linux/drivers/scsi/device_handler/scsi_dh.c

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/*
* SCSI device handler infrastruture.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
* Copyright IBM Corporation, 2007
* Authors:
* Chandra Seetharaman <sekharan@us.ibm.com>
* Mike Anderson <andmike@linux.vnet.ibm.com>
*/
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-24 08:04:11 +00:00
#include <linux/slab.h>
#include <scsi/scsi_dh.h>
#include "../scsi_priv.h"
struct scsi_dh_devinfo_list {
struct list_head node;
char vendor[9];
char model[17];
struct scsi_device_handler *handler;
};
static DEFINE_SPINLOCK(list_lock);
static LIST_HEAD(scsi_dh_list);
static LIST_HEAD(scsi_dh_dev_list);
static struct scsi_device_handler *get_device_handler(const char *name)
{
struct scsi_device_handler *tmp, *found = NULL;
spin_lock(&list_lock);
list_for_each_entry(tmp, &scsi_dh_list, list) {
if (!strncmp(tmp->name, name, strlen(tmp->name))) {
found = tmp;
break;
}
}
spin_unlock(&list_lock);
return found;
}
static struct scsi_device_handler *
scsi_dh_cache_lookup(struct scsi_device *sdev)
{
struct scsi_dh_devinfo_list *tmp;
struct scsi_device_handler *found_dh = NULL;
spin_lock(&list_lock);
list_for_each_entry(tmp, &scsi_dh_dev_list, node) {
if (!strncmp(sdev->vendor, tmp->vendor, strlen(tmp->vendor)) &&
!strncmp(sdev->model, tmp->model, strlen(tmp->model))) {
found_dh = tmp->handler;
break;
}
}
spin_unlock(&list_lock);
return found_dh;
}
static int scsi_dh_handler_lookup(struct scsi_device_handler *scsi_dh,
struct scsi_device *sdev)
{
int i, found = 0;
for(i = 0; scsi_dh->devlist[i].vendor; i++) {
if (!strncmp(sdev->vendor, scsi_dh->devlist[i].vendor,
strlen(scsi_dh->devlist[i].vendor)) &&
!strncmp(sdev->model, scsi_dh->devlist[i].model,
strlen(scsi_dh->devlist[i].model))) {
found = 1;
break;
}
}
return found;
}
/*
* device_handler_match - Attach a device handler to a device
* @scsi_dh - The device handler to match against or NULL
* @sdev - SCSI device to be tested against @scsi_dh
*
* Tests @sdev against the device handler @scsi_dh or against
* all registered device_handler if @scsi_dh == NULL.
* Returns the found device handler or NULL if not found.
*/
static struct scsi_device_handler *
device_handler_match(struct scsi_device_handler *scsi_dh,
struct scsi_device *sdev)
{
struct scsi_device_handler *found_dh = NULL;
struct scsi_dh_devinfo_list *tmp;
found_dh = scsi_dh_cache_lookup(sdev);
if (found_dh)
return found_dh;
if (scsi_dh) {
if (scsi_dh_handler_lookup(scsi_dh, sdev))
found_dh = scsi_dh;
} else {
struct scsi_device_handler *tmp_dh;
spin_lock(&list_lock);
list_for_each_entry(tmp_dh, &scsi_dh_list, list) {
if (scsi_dh_handler_lookup(tmp_dh, sdev))
found_dh = tmp_dh;
}
spin_unlock(&list_lock);
}
if (found_dh) { /* If device is found, add it to the cache */
tmp = kmalloc(sizeof(*tmp), GFP_KERNEL);
if (tmp) {
strncpy(tmp->vendor, sdev->vendor, 8);
strncpy(tmp->model, sdev->model, 16);
tmp->vendor[8] = '\0';
tmp->model[16] = '\0';
tmp->handler = found_dh;
spin_lock(&list_lock);
list_add(&tmp->node, &scsi_dh_dev_list);
spin_unlock(&list_lock);
} else {
found_dh = NULL;
}
}
return found_dh;
}
/*
* scsi_dh_handler_attach - Attach a device handler to a device
* @sdev - SCSI device the device handler should attach to
* @scsi_dh - The device handler to attach
*/
static int scsi_dh_handler_attach(struct scsi_device *sdev,
struct scsi_device_handler *scsi_dh)
{
int err = 0;
if (sdev->scsi_dh_data) {
if (sdev->scsi_dh_data->scsi_dh != scsi_dh)
err = -EBUSY;
else
kref_get(&sdev->scsi_dh_data->kref);
} else if (scsi_dh->attach) {
err = scsi_dh->attach(sdev);
if (!err) {
kref_init(&sdev->scsi_dh_data->kref);
sdev->scsi_dh_data->sdev = sdev;
}
}
return err;
}
static void __detach_handler (struct kref *kref)
{
struct scsi_dh_data *scsi_dh_data = container_of(kref, struct scsi_dh_data, kref);
scsi_dh_data->scsi_dh->detach(scsi_dh_data->sdev);
}
/*
* scsi_dh_handler_detach - Detach a device handler from a device
* @sdev - SCSI device the device handler should be detached from
* @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 matches @scsi_dh.
