mm owner: fix race between swapoff and exit

[linux-2.6/next.git] / drivers / edac / edac_device.c

/*
 * edac_device.c
 * (C) 2007 www.douglaskthompson.com
 *
 * This file may be distributed under the terms of the
 * GNU General Public License.
 *
 * Written by Doug Thompson <norsk5@xmission.com>
 *
 * edac_device API implementation
 * 19 Jan 2007
 */

#include <linux/module.h>
#include <linux/types.h>
#include <linux/smp.h>
#include <linux/init.h>
#include <linux/sysctl.h>
#include <linux/highmem.h>
#include <linux/timer.h>
#include <linux/slab.h>
#include <linux/jiffies.h>
#include <linux/spinlock.h>
#include <linux/list.h>
#include <linux/sysdev.h>
#include <linux/ctype.h>
#include <linux/workqueue.h>
#include <asm/uaccess.h>
#include <asm/page.h>

#include "edac_core.h"
#include "edac_module.h"

/* lock for the list: 'edac_device_list', manipulation of this list
 * is protected by the 'device_ctls_mutex' lock
 */
static DEFINE_MUTEX(device_ctls_mutex);
static LIST_HEAD(edac_device_list);

#ifdef CONFIG_EDAC_DEBUG
static void edac_device_dump_device(struct edac_device_ctl_info *edac_dev)
{
        debugf3("\tedac_dev = %p dev_idx=%d \n", edac_dev, edac_dev->dev_idx);
        debugf4("\tedac_dev->edac_check = %p\n", edac_dev->edac_check);
        debugf3("\tdev = %p\n", edac_dev->dev);
        debugf3("\tmod_name:ctl_name = %s:%s\n",
                edac_dev->mod_name, edac_dev->ctl_name);
        debugf3("\tpvt_info = %p\n\n", edac_dev->pvt_info);
}
#endif                          /* CONFIG_EDAC_DEBUG */


/*
 * edac_device_alloc_ctl_info()
 *      Allocate a new edac device control info structure
 *
 *      The control structure is allocated in complete chunk
 *      from the OS. It is in turn sub allocated to the
 *      various objects that compose the struture
 *
 *      The structure has a 'nr_instance' array within itself.
 *      Each instance represents a major component
 *              Example:  L1 cache and L2 cache are 2 instance components
 *
 *      Within each instance is an array of 'nr_blocks' blockoffsets
 */
struct edac_device_ctl_info *edac_device_alloc_ctl_info(
        unsigned sz_private,
        char *edac_device_name, unsigned nr_instances,
        char *edac_block_name, unsigned nr_blocks,
        unsigned offset_value,          /* zero, 1, or other based offset */
        struct edac_dev_sysfs_block_attribute *attrib_spec, unsigned nr_attrib,
        int device_index)
{
        struct edac_device_ctl_info *dev_ctl;
        struct edac_device_instance *dev_inst, *inst;
        struct edac_device_block *dev_blk, *blk_p, *blk;
        struct edac_dev_sysfs_block_attribute *dev_attrib, *attrib_p, *attrib;
        unsigned total_size;
        unsigned count;
        unsigned instance, block, attr;
        void *pvt;
        int err;

        debugf4("%s() instances=%d blocks=%d\n",
                __func__, nr_instances, nr_blocks);

        /* Calculate the size of memory we need to allocate AND
         * determine the offsets of the various item arrays
         * (instance,block,attrib) from the start of an  allocated structure.
         * We want the alignment of each item  (instance,block,attrib)
         * to be at least as stringent as what the compiler would
         * provide if we could simply hardcode everything into a single struct.
         */
        dev_ctl = (struct edac_device_ctl_info *)NULL;

        /* Calc the 'end' offset past end of ONE ctl_info structure
         * which will become the start of the 'instance' array
         */
        dev_inst = edac_align_ptr(&dev_ctl[1], sizeof(*dev_inst));

        /* Calc the 'end' offset past the instance array within the ctl_info
         * which will become the start of the block array
         */
        dev_blk = edac_align_ptr(&dev_inst[nr_instances], sizeof(*dev_blk));

