Commit 6d400d7c authored by Fabio M. De Francesco's avatar Fabio M. De Francesco Committed by Greg Kroah-Hartman
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staging: unisys: visorhba: Convert module from IDR to XArray 



Converted visorhba from IDR to XArray. The abstract data type XArray is
more memory-efficient, parallelizable, and cache friendly. It takes
advantage of RCU to perform lookups without locking. Furthermore, IDR is
deprecated because XArray has a better (cleaner and more consistent)
API.

Reviewed-by: default avatarDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: default avatarFabio M. De Francesco <fmdefrancesco@gmail.com>
Link: https://lore.kernel.org/r/20210514081112.19542-1-fmdefrancesco@gmail.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent e02a3b94

drivers/staging/unisys/visorhba/visorhba_main.c

+41 −60
Original line number Diff line number Diff line
@@ -6,10 +6,10 @@ 


#include <linux/debugfs.h>

#include <linux/kthread.h>

#include <linux/idr.h>

#include <linux/module.h>

#include <linux/seq_file.h>

#include <linux/visorbus.h>

#include <linux/xarray.h>

#include <scsi/scsi.h>

#include <scsi/scsi_host.h>

#include <scsi/scsi_cmnd.h>
@@ -82,8 +82,7 @@ struct visorhba_devdata { 
	 * allows us to pass int handles back-and-forth between us and

	 * iovm, instead of raw pointers

	 */

	struct idr idr;



	struct xarray xa;

	struct dentry *debugfs_dir;

	struct dentry *debugfs_info;

};
@@ -182,71 +181,48 @@ static struct uiscmdrsp *get_scsipending_cmdrsp(struct visorhba_devdata *ddata, 
	return NULL;

}



/*

 * simple_idr_get - Associate a provided pointer with an int value

 *		    1 <= value <= INT_MAX, and return this int value;

 *		    the pointer value can be obtained later by passing

 *		    this int value to idr_find()

 * @idrtable: The data object maintaining the pointer<-->int mappings

 * @p:	      The pointer value to be remembered

 * @lock:     A spinlock used when exclusive access to idrtable is needed

 *

 * Return: The id number mapped to pointer 'p', 0 on failure

 */

static unsigned int simple_idr_get(struct idr *idrtable, void *p,

				   spinlock_t *lock)

{

	int id;

	unsigned long flags;



	idr_preload(GFP_KERNEL);

	spin_lock_irqsave(lock, flags);

	id = idr_alloc(idrtable, p, 1, INT_MAX, GFP_NOWAIT);

	spin_unlock_irqrestore(lock, flags);

	idr_preload_end();

	/* failure */

	if (id < 0)

		return 0;

	/* idr_alloc() guarantees > 0 */

	return (unsigned int)(id);

}



/*

 * setup_scsitaskmgmt_handles - Stash the necessary handles so that the

 *				completion processing logic for a taskmgmt

 *				cmd will be able to find who to wake up

 *				and where to stash the result

 * @idrtable: The data object maintaining the pointer<-->int mappings

 * @lock:     A spinlock used when exclusive access to idrtable is needed

 * @xa:       The data object maintaining the pointer<-->int mappings

 * @cmdrsp:   Response from the IOVM

 * @event:    The event handle to associate with an id

 * @result:   The location to place the result of the event handle into

 */

static void setup_scsitaskmgmt_handles(struct idr *idrtable, spinlock_t *lock,

				       struct uiscmdrsp *cmdrsp,

static int setup_scsitaskmgmt_handles(struct xarray *xa, struct uiscmdrsp *cmdrsp,

				       wait_queue_head_t *event, int *result)

{

	/* specify the event that has to be triggered when this */

	/* cmd is complete */

	cmdrsp->scsitaskmgmt.notify_handle =

		simple_idr_get(idrtable, event, lock);

	cmdrsp->scsitaskmgmt.notifyresult_handle =

		simple_idr_get(idrtable, result, lock);

	int ret;

	u32 id;



	/* specify the event that has to be triggered when this cmd is complete */

	ret = xa_alloc_irq(xa, &id, event, xa_limit_32b, GFP_KERNEL);

	if (ret)

		return ret;

	cmdrsp->scsitaskmgmt.notify_handle = id;

	ret = xa_alloc_irq(xa, &id, result, xa_limit_32b, GFP_KERNEL);

	if (ret) {

		xa_erase_irq(xa, cmdrsp->scsitaskmgmt.notify_handle);

		return ret;

	}

	cmdrsp->scsitaskmgmt.notifyresult_handle = id;



	return 0;

}



/*

 * cleanup_scsitaskmgmt_handles - Forget handles created by

 *				  setup_scsitaskmgmt_handles()

 * @idrtable: The data object maintaining the pointer<-->int mappings

 * @xa: The data object maintaining the pointer<-->int mappings

 * @cmdrsp:   Response from the IOVM

 */

static void cleanup_scsitaskmgmt_handles(struct idr *idrtable,

static void cleanup_scsitaskmgmt_handles(struct xarray *xa,

					 struct uiscmdrsp *cmdrsp)