*/
static void scsi_dh_handler_detach(struct scsi_device *sdev,
struct scsi_device_handler *scsi_dh)
{
if (!sdev->scsi_dh_data)
return;
if (scsi_dh && scsi_dh != sdev->scsi_dh_data->scsi_dh)
return;
if (!scsi_dh)
scsi_dh = sdev->scsi_dh_data->scsi_dh;
if (scsi_dh && scsi_dh->detach)
kref_put(&sdev->scsi_dh_data->kref, __detach_handler);
}
/*
* 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, NULL, NULL);
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,
unsigned long action, void *data)
{
struct device *dev = data;
struct scsi_device *sdev;
int err = 0;
struct scsi_device_handler *devinfo = NULL;
if (!scsi_is_sdev_device(dev))
return 0;
sdev = to_scsi_device(dev);
if (action == BUS_NOTIFY_ADD_DEVICE) {
err = device_create_file(dev, &scsi_dh_state_attr);
/* don't care about err */
devinfo = device_handler_match(NULL, sdev);
if (devinfo)
err = scsi_dh_handler_attach(sdev, devinfo);
} else if (action == BUS_NOTIFY_DEL_DEVICE) {
device_remove_file(dev, &scsi_dh_state_attr);
scsi_dh_handler_detach(sdev, NULL);
}
return err;
}
/*
* scsi_dh_notifier_add - Callback for scsi_register_device_handler
*/
static int scsi_dh_notifier_add(struct device *dev, void *data)
{
struct scsi_device_handler *scsi_dh = data;
struct scsi_device *sdev;
if (!scsi_is_sdev_device(dev))
return 0;
if (!get_device(dev))
return 0;
sdev = to_scsi_device(dev);
if (device_handler_match(scsi_dh, sdev))
scsi_dh_handler_attach(sdev, scsi_dh);
put_device(dev);
return 0;
}
/*
* scsi_dh_notifier_remove - Callback for scsi_unregister_device_handler
*/
static int scsi_dh_notifier_remove(struct device *dev, void *data)
{
struct scsi_device_handler *scsi_dh = data;
struct scsi_device *sdev;
if (!scsi_is_sdev_device(dev))
return 0;
if (!get_device(dev))
return 0;
sdev = to_scsi_device(dev);
scsi_dh_handler_detach(sdev, scsi_dh);
put_device(dev);
return 0;
}
/*
* scsi_register_device_handler - register a device handler personality
* module.
* @scsi_dh - device handler to be registered.
*
* Returns 0 on success, -EBUSY if handler already registered.
*/
int scsi_register_device_handler(struct scsi_device_handler *scsi_dh)
{
if (get_device_handler(scsi_dh->name))
return -EBUSY;
spin_lock(&list_lock);
list_add(&scsi_dh->list, &scsi_dh_list);
spin_unlock(&list_lock);
bus_for_each_dev(&scsi_bus_type, NULL, scsi_dh, scsi_dh_notifier_add);
printk(KERN_INFO "%s: device handler registered\n", scsi_dh->name);
return SCSI_DH_OK;
}
EXPORT_SYMBOL_GPL(scsi_register_device_handler);
/*
* scsi_unregister_device_handler - register a device handler personality
* module.
* @scsi_dh - device handler to be unregistered.
*
* Returns 0 on success, -ENODEV if handler not registered.
*/
int scsi_unregister_device_handler(struct scsi_device_handler *scsi_dh)
{
struct scsi_dh_devinfo_list *tmp, *pos;
if (!get_device_handler(scsi_dh->name))
return -ENODEV;
bus_for_each_dev(&scsi_bus_type, NULL, scsi_dh,
scsi_dh_notifier_remove);
spin_lock(&list_lock);
list_del(&scsi_dh->list);
list_for_each_entry_safe(pos, tmp, &scsi_dh_dev_list, node) {
if (pos->handler == scsi_dh) {
list_del(&pos->node);
kfree(pos);
}
}
spin_unlock(&list_lock);
printk(KERN_INFO "%s: device handler unregistered\n", scsi_dh->name);
return SCSI_DH_OK;
}
EXPORT_SYMBOL_GPL(scsi_unregister_device_handler);
/*
* scsi_dh_activate - activate the path associated with the scsi_device
* corresponding to the given request queue.
* Returns immediately without waiting for activation to be completed.
* @q - Request queue that is associated with the scsi_device to be
* activated.
* @fn - Function to be called upon completion of the activation.
* Function fn is called with data (below) and the error code.