        /* Calc the 'end' offset past the dev_blk array
         * which will become the start of the attrib array, if any.
         */
        count = nr_instances * nr_blocks;
        dev_attrib = edac_align_ptr(&dev_blk[count], sizeof(*dev_attrib));

        /* Check for case of when an attribute array is specified */
        if (nr_attrib > 0) {
                /* calc how many nr_attrib we need */
                count *= nr_attrib;

                /* Calc the 'end' offset past the attributes array */
                pvt = edac_align_ptr(&dev_attrib[count], sz_private);
        } else {
                /* no attribute array specificed */
                pvt = edac_align_ptr(dev_attrib, sz_private);
        }

        /* 'pvt' now points to where the private data area is.
         * At this point 'pvt' (like dev_inst,dev_blk and dev_attrib)
         * is baselined at ZERO
         */
        total_size = ((unsigned long)pvt) + sz_private;

        /* Allocate the amount of memory for the set of control structures */
        dev_ctl = kzalloc(total_size, GFP_KERNEL);
        if (dev_ctl == NULL)
                return NULL;

        /* Adjust pointers so they point within the actual memory we
         * just allocated rather than an imaginary chunk of memory
         * located at address 0.
         * 'dev_ctl' points to REAL memory, while the others are
         * ZERO based and thus need to be adjusted to point within
         * the allocated memory.
         */
        dev_inst = (struct edac_device_instance *)
                (((char *)dev_ctl) + ((unsigned long)dev_inst));
        dev_blk = (struct edac_device_block *)
                (((char *)dev_ctl) + ((unsigned long)dev_blk));
        dev_attrib = (struct edac_dev_sysfs_block_attribute *)
                (((char *)dev_ctl) + ((unsigned long)dev_attrib));
        pvt = sz_private ? (((char *)dev_ctl) + ((unsigned long)pvt)) : NULL;

        /* Begin storing the information into the control info structure */
        dev_ctl->dev_idx = device_index;
        dev_ctl->nr_instances = nr_instances;
        dev_ctl->instances = dev_inst;
        dev_ctl->pvt_info = pvt;

        /* Default logging of CEs and UEs */
        dev_ctl->log_ce = 1;
        dev_ctl->log_ue = 1;

        /* Name of this edac device */
        snprintf(dev_ctl->name,sizeof(dev_ctl->name),"%s",edac_device_name);

        debugf4("%s() edac_dev=%p next after end=%p\n",
                __func__, dev_ctl, pvt + sz_private );

        /* Initialize every Instance */
        for (instance = 0; instance < nr_instances; instance++) {
                inst = &dev_inst[instance];
                inst->ctl = dev_ctl;
                inst->nr_blocks = nr_blocks;
                blk_p = &dev_blk[instance * nr_blocks];
                inst->blocks = blk_p;

                /* name of this instance */
                snprintf(inst->name, sizeof(inst->name),
                         "%s%u", edac_device_name, instance);

                /* Initialize every block in each instance */
                for (block = 0; block < nr_blocks; block++) {
                        blk = &blk_p[block];
                        blk->instance = inst;
                        snprintf(blk->name, sizeof(blk->name),
                                 "%s%d", edac_block_name, block+offset_value);

                        debugf4("%s() instance=%d inst_p=%p block=#%d "
                                "block_p=%p name='%s'\n",
                                __func__, instance, inst, block,
                                blk, blk->name);

                        /* if there are NO attributes OR no attribute pointer
                         * then continue on to next block iteration
                         */
                        if ((nr_attrib == 0) || (attrib_spec == NULL))
                                continue;

                        /* setup the attribute array for this block */
                        blk->nr_attribs = nr_attrib;
                        attrib_p = &dev_attrib[block*nr_instances*nr_attrib];
                        blk->block_attributes = attrib_p;

                        debugf4("%s() THIS BLOCK_ATTRIB=%p\n",
                                __func__, blk->block_attributes);

                        /* Initialize every user specified attribute in this
                         * block with the data the caller passed in
                         * Each block gets its own copy of pointers,
                         * and its unique 'value'
                         */
                        for (attr = 0; attr < nr_attrib; attr++) {
                                attrib = &attrib_p[attr];

