cftype *cft,
861   - struct file *file, const char __user *userbuf,
862   - size_t nbytes, loff_t *ppos)
  847 +static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft,
  848 + const char *buffer)
863 849 {
864 850 return res_counter_write(&mem_cgroup_from_cont(cont)->res,
865   - cft->private, userbuf, nbytes, ppos,
866   - mem_cgroup_write_strategy);
  851 + cft->private, buffer,
  852 + res_counter_memparse_write_strategy);
867 853 }
868 854  
869 855 static int mem_cgroup_reset(struct cgroup *cont, unsigned int event)
... ... @@ -940,7 +926,7 @@
940 926 {
941 927 .name = "limit_in_bytes",
942 928 .private = RES_LIMIT,
943   - .write = mem_cgroup_write,
  929 + .write_string = mem_cgroup_write,
944 930 .read_u64 = mem_cgroup_read,
945 931 },
946 932 {