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-rw-r--r--kernel/relay.c192
1 files changed, 133 insertions, 59 deletions
diff --git a/kernel/relay.c b/kernel/relay.c
index 284e2e8..ef8a935 100644
--- a/kernel/relay.c
+++ b/kernel/relay.c
@@ -7,6 +7,8 @@
* Copyright (C) 1999-2005 - Karim Yaghmour (karim@opersys.com)
*
* Moved to kernel/relay.c by Paul Mundt, 2006.
+ * November 2006 - CPU hotplug support by Mathieu Desnoyers
+ * (mathieu.desnoyers@polymtl.ca)
*
* This file is released under the GPL.
*/
@@ -18,6 +20,11 @@
#include <linux/relay.h>
#include <linux/vmalloc.h>
#include <linux/mm.h>
+#include <linux/cpu.h>
+
+/* list of open channels, for cpu hotplug */
+static DEFINE_MUTEX(relay_channels_mutex);
+static LIST_HEAD(relay_channels);
/*
* close() vm_op implementation for relay file mapping.
@@ -187,6 +194,7 @@ void relay_destroy_buf(struct rchan_buf *buf)
__free_page(buf->page_array[i]);
kfree(buf->page_array);
}
+ chan->buf[buf->cpu] = NULL;
kfree(buf->padding);
kfree(buf);
kref_put(&chan->kref, relay_destroy_channel);
@@ -320,7 +328,7 @@ static void wakeup_readers(struct work_struct *work)
* @buf: the channel buffer
* @init: 1 if this is a first-time initialization
*
- * See relay_reset for description of effect.
+ * See relay_reset() for description of effect.
*/
static void __relay_reset(struct rchan_buf *buf, unsigned int init)
{
@@ -356,57 +364,75 @@ static void __relay_reset(struct rchan_buf *buf, unsigned int init)
* and restarting the channel in its initial state. The buffers
* are not freed, so any mappings are still in effect.
*
- * NOTE: Care should be taken that the channel isn't actually
+ * NOTE. Care should be taken that the channel isn't actually
* being used by anything when this call is made.
*/
void relay_reset(struct rchan *chan)
{
unsigned int i;
- struct rchan_buf *prev = NULL;
if (!chan)
return;
- for (i = 0; i < NR_CPUS; i++) {
- if (!chan->buf[i] || chan->buf[i] == prev)
- break;
- __relay_reset(chan->buf[i], 0);
- prev = chan->buf[i];
+ if (chan->is_global && chan->buf[0]) {
+ __relay_reset(chan->buf[0], 0);
+ return;
}
+
+ mutex_lock(&relay_channels_mutex);
+ for_each_online_cpu(i)
+ if (chan->buf[i])
+ __relay_reset(chan->buf[i], 0);
+ mutex_unlock(&relay_channels_mutex);
}
EXPORT_SYMBOL_GPL(relay_reset);
/*
* relay_open_buf - create a new relay channel buffer
*
- * Internal - used by relay_open().
+ * used by relay_open() and CPU hotplug.
