Commit ae781774 authored by Mike Waychison's avatar Mike Waychison Committed by Linus Torvalds
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[PATCH] ipc: add generic struct ipc_ids seq_file iteration



The following two patches convert /proc/sysvipc/* to use seq_file.

This gives us the following:

 - Self-consistent IPC records in proc.
 - O(n) reading of the files themselves.

This patch:

Add a generic method for ipc types to be displayed using seq_file.  This
patch abstracts out seq_file iterating over struct ipc_ids into ipc/util.c
Signed-off-by: default avatarMike Waychison <mikew@google.com>
Cc: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent f35279d3
......@@ -24,11 +24,20 @@
#include <linux/security.h>
#include <linux/rcupdate.h>
#include <linux/workqueue.h>
#include <linux/seq_file.h>
#include <linux/proc_fs.h>
#include <asm/unistd.h>
#include "util.h"
struct ipc_proc_iface {
const char *path;
const char *header;
struct ipc_ids *ids;
int (*show)(struct seq_file *, void *);
};
/**
* ipc_init - initialise IPC subsystem
*
......@@ -86,6 +95,43 @@ void __init ipc_init_ids(struct ipc_ids* ids, int size)
ids->entries->p[i] = NULL;
}
#ifdef CONFIG_PROC_FS
static struct file_operations sysvipc_proc_fops;
/**
* ipc_init_proc_interface - Create a proc interface for sysipc types
* using a seq_file interface.
* @path: Path in procfs
* @header: Banner to be printed at the beginning of the file.
* @ids: ipc id table to iterate.
* @show: show routine.
*/
void __init ipc_init_proc_interface(const char *path, const char *header,
struct ipc_ids *ids,
int (*show)(struct seq_file *, void *))
{
struct proc_dir_entry *pde;
struct ipc_proc_iface *iface;
iface = kmalloc(sizeof(*iface), GFP_KERNEL);
if (!iface)
return;
iface->path = path;
iface->header = header;
iface->ids = ids;
iface->show = show;
pde = create_proc_entry(path,
S_IRUGO, /* world readable */
NULL /* parent dir */);
if (pde) {
pde->data = iface;
pde->proc_fops = &sysvipc_proc_fops;
} else {
kfree(iface);
}
}
#endif
/**
* ipc_findkey - find a key in an ipc identifier set
* @ids: Identifier set
......@@ -578,3 +624,113 @@ int ipc_parse_version (int *cmd)
}
#endif /* __ARCH_WANT_IPC_PARSE_VERSION */
#ifdef CONFIG_PROC_FS
static void *sysvipc_proc_next(struct seq_file *s, void *it, loff_t *pos)
{
struct ipc_proc_iface *iface = s->private;
struct kern_ipc_perm *ipc = it;
loff_t p;
/* If we had an ipc id locked before, unlock it */
if (ipc && ipc != SEQ_START_TOKEN)
ipc_unlock(ipc);
/*
* p = *pos - 1 (because id 0 starts at position 1)
* + 1 (because we increment the position by one)
*/
for (p = *pos; p <= iface->ids->max_id; p++) {
if ((ipc = ipc_lock(iface->ids, p)) != NULL) {
*pos = p + 1;
return ipc;
}
}
/* Out of range - return NULL to terminate iteration */
return NULL;
}
/*
* File positions: pos 0 -> header, pos n -> ipc id + 1.
* SeqFile iterator: iterator value locked shp or SEQ_TOKEN_START.
*/
static void *sysvipc_proc_start(struct seq_file *s, loff_t *pos)
{
struct ipc_proc_iface *iface = s->private;
struct kern_ipc_perm *ipc;
loff_t p;
/*
* Take the lock - this will be released by the corresponding
* call to stop().
*/
down(&iface->ids->sem);
/* pos < 0 is invalid */
if (*pos < 0)
return NULL;
/* pos == 0 means header */
if (*pos == 0)
return SEQ_START_TOKEN;
/* Find the (pos-1)th ipc */
for (p = *pos - 1; p <= iface->ids->max_id; p++) {
if ((ipc = ipc_lock(iface->ids, p)) != NULL) {
*pos = p + 1;
return ipc;
}
}
return NULL;
}
static void sysvipc_proc_stop(struct seq_file *s, void *it)
{
struct kern_ipc_perm *ipc = it;
struct ipc_proc_iface *iface = s->private;
/* If we had a locked segment, release it */
if (ipc && ipc != SEQ_START_TOKEN)
ipc_unlock(ipc);
/* Release the lock we took in start() */
up(&iface->ids->sem);
}
static int sysvipc_proc_show(struct seq_file *s, void *it)
{
struct ipc_proc_iface *iface = s->private;
if (it == SEQ_START_TOKEN)
return seq_puts(s, iface->header);
return iface->show(s, it);
}
static struct seq_operations sysvipc_proc_seqops = {
.start = sysvipc_proc_start,
.stop = sysvipc_proc_stop,
.next = sysvipc_proc_next,
.show = sysvipc_proc_show,
};
static int sysvipc_proc_open(struct inode *inode, struct file *file) {
int ret;
struct seq_file *seq;
ret = seq_open(file, &sysvipc_proc_seqops);
if (!ret) {
seq = file->private_data;
seq->private = PDE(inode)->data;
}
return ret;
}
static struct file_operations sysvipc_proc_fops = {
.open = sysvipc_proc_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release,
};
#endif /* CONFIG_PROC_FS */
......@@ -30,7 +30,15 @@ struct ipc_ids {
struct ipc_id_ary* entries;
};
struct seq_file;
void __init ipc_init_ids(struct ipc_ids* ids, int size);
#ifdef CONFIG_PROC_FS
void __init ipc_init_proc_interface(const char *path, const char *header,
struct ipc_ids *ids,
int (*show)(struct seq_file *, void *));
#else
#define ipc_init_proc_interface(path, header, ids, show) do {} while (0)
#endif
/* must be called with ids->sem acquired.*/
int ipc_findkey(struct ipc_ids* ids, key_t key);
......
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