The patch titled cgroup files: add write_string cgroup control file method has been added to the -mm tree. Its filename is cgroup-files-add-write_string-cgroup-control-file-method.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find out what to do about this The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ Subject: cgroup files: add write_string cgroup control file method From: Paul Menage <menage@xxxxxxxxxx> This patch adds a write_string() method for cgroups control files. The semantics are that a buffer is copied from userspace to kernelspace and the handler function invoked on that buffer. The buffer is guaranteed to be nul-terminated, and no longer than max_write_len (defaulting to 64 bytes if unspecified). Later patches will convert existing raw file write handlers in control group subsystems to use this method. Signed-off-by: Paul Menage <menage@xxxxxxxxxx> Cc: Paul Jackson <pj@xxxxxxx> Cc: Pavel Emelyanov <xemul@xxxxxxxxxx> Acked-by: Balbir Singh <balbir@xxxxxxxxxx> Acked-by: Serge Hallyn <serue@xxxxxxxxxx> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- include/linux/cgroup.h | 14 ++++++++++++++ kernel/cgroup.c | 35 +++++++++++++++++++++++++++++++++++ 2 files changed, 49 insertions(+) diff -puN include/linux/cgroup.h~cgroup-files-add-write_string-cgroup-control-file-method include/linux/cgroup.h --- a/include/linux/cgroup.h~cgroup-files-add-write_string-cgroup-control-file-method +++ a/include/linux/cgroup.h @@ -205,6 +205,13 @@ struct cftype { * subsystem, followed by a period */ char name[MAX_CFTYPE_NAME]; int private; + + /* + * If non-zero, defines the maximum length of string that can + * be passed to write_string; defaults to 64 + */ + size_t max_write_len; + int (*open)(struct inode *inode, struct file *file); ssize_t (*read)(struct cgroup *cgrp, struct cftype *cft, struct file *file, @@ -249,6 +256,13 @@ struct cftype { int (*write_s64)(struct cgroup *cgrp, struct cftype *cft, s64 val); /* + * write_string() is passed a nul-terminated kernelspace + * buffer of maximum length determined by max_write_len. + * Returns 0 or -ve error code. + */ + int (*write_string)(struct cgroup *cgrp, struct cftype *cft, + const char *buffer); + /* * trigger() callback can be used to get some kick from the * userspace, when the actual string written is not important * at all. The private field can be used to determine the diff -puN kernel/cgroup.c~cgroup-files-add-write_string-cgroup-control-file-method kernel/cgroup.c --- a/kernel/cgroup.c~cgroup-files-add-write_string-cgroup-control-file-method +++ a/kernel/cgroup.c @@ -1363,6 +1363,39 @@ static ssize_t cgroup_write_X64(struct c return retval; } +static ssize_t cgroup_write_string(struct cgroup *cgrp, struct cftype *cft, + struct file *file, + const char __user *userbuf, + size_t nbytes, loff_t *unused_ppos) +{ + char local_buffer[64]; + int retval = 0; + size_t max_bytes = cft->max_write_len; + char *buffer = local_buffer; + + if (!max_bytes) + max_bytes = sizeof(local_buffer) - 1; + if (nbytes >= max_bytes) + return -E2BIG; + /* Allocate a dynamic buffer if we need one */ + if (nbytes >= sizeof(local_buffer)) { + buffer = kmalloc(nbytes + 1, GFP_KERNEL); + if (buffer == NULL) + return -ENOMEM; + } + if (nbytes && copy_from_user(buffer, userbuf, nbytes)) + return -EFAULT; + + buffer[nbytes] = 0; /* nul-terminate */ + strstrip(buffer); + retval = cft->write_string(cgrp, cft, buffer); + if (!retval) + retval = nbytes; + if (buffer != local_buffer) + kfree(buffer); + return retval; +} + static ssize_t cgroup_common_file_write(struct cgroup *cgrp, struct cftype *cft, struct file *file, @@ -1440,6 +1473,8 @@ static ssize_t cgroup_file_write(struct return cft->write(cgrp, cft, file, buf, nbytes, ppos); if (cft->write_u64 || cft->write_s64) return cgroup_write_X64(cgrp, cft, file, buf, nbytes, ppos); + if (cft->write_string) + return cgroup_write_string(cgrp, cft, file, buf, nbytes, ppos); if (cft->trigger) { int ret = cft->trigger(cgrp, (unsigned int)cft->private); return ret ? ret : nbytes; _ Patches currently in -mm which might be from menage@xxxxxxxxxx are call_usermodehelper-increase-reliability.patch cgroup-use-read-lock-to-guard-find_existing_css_set.patch mark-res_counter_charge_locked-with-__must_check.patch cgroup-list_for_each-cleanup-v2.patch cgroup-anotate-two-variables-with-__read_mostly.patch cgroup-files-clean-up-whitespace-in-struct-cftype.patch cgroup-files-add-write_string-cgroup-control-file-method.patch cgroup-files-move-the-release_agent-file-to-use-typed-handlers.patch cgroup-files-move-notify_on_release-file-to-separate-write-handler.patch cgroup-files-turn-attach_task_by_pid-directly-into-a-cgroup-write-handler.patch cgroup-files-remove-cpuset_common_file_write.patch cgroup-files-convert-devcgroup_access_write-into-a-cgroup-write_string-handler.patch cgroup-files-convert-res_counter_write-to-be-a-cgroups-write_string-handler.patch memcg-remove-refcnt-from-page_cgroup.patch memcg-remove-refcnt-from-page_cgroup-fix.patch memcg-remove-refcnt-from-page_cgroup-fix-2.patch memcg-handle-swap-cache.patch memcg-handle-swap-cache-fix.patch memcg-helper-function-for-relcaim-from-shmem.patch memcg-add-hints-for-branch.patch memcg-remove-a-redundant-check.patch memrlimit-add-memrlimit-controller-documentation.patch memrlimit-setup-the-memrlimit-controller.patch memrlimit-cgroup-mm-owner-callback-changes-to-add-task-info.patch memrlimit-add-memrlimit-controller-accounting-and-control.patch memrlimit-setup-the-memrlimit-controller-cgroup-files-convert-res_counter_write-to-be-a-cgroups-write_string-handler-memrlimitcgroup.patch cpusets-update-tasks-cpus_allowed-and-mems_allowed-after-cpu-node-offline-online.patch make-cgroup_seqfile_release-static.patch add-a-refcount-check-in-dput.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html