*/
-static struct rchan_buf *relay_open_buf(struct rchan *chan,
- const char *filename,
- struct dentry *parent,
- int *is_global)
+static struct rchan_buf *relay_open_buf(struct rchan *chan, unsigned int cpu)
{
- struct rchan_buf *buf;
+ struct rchan_buf *buf = NULL;
struct dentry *dentry;
+ char *tmpname;
- if (*is_global)
+ if (chan->is_global)
return chan->buf[0];
+ tmpname = kzalloc(NAME_MAX + 1, GFP_KERNEL);
+ if (!tmpname)
+ goto end;
+ snprintf(tmpname, NAME_MAX, "%s%d", chan->base_filename, cpu);
+
buf = relay_create_buf(chan);
if (!buf)
- return NULL;
+ goto free_name;
+
+ buf->cpu = cpu;
+ __relay_reset(buf, 1);
/* Create file in fs */
- dentry = chan->cb->create_buf_file(filename, parent, S_IRUSR,
- buf, is_global);
- if (!dentry) {
- relay_destroy_buf(buf);
- return NULL;
- }
+ dentry = chan->cb->create_buf_file(tmpname, chan->parent, S_IRUSR,
+ buf, &chan->is_global);
+ if (!dentry)
+ goto free_buf;
buf->dentry = dentry;
- __relay_reset(buf, 1);
+ if(chan->is_global) {
+ chan->buf[0] = buf;
+ buf->cpu = 0;
+ }
+
+ goto free_name;
+
+free_buf:
+ relay_destroy_buf(buf);
+free_name:
+ kfree(tmpname);
+end:
return buf;
}
@@ -448,31 +474,71 @@ static void setup_callbacks(struct rchan *chan,
}
/**
+ *
+ * relay_hotcpu_callback - CPU hotplug callback
+ * @nb: notifier block
+ * @action: hotplug action to take
+ * @hcpu: CPU number
+ *
+ * Returns the success/failure of the operation. (NOTIFY_OK, NOTIFY_BAD)
+ */
+static int __cpuinit relay_hotcpu_callback(struct notifier_block *nb,
+ unsigned long action,
+ void *hcpu)
+{
+ unsigned int hotcpu = (unsigned long)hcpu;
+ struct rchan *chan;
+
+ switch(action) {
+ case CPU_UP_PREPARE:
+ mutex_lock(&relay_channels_mutex);
+ list_for_each_entry(chan, &relay_channels, list) {
+ if (chan->buf[hotcpu])
+ continue;
+ chan->buf[hotcpu] = relay_open_buf(chan, hotcpu);
+ if(!chan->buf[hotcpu]) {
+ printk(KERN_ERR
+ "relay_hotcpu_callback: cpu %d buffer "
+ "creation failed\n", hotcpu);
+ mutex_unlock(&relay_channels_mutex);
+ return NOTIFY_BAD;
+ }
+ }
+ mutex_unlock(&relay_channels_mutex);
+ break;
+ case CPU_DEAD:
+ /* No need to flush the cpu : will be flushed upon
+ * final relay_flush() call. */
+ break;
+ }
+ return NOTIFY_OK;
+}
+
+/**
* relay_open - create a new relay channel
* @base_filename: base name of files to create
* @parent: dentry of parent directory, %NULL for root directory
* @subbuf_size: size of sub-buffers
* @n_subbufs: number of sub-buffers
* @cb: client callback functions
+ * @private_data: user-defined data
*
* Returns channel pointer if successful, %NULL otherwise.
*
* Creates a channel buffer for each cpu using the sizes and
* attributes specified. The created channel buffer files
* will be named base_filename0...base_filenameN-1. File
- * permissions will be S_IRUSR.
+ * permissions will be %S_IRUSR.
*/
struct rchan *relay_open(const char *base_filename,
struct dentry *parent,
size_t subbuf_size,
size_t n_subbufs,
- struct rchan_callbacks *cb)
+ struct rchan_callbacks *cb,
+ void *private_data)
{
unsigned int i;
struct rchan *chan;
- char *tmpname;
- int is_global = 0;
-
if (!base_filename)
return NULL;
@@ -487,38 +553,32 @@ struct rchan *relay_open(const char *base_filename,
chan->n_subbufs = n_subbufs;
chan->subbuf_size = subbuf_size;
chan->alloc_size = FIX_SIZE(subbuf_size * n_subbufs);
+ chan->parent = parent;
+ chan->private_data = private_data;
+ strlcpy(chan->base_filename, base_filename, NAME_MAX);
setup_callbacks(chan, cb);
kref_init(&chan->kref);
- tmpname = kmalloc(NAME_MAX + 1, GFP_KERNEL);
- if (!tmpname)
- goto free_chan;
-
+ mutex_lock(&relay_channels_mutex);
for_each_online_cpu(i) {
- sprintf(tmpname, "%s%d", base_filename, i);
- chan->buf[i] = relay_open_buf(chan, tmpname, parent,
- &is_global);
+ chan->buf[i] = relay_open_buf(chan, i);
if (!chan->buf[i])
goto free_bufs;
-
- chan->buf[i]->cpu = i;
}
+ list_add(&chan->list, &relay_channels);
+ mutex_unlock(&relay_channels_mutex);
- kfree(tmpname);
return chan;
free_bufs:
- for (i = 0; i < NR_CPUS; i++) {
+ for_each_online_cpu(i) {
if (!chan->buf[i])
break;
relay_close_buf(chan->buf[i]);
- if (is_global)
- break;
}
- kfree(tmpname);
-free_chan:
kref_put(&chan->kref, relay_destroy_channel);
+ mutex_unlock(&relay_channels_mutex);
return NULL;
}
EXPORT_SYMBOL_GPL(relay_open);
@@ -588,7 +648,7 @@ EXPORT_SYMBOL_GPL(relay_switch_subbuf);
* subbufs_consumed should be the number of sub-buffers newly consumed,
* not the total consumed.
