linux-stable/drivers/net/ethernet/mellanox/mlx4/alloc.c
Haggai Abramovsky 73898db043 net/mlx4: Avoid wrong virtual mappings
The dma_alloc_coherent() function returns a virtual address which can
be used for coherent access to the underlying memory.  On some
architectures, like arm64, undefined behavior results if this memory is
also accessed via virtual mappings that are not coherent.  Because of
their undefined nature, operations like virt_to_page() return garbage
when passed virtual addresses obtained from dma_alloc_coherent().  Any
subsequent mappings via vmap() of the garbage page values are unusable
and result in bad things like bus errors (synchronous aborts in ARM64
speak).

The mlx4 driver contains code that does the equivalent of:
vmap(virt_to_page(dma_alloc_coherent)), this results in an OOPs when the
device is opened.

Prevent Ethernet driver to run this problematic code by forcing it to
allocate contiguous memory. As for the Infiniband driver, at first we
are trying to allocate contiguous memory, but in case of failure roll
back to work with fragmented memory.

Signed-off-by: Haggai Abramovsky <hagaya@mellanox.com>
Signed-off-by: Yishai Hadas <yishaih@mellanox.com>
Reported-by: David Daney <david.daney@cavium.com>
Tested-by: Sinan Kaya <okaya@codeaurora.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-05-05 23:23:05 -04:00

822 lines
18 KiB
C

/*
* Copyright (c) 2006, 2007 Cisco Systems, Inc. All rights reserved.
* Copyright (c) 2007, 2008 Mellanox Technologies. All rights reserved.
*
* This software is available to you under a choice of one of two
* licenses. You may choose to be licensed under the terms of the GNU
* General Public License (GPL) Version 2, available from the file
* COPYING in the main directory of this source tree, or the
* OpenIB.org BSD license below:
*
* Redistribution and use in source and binary forms, with or
* without modification, are permitted provided that the following
* conditions are met:
*
* - Redistributions of source code must retain the above
* copyright notice, this list of conditions and the following
* disclaimer.
*
* - Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials
* provided with the distribution.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/export.h>
#include <linux/bitmap.h>
#include <linux/dma-mapping.h>
#include <linux/vmalloc.h>
#include "mlx4.h"
u32 mlx4_bitmap_alloc(struct mlx4_bitmap *bitmap)
{
u32 obj;
spin_lock(&bitmap->lock);
obj = find_next_zero_bit(bitmap->table, bitmap->max, bitmap->last);
if (obj >= bitmap->max) {
bitmap->top = (bitmap->top + bitmap->max + bitmap->reserved_top)
& bitmap->mask;
obj = find_first_zero_bit(bitmap->table, bitmap->max);
}
if (obj < bitmap->max) {
set_bit(obj, bitmap->table);
bitmap->last = (obj + 1);
if (bitmap->last == bitmap->max)
bitmap->last = 0;
obj |= bitmap->top;
} else
obj = -1;
if (obj != -1)
--bitmap->avail;
spin_unlock(&bitmap->lock);
return obj;
}
void mlx4_bitmap_free(struct mlx4_bitmap *bitmap, u32 obj, int use_rr)
{
mlx4_bitmap_free_range(bitmap, obj, 1, use_rr);
