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staging: unisys: visorhba: Convert module from IDR to XArray

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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: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
Link: https://lore.kernel.org/r/20210514081112.19542-1-fmdefrancesco@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Fabio M. De Francesco 2021-05-14 10:11:11 +02:00 committed by Greg Kroah-Hartman
parent e02a3b9458
commit 6d400d7cee
1 changed files with 41 additions and 60 deletions
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101
drivers/staging/unisys/visorhba/visorhba_main.c
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@ -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,
&notifyevent, &notifyresult);
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);