* Function fn may be called from the same calling context. So,
* do not hold the lock in the caller which may be needed in fn.
* @data - data passed to the function fn upon completion.
*
*/
int scsi_dh_activate(struct request_queue *q, activate_complete fn, void *data)
{
int err = 0;
unsigned long flags;
struct scsi_device *sdev;
struct scsi_device_handler *scsi_dh = NULL;
spin_lock_irqsave(q->queue_lock, flags);
sdev = q->queuedata;
if (sdev && sdev->scsi_dh_data)
scsi_dh = sdev->scsi_dh_data->scsi_dh;
if (!scsi_dh || !get_device(&sdev->sdev_gendev))
err = SCSI_DH_NOSYS;
spin_unlock_irqrestore(q->queue_lock, flags);
if (err)
return err;
if (scsi_dh->activate)
err = scsi_dh->activate(sdev, fn, data);
put_device(&sdev->sdev_gendev);
return err;
}
EXPORT_SYMBOL_GPL(scsi_dh_activate);
/*
* scsi_dh_set_params - set the parameters for the device as per the
* string specified in params.
* @q - Request queue that is associated with the scsi_device for
* which the parameters to be set.
* @params - parameters in the following format
* "no_of_params\0param1\0param2\0param3\0...\0"
* for example, string for 2 parameters with value 10 and 21
* is specified as "2\010\021\0".
*/
int scsi_dh_set_params(struct request_queue *q, const char *params)
{
int err = -SCSI_DH_NOSYS;
unsigned long flags;
struct scsi_device *sdev;
struct scsi_device_handler *scsi_dh = NULL;
spin_lock_irqsave(q->queue_lock, flags);
sdev = q->queuedata;
if (sdev && sdev->scsi_dh_data)
scsi_dh = sdev->scsi_dh_data->scsi_dh;
if (scsi_dh && scsi_dh->set_params && get_device(&sdev->sdev_gendev))
err = 0;
spin_unlock_irqrestore(q->queue_lock, flags);
if (err)
return err;
err = scsi_dh->set_params(sdev, params);
put_device(&sdev->sdev_gendev);
return err;
}
EXPORT_SYMBOL_GPL(scsi_dh_set_params);
/*
* scsi_dh_handler_exist - Return TRUE(1) if a device handler exists for
* the given name. FALSE(0) otherwise.
* @name - name of the device handler.
*/
int scsi_dh_handler_exist(const char *name)
{
return (get_device_handler(name) != NULL);
}
EXPORT_SYMBOL_GPL(scsi_dh_handler_exist);
/*
* scsi_dh_handler_attach - Attach device handler
* @sdev - sdev the handler should be attached to
* @name - name of the handler to attach
*/
int scsi_dh_attach(struct request_queue *q, const char *name)
{
unsigned long flags;
struct scsi_device *sdev;
struct scsi_device_handler *scsi_dh;
int err = 0;
scsi_dh = get_device_handler(name);
if (!scsi_dh)
return -EINVAL;
spin_lock_irqsave(q->queue_lock, flags);
sdev = q->queuedata;
if (!sdev || !get_device(&sdev->sdev_gendev))
err = -ENODEV;
spin_unlock_irqrestore(q->queue_lock, flags);
if (!err) {
err = scsi_dh_handler_attach(sdev, scsi_dh);
put_device(&sdev->sdev_gendev);
}
return err;
}
EXPORT_SYMBOL_GPL(scsi_dh_attach);
/*
* scsi_dh_handler_detach - Detach device handler
* @sdev - sdev the handler should be detached from
*
* This function will detach the device handler only
* if the sdev is not part of the internal list, ie
* if it has been attached manually.
*/
void scsi_dh_detach(struct request_queue *q)
{
unsigned long flags;
struct scsi_device *sdev;
struct scsi_device_handler *scsi_dh = NULL;
spin_lock_irqsave(q->queue_lock, flags);
sdev = q->queuedata;
if (!sdev || !get_device(&sdev->sdev_gendev))
sdev = NULL;
spin_unlock_irqrestore(q->queue_lock, flags);
if (!sdev)
return;
if (sdev->scsi_dh_data) {
scsi_dh = sdev->scsi_dh_data->scsi_dh;
scsi_dh_handler_detach(sdev, scsi_dh);
}
put_device(&sdev->sdev_gendev);
}
EXPORT_SYMBOL_GPL(scsi_dh_detach);
static struct notifier_block scsi_dh_nb = {
.notifier_call = scsi_dh_notifier
};
static int __init scsi_dh_init(void)
{
int r;
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);
}
module_init(scsi_dh_init);
module_exit(scsi_dh_exit);
MODULE_DESCRIPTION("SCSI device handler");
MODULE_AUTHOR("Chandra Seetharaman <sekharan@us.ibm.com>");
MODULE_LICENSE("GPL");