}
static unsigned long find_aligned_range(unsigned long *bitmap,
u32 start, u32 nbits,
int len, int align, u32 skip_mask)
{
unsigned long end, i;
again:
start = ALIGN(start, align);
while ((start < nbits) && (test_bit(start, bitmap) ||
(start & skip_mask)))
start += align;
if (start >= nbits)
return -1;
end = start+len;
if (end > nbits)
return -1;
for (i = start + 1; i < end; i++) {
if (test_bit(i, bitmap) || ((u32)i & skip_mask)) {
start = i + 1;
goto again;
}
}
return start;
}
u32 mlx4_bitmap_alloc_range(struct mlx4_bitmap *bitmap, int cnt,
int align, u32 skip_mask)
{
u32 obj;
if (likely(cnt == 1 && align == 1 && !skip_mask))
return mlx4_bitmap_alloc(bitmap);
spin_lock(&bitmap->lock);
obj = find_aligned_range(bitmap->table, bitmap->last,
bitmap->max, cnt, align, skip_mask);
if (obj >= bitmap->max) {
bitmap->top = (bitmap->top + bitmap->max + bitmap->reserved_top)
& bitmap->mask;
obj = find_aligned_range(bitmap->table, 0, bitmap->max,
cnt, align, skip_mask);
}
if (obj < bitmap->max) {
bitmap_set(bitmap->table, obj, cnt);
if (obj == bitmap->last) {
bitmap->last = (obj + cnt);
if (bitmap->last >= bitmap->max)
bitmap->last = 0;
}
obj |= bitmap->top;
} else
obj = -1;
if (obj != -1)
bitmap->avail -= cnt;
spin_unlock(&bitmap->lock);
return obj;
}
u32 mlx4_bitmap_avail(struct mlx4_bitmap *bitmap)
{
return bitmap->avail;
}
static u32 mlx4_bitmap_masked_value(struct mlx4_bitmap *bitmap, u32 obj)
{
return obj & (bitmap->max + bitmap->reserved_top - 1);
}
void mlx4_bitmap_free_range(struct mlx4_bitmap *bitmap, u32 obj, int cnt,
int use_rr)
{
obj &= bitmap->max + bitmap->reserved_top - 1;
spin_lock(&bitmap->lock);
if (!use_rr) {
bitmap->last = min(bitmap->last, obj);
bitmap->top = (bitmap->top + bitmap->max + bitmap->reserved_top)
& bitmap->mask;
}
bitmap_clear(bitmap->table, obj, cnt);
bitmap->avail += cnt;
spin_unlock(&bitmap->lock);
}
int mlx4_bitmap_init(struct mlx4_bitmap *bitmap, u32 num, u32 mask,
u32 reserved_bot, u32 reserved_top)
{
/* num must be a power of 2 */
if (num != roundup_pow_of_two(num))
return -EINVAL;
bitmap->last = 0;
bitmap->top = 0;
bitmap->max = num - reserved_top;
bitmap->mask = mask;
bitmap->reserved_top = reserved_top;
bitmap->avail = num - reserved_top - reserved_bot;
bitmap->effective_len = bitmap->avail;
spin_lock_init(&bitmap->lock);
bitmap->table = kzalloc(BITS_TO_LONGS(bitmap->max) *
sizeof (long), GFP_KERNEL);
if (!bitmap->table)
return -ENOMEM;
bitmap_set(bitmap->table, 0, reserved_bot);
return 0;
}
void mlx4_bitmap_cleanup(struct mlx4_bitmap *bitmap)
{
kfree(bitmap->table);
}
struct mlx4_zone_allocator {
struct list_head entries;
struct list_head prios;
u32 last_uid;
u32 mask;
/* protect the zone_allocator from concurrent accesses */
spinlock_t lock;
enum mlx4_zone_alloc_flags flags;
};
struct mlx4_zone_entry {
struct list_head list;
struct list_head prio_list;
u32 uid;
struct mlx4_zone_allocator *allocator;
struct mlx4_bitmap *bitmap;
int use_rr;
int priority;
int offset;
enum mlx4_zone_flags flags;
};
struct mlx4_zone_allocator *mlx4_zone_allocator_create(enum mlx4_zone_alloc_flags flags)