*
- * NOTE: Kernel clients don't need to call this function if the channel
+ * NOTE. Kernel clients don't need to call this function if the channel
* mode is 'overwrite'.
*/
void relay_subbufs_consumed(struct rchan *chan,
@@ -619,24 +679,26 @@ EXPORT_SYMBOL_GPL(relay_subbufs_consumed);
void relay_close(struct rchan *chan)
{
unsigned int i;
- struct rchan_buf *prev = NULL;
if (!chan)
return;
- for (i = 0; i < NR_CPUS; i++) {
- if (!chan->buf[i] || chan->buf[i] == prev)
- break;
- relay_close_buf(chan->buf[i]);
- prev = chan->buf[i];
- }
+ mutex_lock(&relay_channels_mutex);
+ if (chan->is_global && chan->buf[0])
+ relay_close_buf(chan->buf[0]);
+ else
+ for_each_possible_cpu(i)
+ if (chan->buf[i])
+ relay_close_buf(chan->buf[i]);
if (chan->last_toobig)
printk(KERN_WARNING "relay: one or more items not logged "
"[item size (%Zd) > sub-buffer size (%Zd)]\n",
chan->last_toobig, chan->subbuf_size);
+ list_del(&chan->list);
kref_put(&chan->kref, relay_destroy_channel);
+ mutex_unlock(&relay_channels_mutex);
}
EXPORT_SYMBOL_GPL(relay_close);
@@ -649,17 +711,20 @@ EXPORT_SYMBOL_GPL(relay_close);
void relay_flush(struct rchan *chan)
{
unsigned int i;
- struct rchan_buf *prev = NULL;
if (!chan)
return;
- for (i = 0; i < NR_CPUS; i++) {
- if (!chan->buf[i] || chan->buf[i] == prev)
- break;
- relay_switch_subbuf(chan->buf[i], 0);
- prev = chan->buf[i];
+ if (chan->is_global && chan->buf[0]) {
+ relay_switch_subbuf(chan->buf[0], 0);
+ return;
}
+
+ mutex_lock(&relay_channels_mutex);
+ for_each_possible_cpu(i)
+ if (chan->buf[i])
+ relay_switch_subbuf(chan->buf[i], 0);
+ mutex_unlock(&relay_channels_mutex);
}
EXPORT_SYMBOL_GPL(relay_flush);
@@ -684,7 +749,7 @@ static int relay_file_open(struct inode *inode, struct file *filp)
* @filp: the file
* @vma: the vma describing what to map
*
- * Calls upon relay_mmap_buf to map the file into user space.
+ * Calls upon relay_mmap_buf() to map the file into user space.
*/
static int relay_file_mmap(struct file *filp, struct vm_area_struct *vma)
{
@@ -826,7 +891,7 @@ static size_t relay_file_read_subbuf_avail(size_t read_pos,
* @read_pos: file read position
* @buf: relay channel buffer
*
- * If the read_pos is in the middle of padding, return the
+ * If the @read_pos is in the middle of padding, return the
* position of the first actually available byte, otherwise
* return the original value.
*/
@@ -1022,3 +1087,12 @@ const struct file_operations relay_file_operations = {
.sendfile = relay_file_sendfile,
};
EXPORT_SYMBOL_GPL(relay_file_operations);
+
+static __init int relay_init(void)
+{
+
+ hotcpu_notifier(relay_hotcpu_callback, 0);
+ return 0;
+}
+
+module_init(relay_init);