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/**************************************************************************
*
* This kernel module 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., 675 Mass Ave, Cambridge, MA 02139, USA.
*
**************************************************************************/
/*
* This code provides access to unexported mm kernel features. It is necessary
* to use the new DRM memory manager code with kernels that don't support it
* directly.
*
* Authors: Thomas Hellstrom <thomas-at-tungstengraphics-dot-com>
* Linux kernel mm subsystem authors.
* (Most code taken from there).
*/
#include "drmP.h"
#ifdef DRM_IDR_COMPAT_FN
/* only called when idp->lock is held */
static void __free_layer(struct idr *idp, struct idr_layer *p)
{
p->ary[0] = idp->id_free;
idp->id_free = p;
idp->id_free_cnt++;
}
static void free_layer(struct idr *idp, struct idr_layer *p)
{
unsigned long flags;
/*
* Depends on the return element being zeroed.
*/
spin_lock_irqsave(&idp->lock, flags);
__free_layer(idp, p);
spin_unlock_irqrestore(&idp->lock, flags);
}
/**
* idr_for_each - iterate through all stored pointers
* @idp: idr handle
* @fn: function to be called for each pointer
* @data: data passed back to callback function
*
* Iterate over the pointers registered with the given idr. The
* callback function will be called for each pointer currently
* registered, passing the id, the pointer and the data pointer passed
* to this function. It is not safe to modify the idr tree while in
* the callback, so functions such as idr_get_new and idr_remove are
* not allowed.
*
* We check the return of @fn each time. If it returns anything other
* than 0, we break out and return that value.
*
* The caller must serialize idr_find() vs idr_get_new() and idr_remove().
*/
int idr_for_each(struct idr *idp,
int (*fn)(int id, void *p, void *data), void *data)
{
int n, id, max, error = 0;
struct idr_layer *p;
struct idr_layer *pa[MAX_LEVEL];
struct idr_layer **paa = &pa[0];
n = idp->layers * IDR_BITS;
p = idp->top;
max = 1 << n;
id = 0;
while (id < max) {
while (n > 0 && p) {
n -= IDR_BITS;
*paa++ = p;
p = p->ary[(id >> n) & IDR_MASK];
}
if (p) {
error = fn(id, (void *)p, data);
if (error)
break;
}
id += 1 << n;
while (n < fls(id)) {
n += IDR_BITS;
p = *--paa;
}
}
return error;
}
EXPORT_SYMBOL(idr_for_each);
/**
* idr_remove_all - remove all ids from the given idr tree
* @idp: idr handle
*
* idr_destroy() only frees up unused, cached idp_layers, but this
* function will remove all id mappings and leave all idp_layers
* unused.
*
* A typical clean-up sequence for objects stored in an idr tree, will
* use idr_for_each() to free all objects, if necessay, then
* idr_remove_all() to remove all ids, and idr_destroy() to free
* up the cached idr_layers.
*/
void idr_remove_all(struct idr *idp)
{
int n, id, max, error = 0;
struct idr_layer *p;
struct idr_layer *pa[MAX_LEVEL];
struct idr_layer **paa = &pa[0];
n = idp->layers * IDR_BITS;
p = idp->top;
max = 1 << n;
id = 0;
while (id < max && !error) {
while (n > IDR_BITS && p) {
n -= IDR_BITS;
*paa++ = p;
p = p->ary[(id >> n) & IDR_MASK];
}
id += 1 << n;
while (n < fls(id)) {
if (p) {
memset(p, 0, sizeof *p);
free_layer(idp, p);
}
n += IDR_BITS;
p = *--paa;
}
}
idp->top = NULL;
idp->layers = 0;
}
EXPORT_SYMBOL(idr_remove_all);
#endif /* DRM_IDR_COMPAT_FN */
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