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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-09-06 10:57:46 +00:00
cciss: Use one scan thread per controller and fix hang during rmmod
Replace the use of one scan kthread per controller with one per driver. Use a queue to hold a list of controllers that need to be rescanned with routines to add and remove controllers from the queue. Fix locking and completion handling to prevent a hang during rmmod. Signed-off-by: Andrew Patterson <andrew.patterson@hp.com> Signed-off-by: Stephen M. Cameron <scameron@beardog.cce.hp.com> Acked-by: Mike Miller <mike.miller@hp.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
This commit is contained in:
parent
c64bebcd7f
commit
b368c9dd65
2 changed files with 141 additions and 22 deletions
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@ -40,6 +40,7 @@
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#include <linux/hdreg.h>
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#include <linux/spinlock.h>
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#include <linux/compat.h>
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#include <linux/mutex.h>
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#include <asm/uaccess.h>
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#include <asm/io.h>
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@ -156,6 +157,10 @@ static struct board_type products[] = {
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static ctlr_info_t *hba[MAX_CTLR];
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static struct task_struct *cciss_scan_thread;
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static DEFINE_MUTEX(scan_mutex);
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static LIST_HEAD(scan_q);
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static void do_cciss_request(struct request_queue *q);
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static irqreturn_t do_cciss_intr(int irq, void *dev_id);
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static int cciss_open(struct block_device *bdev, fmode_t mode);
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@ -3233,20 +3238,121 @@ static irqreturn_t do_cciss_intr(int irq, void *dev_id)
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return IRQ_HANDLED;
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}
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/**
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* add_to_scan_list() - add controller to rescan queue
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* @h: Pointer to the controller.
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*
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* Adds the controller to the rescan queue if not already on the queue.
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*
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* returns 1 if added to the queue, 0 if skipped (could be on the
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* queue already, or the controller could be initializing or shutting
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* down).
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**/
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static int add_to_scan_list(struct ctlr_info *h)
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{
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struct ctlr_info *test_h;
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int found = 0;
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int ret = 0;
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if (h->busy_initializing)
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return 0;
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if (!mutex_trylock(&h->busy_shutting_down))
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return 0;
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mutex_lock(&scan_mutex);
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list_for_each_entry(test_h, &scan_q, scan_list) {
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if (test_h == h) {
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found = 1;
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break;
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}
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}
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if (!found && !h->busy_scanning) {
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INIT_COMPLETION(h->scan_wait);
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list_add_tail(&h->scan_list, &scan_q);
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ret = 1;
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}
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mutex_unlock(&scan_mutex);
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mutex_unlock(&h->busy_shutting_down);
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return ret;
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}
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/**
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* remove_from_scan_list() - remove controller from rescan queue
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* @h: Pointer to the controller.
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*
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* Removes the controller from the rescan queue if present. Blocks if
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* the controller is currently conducting a rescan.
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**/
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static void remove_from_scan_list(struct ctlr_info *h)
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{
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struct ctlr_info *test_h, *tmp_h;
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int scanning = 0;
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mutex_lock(&scan_mutex);
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list_for_each_entry_safe(test_h, tmp_h, &scan_q, scan_list) {
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if (test_h == h) {
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list_del(&h->scan_list);
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complete_all(&h->scan_wait);
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mutex_unlock(&scan_mutex);
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return;
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}
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}
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if (&h->busy_scanning)
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scanning = 0;
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mutex_unlock(&scan_mutex);
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if (scanning)
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wait_for_completion(&h->scan_wait);
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}
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/**
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* scan_thread() - kernel thread used to rescan controllers
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* @data: Ignored.
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*
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* A kernel thread used scan for drive topology changes on
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* controllers. The thread processes only one controller at a time
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* using a queue. Controllers are added to the queue using
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* add_to_scan_list() and removed from the queue either after done
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* processing or using remove_from_scan_list().
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*
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* returns 0.