{
struct mlx4_zone_allocator *zones = kmalloc(sizeof(*zones), GFP_KERNEL);
if (NULL == zones)
return NULL;
INIT_LIST_HEAD(&zones->entries);
INIT_LIST_HEAD(&zones->prios);
spin_lock_init(&zones->lock);
zones->last_uid = 0;
zones->mask = 0;
zones->flags = flags;
return zones;
}
int mlx4_zone_add_one(struct mlx4_zone_allocator *zone_alloc,
struct mlx4_bitmap *bitmap,
u32 flags,
int priority,
int offset,
u32 *puid)
{
u32 mask = mlx4_bitmap_masked_value(bitmap, (u32)-1);
struct mlx4_zone_entry *it;
struct mlx4_zone_entry *zone = kmalloc(sizeof(*zone), GFP_KERNEL);
if (NULL == zone)
return -ENOMEM;
zone->flags = flags;
zone->bitmap = bitmap;
zone->use_rr = (flags & MLX4_ZONE_USE_RR) ? MLX4_USE_RR : 0;
zone->priority = priority;
zone->offset = offset;
spin_lock(&zone_alloc->lock);
zone->uid = zone_alloc->last_uid++;
zone->allocator = zone_alloc;
if (zone_alloc->mask < mask)
zone_alloc->mask = mask;
list_for_each_entry(it, &zone_alloc->prios, prio_list)
if (it->priority >= priority)
break;
if (&it->prio_list == &zone_alloc->prios || it->priority > priority)
list_add_tail(&zone->prio_list, &it->prio_list);
list_add_tail(&zone->list, &it->list);
spin_unlock(&zone_alloc->lock);
*puid = zone->uid;
return 0;
}
/* Should be called under a lock */
static int __mlx4_zone_remove_one_entry(struct mlx4_zone_entry *entry)
{
struct mlx4_zone_allocator *zone_alloc = entry->allocator;
if (!list_empty(&entry->prio_list)) {
/* Check if we need to add an alternative node to the prio list */
if (!list_is_last(&entry->list, &zone_alloc->entries)) {
struct mlx4_zone_entry *next = list_first_entry(&entry->list,
typeof(*next),
list);
if (next->priority == entry->priority)
list_add_tail(&next->prio_list, &entry->prio_list);
}
list_del(&entry->prio_list);
}
list_del(&entry->list);
if (zone_alloc->flags & MLX4_ZONE_ALLOC_FLAGS_NO_OVERLAP) {
u32 mask = 0;
struct mlx4_zone_entry *it;
list_for_each_entry(it, &zone_alloc->prios, prio_list) {
u32 cur_mask = mlx4_bitmap_masked_value(it->bitmap, (u32)-1);
if (mask < cur_mask)
mask = cur_mask;
}
zone_alloc->mask = mask;
}
return 0;
}
void mlx4_zone_allocator_destroy(struct mlx4_zone_allocator *zone_alloc)
{
struct mlx4_zone_entry *zone, *tmp;
spin_lock(&zone_alloc->lock);
list_for_each_entry_safe(zone, tmp, &zone_alloc->entries, list) {
list_del(&zone->list);
list_del(&zone->prio_list);
kfree(zone);
}
spin_unlock(&zone_alloc->lock);
kfree(zone_alloc);
}
/* Should be called under a lock */
static u32 __mlx4_alloc_from_zone(struct mlx4_zone_entry *zone, int count,
int align, u32 skip_mask, u32 *puid)
{
u32 uid;
u32 res;
struct mlx4_zone_allocator *zone_alloc = zone->allocator;
struct mlx4_zone_entry *curr_node;
res = mlx4_bitmap_alloc_range(zone->bitmap, count,
align, skip_mask);
if (res != (u32)-1) {
res += zone->offset;
uid = zone->uid;
goto out;
}
list_for_each_entry(curr_node, &zone_alloc->prios, prio_list) {
if (unlikely(curr_node->priority == zone->priority))
break;
}
if (zone->flags & MLX4_ZONE_ALLOW_ALLOC_FROM_LOWER_PRIO) {
