diff options
Diffstat (limited to 'drivers/block')
| -rw-r--r-- | drivers/block/cciss.c | 156 | ||||
| -rw-r--r-- | drivers/block/cciss.h | 7 |
2 files changed, 141 insertions, 22 deletions
diff --git a/drivers/block/cciss.c b/drivers/block/cciss.c index f162f96c36e6..4fb63b898798 100644 --- a/drivers/block/cciss.c +++ b/drivers/block/cciss.c @@ -40,6 +40,7 @@ #include <linux/hdreg.h> #include <linux/spinlock.h> #include <linux/compat.h> +#include <linux/mutex.h> #include <asm/uaccess.h> #include <asm/io.h> @@ -156,6 +157,10 @@ static struct board_type products[] = { static ctlr_info_t *hba[MAX_CTLR]; +static struct task_struct *cciss_scan_thread; +static DEFINE_MUTEX(scan_mutex); +static LIST_HEAD(scan_q); + static void do_cciss_request(struct request_queue *q); static irqreturn_t do_cciss_intr(int irq, void *dev_id); static int cciss_open(struct block_device *bdev, fmode_t mode); @@ -3233,20 +3238,121 @@ static irqreturn_t do_cciss_intr(int irq, void *dev_id) return IRQ_HANDLED; } +/** + * add_to_scan_list() - add controller to rescan queue + * @h: Pointer to the controller. + * + * Adds the controller to the rescan queue if not already on the queue. + * + * returns 1 if added to the queue, 0 if skipped (could be on the + * queue already, or the controller could be initializing or shutting + * down). + **/ +static int add_to_scan_list(struct ctlr_info *h) +{ + struct ctlr_info *test_h; + int found = 0; + int ret = 0; + + if (h->busy_initializing) + return 0; + + if (!mutex_trylock(&h->busy_shutting_down)) + return 0; + + mutex_lock(&scan_mutex); + list_for_each_entry(test_h, &scan_q, scan_list) { + if (test_h == h) { + found = 1; + break; + } + } + if (!found && !h->busy_scanning) { + INIT_COMPLETION(h->scan_wait); + list_add_tail(&h->scan_list, &scan_q); + ret = 1; + } + mutex_unlock(&scan_mutex); + mutex_unlock(&h->busy_shutting_down); + + return ret; +} + +/** + * remove_from_scan_list() - remove controller from rescan queue + * @h: Pointer to the controller. + * + * Removes the controller from the rescan queue if present. Blocks if + * the controller is currently conducting a rescan. + **/ +static void remove_from_scan_list(struct ctlr_info *h) +{ + struct ctlr_info *test_h, *tmp_h; + int scanning = 0; + + mutex_lock(&scan_mutex); + list_for_each_entry_safe(test_h, tmp_h, &scan_q, scan_list) { + if (test_h == h) { + list_del(&h->scan_list); + complete_all(&h->scan_wait); + mutex_unlock(&scan_mutex); + return; + } + } + if (&h->busy_scanning) + scanning = 0; + mutex_unlock(&scan_mutex); + + if (scanning) + wait_for_completion(&h->scan_wait); +} + +/** + * scan_thread() - kernel thread used to rescan controllers + * @data: Ignored. + * + * A kernel thread used scan for drive topology changes on + * controllers. The thread processes only one controller at a time + * using a queue. Controllers are added to the queue using + * add_to_scan_list() and removed from the queue either after done + * processing or using remove_from_scan_list(). + * + * returns 0. + **/ static int scan_thread(void *data) { - ctlr_info_t *h = data; - int rc; - DECLARE_COMPLETION_ONSTACK(wait); - h->rescan_wait = &wait; + struct ctlr_info *h; - for (;;) { - rc = wait_for_completion_interruptible(&wait); + while (1) { + set_current_state(TASK_INTERRUPTIBLE); + schedule(); if (kthread_should_stop()) break; - if (!rc) - rebuild_lun_table(h, 0); + + while (1) { + mutex_lock(&scan_mutex); + if (list_empty(&scan_q)) { + mutex_unlock(&scan_mutex); + break; + } + + h = list_entry(scan_q.next, + struct ctlr_info, + scan_list); + list_del(&h->scan_list); + h->busy_scanning = 1; + mutex_unlock(&scan_mutex); + + if (h) { + rebuild_lun_table(h, 0); + complete_all(&h->scan_wait); + mutex_lock(&scan_mutex); + h->busy_scanning = 0; + mutex_unlock(&scan_mutex); + } + } } + return 0; } @@ -3269,8 +3375,8 @@ static int check_for_unit_attention(ctlr_info_t *h, CommandList_struct *c) case REPORT_LUNS_CHANGED: printk(KERN_WARNING "cciss%d: report LUN data " "changed\n", h->ctlr); - if (h->rescan_wait) - complete(h->rescan_wait); + add_to_scan_list(h); + wake_up_process(cciss_scan_thread); return 1; break; case POWER_OR_RESET: @@ -3919,6 +4025,7 @@ static int __devinit cciss_init_one(struct pci_dev *pdev, hba[i]->busy_initializing = 1; INIT_HLIST_HEAD(&hba[i]->cmpQ); INIT_HLIST_HEAD(&hba[i]->reqQ); + mutex_init(&hba[i]->busy_shutting_down); if (cciss_pci_init(hba[i], pdev) != 0) goto clean0; @@ -3927,6 +4034,8 @@ static int __devinit cciss_init_one(struct pci_dev *pdev, hba[i]->ctlr = i; hba[i]->pdev = pdev; + init_completion(&hba[i]->scan_wait); + if (cciss_create_hba_sysfs_entry(hba[i])) goto clean0; @@ -4036,14 +4145,8 @@ static int __devinit cciss_init_one(struct pci_dev *pdev, hba[i]->cciss_max_sectors = 2048; - hba[i]->busy_initializing = 0; - rebuild_lun_table(hba[i], 1); - hba[i]->cciss_scan_thread = kthread_run(scan_thread, hba[i], - "cciss_scan%02d", i); - if (IS_ERR(hba[i]->cciss_scan_thread)) - return PTR_ERR(hba[i]->cciss_scan_thread); - + hba[i]->busy_initializing = 0; return 1; clean4: @@ -4126,8 +4229,9 @@ static void __devexit cciss_remove_one(struct pci_dev *pdev) return; } - kthread_stop(hba[i]->cciss_scan_thread); + mutex_lock(&hba[i]->busy_shutting_down); + remove_from_scan_list(hba[i]); remove_proc_entry(hba[i]->devname, proc_cciss); unregister_blkdev(hba[i]->major, hba[i]->devname); @@ -4174,6 +4278,7 @@ static void __devexit cciss_remove_one(struct pci_dev *pdev) pci_release_regions(pdev); pci_set_drvdata(pdev, NULL); cciss_destroy_hba_sysfs_entry(hba[i]); + mutex_unlock(&hba[i]->busy_shutting_down); free_hba(i); } @@ -4206,15 +4311,25 @@ static int __init cciss_init(void) if (err) return err; + /* Start the scan thread */ + cciss_scan_thread = kthread_run(scan_thread, NULL, "cciss_scan"); + if (IS_ERR(cciss_scan_thread)) { + err = PTR_ERR(cciss_scan_thread); + goto err_bus_unregister; + } + /* Register for our PCI devices */ err = pci_register_driver(&cciss_pci_driver); if (err) - goto err_bus_register; + goto err_thread_stop; return 0; -err_bus_register: +err_thread_stop: + kthread_stop(cciss_scan_thread); +err_bus_unregister: bus_unregister(&cciss_bus_type); + return err; } @@ -4231,6 +4346,7 @@ static void __exit cciss_cleanup(void) cciss_remove_one(hba[i]->pdev); } } + kthread_stop(cciss_scan_thread); remove_proc_entry("driver/cciss", NULL); bus_unregister(&cciss_bus_type); } diff --git a/drivers/block/cciss.h b/drivers/block/cciss.h index 06a5db25b298..4fb3639b6cff 100644 --- a/drivers/block/cciss.h +++ b/drivers/block/cciss.h @@ -2,6 +2,7 @@ #define CCISS_H #include <linux/genhd.h> +#include <linux/mutex.h> #include "cciss_cmd.h" @@ -108,6 +109,8 @@ struct ctlr_info int nr_frees; int busy_configuring; int busy_initializing; + int busy_scanning; + struct mutex busy_shutting_down; /* This element holds the zero based queue number of the last * queue to be started. It is used for fairness. @@ -122,8 +125,8 @@ struct ctlr_info /* and saved for later processing */ #endif unsigned char alive; - struct completion *rescan_wait; - struct task_struct *cciss_scan_thread; + struct list_head scan_list; + struct completion scan_wait; struct device dev; }; |