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@@ -7,6 +7,8 @@
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* Copyright (C) 1999-2005 - Karim Yaghmour (karim@opersys.com)
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*
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* Moved to kernel/relay.c by Paul Mundt, 2006.
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+ * November 2006 - CPU hotplug support by Mathieu Desnoyers
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+ * (mathieu.desnoyers@polymtl.ca)
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*
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* This file is released under the GPL.
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*/
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@@ -18,6 +20,11 @@
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#include <linux/relay.h>
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#include <linux/vmalloc.h>
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#include <linux/mm.h>
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+#include <linux/cpu.h>
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+
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+/* list of open channels, for cpu hotplug */
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+static DEFINE_MUTEX(relay_channels_mutex);
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+static LIST_HEAD(relay_channels);
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/*
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* close() vm_op implementation for relay file mapping.
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@@ -187,6 +194,7 @@ void relay_destroy_buf(struct rchan_buf *buf)
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__free_page(buf->page_array[i]);
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kfree(buf->page_array);
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}
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+ chan->buf[buf->cpu] = NULL;
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kfree(buf->padding);
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kfree(buf);
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kref_put(&chan->kref, relay_destroy_channel);
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@@ -362,51 +370,69 @@ static void __relay_reset(struct rchan_buf *buf, unsigned int init)
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void relay_reset(struct rchan *chan)
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{
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unsigned int i;
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- struct rchan_buf *prev = NULL;
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if (!chan)
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return;
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- for (i = 0; i < NR_CPUS; i++) {
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- if (!chan->buf[i] || chan->buf[i] == prev)
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- break;
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- __relay_reset(chan->buf[i], 0);
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- prev = chan->buf[i];
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+ if (chan->is_global && chan->buf[0]) {
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+ __relay_reset(chan->buf[0], 0);
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+ return;
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}
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+
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+ mutex_lock(&relay_channels_mutex);
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+ for_each_online_cpu(i)
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+ if (chan->buf[i])
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+ __relay_reset(chan->buf[i], 0);
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+ mutex_unlock(&relay_channels_mutex);
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}
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EXPORT_SYMBOL_GPL(relay_reset);
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/*
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* relay_open_buf - create a new relay channel buffer
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*
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- * Internal - used by relay_open().
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+ * used by relay_open() and CPU hotplug.
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*/
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-static struct rchan_buf *relay_open_buf(struct rchan *chan,
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- const char *filename,
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- struct dentry *parent,
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- int *is_global)
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+static struct rchan_buf *relay_open_buf(struct rchan *chan, unsigned int cpu)
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{
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- struct rchan_buf *buf;
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+ struct rchan_buf *buf = NULL;
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struct dentry *dentry;
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+ char *tmpname;
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- if (*is_global)
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+ if (chan->is_global)
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return chan->buf[0];
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+ tmpname = kzalloc(NAME_MAX + 1, GFP_KERNEL);
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+ if (!tmpname)
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+ goto end;
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+ snprintf(tmpname, NAME_MAX, "%s%d", chan->base_filename, cpu);
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+
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buf = relay_create_buf(chan);
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if (!buf)
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- return NULL;
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+ goto free_name;
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+
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+ buf->cpu = cpu;
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+ __relay_reset(buf, 1);
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/* Create file in fs */
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- dentry = chan->cb->create_buf_file(filename, parent, S_IRUSR,
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- buf, is_global);
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- if (!dentry) {
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- relay_destroy_buf(buf);
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- return NULL;
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- }
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+ dentry = chan->cb->create_buf_file(tmpname, chan->parent, S_IRUSR,
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+ buf, &chan->is_global);
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+ if (!dentry)
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+ goto free_buf;
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buf->dentry = dentry;
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- __relay_reset(buf, 1);
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+ if(chan->is_global) {
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+ chan->buf[0] = buf;
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+ buf->cpu = 0;
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+ }
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+
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+ goto free_name;
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+
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+free_buf:
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+ relay_destroy_buf(buf);
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+free_name:
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+ kfree(tmpname);
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+end:
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return buf;
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}
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@@ -447,6 +473,47 @@ static void setup_callbacks(struct rchan *chan,
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chan->cb = cb;
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}
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+/**
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+ *
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+ * relay_hotcpu_callback - CPU hotplug callback
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+ * @nb: notifier block
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+ * @action: hotplug action to take
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+ * @hcpu: CPU number
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+ *
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+ * Returns the success/failure of the operation. (NOTIFY_OK, NOTIFY_BAD)
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+ */
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+static int __cpuinit relay_hotcpu_callback(struct notifier_block *nb,
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+ unsigned long action,
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+ void *hcpu)
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+{
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+ unsigned int hotcpu = (unsigned long)hcpu;
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+ struct rchan *chan;
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+
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+ switch(action) {
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+ case CPU_UP_PREPARE:
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+ mutex_lock(&relay_channels_mutex);
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+ list_for_each_entry(chan, &relay_channels, list) {
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+ if (chan->buf[hotcpu])
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+ continue;
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+ chan->buf[hotcpu] = relay_open_buf(chan, hotcpu);
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+ if(!chan->buf[hotcpu]) {
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+ printk(KERN_ERR
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+ "relay_hotcpu_callback: cpu %d buffer "
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+ "creation failed\n", hotcpu);
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+ mutex_unlock(&relay_channels_mutex);
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+ return NOTIFY_BAD;
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+ }
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+ }
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+ mutex_unlock(&relay_channels_mutex);
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+ break;
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+ case CPU_DEAD:
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+ /* No need to flush the cpu : will be flushed upon
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+ * final relay_flush() call. */
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+ break;
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+ }
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+ return NOTIFY_OK;
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+}
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+
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/**
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* relay_open - create a new relay channel
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* @base_filename: base name of files to create
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@@ -454,6 +521,7 @@ static void setup_callbacks(struct rchan *chan,
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* @subbuf_size: size of sub-buffers
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* @n_subbufs: number of sub-buffers
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* @cb: client callback functions
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+ * @private_data: user-defined data
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*
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* Returns channel pointer if successful, %NULL otherwise.