                                /* populate the unique per attrib
                                 * with the code pointers and info
                                 */
                                attrib->attr = attrib_spec[attr].attr;
                                attrib->show = attrib_spec[attr].show;
                                attrib->store = attrib_spec[attr].store;

                                attrib->block = blk;    /* up link */

                                debugf4("%s() alloc-attrib=%p attrib_name='%s' "
                                        "attrib-spec=%p spec-name=%s\n",
                                        __func__, attrib, attrib->attr.name,
                                        &attrib_spec[attr],
                                        attrib_spec[attr].attr.name
                                        );
                        }
                }
        }

        /* Mark this instance as merely ALLOCATED */
        dev_ctl->op_state = OP_ALLOC;

        /*
         * Initialize the 'root' kobj for the edac_device controller
         */
        err = edac_device_register_sysfs_main_kobj(dev_ctl);
        if (err) {
                kfree(dev_ctl);
                return NULL;
        }

        /* at this point, the root kobj is valid, and in order to
         * 'free' the object, then the function:
         *      edac_device_unregister_sysfs_main_kobj() must be called
         * which will perform kobj unregistration and the actual free
         * will occur during the kobject callback operation
         */

        return dev_ctl;
}
EXPORT_SYMBOL_GPL(edac_device_alloc_ctl_info);

/*
 * edac_device_free_ctl_info()
 *      frees the memory allocated by the edac_device_alloc_ctl_info()
 *      function
 */
void edac_device_free_ctl_info(struct edac_device_ctl_info *ctl_info)
{
        edac_device_unregister_sysfs_main_kobj(ctl_info);
}
EXPORT_SYMBOL_GPL(edac_device_free_ctl_info);

/*
 * find_edac_device_by_dev
 *      scans the edac_device list for a specific 'struct device *'
 *
 *      lock to be held prior to call:  device_ctls_mutex
 *
 *      Return:
 *              pointer to control structure managing 'dev'
 *              NULL if not found on list
 */
static struct edac_device_ctl_info *find_edac_device_by_dev(struct device *dev)
{
        struct edac_device_ctl_info *edac_dev;
        struct list_head *item;

        debugf0("%s()\n", __func__);

        list_for_each(item, &edac_device_list) {
                edac_dev = list_entry(item, struct edac_device_ctl_info, link);

                if (edac_dev->dev == dev)
                        return edac_dev;
        }

        return NULL;
}

/*
 * add_edac_dev_to_global_list
 *      Before calling this function, caller must
 *      assign a unique value to edac_dev->dev_idx.
 *
 *      lock to be held prior to call:  device_ctls_mutex
 *
 *      Return:
 *              0 on success
 *              1 on failure.
 */
static int add_edac_dev_to_global_list(struct edac_device_ctl_info *edac_dev)
{
        struct list_head *item, *insert_before;
        struct edac_device_ctl_info *rover;

        insert_before = &edac_device_list;

        /* Determine if already on the list */
        rover = find_edac_device_by_dev(edac_dev->dev);
        if (unlikely(rover != NULL))
                goto fail0;

        /* Insert in ascending order by 'dev_idx', so find position */
        list_for_each(item, &edac_device_list) {
                rover = list_entry(item, struct edac_device_ctl_info, link);

                if (rover->dev_idx >= edac_dev->dev_idx) {
                        if (unlikely(rover->dev_idx == edac_dev->dev_idx))
                                goto fail1;

                        insert_before = item;
                        break;
                }
        }

        list_add_tail_rcu(&edac_dev->link, insert_before);
        return 0;

fail0:
        edac_printk(KERN_WARNING, EDAC_MC,
                        "%s (%s) %s %s already assigned %d\n",
                        rover->dev->bus_id, edac_dev_name(rover),
                        rover->mod_name, rover->ctl_name, rover->dev_idx);
        return 1;

fail1:
        edac_printk(KERN_WARNING, EDAC_MC,
                        "bug in low-level driver: attempt to assign\n"
                        "    duplicate dev_idx %d in %s()\n", rover->dev_idx,
                        __func__);
        return 1;
}