struct mlx4_zone_entry *it = curr_node;
list_for_each_entry_continue_reverse(it, &zone_alloc->entries, list) {
res = mlx4_bitmap_alloc_range(it->bitmap, count,
align, skip_mask);
if (res != (u32)-1) {
res += it->offset;
uid = it->uid;
goto out;
}
}
}
if (zone->flags & MLX4_ZONE_ALLOW_ALLOC_FROM_EQ_PRIO) {
struct mlx4_zone_entry *it = curr_node;
list_for_each_entry_from(it, &zone_alloc->entries, list) {
if (unlikely(it == zone))
continue;
if (unlikely(it->priority != curr_node->priority))
break;
res = mlx4_bitmap_alloc_range(it->bitmap, count,
align, skip_mask);
if (res != (u32)-1) {
res += it->offset;
uid = it->uid;
goto out;
}
}
}
if (zone->flags & MLX4_ZONE_FALLBACK_TO_HIGHER_PRIO) {
if (list_is_last(&curr_node->prio_list, &zone_alloc->prios))
goto out;
curr_node = list_first_entry(&curr_node->prio_list,
typeof(*curr_node),
prio_list);
list_for_each_entry_from(curr_node, &zone_alloc->entries, list) {
res = mlx4_bitmap_alloc_range(curr_node->bitmap, count,
align, skip_mask);
if (res != (u32)-1) {
res += curr_node->offset;
uid = curr_node->uid;
goto out;
}
}
}
out:
if (NULL != puid && res != (u32)-1)
*puid = uid;
return res;
}
/* Should be called under a lock */
static void __mlx4_free_from_zone(struct mlx4_zone_entry *zone, u32 obj,
u32 count)
{
mlx4_bitmap_free_range(zone->bitmap, obj - zone->offset, count, zone->use_rr);
}
/* Should be called under a lock */
static struct mlx4_zone_entry *__mlx4_find_zone_by_uid(
struct mlx4_zone_allocator *zones, u32 uid)
{
struct mlx4_zone_entry *zone;
list_for_each_entry(zone, &zones->entries, list) {
if (zone->uid == uid)
return zone;
}
return NULL;
}
struct mlx4_bitmap *mlx4_zone_get_bitmap(struct mlx4_zone_allocator *zones, u32 uid)
{
struct mlx4_zone_entry *zone;
struct mlx4_bitmap *bitmap;
spin_lock(&zones->lock);
zone = __mlx4_find_zone_by_uid(zones, uid);
bitmap = zone == NULL ? NULL : zone->bitmap;
spin_unlock(&zones->lock);
return bitmap;
}
int mlx4_zone_remove_one(struct mlx4_zone_allocator *zones, u32 uid)
{
struct mlx4_zone_entry *zone;
int res;
spin_lock(&zones->lock);
zone = __mlx4_find_zone_by_uid(zones, uid);
if (NULL == zone) {
res = -1;
goto out;
}
res = __mlx4_zone_remove_one_entry(zone);
out:
spin_unlock(&zones->lock);
kfree(zone);
return res;
}
/* Should be called under a lock */
static struct mlx4_zone_entry *__mlx4_find_zone_by_uid_unique(
struct mlx4_zone_allocator *zones, u32 obj)
{
struct mlx4_zone_entry *zone, *zone_candidate = NULL;
u32 dist = (u32)-1;
/* Search for the smallest zone that this obj could be
* allocated from. This is done in order to handle
* situations when small bitmaps are allocated from bigger
* bitmaps (and the allocated space is marked as reserved in
* the bigger bitmap.
*/
list_for_each_entry(zone, &zones->entries, list) {
if (obj >= zone->offset) {
u32 mobj = (obj - zone->offset) & zones->mask;
if (mobj < zone->bitmap->max) {
u32 curr_dist = zone->bitmap->effective_len;
if (curr_dist < dist) {
dist = curr_dist;
zone_candidate = zone;
}
}
}
}
return zone_candidate;
}