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**/
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static int scan_thread(void *data)
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{
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ctlr_info_t *h = data;
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int rc;
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DECLARE_COMPLETION_ONSTACK(wait);
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h->rescan_wait = &wait;
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struct ctlr_info *h;
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for (;;) {
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rc = wait_for_completion_interruptible(&wait);
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while (1) {
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set_current_state(TASK_INTERRUPTIBLE);
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schedule();
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if (kthread_should_stop())
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break;
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if (!rc)
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rebuild_lun_table(h, 0);
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while (1) {
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mutex_lock(&scan_mutex);
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if (list_empty(&scan_q)) {
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mutex_unlock(&scan_mutex);
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break;
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}
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h = list_entry(scan_q.next,
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struct ctlr_info,
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scan_list);
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list_del(&h->scan_list);
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h->busy_scanning = 1;
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mutex_unlock(&scan_mutex);
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if (h) {
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rebuild_lun_table(h, 0);
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complete_all(&h->scan_wait);
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mutex_lock(&scan_mutex);
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h->busy_scanning = 0;
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mutex_unlock(&scan_mutex);
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}
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}
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}
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return 0;
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}
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@ -3269,8 +3375,8 @@ static int check_for_unit_attention(ctlr_info_t *h, CommandList_struct *c)
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case REPORT_LUNS_CHANGED:
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printk(KERN_WARNING "cciss%d: report LUN data "
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"changed\n", h->ctlr);
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if (h->rescan_wait)
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complete(h->rescan_wait);
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add_to_scan_list(h);
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wake_up_process(cciss_scan_thread);
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return 1;
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break;
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case POWER_OR_RESET:
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@ -3919,6 +4025,7 @@ static int __devinit cciss_init_one(struct pci_dev *pdev,
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hba[i]->busy_initializing = 1;
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INIT_HLIST_HEAD(&hba[i]->cmpQ);
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INIT_HLIST_HEAD(&hba[i]->reqQ);
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mutex_init(&hba[i]->busy_shutting_down);
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if (cciss_pci_init(hba[i], pdev) != 0)
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goto clean0;
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@ -3927,6 +4034,8 @@ static int __devinit cciss_init_one(struct pci_dev *pdev,
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hba[i]->ctlr = i;
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hba[i]->pdev = pdev;
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init_completion(&hba[i]->scan_wait);
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if (cciss_create_hba_sysfs_entry(hba[i]))
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goto clean0;
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@ -4036,14 +4145,8 @@ static int __devinit cciss_init_one(struct pci_dev *pdev,
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hba[i]->cciss_max_sectors = 2048;
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hba[i]->busy_initializing = 0;
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rebuild_lun_table(hba[i], 1);
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hba[i]->cciss_scan_thread = kthread_run(scan_thread, hba[i],
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"cciss_scan%02d", i);
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if (IS_ERR(hba[i]->cciss_scan_thread))
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return PTR_ERR(hba[i]->cciss_scan_thread);
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hba[i]->busy_initializing = 0;
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return 1;
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clean4:
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@ -4126,8 +4229,9 @@ static void __devexit cciss_remove_one(struct pci_dev *pdev)
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return;
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}
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kthread_stop(hba[i]->cciss_scan_thread);
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mutex_lock(&hba[i]->busy_shutting_down);
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remove_from_scan_list(hba[i]);
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remove_proc_entry(hba[i]->devname, proc_cciss);
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unregister_blkdev(hba[i]->major, hba[i]->devname);
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@ -4174,6 +4278,7 @@ static void __devexit cciss_remove_one(struct pci_dev *pdev)
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pci_release_regions(pdev);
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pci_set_drvdata(pdev, NULL);
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cciss_destroy_hba_sysfs_entry(hba[i]);
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mutex_unlock(&hba[i]->busy_shutting_down);
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free_hba(i);
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}
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@ -4206,15 +4311,25 @@ static int __init cciss_init(void)
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if (err)
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return err;
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/* Start the scan thread */
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cciss_scan_thread = kthread_run(scan_thread, NULL, "cciss_scan");
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if (IS_ERR(cciss_scan_thread)) {
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err = PTR_ERR(cciss_scan_thread);
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goto err_bus_unregister;
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}
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/* Register for our PCI devices */
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err = pci_register_driver(&cciss_pci_driver);
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if (err)
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goto err_bus_register;
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goto err_thread_stop;
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return 0;
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err_bus_register:
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err_thread_stop:
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kthread_stop(cciss_scan_thread);
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err_bus_unregister:
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bus_unregister(&cciss_bus_type);
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return err;
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}
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@ -4231,6 +4346,7 @@ static void __exit cciss_cleanup(void)
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cciss_remove_one(hba[i]->pdev);
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}
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}
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kthread_stop(cciss_scan_thread);
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remove_proc_entry("driver/cciss", NULL);
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bus_unregister(&cciss_bus_type);
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}
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@ -2,6 +2,7 @@
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#define CCISS_H
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#include <linux/genhd.h>
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#include <linux/mutex.h>
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#include "cciss_cmd.h"
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int nr_frees;
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int busy_configuring;
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int busy_initializing;
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int busy_scanning;
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struct mutex busy_shutting_down;
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/* This element holds the zero based queue number of the last
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* queue to be started. It is used for fairness.
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/* and saved for later processing */
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#endif
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unsigned char alive;
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struct completion *rescan_wait;
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struct task_struct *cciss_scan_thread;
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struct list_head scan_list;
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struct completion scan_wait;
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struct device dev;
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};
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