In testing 2.6.23-rc3, there is a small window where the async-per-target scan of the transport can beat the call from the LLDD to scsi_scan_host(). If so, the target scan starts, and can add the sdev (and the sysfslinks) before the flags for async scan can prevent it. Thus, when async scan finishes and asks for all sdevs to be enumerated -EEXIST errors will pop up. This patch has scsi_alloc_host() look for the async scan hooks, and if they exist, sets the async_scan flag to a pre-state, which still allows the async target scan to continue, but stops the sysfs enumeration. -- james s This patch cut against 2.6.23-rc3 plus the following patch: http://marc.info/?l=linux-scsi&m=118289275414202&w=2 PS: there really should be better hooks for knowing if the driver expects async or background scanning (perhaps the whole pre-state should be set by the driver). Signed-off-by: James Smart <James.Smart@xxxxxxxxxx> diff -upNr a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c --- a/drivers/scsi/hosts.c 2007-08-17 11:49:47.000000000 -0400 +++ b/drivers/scsi/hosts.c 2007-08-19 12:23:06.000000000 -0400 @@ -343,6 +343,12 @@ struct Scsi_Host *scsi_host_alloc(struct shost->use_clustering = sht->use_clustering; shost->ordered_tag = sht->ordered_tag; + if ((strncmp(scsi_scan_type, "async", 5) == 0) && + (shost->hostt->scan_finished)) + shost->async_scan = ASYNC_SCAN_PREASYNC; + else + shost->async_scan = ASYNC_SCAN_CMPLT; + if (sht->max_host_blocked) shost->max_host_blocked = sht->max_host_blocked; else diff -upNr a/drivers/scsi/scsi_priv.h b/drivers/scsi/scsi_priv.h --- a/drivers/scsi/scsi_priv.h 2007-07-08 19:32:17.000000000 -0400 +++ b/drivers/scsi/scsi_priv.h 2007-08-19 12:23:49.000000000 -0400 @@ -38,9 +38,6 @@ static inline void scsi_log_completion(s { }; #endif -/* scsi_scan.c */ -int scsi_complete_async_scans(void); - /* scsi_devinfo.c */ extern int scsi_get_device_flags(struct scsi_device *sdev, const unsigned char *vendor, @@ -96,6 +93,8 @@ extern int scsi_scan_host_selected(struc unsigned int, unsigned int, int); extern void scsi_forget_host(struct Scsi_Host *); extern void scsi_rescan_device(struct device *); +extern char scsi_scan_type[]; +int scsi_complete_async_scans(void); /* scsi_sysctl.c */ #ifdef CONFIG_SYSCTL diff -upNr a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c --- a/drivers/scsi/scsi_scan.c 2007-08-19 12:21:10.000000000 -0400 +++ b/drivers/scsi/scsi_scan.c 2007-08-19 12:33:06.000000000 -0400 @@ -95,7 +95,7 @@ MODULE_PARM_DESC(max_luns, #define SCSI_SCAN_TYPE_DEFAULT "sync" #endif -static char scsi_scan_type[6] = SCSI_SCAN_TYPE_DEFAULT; +char scsi_scan_type[6] = SCSI_SCAN_TYPE_DEFAULT; module_param_string(scan, scsi_scan_type, sizeof(scsi_scan_type), S_IRUGO); MODULE_PARM_DESC(scan, "sync, async or none"); @@ -908,7 +908,7 @@ static int scsi_add_lun(struct scsi_devi * register it and tell the rest of the kernel * about it. */ - if (!async && scsi_sysfs_add_sdev(sdev) != 0) + if ((async == ASYNC_SCAN_CMPLT) && scsi_sysfs_add_sdev(sdev) != 0) return SCSI_SCAN_NO_RESPONSE; return SCSI_SCAN_LUN_PRESENT; @@ -1472,7 +1472,7 @@ struct scsi_device *__scsi_add_device(st return ERR_PTR(-ENOMEM); mutex_lock(&shost->scan_mutex); - if (!shost->async_scan) + if (shost->async_scan == ASYNC_SCAN_CMPLT) scsi_complete_async_scans(); if (scsi_host_scan_allowed(shost)) @@ -1588,7 +1588,7 @@ void scsi_scan_target(struct device *par return; mutex_lock(&shost->scan_mutex); - if (!shost->async_scan) + if (shost->async_scan == ASYNC_SCAN_CMPLT) scsi_complete_async_scans(); if (scsi_host_scan_allowed(shost)) @@ -1641,7 +1641,7 @@ int scsi_scan_host_selected(struct Scsi_ return -EINVAL; mutex_lock(&shost->scan_mutex); - if (!shost->async_scan) + if (shost->async_scan == ASYNC_SCAN_CMPLT) scsi_complete_async_scans(); if (scsi_host_scan_allowed(shost)) { @@ -1686,7 +1686,7 @@ static struct async_scan_data *scsi_prep if (strncmp(scsi_scan_type, "sync", 4) == 0) return NULL; - if (shost->async_scan) { + if (shost->async_scan == ASYNC_SCAN_RUNNING) { printk("%s called twice for host %d", __FUNCTION__, shost->host_no); dump_stack(); @@ -1703,7 +1703,7 @@ static struct async_scan_data *scsi_prep mutex_lock(&shost->scan_mutex); spin_lock_irqsave(shost->host_lock, flags); - shost->async_scan = 1; + shost->async_scan = ASYNC_SCAN_RUNNING; spin_unlock_irqrestore(shost->host_lock, flags); mutex_unlock(&shost->scan_mutex); @@ -1740,9 +1740,13 @@ static void scsi_finish_async_scan(struc mutex_lock(&shost->scan_mutex); - if (!shost->async_scan) { - printk("%s called twice for host %d", __FUNCTION__, + if (shost->async_scan != ASYNC_SCAN_RUNNING) { + if (shost->async_scan == ASYNC_SCAN_CMPLT) + printk("%s called twice for host %d", __FUNCTION__, shost->host_no); + else /* shost->async_scan == ASYNC_SCAN_PREASYNC */ + printk("%s called prior to async scan %d", + __FUNCTION__, shost->host_no); dump_stack(); return; } @@ -1752,7 +1756,7 @@ static void scsi_finish_async_scan(struc scsi_sysfs_add_devices(shost); spin_lock_irqsave(shost->host_lock, flags); - shost->async_scan = 0; + shost->async_scan = ASYNC_SCAN_CMPLT; spin_unlock_irqrestore(shost->host_lock, flags); mutex_unlock(&shost->scan_mutex); diff -upNr a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h --- a/include/scsi/scsi_host.h 2007-08-17 11:49:56.000000000 -0400 +++ b/include/scsi/scsi_host.h 2007-08-19 12:24:28.000000000 -0400 @@ -603,7 +603,10 @@ struct Scsi_Host { unsigned tmf_in_progress:1; /* Asynchronous scan in progress */ - unsigned async_scan:1; + unsigned async_scan:2; +#define ASYNC_SCAN_CMPLT 0 +#define ASYNC_SCAN_RUNNING 1 +#define ASYNC_SCAN_PREASYNC 2 /* * Optional work queue to be utilized by the transport - To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