u32 mlx4_zone_alloc_entries(struct mlx4_zone_allocator *zones, u32 uid, int count,
int align, u32 skip_mask, u32 *puid)
{
struct mlx4_zone_entry *zone;
int res = -1;
spin_lock(&zones->lock);
zone = __mlx4_find_zone_by_uid(zones, uid);
if (NULL == zone)
goto out;
res = __mlx4_alloc_from_zone(zone, count, align, skip_mask, puid);
out:
spin_unlock(&zones->lock);
return res;
}
u32 mlx4_zone_free_entries(struct mlx4_zone_allocator *zones, u32 uid, u32 obj, u32 count)
{
struct mlx4_zone_entry *zone;
int res = 0;
spin_lock(&zones->lock);
zone = __mlx4_find_zone_by_uid(zones, uid);
if (NULL == zone) {
res = -1;
goto out;
}
__mlx4_free_from_zone(zone, obj, count);
out:
spin_unlock(&zones->lock);
return res;
}
u32 mlx4_zone_free_entries_unique(struct mlx4_zone_allocator *zones, u32 obj, u32 count)
{
struct mlx4_zone_entry *zone;
int res;
if (!(zones->flags & MLX4_ZONE_ALLOC_FLAGS_NO_OVERLAP))
return -EFAULT;
spin_lock(&zones->lock);
zone = __mlx4_find_zone_by_uid_unique(zones, obj);
if (NULL == zone) {
res = -1;
goto out;
}
__mlx4_free_from_zone(zone, obj, count);
res = 0;
out:
spin_unlock(&zones->lock);
return res;
}
static int mlx4_buf_direct_alloc(struct mlx4_dev *dev, int size,
struct mlx4_buf *buf, gfp_t gfp)
{
dma_addr_t t;
buf->nbufs = 1;
buf->npages = 1;
buf->page_shift = get_order(size) + PAGE_SHIFT;
buf->direct.buf =
dma_zalloc_coherent(&dev->persist->pdev->dev,
size, &t, gfp);
if (!buf->direct.buf)
return -ENOMEM;
buf->direct.map = t;
while (t & ((1 << buf->page_shift) - 1)) {
--buf->page_shift;
buf->npages *= 2;
}
return 0;
}
/* Handling for queue buffers -- we allocate a bunch of memory and
* register it in a memory region at HCA virtual address 0. If the
* requested size is > max_direct, we split the allocation into
* multiple pages, so we don't require too much contiguous memory.
*/
int mlx4_buf_alloc(struct mlx4_dev *dev, int size, int max_direct,
struct mlx4_buf *buf, gfp_t gfp)
{
if (size <= max_direct) {
return mlx4_buf_direct_alloc(dev, size, buf, gfp);
} else {
dma_addr_t t;
int i;
buf->direct.buf = NULL;
buf->nbufs = (size + PAGE_SIZE - 1) / PAGE_SIZE;
buf->npages = buf->nbufs;
buf->page_shift = PAGE_SHIFT;
buf->page_list = kcalloc(buf->nbufs, sizeof(*buf->page_list),
gfp);
if (!buf->page_list)
return -ENOMEM;
for (i = 0; i < buf->nbufs; ++i) {
buf->page_list[i].buf =
dma_zalloc_coherent(&dev->persist->pdev->dev,
PAGE_SIZE, &t, gfp);
if (!buf->page_list[i].buf)
goto err_free;
buf->page_list[i].map = t;
}
}
return 0;
err_free:
mlx4_buf_free(dev, size, buf);
return -ENOMEM;
}
EXPORT_SYMBOL_GPL(mlx4_buf_alloc);
void mlx4_buf_free(struct mlx4_dev *dev, int size, struct mlx4_buf *buf)
{
if (buf->nbufs == 1) {
dma_free_coherent(&dev->persist->pdev->dev, size,
buf->direct.buf, buf->direct.map);
} else {
int i;
for (i = 0; i < buf->nbufs; ++i)
if (buf->page_list[i].buf)
dma_free_coherent(&dev->persist->pdev->dev,
PAGE_SIZE,
buf->page_list[i].buf,
buf->page_list[i].map);
kfree(buf->page_list);
}
}
EXPORT_SYMBOL_GPL(mlx4_buf_free);
static struct mlx4_db_pgdir *mlx4_alloc_db_pgdir(struct device *dma_device,
gfp_t gfp)
