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https://github.com/edk2-porting/linux-next.git
synced 2024-12-25 21:54:06 +08:00
793b62337e
Crashing on a null pointer deref is never a nice thing to do. It seems to me that it's better to simply return UWB_RSV_ALLOC_NOT_FOUND if kzalloc() fails in uwb_rsv_find_best_allocation(). Signed-off-by: Jesper Juhl <jj@chaosbits.net> Acked-by: David Vrabel <david.vrabel@csr.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
388 lines
10 KiB
C
388 lines
10 KiB
C
/*
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* UWB reservation management.
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*
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* Copyright (C) 2008 Cambridge Silicon Radio Ltd.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License version
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* 2 as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <linux/kernel.h>
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#include <linux/slab.h>
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#include <linux/uwb.h>
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#include "uwb-internal.h"
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static void uwb_rsv_fill_column_alloc(struct uwb_rsv_alloc_info *ai)
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{
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int col, mas, safe_mas, unsafe_mas;
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unsigned char *bm = ai->bm;
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struct uwb_rsv_col_info *ci = ai->ci;
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unsigned char c;
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for (col = ci->csi.start_col; col < UWB_NUM_ZONES; col += ci->csi.interval) {
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safe_mas = ci->csi.safe_mas_per_col;
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unsafe_mas = ci->csi.unsafe_mas_per_col;
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for (mas = 0; mas < UWB_MAS_PER_ZONE; mas++ ) {
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if (bm[col * UWB_MAS_PER_ZONE + mas] == 0) {
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if (safe_mas > 0) {
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safe_mas--;
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c = UWB_RSV_MAS_SAFE;
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} else if (unsafe_mas > 0) {
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unsafe_mas--;
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c = UWB_RSV_MAS_UNSAFE;
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} else {
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break;
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}
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bm[col * UWB_MAS_PER_ZONE + mas] = c;
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}
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}
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}
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}
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static void uwb_rsv_fill_row_alloc(struct uwb_rsv_alloc_info *ai)
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{
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int mas, col, rows;
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unsigned char *bm = ai->bm;
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struct uwb_rsv_row_info *ri = &ai->ri;
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unsigned char c;
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rows = 1;
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c = UWB_RSV_MAS_SAFE;
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for (mas = UWB_MAS_PER_ZONE - 1; mas >= 0; mas--) {
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if (ri->avail[mas] == 1) {
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if (rows > ri->used_rows) {
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break;
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} else if (rows > 7) {
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c = UWB_RSV_MAS_UNSAFE;
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}
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for (col = 0; col < UWB_NUM_ZONES; col++) {
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if (bm[col * UWB_NUM_ZONES + mas] != UWB_RSV_MAS_NOT_AVAIL) {
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bm[col * UWB_NUM_ZONES + mas] = c;
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if(c == UWB_RSV_MAS_SAFE)
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ai->safe_allocated_mases++;
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else
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ai->unsafe_allocated_mases++;
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}
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}
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rows++;
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}
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}
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ai->total_allocated_mases = ai->safe_allocated_mases + ai->unsafe_allocated_mases;
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}
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/*
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* Find the best column set for a given availability, interval, num safe mas and
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* num unsafe mas.
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*
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* The different sets are tried in order as shown below, depending on the interval.
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*
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* interval = 16
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* deep = 0
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* set 1 -> { 8 }
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* deep = 1
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* set 1 -> { 4 }
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* set 2 -> { 12 }
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* deep = 2
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* set 1 -> { 2 }
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* set 2 -> { 6 }
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* set 3 -> { 10 }
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* set 4 -> { 14 }
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* deep = 3
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* set 1 -> { 1 }
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* set 2 -> { 3 }
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* set 3 -> { 5 }
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* set 4 -> { 7 }
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* set 5 -> { 9 }
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* set 6 -> { 11 }
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* set 7 -> { 13 }
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* set 8 -> { 15 }
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*
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* interval = 8
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* deep = 0
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* set 1 -> { 4 12 }
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* deep = 1
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* set 1 -> { 2 10 }
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* set 2 -> { 6 14 }
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* deep = 2
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* set 1 -> { 1 9 }
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* set 2 -> { 3 11 }
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* set 3 -> { 5 13 }
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* set 4 -> { 7 15 }
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*
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* interval = 4
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* deep = 0
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* set 1 -> { 2 6 10 14 }
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* deep = 1
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* set 1 -> { 1 5 9 13 }
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* set 2 -> { 3 7 11 15 }
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*
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* interval = 2
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* deep = 0
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* set 1 -> { 1 3 5 7 9 11 13 15 }
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*/
