diff options
| -rw-r--r-- | Documentation/filesystems/relay.txt | 9 | ||||
| -rw-r--r-- | block/blktrace.c | 3 | ||||
| -rw-r--r-- | include/linux/relay.h | 9 | ||||
| -rw-r--r-- | kernel/relay.c | 180 |
4 files changed, 142 insertions, 59 deletions
diff --git a/Documentation/filesystems/relay.txt b/Documentation/filesystems/relay.txt index d6788dae0349..7fbb6ffe5769 100644 --- a/Documentation/filesystems/relay.txt +++ b/Documentation/filesystems/relay.txt @@ -157,7 +157,7 @@ TBD(curr. line MT:/API/) channel management functions: relay_open(base_filename, parent, subbuf_size, n_subbufs, - callbacks) + callbacks, private_data) relay_close(chan) relay_flush(chan) relay_reset(chan) @@ -251,7 +251,7 @@ static struct rchan_callbacks relay_callbacks = And an example relay_open() invocation using them: - chan = relay_open("cpu", NULL, SUBBUF_SIZE, N_SUBBUFS, &relay_callbacks); + chan = relay_open("cpu", NULL, SUBBUF_SIZE, N_SUBBUFS, &relay_callbacks, NULL); If the create_buf_file() callback fails, or isn't defined, channel creation and thus relay_open() will fail. @@ -289,6 +289,11 @@ they use the proper locking for such a buffer, either by wrapping writes in a spinlock, or by copying a write function from relay.h and creating a local version that internally does the proper locking. +The private_data passed into relay_open() allows clients to associate +user-defined data with a channel, and is immediately available +(including in create_buf_file()) via chan->private_data or +buf->chan->private_data. + Channel 'modes' --------------- diff --git a/block/blktrace.c b/block/blktrace.c index d3679dd1d220..d36b32ed22f4 100644 --- a/block/blktrace.c +++ b/block/blktrace.c @@ -363,10 +363,9 @@ static int blk_trace_setup(request_queue_t *q, struct block_device *bdev, if (!bt->dropped_file) goto err; - bt->rchan = relay_open("trace", dir, buts.buf_size, buts.buf_nr, &blk_relay_callbacks); + bt->rchan = relay_open("trace", dir, buts.buf_size, buts.buf_nr, &blk_relay_callbacks, bt); if (!bt->rchan) goto err; - bt->rchan->private_data = bt; bt->act_mask = buts.act_mask; if (!bt->act_mask) diff --git a/include/linux/relay.h b/include/linux/relay.h index c6a48bfc8b14..759a0f97bec2 100644 --- a/include/linux/relay.h +++ b/include/linux/relay.h @@ -24,7 +24,7 @@ /* * Tracks changes to rchan/rchan_buf structs */ -#define RELAYFS_CHANNEL_VERSION 6 +#define RELAYFS_CHANNEL_VERSION 7 /* * Per-cpu relay channel buffer @@ -64,6 +64,10 @@ struct rchan void *private_data; /* for user-defined data */ size_t last_toobig; /* tried to log event > subbuf size */ struct rchan_buf *buf[NR_CPUS]; /* per-cpu channel buffers */ + int is_global; /* One global buffer ? */ + struct list_head list; /* for channel list */ + struct dentry *parent; /* parent dentry passed to open */ + char base_filename[NAME_MAX]; /* saved base filename */ }; /* @@ -162,7 +166,8 @@ 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); extern void relay_close(struct rchan *chan); extern void relay_flush(struct rchan *chan); extern void relay_subbufs_consumed(struct rchan *chan, diff --git a/kernel/relay.c b/kernel/relay.c index 284e2e8b4eed..ef923f6de2e7 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); @@ -362,51 +370,69 @@ static void __relay_reset(struct rchan_buf *buf, unsigned int init) 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; } @@ -448,12 +474,54 @@ 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. * @@ -466,13 +534,11 @@ 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); @@ -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); @@ -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); |