From e73d2c61d1fcbd3621688ae457b49509c8d4c601 Mon Sep 17 00:00:00 2001 From: Paul Menage Date: Tue, 29 Apr 2008 01:00:06 -0700 Subject: [PATCH] CGroups _s64 files: add cgroups read_s64/write_s64 file methods These patches add cgroups read_s64 and write_s64 control file methods (the signed equivalent of read_u64/write_u64) and use them to implement the cpu.rt_runtime_us control file in the CFS cgroup subsystem. This patch: These are the signed equivalents of the read_u64/write_u64 methods Signed-off-by: Paul Menage Acked-by: Peter Zijlstra Cc: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/cgroup.h | 8 ++++++++ kernel/cgroup.c | 38 ++++++++++++++++++++++++++++---------- 2 files changed, 36 insertions(+), 10 deletions(-) diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h index b40fd5ee9a7..785a01cfb49 100644 --- a/include/linux/cgroup.h +++ b/include/linux/cgroup.h @@ -215,6 +215,10 @@ struct cftype { * single integer. Use it in place of read() */ u64 (*read_u64) (struct cgroup *cgrp, struct cftype *cft); + /* + * read_s64() is a signed version of read_u64() + */ + s64 (*read_s64) (struct cgroup *cgrp, struct cftype *cft); /* * read_map() is used for defining a map of key/value * pairs. It should call cb->fill(cb, key, value) for each @@ -234,6 +238,10 @@ struct cftype { * userspace. Use in place of write(); return 0 or error. */ int (*write_u64) (struct cgroup *cgrp, struct cftype *cft, u64 val); + /* + * write_s64() is a signed version of write_u64() + */ + int (*write_s64) (struct cgroup *cgrp, struct cftype *cft, s64 val); int (*release) (struct inode *inode, struct file *file); }; diff --git a/kernel/cgroup.c b/kernel/cgroup.c index b5ef0c4772f..bd6122ccc0b 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -1299,14 +1299,13 @@ enum cgroup_filetype { FILE_RELEASE_AGENT, }; -static ssize_t cgroup_write_u64(struct cgroup *cgrp, struct cftype *cft, +static ssize_t cgroup_write_X64(struct cgroup *cgrp, struct cftype *cft, struct file *file, const char __user *userbuf, size_t nbytes, loff_t *unused_ppos) { char buffer[64]; int retval = 0; - u64 val; char *end; if (!nbytes) @@ -1318,12 +1317,17 @@ static ssize_t cgroup_write_u64(struct cgroup *cgrp, struct cftype *cft, buffer[nbytes] = 0; /* nul-terminate */ strstrip(buffer); - val = simple_strtoull(buffer, &end, 0); - if (*end) - return -EINVAL; - - /* Pass to subsystem */ - retval = cft->write_u64(cgrp, cft, val); + if (cft->write_u64) { + u64 val = simple_strtoull(buffer, &end, 0); + if (*end) + return -EINVAL; + retval = cft->write_u64(cgrp, cft, val); + } else { + s64 val = simple_strtoll(buffer, &end, 0); + if (*end) + return -EINVAL; + retval = cft->write_s64(cgrp, cft, val); + } if (!retval) retval = nbytes; return retval; @@ -1404,8 +1408,8 @@ static ssize_t cgroup_file_write(struct file *file, const char __user *buf, return -ENODEV; if (cft->write) return cft->write(cgrp, cft, file, buf, nbytes, ppos); - if (cft->write_u64) - return cgroup_write_u64(cgrp, cft, file, buf, nbytes, ppos); + if (cft->write_u64 || cft->write_s64) + return cgroup_write_X64(cgrp, cft, file, buf, nbytes, ppos); return -EINVAL; } @@ -1421,6 +1425,18 @@ static ssize_t cgroup_read_u64(struct cgroup *cgrp, struct cftype *cft, return simple_read_from_buffer(buf, nbytes, ppos, tmp, len); } +static ssize_t cgroup_read_s64(struct cgroup *cgrp, struct cftype *cft, + struct file *file, + char __user *buf, size_t nbytes, + loff_t *ppos) +{ + char tmp[64]; + s64 val = cft->read_s64(cgrp, cft); + int len = sprintf(tmp, "%lld\n", (long long) val); + + return simple_read_from_buffer(buf, nbytes, ppos, tmp, len); +} + static ssize_t cgroup_common_file_read(struct cgroup *cgrp, struct cftype *cft, struct file *file, @@ -1477,6 +1493,8 @@ static ssize_t cgroup_file_read(struct file *file, char __user *buf, return cft->read(cgrp, cft, file, buf, nbytes, ppos); if (cft->read_u64) return cgroup_read_u64(cgrp, cft, file, buf, nbytes, ppos); + if (cft->read_s64) + return cgroup_read_s64(cgrp, cft, file, buf, nbytes, ppos); return -EINVAL; }