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*
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@@ -466,13 +534,11 @@ struct rchan *relay_open(const char *base_filename,
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struct dentry *parent,
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size_t subbuf_size,
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size_t n_subbufs,
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- struct rchan_callbacks *cb)
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+ struct rchan_callbacks *cb,
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+ void *private_data)
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{
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unsigned int i;
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struct rchan *chan;
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- char *tmpname;
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- int is_global = 0;
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-
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if (!base_filename)
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return NULL;
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@@ -487,38 +553,32 @@ struct rchan *relay_open(const char *base_filename,
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chan->n_subbufs = n_subbufs;
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chan->subbuf_size = subbuf_size;
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chan->alloc_size = FIX_SIZE(subbuf_size * n_subbufs);
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+ chan->parent = parent;
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+ chan->private_data = private_data;
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+ strlcpy(chan->base_filename, base_filename, NAME_MAX);
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setup_callbacks(chan, cb);
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kref_init(&chan->kref);
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- tmpname = kmalloc(NAME_MAX + 1, GFP_KERNEL);
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- if (!tmpname)
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- goto free_chan;
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-
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+ mutex_lock(&relay_channels_mutex);
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for_each_online_cpu(i) {
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- sprintf(tmpname, "%s%d", base_filename, i);
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- chan->buf[i] = relay_open_buf(chan, tmpname, parent,
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- &is_global);
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+ chan->buf[i] = relay_open_buf(chan, i);
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if (!chan->buf[i])
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goto free_bufs;
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-
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- chan->buf[i]->cpu = i;
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}
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+ list_add(&chan->list, &relay_channels);
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+ mutex_unlock(&relay_channels_mutex);
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- kfree(tmpname);
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return chan;
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free_bufs:
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- for (i = 0; i < NR_CPUS; i++) {
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+ for_each_online_cpu(i) {
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if (!chan->buf[i])
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break;
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relay_close_buf(chan->buf[i]);
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- if (is_global)
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- break;
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}
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- kfree(tmpname);
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-free_chan:
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kref_put(&chan->kref, relay_destroy_channel);
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+ mutex_unlock(&relay_channels_mutex);
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return NULL;
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}
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EXPORT_SYMBOL_GPL(relay_open);
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@@ -619,24 +679,26 @@ EXPORT_SYMBOL_GPL(relay_subbufs_consumed);
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void relay_close(struct rchan *chan)
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{
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unsigned int i;
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- struct rchan_buf *prev = NULL;
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if (!chan)
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return;
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- for (i = 0; i < NR_CPUS; i++) {
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- if (!chan->buf[i] || chan->buf[i] == prev)
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- break;
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- relay_close_buf(chan->buf[i]);
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- prev = chan->buf[i];
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- }
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+ mutex_lock(&relay_channels_mutex);
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+ if (chan->is_global && chan->buf[0])
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+ relay_close_buf(chan->buf[0]);
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+ else
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+ for_each_possible_cpu(i)
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+ if (chan->buf[i])
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+ relay_close_buf(chan->buf[i]);
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if (chan->last_toobig)
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printk(KERN_WARNING "relay: one or more items not logged "
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"[item size (%Zd) > sub-buffer size (%Zd)]\n",
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chan->last_toobig, chan->subbuf_size);
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+ list_del(&chan->list);
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kref_put(&chan->kref, relay_destroy_channel);
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+ mutex_unlock(&relay_channels_mutex);
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}
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EXPORT_SYMBOL_GPL(relay_close);
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@@ -649,17 +711,20 @@ EXPORT_SYMBOL_GPL(relay_close);
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void relay_flush(struct rchan *chan)
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{
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unsigned int i;
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- struct rchan_buf *prev = NULL;
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if (!chan)
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return;
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- for (i = 0; i < NR_CPUS; i++) {
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- if (!chan->buf[i] || chan->buf[i] == prev)
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- break;
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- relay_switch_subbuf(chan->buf[i], 0);
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- prev = chan->buf[i];
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+ if (chan->is_global && chan->buf[0]) {
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+ relay_switch_subbuf(chan->buf[0], 0);
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+ return;
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}
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+
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+ mutex_lock(&relay_channels_mutex);
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+ for_each_possible_cpu(i)
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+ if (chan->buf[i])
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+ relay_switch_subbuf(chan->buf[i], 0);
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+ mutex_unlock(&relay_channels_mutex);
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}
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EXPORT_SYMBOL_GPL(relay_flush);
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@@ -1022,3 +1087,12 @@ const struct file_operations relay_file_operations = {
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.sendfile = relay_file_sendfile,
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};
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EXPORT_SYMBOL_GPL(relay_file_operations);
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+
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+static __init int relay_init(void)
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+{
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+
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+ hotcpu_notifier(relay_hotcpu_callback, 0);
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+ return 0;
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+}
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+
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+module_init(relay_init);
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