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/* A data structure to remember modifications to a memory region
Copyright (C) 1995 Free Software Foundation, Inc.
Written by Miles Bader <miles@gnu.ai.mit.edu>
This file is part of the GNU Hurd.
The GNU Hurd 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, or (at
your option) any later version.
The GNU Hurd 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. */
#include "ext2fs.h"
void pokel_init (struct pokel *pokel, struct pager *pager, void *image)
{
pokel->lock = SPIN_LOCK_INITIALIZER;
pokel->pokes = NULL;
pokel->free_pokes = NULL;
pokel->pager = pager;
pokel->image = image;
}
/* Remember that data here on the disk has been modified. */
void
pokel_add (struct pokel *pokel, void *loc, vm_size_t length)
{
struct poke *pl;
vm_offset_t offset = trunc_page (loc - pokel->image);
vm_offset_t end = round_page (loc + length - pokel->image);
ext2_debug ("adding %p[%ul] (range 0x%x to 0x%x)", loc, length, offset, end);
spin_lock (&pokel->lock);
pl = pokel->pokes;
while (pl != NULL)
{
vm_offset_t p_offs = pl->offset;
vm_size_t p_end = p_offs + pl->length;
if (p_offs == offset && p_end == end)
break;
else if (p_end >= offset && end >= p_offs)
{
pl->offset = offset < p_offs ? offset : p_offs;
pl->length = (end > p_end ? end : p_end) - pl->offset;
ext2_debug ("extended 0x%x[%ul] to 0x%x[%ul]",
p_offs, p_end - p_offs, pl->offset, pl->length);
break;
}
pl = pl->next;
}
if (pl == NULL)
{
pl = pokel->free_pokes;
if (pl == NULL)
{
pl = malloc (sizeof (struct poke));
assert (pl);
}
else
pokel->free_pokes = pl->next;
pl->offset = offset;
pl->length = end - offset;
pl->next = pokel->pokes;
pokel->pokes = pl;
}
spin_unlock (&pokel->lock);
}
/* Move all pending pokes from POKEL into its free list. If SYNC is true,
otherwise do nothing. */
void
_pokel_exec (struct pokel *pokel, int sync, int wait)
{
struct poke *pl, *pokes, *last = NULL;
spin_lock (&pokel->lock);
pokes = pokel->pokes;
pokel->pokes = NULL;
spin_unlock (&pokel->lock);
for (pl = pokes; pl; last = pl, pl = pl->next)
if (sync)
{
ext2_debug ("syncing 0x%x[%ul]", pl->offset, pl->length);
pager_sync_some (pokel->pager, pl->offset, pl->length, wait);
}
if (last)
{
spin_lock (&pokel->lock);
last->next = pokel->free_pokes;
pokel->free_pokes = pokes;
spin_unlock (&pokel->lock);
}
}
/* Sync all the modified pieces of disk */
void
pokel_sync (struct pokel *pokel, int wait)
{
_pokel_exec (pokel, 1, wait);
}
/* Flush (that is, drop on the ground) all pending pokes in POKEL. */
void
pokel_flush (struct pokel *pokel)
{
_pokel_exec (pokel, 0, 0);
}
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