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author | Hannes Reinecke <hare@suse.de> | 2008-07-17 23:52:57 (GMT) |
---|---|---|
committer | James Bottomley <James.Bottomley@HansenPartnership.com> | 2008-07-26 19:14:51 (GMT) |
commit | 4c05ae52fcb0e27a2ee4a16d1f31f8c547fd4886 (patch) | |
tree | 4a577f6a1932923bfbcb8592f4a4f2a7935616dd /drivers/scsi/device_handler | |
parent | 765cbc6dad16b87724803e359d6be792ddf08614 (diff) | |
download | linux-4c05ae52fcb0e27a2ee4a16d1f31f8c547fd4886.tar.xz |
[SCSI] scsi_dh: Add 'dh_state' sysfs attribute
Implement a 'dh_state' sdev attribute for dynamic device handler
manipulation. A read on the attribute will return the name of
the currently attached device handler or 'detached' if no handler
is attached.
The attribute allows the following strings to be written:
- The name of the device handler to be attached if the state is
'detached'.
- 'activate' to trigger path activation if a device handler
is attached.
- 'detach' to detach the currently attached device handler.
Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Diffstat (limited to 'drivers/scsi/device_handler')
-rw-r--r-- | drivers/scsi/device_handler/scsi_dh.c | 103 |
1 files changed, 102 insertions, 1 deletions
diff --git a/drivers/scsi/device_handler/scsi_dh.c b/drivers/scsi/device_handler/scsi_dh.c index 3f79817..e90df9d 100644 --- a/drivers/scsi/device_handler/scsi_dh.c +++ b/drivers/scsi/device_handler/scsi_dh.c @@ -84,7 +84,7 @@ static int scsi_dh_handler_attach(struct scsi_device *sdev, * @scsi_dh - Device handler to be detached * * Detach from a device handler. If a device handler is specified, - * only detach if the currently attached handler is equal to it. + * only detach if the currently attached handler matches @scsi_dh. */ static void scsi_dh_handler_detach(struct scsi_device *sdev, struct scsi_device_handler *scsi_dh) @@ -103,6 +103,98 @@ static void scsi_dh_handler_detach(struct scsi_device *sdev, } /* + * Functions for sysfs attribute 'dh_state' + */ +static ssize_t +store_dh_state(struct device *dev, struct device_attribute *attr, + const char *buf, size_t count) +{ + struct scsi_device *sdev = to_scsi_device(dev); + struct scsi_device_handler *scsi_dh; + int err = -EINVAL; + + if (!sdev->scsi_dh_data) { + /* + * Attach to a device handler + */ + if (!(scsi_dh = get_device_handler(buf))) + return err; + err = scsi_dh_handler_attach(sdev, scsi_dh); + } else { + scsi_dh = sdev->scsi_dh_data->scsi_dh; + if (!strncmp(buf, "detach", 6)) { + /* + * Detach from a device handler + */ + scsi_dh_handler_detach(sdev, scsi_dh); + err = 0; + } else if (!strncmp(buf, "activate", 8)) { + /* + * Activate a device handler + */ + if (scsi_dh->activate) + err = scsi_dh->activate(sdev); + else + err = 0; + } + } + + return err<0?err:count; +} + +static ssize_t +show_dh_state(struct device *dev, struct device_attribute *attr, char *buf) +{ + struct scsi_device *sdev = to_scsi_device(dev); + + if (!sdev->scsi_dh_data) + return snprintf(buf, 20, "detached\n"); + + return snprintf(buf, 20, "%s\n", sdev->scsi_dh_data->scsi_dh->name); +} + +static struct device_attribute scsi_dh_state_attr = + __ATTR(dh_state, S_IRUGO | S_IWUSR, show_dh_state, + store_dh_state); + +/* + * scsi_dh_sysfs_attr_add - Callback for scsi_init_dh + */ +static int scsi_dh_sysfs_attr_add(struct device *dev, void *data) +{ + struct scsi_device *sdev; + int err; + + if (!scsi_is_sdev_device(dev)) + return 0; + + sdev = to_scsi_device(dev); + + err = device_create_file(&sdev->sdev_gendev, + &scsi_dh_state_attr); + + return 0; +} + +/* + * scsi_dh_sysfs_attr_remove - Callback for scsi_exit_dh + */ +static int scsi_dh_sysfs_attr_remove(struct device *dev, void *data) +{ + struct scsi_device *sdev; + + if (!scsi_is_sdev_device(dev)) + return 0; + + sdev = to_scsi_device(dev); + + device_remove_file(&sdev->sdev_gendev, + &scsi_dh_state_attr); + + return 0; +} + +/* * scsi_dh_notifier - notifier chain callback */ static int scsi_dh_notifier(struct notifier_block *nb, @@ -132,7 +224,10 @@ static int scsi_dh_notifier(struct notifier_block *nb, if (action == BUS_NOTIFY_ADD_DEVICE) { err = scsi_dh_handler_attach(sdev, devinfo); + if (!err) + err = device_create_file(dev, &scsi_dh_state_attr); } else if (action == BUS_NOTIFY_DEL_DEVICE) { + device_remove_file(dev, &scsi_dh_state_attr); scsi_dh_handler_detach(sdev, NULL); } out: @@ -284,11 +379,17 @@ static int __init scsi_dh_init(void) r = bus_register_notifier(&scsi_bus_type, &scsi_dh_nb); + if (!r) + bus_for_each_dev(&scsi_bus_type, NULL, NULL, + scsi_dh_sysfs_attr_add); + return r; } static void __exit scsi_dh_exit(void) { + bus_for_each_dev(&scsi_bus_type, NULL, NULL, + scsi_dh_sysfs_attr_remove); bus_unregister_notifier(&scsi_bus_type, &scsi_dh_nb); } |