/*
 * complete_edac_device_list_del
 *
 *      callback function when reference count is zero
 */
static void complete_edac_device_list_del(struct rcu_head *head)
{
        struct edac_device_ctl_info *edac_dev;

        edac_dev = container_of(head, struct edac_device_ctl_info, rcu);
        INIT_LIST_HEAD(&edac_dev->link);
        complete(&edac_dev->removal_complete);
}

/*
 * del_edac_device_from_global_list
 *
 *      remove the RCU, setup for a callback call,
 *      then wait for the callback to occur
 */
static void del_edac_device_from_global_list(struct edac_device_ctl_info
                                                *edac_device)
{
        list_del_rcu(&edac_device->link);

        init_completion(&edac_device->removal_complete);
        call_rcu(&edac_device->rcu, complete_edac_device_list_del);
        wait_for_completion(&edac_device->removal_complete);
}

/*
 * edac_device_workq_function
 *      performs the operation scheduled by a workq request
 *
 *      this workq is embedded within an edac_device_ctl_info
 *      structure, that needs to be polled for possible error events.
 *
 *      This operation is to acquire the list mutex lock
 *      (thus preventing insertation or deletion)
 *      and then call the device's poll function IFF this device is
 *      running polled and there is a poll function defined.
 */
static void edac_device_workq_function(struct work_struct *work_req)
{
        struct delayed_work *d_work = (struct delayed_work *)work_req;
        struct edac_device_ctl_info *edac_dev = to_edac_device_ctl_work(d_work);

        mutex_lock(&device_ctls_mutex);

        /* Only poll controllers that are running polled and have a check */
        if ((edac_dev->op_state == OP_RUNNING_POLL) &&
                (edac_dev->edac_check != NULL)) {
                        edac_dev->edac_check(edac_dev);
        }

        mutex_unlock(&device_ctls_mutex);

        /* Reschedule the workq for the next time period to start again
         * if the number of msec is for 1 sec, then adjust to the next
         * whole one second to save timers fireing all over the period
         * between integral seconds
         */
        if (edac_dev->poll_msec == 1000)
                queue_delayed_work(edac_workqueue, &edac_dev->work,
                                round_jiffies_relative(edac_dev->delay));
        else
                queue_delayed_work(edac_workqueue, &edac_dev->work,
                                edac_dev->delay);
}

/*
 * edac_device_workq_setup
 *      initialize a workq item for this edac_device instance
 *      passing in the new delay period in msec
 */
void edac_device_workq_setup(struct edac_device_ctl_info *edac_dev,
                                unsigned msec)
{
        debugf0("%s()\n", __func__);

        /* take the arg 'msec' and set it into the control structure
         * to used in the time period calculation
         * then calc the number of jiffies that represents
         */
        edac_dev->poll_msec = msec;
        edac_dev->delay = msecs_to_jiffies(msec);

        INIT_DELAYED_WORK(&edac_dev->work, edac_device_workq_function);

        /* optimize here for the 1 second case, which will be normal value, to
         * fire ON the 1 second time event. This helps reduce all sorts of
         * timers firing on sub-second basis, while they are happy
         * to fire together on the 1 second exactly
         */
        if (edac_dev->poll_msec == 1000)
                queue_delayed_work(edac_workqueue, &edac_dev->work,
                                round_jiffies_relative(edac_dev->delay));
        else
                queue_delayed_work(edac_workqueue, &edac_dev->work,
                                edac_dev->delay);
}

/*
 * edac_device_workq_teardown
 *      stop the workq processing on this edac_dev
 */
void edac_device_workq_teardown(struct edac_device_ctl_info *edac_dev)
{
        int status;

        status = cancel_delayed_work(&edac_dev->work);
        if (status == 0) {
                /* workq instance might be running, wait for it */
                flush_workqueue(edac_workqueue);
        }
}

/*
 * edac_device_reset_delay_period
 *
 *      need to stop any outstanding workq queued up at this time
 *      because we will be resetting the sleep time.
 *      Then restart the workq on the new delay
 */
void edac_device_reset_delay_period(struct edac_device_ctl_info *edac_dev,
                                        unsigned long value)
{
        /* cancel the current workq request, without the mutex lock */
        edac_device_workq_teardown(edac_dev);