{
struct mlx4_db_pgdir *pgdir;
pgdir = kzalloc(sizeof *pgdir, gfp);
if (!pgdir)
return NULL;
bitmap_fill(pgdir->order1, MLX4_DB_PER_PAGE / 2);
pgdir->bits[0] = pgdir->order0;
pgdir->bits[1] = pgdir->order1;
pgdir->db_page = dma_alloc_coherent(dma_device, PAGE_SIZE,
&pgdir->db_dma, gfp);
if (!pgdir->db_page) {
kfree(pgdir);
return NULL;
}
return pgdir;
}
static int mlx4_alloc_db_from_pgdir(struct mlx4_db_pgdir *pgdir,
struct mlx4_db *db, int order)
{
int o;
int i;
for (o = order; o <= 1; ++o) {
i = find_first_bit(pgdir->bits[o], MLX4_DB_PER_PAGE >> o);
if (i < MLX4_DB_PER_PAGE >> o)
goto found;
}
return -ENOMEM;
found:
clear_bit(i, pgdir->bits[o]);
i <<= o;
if (o > order)
set_bit(i ^ 1, pgdir->bits[order]);
db->u.pgdir = pgdir;
db->index = i;
db->db = pgdir->db_page + db->index;
db->dma = pgdir->db_dma + db->index * 4;
db->order = order;
return 0;
}
int mlx4_db_alloc(struct mlx4_dev *dev, struct mlx4_db *db, int order, gfp_t gfp)
{
struct mlx4_priv *priv = mlx4_priv(dev);
struct mlx4_db_pgdir *pgdir;
int ret = 0;
mutex_lock(&priv->pgdir_mutex);
list_for_each_entry(pgdir, &priv->pgdir_list, list)
if (!mlx4_alloc_db_from_pgdir(pgdir, db, order))
goto out;
pgdir = mlx4_alloc_db_pgdir(&dev->persist->pdev->dev, gfp);
if (!pgdir) {
ret = -ENOMEM;
goto out;
}
list_add(&pgdir->list, &priv->pgdir_list);
/* This should never fail -- we just allocated an empty page: */
WARN_ON(mlx4_alloc_db_from_pgdir(pgdir, db, order));
out:
mutex_unlock(&priv->pgdir_mutex);
return ret;
}
EXPORT_SYMBOL_GPL(mlx4_db_alloc);
void mlx4_db_free(struct mlx4_dev *dev, struct mlx4_db *db)
{
struct mlx4_priv *priv = mlx4_priv(dev);
int o;
int i;
mutex_lock(&priv->pgdir_mutex);
o = db->order;
i = db->index;
if (db->order == 0 && test_bit(i ^ 1, db->u.pgdir->order0)) {
clear_bit(i ^ 1, db->u.pgdir->order0);
++o;
}
i >>= o;
set_bit(i, db->u.pgdir->bits[o]);
if (bitmap_full(db->u.pgdir->order1, MLX4_DB_PER_PAGE / 2)) {
dma_free_coherent(&dev->persist->pdev->dev, PAGE_SIZE,
db->u.pgdir->db_page, db->u.pgdir->db_dma);
list_del(&db->u.pgdir->list);
kfree(db->u.pgdir);
}
mutex_unlock(&priv->pgdir_mutex);
}
EXPORT_SYMBOL_GPL(mlx4_db_free);
int mlx4_alloc_hwq_res(struct mlx4_dev *dev, struct mlx4_hwq_resources *wqres,
int size)
{
int err;
err = mlx4_db_alloc(dev, &wqres->db, 1, GFP_KERNEL);
if (err)
return err;
*wqres->db.db = 0;
err = mlx4_buf_direct_alloc(dev, size, &wqres->buf, GFP_KERNEL);
if (err)
goto err_db;
err = mlx4_mtt_init(dev, wqres->buf.npages, wqres->buf.page_shift,
&wqres->mtt);
if (err)
goto err_buf;
err = mlx4_buf_write_mtt(dev, &wqres->mtt, &wqres->buf, GFP_KERNEL);
if (err)
goto err_mtt;
return 0;
err_mtt:
mlx4_mtt_cleanup(dev, &wqres->mtt);
err_buf:
mlx4_buf_free(dev, size, &wqres->buf);
err_db:
mlx4_db_free(dev, &wqres->db);
return err;
}
EXPORT_SYMBOL_GPL(mlx4_alloc_hwq_res);
void mlx4_free_hwq_res(struct mlx4_dev *dev, struct mlx4_hwq_resources *wqres,
int size)
{
mlx4_mtt_cleanup(dev, &wqres->mtt);
mlx4_buf_free(dev, size, &wqres->buf);
mlx4_db_free(dev, &wqres->db);
}
EXPORT_SYMBOL_GPL(mlx4_free_hwq_res);