{

	if (cmdrsp->scsitaskmgmt.notify_handle)

		idr_remove(idrtable, cmdrsp->scsitaskmgmt.notify_handle);

	if (cmdrsp->scsitaskmgmt.notifyresult_handle)

		idr_remove(idrtable, cmdrsp->scsitaskmgmt.notifyresult_handle);

	xa_erase_irq(xa, cmdrsp->scsitaskmgmt.notify_handle);

	xa_erase_irq(xa, cmdrsp->scsitaskmgmt.notifyresult_handle);

}



/*
@@ -269,6 +245,7 @@ static int forward_taskmgmt_command(enum task_mgmt_types tasktype, 
	int notifyresult = 0xffff;

	wait_queue_head_t notifyevent;

	int scsicmd_id;

	int ret;



	if (devdata->serverdown || devdata->serverchangingstate)

		return FAILED;
@@ -284,8 +261,14 @@ static int forward_taskmgmt_command(enum task_mgmt_types tasktype, 


	/* issue TASK_MGMT_ABORT_TASK */

	cmdrsp->cmdtype = CMD_SCSITASKMGMT_TYPE;

	setup_scsitaskmgmt_handles(&devdata->idr, &devdata->privlock, cmdrsp,



	ret = setup_scsitaskmgmt_handles(&devdata->xa, cmdrsp,

					 &notifyevent, &notifyresult);

	if (ret) {

		dev_dbg(&scsidev->sdev_gendev,

		        "visorhba: setup_scsitaskmgmt_handles returned %d\n", ret);

		return FAILED;

	}



	/* save destination */

	cmdrsp->scsitaskmgmt.tasktype = tasktype;
@@ -311,14 +294,14 @@ static int forward_taskmgmt_command(enum task_mgmt_types tasktype, 
	dev_dbg(&scsidev->sdev_gendev,

		"visorhba: taskmgmt type=%d success; result=0x%x\n",

		 tasktype, notifyresult);

	cleanup_scsitaskmgmt_handles(&devdata->idr, cmdrsp);

	cleanup_scsitaskmgmt_handles(&devdata->xa, cmdrsp);

	return SUCCESS;



err_del_scsipending_ent:

	dev_dbg(&scsidev->sdev_gendev,

		"visorhba: taskmgmt type=%d not executed\n", tasktype);

	del_scsipending_ent(devdata, scsicmd_id);

	cleanup_scsitaskmgmt_handles(&devdata->idr, cmdrsp);

	cleanup_scsitaskmgmt_handles(&devdata->xa, cmdrsp);

	return FAILED;

}
@@ -654,13 +637,13 @@ DEFINE_SHOW_ATTRIBUTE(info_debugfs); 
 * Service Partition returned the result of the task management

 * command. Wake up anyone waiting for it.

 */

static void complete_taskmgmt_command(struct idr *idrtable,

static void complete_taskmgmt_command(struct xarray *xa,

				      struct uiscmdrsp *cmdrsp, int result)

{

	wait_queue_head_t *wq =

		idr_find(idrtable, cmdrsp->scsitaskmgmt.notify_handle);

		xa_load(xa, cmdrsp->scsitaskmgmt.notify_handle);

	int *scsi_result_ptr =

		idr_find(idrtable, cmdrsp->scsitaskmgmt.notifyresult_handle);

		xa_load(xa, cmdrsp->scsitaskmgmt.notifyresult_handle);

	if (unlikely(!(wq && scsi_result_ptr))) {

		pr_err("visorhba: no completion context; cmd will time out\n");

		return;
@@ -708,7 +691,7 @@ static void visorhba_serverdown_complete(struct visorhba_devdata *devdata) 
			break;

		case CMD_SCSITASKMGMT_TYPE:

			cmdrsp = pendingdel->sent;

			complete_taskmgmt_command(&devdata->idr, cmdrsp,

			complete_taskmgmt_command(&devdata->xa, cmdrsp,

						  TASK_MGMT_FAILED);

			break;

		default:
@@ -905,7 +888,7 @@ static void drain_queue(struct uiscmdrsp *cmdrsp, 
			if (!del_scsipending_ent(devdata,

						 cmdrsp->scsitaskmgmt.handle))

				break;

			complete_taskmgmt_command(&devdata->idr, cmdrsp,

			complete_taskmgmt_command(&devdata->xa, cmdrsp,

						  cmdrsp->scsitaskmgmt.result);

		} else if (cmdrsp->cmdtype == CMD_NOTIFYGUEST_TYPE)

			dev_err_once(&devdata->dev->device,
@@ -1053,7 +1036,7 @@ static int visorhba_probe(struct visor_device *dev) 
	if (err)

		goto err_debugfs_info;



	idr_init(&devdata->idr);

	xa_init(&devdata->xa);



	devdata->cmdrsp = kmalloc(sizeof(*devdata->cmdrsp), GFP_ATOMIC);

	visorbus_enable_channel_interrupts(dev);
@@ -1096,8 +1079,6 @@ static void visorhba_remove(struct visor_device *dev) 
	scsi_remove_host(scsihost);

	scsi_host_put(scsihost);



	idr_destroy(&devdata->idr);



	dev_set_drvdata(&dev->device, NULL);

	debugfs_remove(devdata->debugfs_info);

	debugfs_remove_recursive(devdata->debugfs_dir);