From 6778948f9de86c3cfaf36725a7c87dcff9ba247f Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Mon, 11 Dec 2023 08:20:59 +0000
Subject: [PATCH] kernel_5.10 no rt
---
kernel/ipc/util.c | 66 ++++++++++++++++++++++++---------
1 files changed, 48 insertions(+), 18 deletions(-)
diff --git a/kernel/ipc/util.c b/kernel/ipc/util.c
index 8f84837..bbb5190 100644
--- a/kernel/ipc/util.c
+++ b/kernel/ipc/util.c
@@ -100,8 +100,7 @@
static const struct rhashtable_params ipc_kht_params = {
.head_offset = offsetof(struct kern_ipc_perm, khtnode),
.key_offset = offsetof(struct kern_ipc_perm, key),
- .key_len = FIELD_SIZEOF(struct kern_ipc_perm, key),
- .locks_mul = 1,
+ .key_len = sizeof_field(struct kern_ipc_perm, key),
.automatic_shrinking = true,
};
@@ -110,7 +109,7 @@
* @ids: ipc identifier set
*
* Set up the sequence range to use for the ipc identifier range (limited
- * below IPCMNI) then initialise the keys hashtable and ids idr.
+ * below ipc_mni) then initialise the keys hashtable and ids idr.
*/
void ipc_init_ids(struct ipc_ids *ids)
{
@@ -120,13 +119,14 @@
rhashtable_init(&ids->key_ht, &ipc_kht_params);
idr_init(&ids->ipcs_idr);
ids->max_idx = -1;
+ ids->last_idx = -1;
#ifdef CONFIG_CHECKPOINT_RESTORE
ids->next_id = -1;
#endif
}
#ifdef CONFIG_PROC_FS
-static const struct file_operations sysvipc_proc_fops;
+static const struct proc_ops sysvipc_proc_ops;
/**
* ipc_init_proc_interface - create a proc interface for sysipc types using a seq_file interface.
* @path: Path in procfs
@@ -151,7 +151,7 @@
pde = proc_create_data(path,
S_IRUGO, /* world readable */
NULL, /* parent dir */
- &sysvipc_proc_fops,
+ &sysvipc_proc_ops,
iface);
if (!pde)
kfree(iface);
@@ -193,6 +193,10 @@
*
* The caller must own kern_ipc_perm.lock.of the new object.
* On error, the function returns a (negative) error code.
+ *
+ * To conserve sequence number space, especially with extended ipc_mni,
+ * the sequence number is incremented only when the returned ID is less than
+ * the last one.
*/
static inline int ipc_idr_alloc(struct ipc_ids *ids, struct kern_ipc_perm *new)
{
@@ -216,17 +220,42 @@
*/
if (next_id < 0) { /* !CHECKPOINT_RESTORE or next_id is unset */
- new->seq = ids->seq++;
- if (ids->seq > IPCID_SEQ_MAX)
- ids->seq = 0;
- idx = idr_alloc(&ids->ipcs_idr, new, 0, 0, GFP_NOWAIT);
+ int max_idx;
+
+ max_idx = max(ids->in_use*3/2, ipc_min_cycle);
+ max_idx = min(max_idx, ipc_mni);
+
+ /* allocate the idx, with a NULL struct kern_ipc_perm */
+ idx = idr_alloc_cyclic(&ids->ipcs_idr, NULL, 0, max_idx,
+ GFP_NOWAIT);
+
+ if (idx >= 0) {
+ /*
+ * idx got allocated successfully.
+ * Now calculate the sequence number and set the
+ * pointer for real.
+ */
+ if (idx <= ids->last_idx) {
+ ids->seq++;
+ if (ids->seq >= ipcid_seq_max())
+ ids->seq = 0;
+ }
+ ids->last_idx = idx;
+
+ new->seq = ids->seq;
+ /* no need for smp_wmb(), this is done
+ * inside idr_replace, as part of
+ * rcu_assign_pointer
+ */
+ idr_replace(&ids->ipcs_idr, new, idx);
+ }
} else {
new->seq = ipcid_to_seqx(next_id);
idx = idr_alloc(&ids->ipcs_idr, new, ipcid_to_idx(next_id),
0, GFP_NOWAIT);
}
if (idx >= 0)
- new->id = SEQ_MULTIPLIER * new->seq + idx;
+ new->id = (new->seq << ipcmni_seq_shift()) + idx;
return idx;
}
@@ -254,8 +283,8 @@
/* 1) Initialize the refcount so that ipc_rcu_putref works */
refcount_set(&new->refcount, 1);
- if (limit > IPCMNI)
- limit = IPCMNI;
+ if (limit > ipc_mni)
+ limit = ipc_mni;
if (ids->in_use >= limit)
return -ENOSPC;
@@ -739,7 +768,7 @@
if (total >= ids->in_use)
goto out;
- for (; pos < IPCMNI; pos++) {
+ for (; pos < ipc_mni; pos++) {
ipc = idr_find(&ids->ipcs_idr, pos);
if (ipc != NULL) {
rcu_read_lock();
@@ -855,10 +884,11 @@
return seq_release_private(inode, file);
}
-static const struct file_operations sysvipc_proc_fops = {
- .open = sysvipc_proc_open,
- .read = seq_read,
- .llseek = seq_lseek,
- .release = sysvipc_proc_release,
+static const struct proc_ops sysvipc_proc_ops = {
+ .proc_flags = PROC_ENTRY_PERMANENT,
+ .proc_open = sysvipc_proc_open,
+ .proc_read = seq_read,
+ .proc_lseek = seq_lseek,
+ .proc_release = sysvipc_proc_release,
};
#endif /* CONFIG_PROC_FS */
--
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