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static int uwb_rsv_find_best_column_set(struct uwb_rsv_alloc_info *ai, int interval,
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int num_safe_mas, int num_unsafe_mas)
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{
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struct uwb_rsv_col_info *ci = ai->ci;
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struct uwb_rsv_col_set_info *csi = &ci->csi;
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struct uwb_rsv_col_set_info tmp_csi;
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int deep, set, col, start_col_deep, col_start_set;
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int start_col, max_mas_in_set, lowest_max_mas_in_deep;
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int n_mas;
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int found = UWB_RSV_ALLOC_NOT_FOUND;
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tmp_csi.start_col = 0;
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start_col_deep = interval;
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n_mas = num_unsafe_mas + num_safe_mas;
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for (deep = 0; ((interval >> deep) & 0x1) == 0; deep++) {
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start_col_deep /= 2;
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col_start_set = 0;
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lowest_max_mas_in_deep = UWB_MAS_PER_ZONE;
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for (set = 1; set <= (1 << deep); set++) {
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max_mas_in_set = 0;
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start_col = start_col_deep + col_start_set;
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for (col = start_col; col < UWB_NUM_ZONES; col += interval) {
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if (ci[col].max_avail_safe >= num_safe_mas &&
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ci[col].max_avail_unsafe >= n_mas) {
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if (ci[col].highest_mas[n_mas] > max_mas_in_set)
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max_mas_in_set = ci[col].highest_mas[n_mas];
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} else {
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max_mas_in_set = 0;
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break;
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}
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}
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if ((lowest_max_mas_in_deep > max_mas_in_set) && max_mas_in_set) {
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lowest_max_mas_in_deep = max_mas_in_set;
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tmp_csi.start_col = start_col;
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}
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col_start_set += (interval >> deep);
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}
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if (lowest_max_mas_in_deep < 8) {
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csi->start_col = tmp_csi.start_col;
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found = UWB_RSV_ALLOC_FOUND;
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break;
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} else if ((lowest_max_mas_in_deep > 8) &&
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(lowest_max_mas_in_deep != UWB_MAS_PER_ZONE) &&
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(found == UWB_RSV_ALLOC_NOT_FOUND)) {
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csi->start_col = tmp_csi.start_col;
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found = UWB_RSV_ALLOC_FOUND;
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}
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}
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if (found == UWB_RSV_ALLOC_FOUND) {
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csi->interval = interval;
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csi->safe_mas_per_col = num_safe_mas;
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csi->unsafe_mas_per_col = num_unsafe_mas;
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ai->safe_allocated_mases = (UWB_NUM_ZONES / interval) * num_safe_mas;
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ai->unsafe_allocated_mases = (UWB_NUM_ZONES / interval) * num_unsafe_mas;
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ai->total_allocated_mases = ai->safe_allocated_mases + ai->unsafe_allocated_mases;
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ai->interval = interval;
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}
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return found;
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}
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static void get_row_descriptors(struct uwb_rsv_alloc_info *ai)
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{
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unsigned char *bm = ai->bm;
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struct uwb_rsv_row_info *ri = &ai->ri;
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int col, mas;
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ri->free_rows = 16;
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for (mas = 0; mas < UWB_MAS_PER_ZONE; mas ++) {
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ri->avail[mas] = 1;
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for (col = 1; col < UWB_NUM_ZONES; col++) {
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if (bm[col * UWB_NUM_ZONES + mas] == UWB_RSV_MAS_NOT_AVAIL) {
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ri->free_rows--;
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ri->avail[mas]=0;
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break;
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}
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}
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}
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}
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static void uwb_rsv_fill_column_info(unsigned char *bm, int column, struct uwb_rsv_col_info *rci)
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{
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int mas;
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int block_count = 0, start_block = 0;
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int previous_avail = 0;
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int available = 0;
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int safe_mas_in_row[UWB_MAS_PER_ZONE] = {
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8, 7, 6, 5, 4, 4, 4, 4, 4, 4, 4, 4, 4, 3, 2, 1,
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};
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rci->max_avail_safe = 0;
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for (mas = 0; mas < UWB_MAS_PER_ZONE; mas ++) {
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if (!bm[column * UWB_NUM_ZONES + mas]) {
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available++;
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rci->max_avail_unsafe = available;
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rci->highest_mas[available] = mas;
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if (previous_avail) {
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block_count++;
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if ((block_count > safe_mas_in_row[start_block]) &&
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(!rci->max_avail_safe))
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rci->max_avail_safe = available - 1;
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} else {
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previous_avail = 1;
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start_block = mas;
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block_count = 1;
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}
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} else {
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previous_avail = 0;
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}
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}
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if (!rci->max_avail_safe)
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rci->max_avail_safe = rci->max_avail_unsafe;
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}
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static void get_column_descriptors(struct uwb_rsv_alloc_info *ai)
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{