        /* acquire the mutex before doing the workq setup */
        mutex_lock(&device_ctls_mutex);

        /* restart the workq request, with new delay value */
        edac_device_workq_setup(edac_dev, value);

        mutex_unlock(&device_ctls_mutex);
}

/**
 * edac_device_add_device: Insert the 'edac_dev' structure into the
 * edac_device global list and create sysfs entries associated with
 * edac_device structure.
 * @edac_device: pointer to the edac_device structure to be added to the list
 * 'edac_device' structure.
 *
 * Return:
 *      0       Success
 *      !0      Failure
 */
int edac_device_add_device(struct edac_device_ctl_info *edac_dev)
{
        debugf0("%s()\n", __func__);

#ifdef CONFIG_EDAC_DEBUG
        if (edac_debug_level >= 3)
                edac_device_dump_device(edac_dev);
#endif
        mutex_lock(&device_ctls_mutex);

        if (add_edac_dev_to_global_list(edac_dev))
                goto fail0;

        /* set load time so that error rate can be tracked */
        edac_dev->start_time = jiffies;

        /* create this instance's sysfs entries */
        if (edac_device_create_sysfs(edac_dev)) {
                edac_device_printk(edac_dev, KERN_WARNING,
                                        "failed to create sysfs device\n");
                goto fail1;
        }

        /* If there IS a check routine, then we are running POLLED */
        if (edac_dev->edac_check != NULL) {
                /* This instance is NOW RUNNING */
                edac_dev->op_state = OP_RUNNING_POLL;

                /*
                 * enable workq processing on this instance,
                 * default = 1000 msec
                 */
                edac_device_workq_setup(edac_dev, 1000);
        } else {
                edac_dev->op_state = OP_RUNNING_INTERRUPT;
        }

        /* Report action taken */
        edac_device_printk(edac_dev, KERN_INFO,
                                "Giving out device to module '%s' controller "
                                "'%s': DEV '%s' (%s)\n",
                                edac_dev->mod_name,
                                edac_dev->ctl_name,
                                edac_dev_name(edac_dev),
                                edac_op_state_to_string(edac_dev->op_state));

        mutex_unlock(&device_ctls_mutex);
        return 0;

fail1:
        /* Some error, so remove the entry from the lsit */
        del_edac_device_from_global_list(edac_dev);

fail0:
        mutex_unlock(&device_ctls_mutex);
        return 1;
}
EXPORT_SYMBOL_GPL(edac_device_add_device);

/**
 * edac_device_del_device:
 *      Remove sysfs entries for specified edac_device structure and
 *      then remove edac_device structure from global list
 *
 * @pdev:
 *      Pointer to 'struct device' representing edac_device
 *      structure to remove.
 *
 * Return:
 *      Pointer to removed edac_device structure,
 *      OR NULL if device not found.
 */
struct edac_device_ctl_info *edac_device_del_device(struct device *dev)
{
        struct edac_device_ctl_info *edac_dev;

        debugf0("%s()\n", __func__);

        mutex_lock(&device_ctls_mutex);

        /* Find the structure on the list, if not there, then leave */
        edac_dev = find_edac_device_by_dev(dev);
        if (edac_dev == NULL) {
                mutex_unlock(&device_ctls_mutex);
                return NULL;
        }

        /* mark this instance as OFFLINE */
        edac_dev->op_state = OP_OFFLINE;

        /* clear workq processing on this instance */
        edac_device_workq_teardown(edac_dev);

        /* deregister from global list */
        del_edac_device_from_global_list(edac_dev);

        mutex_unlock(&device_ctls_mutex);

