[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: Mike Waychison <mikew@google.com> Cc: Manfred Spraul <manfred@colorfullife.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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ipc/util.c
156
ipc/util.c
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@ -24,11 +24,20 @@
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#include <linux/security.h>
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#include <linux/security.h>
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#include <linux/rcupdate.h>
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#include <linux/rcupdate.h>
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#include <linux/workqueue.h>
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#include <linux/workqueue.h>
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#include <linux/seq_file.h>
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#include <linux/proc_fs.h>
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#include <asm/unistd.h>
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#include <asm/unistd.h>
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#include "util.h"
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#include "util.h"
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struct ipc_proc_iface {
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const char *path;
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const char *header;
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struct ipc_ids *ids;
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int (*show)(struct seq_file *, void *);
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};
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/**
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/**
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* ipc_init - initialise IPC subsystem
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* ipc_init - initialise IPC subsystem
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*
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*
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@ -86,6 +95,43 @@ void __init ipc_init_ids(struct ipc_ids* ids, int size)
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ids->entries->p[i] = NULL;
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ids->entries->p[i] = NULL;
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}
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}
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#ifdef CONFIG_PROC_FS
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static struct file_operations sysvipc_proc_fops;
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/**
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* ipc_init_proc_interface - Create a proc interface for sysipc types
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* using a seq_file interface.
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* @path: Path in procfs
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* @header: Banner to be printed at the beginning of the file.
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* @ids: ipc id table to iterate.
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* @show: show routine.
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*/
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void __init ipc_init_proc_interface(const char *path, const char *header,
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struct ipc_ids *ids,
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int (*show)(struct seq_file *, void *))
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{
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struct proc_dir_entry *pde;
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struct ipc_proc_iface *iface;
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iface = kmalloc(sizeof(*iface), GFP_KERNEL);
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if (!iface)
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return;
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iface->path = path;
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iface->header = header;
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iface->ids = ids;
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iface->show = show;
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pde = create_proc_entry(path,
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S_IRUGO, /* world readable */
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NULL /* parent dir */);
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if (pde) {
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pde->data = iface;
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pde->proc_fops = &sysvipc_proc_fops;
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} else {
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kfree(iface);
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}
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}
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#endif
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/**
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/**
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* ipc_findkey - find a key in an ipc identifier set
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* ipc_findkey - find a key in an ipc identifier set
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* @ids: Identifier set
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* @ids: Identifier set
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@ -578,3 +624,113 @@ int ipc_parse_version (int *cmd)
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}
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}
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#endif /* __ARCH_WANT_IPC_PARSE_VERSION */
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#endif /* __ARCH_WANT_IPC_PARSE_VERSION */
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#ifdef CONFIG_PROC_FS
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static void *sysvipc_proc_next(struct seq_file *s, void *it, loff_t *pos)
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{
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struct ipc_proc_iface *iface = s->private;
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struct kern_ipc_perm *ipc = it;
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loff_t p;
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/* If we had an ipc id locked before, unlock it */
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if (ipc && ipc != SEQ_START_TOKEN)
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ipc_unlock(ipc);
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/*
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* p = *pos - 1 (because id 0 starts at position 1)
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* + 1 (because we increment the position by one)
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*/
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for (p = *pos; p <= iface->ids->max_id; p++) {
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if ((ipc = ipc_lock(iface->ids, p)) != NULL) {
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*pos = p + 1;
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return ipc;
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}
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}
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/* Out of range - return NULL to terminate iteration */
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return NULL;
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}
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/*
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* File positions: pos 0 -> header, pos n -> ipc id + 1.
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* SeqFile iterator: iterator value locked shp or SEQ_TOKEN_START.
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*/
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static void *sysvipc_proc_start(struct seq_file *s, loff_t *pos)
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{
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struct ipc_proc_iface *iface = s->private;
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struct kern_ipc_perm *ipc;
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loff_t p;
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/*
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* Take the lock - this will be released by the corresponding
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* call to stop().
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*/
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down(&iface->ids->sem);
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/* pos < 0 is invalid */
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if (*pos < 0)
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return NULL;
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/* pos == 0 means header */
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if (*pos == 0)
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return SEQ_START_TOKEN;
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/* Find the (pos-1)th ipc */
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for (p = *pos - 1; p <= iface->ids->max_id; p++) {
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if ((ipc = ipc_lock(iface->ids, p)) != NULL) {
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*pos = p + 1;
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return ipc;
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}
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}
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return NULL;
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}
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static void sysvipc_proc_stop(struct seq_file *s, void *it)
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{
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struct kern_ipc_perm *ipc = it;
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struct ipc_proc_iface *iface = s->private;
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/* If we had a locked segment, release it */
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if (ipc && ipc != SEQ_START_TOKEN)
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ipc_unlock(ipc);
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/* Release the lock we took in start() */
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up(&iface->ids->sem);
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}
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static int sysvipc_proc_show(struct seq_file *s, void *it)
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{
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struct ipc_proc_iface *iface = s->private;
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if (it == SEQ_START_TOKEN)
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return seq_puts(s, iface->header);
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return iface->show(s, it);
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}
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static struct seq_operations sysvipc_proc_seqops = {
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.start = sysvipc_proc_start,
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.stop = sysvipc_proc_stop,
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.next = sysvipc_proc_next,
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.show = sysvipc_proc_show,
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};
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static int sysvipc_proc_open(struct inode *inode, struct file *file) {
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int ret;
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struct seq_file *seq;
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ret = seq_open(file, &sysvipc_proc_seqops);
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if (!ret) {
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seq = file->private_data;
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seq->private = PDE(inode)->data;
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}
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return ret;
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}
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static struct file_operations sysvipc_proc_fops = {
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.open = sysvipc_proc_open,
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.read = seq_read,
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.llseek = seq_lseek,
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.release = seq_release,
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};
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#endif /* CONFIG_PROC_FS */
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@ -30,7 +30,15 @@ struct ipc_ids {
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struct ipc_id_ary* entries;
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struct ipc_id_ary* entries;
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};
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};
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struct seq_file;
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void __init ipc_init_ids(struct ipc_ids* ids, int size);
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void __init ipc_init_ids(struct ipc_ids* ids, int size);
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#ifdef CONFIG_PROC_FS
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void __init ipc_init_proc_interface(const char *path, const char *header,
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struct ipc_ids *ids,
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int (*show)(struct seq_file *, void *));
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#else
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#define ipc_init_proc_interface(path, header, ids, show) do {} while (0)
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#endif
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/* must be called with ids->sem acquired.*/
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/* must be called with ids->sem acquired.*/
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int ipc_findkey(struct ipc_ids* ids, key_t key);
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int ipc_findkey(struct ipc_ids* ids, key_t key);
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