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unsigned char *bm = ai->bm;
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struct uwb_rsv_col_info *ci = ai->ci;
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int col;
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for (col = 1; col < UWB_NUM_ZONES; col++) {
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uwb_rsv_fill_column_info(bm, col, &ci[col]);
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}
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}
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static int uwb_rsv_find_best_row_alloc(struct uwb_rsv_alloc_info *ai)
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{
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int n_rows;
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int max_rows = ai->max_mas / UWB_USABLE_MAS_PER_ROW;
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int min_rows = ai->min_mas / UWB_USABLE_MAS_PER_ROW;
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if (ai->min_mas % UWB_USABLE_MAS_PER_ROW)
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min_rows++;
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for (n_rows = max_rows; n_rows >= min_rows; n_rows--) {
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if (n_rows <= ai->ri.free_rows) {
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ai->ri.used_rows = n_rows;
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ai->interval = 1; /* row reservation */
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uwb_rsv_fill_row_alloc(ai);
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return UWB_RSV_ALLOC_FOUND;
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}
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}
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return UWB_RSV_ALLOC_NOT_FOUND;
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}
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static int uwb_rsv_find_best_col_alloc(struct uwb_rsv_alloc_info *ai, int interval)
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{
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int n_safe, n_unsafe, n_mas;
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int n_column = UWB_NUM_ZONES / interval;
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int max_per_zone = ai->max_mas / n_column;
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int min_per_zone = ai->min_mas / n_column;
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if (ai->min_mas % n_column)
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min_per_zone++;
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if (min_per_zone > UWB_MAS_PER_ZONE) {
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return UWB_RSV_ALLOC_NOT_FOUND;
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}
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if (max_per_zone > UWB_MAS_PER_ZONE) {
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max_per_zone = UWB_MAS_PER_ZONE;
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}
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for (n_mas = max_per_zone; n_mas >= min_per_zone; n_mas--) {
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if (uwb_rsv_find_best_column_set(ai, interval, 0, n_mas) == UWB_RSV_ALLOC_NOT_FOUND)
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continue;
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for (n_safe = n_mas; n_safe >= 0; n_safe--) {
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n_unsafe = n_mas - n_safe;
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if (uwb_rsv_find_best_column_set(ai, interval, n_safe, n_unsafe) == UWB_RSV_ALLOC_FOUND) {
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uwb_rsv_fill_column_alloc(ai);
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return UWB_RSV_ALLOC_FOUND;
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}
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}
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}
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return UWB_RSV_ALLOC_NOT_FOUND;
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}
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int uwb_rsv_find_best_allocation(struct uwb_rsv *rsv, struct uwb_mas_bm *available,
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struct uwb_mas_bm *result)
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{
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struct uwb_rsv_alloc_info *ai;
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int interval;
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int bit_index;
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ai = kzalloc(sizeof(struct uwb_rsv_alloc_info), GFP_KERNEL);
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if (!ai)
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return UWB_RSV_ALLOC_NOT_FOUND;
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ai->min_mas = rsv->min_mas;
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ai->max_mas = rsv->max_mas;
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ai->max_interval = rsv->max_interval;
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/* fill the not available vector from the available bm */
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for (bit_index = 0; bit_index < UWB_NUM_MAS; bit_index++) {
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if (!test_bit(bit_index, available->bm))
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ai->bm[bit_index] = UWB_RSV_MAS_NOT_AVAIL;
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}
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if (ai->max_interval == 1) {
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get_row_descriptors(ai);
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if (uwb_rsv_find_best_row_alloc(ai) == UWB_RSV_ALLOC_FOUND)
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goto alloc_found;
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else
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goto alloc_not_found;
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}
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get_column_descriptors(ai);
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for (interval = 16; interval >= 2; interval>>=1) {
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if (interval > ai->max_interval)
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continue;
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if (uwb_rsv_find_best_col_alloc(ai, interval) == UWB_RSV_ALLOC_FOUND)
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goto alloc_found;
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}
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/* try row reservation if no column is found */
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get_row_descriptors(ai);
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if (uwb_rsv_find_best_row_alloc(ai) == UWB_RSV_ALLOC_FOUND)
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goto alloc_found;
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else
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goto alloc_not_found;
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alloc_found:
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bitmap_zero(result->bm, UWB_NUM_MAS);
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bitmap_zero(result->unsafe_bm, UWB_NUM_MAS);
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/* fill the safe and unsafe bitmaps */
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for (bit_index = 0; bit_index < UWB_NUM_MAS; bit_index++) {
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if (ai->bm[bit_index] == UWB_RSV_MAS_SAFE)
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set_bit(bit_index, result->bm);
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else if (ai->bm[bit_index] == UWB_RSV_MAS_UNSAFE)
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set_bit(bit_index, result->unsafe_bm);
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}
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bitmap_or(result->bm, result->bm, result->unsafe_bm, UWB_NUM_MAS);
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result->safe = ai->safe_allocated_mases;
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result->unsafe = ai->unsafe_allocated_mases;
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kfree(ai);
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return UWB_RSV_ALLOC_FOUND;
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alloc_not_found:
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kfree(ai);
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return UWB_RSV_ALLOC_NOT_FOUND;
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}
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