        /* Tear down the sysfs entries for this instance */
        edac_device_remove_sysfs(edac_dev);

        edac_printk(KERN_INFO, EDAC_MC,
                "Removed device %d for %s %s: DEV %s\n",
                edac_dev->dev_idx,
                edac_dev->mod_name, edac_dev->ctl_name, edac_dev_name(edac_dev));

        return edac_dev;
}
EXPORT_SYMBOL_GPL(edac_device_del_device);

static inline int edac_device_get_log_ce(struct edac_device_ctl_info *edac_dev)
{
        return edac_dev->log_ce;
}

static inline int edac_device_get_log_ue(struct edac_device_ctl_info *edac_dev)
{
        return edac_dev->log_ue;
}

static inline int edac_device_get_panic_on_ue(struct edac_device_ctl_info
                                        *edac_dev)
{
        return edac_dev->panic_on_ue;
}

/*
 * edac_device_handle_ce
 *      perform a common output and handling of an 'edac_dev' CE event
 */
void edac_device_handle_ce(struct edac_device_ctl_info *edac_dev,
                        int inst_nr, int block_nr, const char *msg)
{
        struct edac_device_instance *instance;
        struct edac_device_block *block = NULL;

        if ((inst_nr >= edac_dev->nr_instances) || (inst_nr < 0)) {
                edac_device_printk(edac_dev, KERN_ERR,
                                "INTERNAL ERROR: 'instance' out of range "
                                "(%d >= %d)\n", inst_nr,
                                edac_dev->nr_instances);
                return;
        }

        instance = edac_dev->instances + inst_nr;

        if ((block_nr >= instance->nr_blocks) || (block_nr < 0)) {
                edac_device_printk(edac_dev, KERN_ERR,
                                "INTERNAL ERROR: instance %d 'block' "
                                "out of range (%d >= %d)\n",
                                inst_nr, block_nr,
                                instance->nr_blocks);
                return;
        }

        if (instance->nr_blocks > 0) {
                block = instance->blocks + block_nr;
                block->counters.ce_count++;
        }

        /* Propogate the count up the 'totals' tree */
        instance->counters.ce_count++;
        edac_dev->counters.ce_count++;

        if (edac_device_get_log_ce(edac_dev))
                edac_device_printk(edac_dev, KERN_WARNING,
                                "CE: %s instance: %s block: %s '%s'\n",
                                edac_dev->ctl_name, instance->name,
                                block ? block->name : "N/A", msg);
}
EXPORT_SYMBOL_GPL(edac_device_handle_ce);

/*
 * edac_device_handle_ue
 *      perform a common output and handling of an 'edac_dev' UE event
 */
void edac_device_handle_ue(struct edac_device_ctl_info *edac_dev,
                        int inst_nr, int block_nr, const char *msg)
{
        struct edac_device_instance *instance;
        struct edac_device_block *block = NULL;

        if ((inst_nr >= edac_dev->nr_instances) || (inst_nr < 0)) {
                edac_device_printk(edac_dev, KERN_ERR,
                                "INTERNAL ERROR: 'instance' out of range "
                                "(%d >= %d)\n", inst_nr,
                                edac_dev->nr_instances);
                return;
        }

        instance = edac_dev->instances + inst_nr;

        if ((block_nr >= instance->nr_blocks) || (block_nr < 0)) {
                edac_device_printk(edac_dev, KERN_ERR,
                                "INTERNAL ERROR: instance %d 'block' "
                                "out of range (%d >= %d)\n",
                                inst_nr, block_nr,
                                instance->nr_blocks);
                return;
        }

        if (instance->nr_blocks > 0) {
                block = instance->blocks + block_nr;
                block->counters.ue_count++;
        }

        /* Propogate the count up the 'totals' tree */
        instance->counters.ue_count++;
        edac_dev->counters.ue_count++;

        if (edac_device_get_log_ue(edac_dev))
                edac_device_printk(edac_dev, KERN_EMERG,
                                "UE: %s instance: %s block: %s '%s'\n",
                                edac_dev->ctl_name, instance->name,
                                block ? block->name : "N/A", msg);

        if (edac_device_get_panic_on_ue(edac_dev))
                panic("EDAC %s: UE instance: %s block %s '%s'\n",
                        edac_dev->ctl_name, instance->name,
                        block ? block->name : "N/A", msg);
}
EXPORT_SYMBOL_GPL(edac_device_handle_ue);