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Subject[patch 1/13] Qsort
Add a quicksort from glibc as a kernel library function, and switch
xfs over to using it. The implementations are equivalent. The nfsacl
protocol also requires a sort function, so it makes more sense in
the common code.

Signed-off-by: Andreas Gruenbacher <agruen@suse.de>
Acked-by: Olaf Kirch <okir@suse.de>

Index: linux-2.6.11-rc2/include/linux/kernel.h
===================================================================
--- linux-2.6.11-rc2.orig/include/linux/kernel.h
+++ linux-2.6.11-rc2/include/linux/kernel.h
@@ -93,6 +93,8 @@ extern int sscanf(const char *, const ch
__attribute__ ((format (scanf,2,3)));
extern int vsscanf(const char *, const char *, va_list);

+extern void qsort(void *, size_t, size_t, int (*)(const void *,const void *));
+
extern int get_option(char **str, int *pint);
extern char *get_options(const char *str, int nints, int *ints);
extern unsigned long long memparse(char *ptr, char **retptr);
Index: linux-2.6.11-rc2/lib/Kconfig
===================================================================
--- linux-2.6.11-rc2.orig/lib/Kconfig
+++ linux-2.6.11-rc2/lib/Kconfig
@@ -30,6 +30,9 @@ config LIBCRC32C
require M here. See Castagnoli93.
Module will be libcrc32c.

+config QSORT
+ bool "Quick Sort"
+
#
# compression support is select'ed if needed
#
Index: linux-2.6.11-rc2/lib/Makefile
===================================================================
--- linux-2.6.11-rc2.orig/lib/Makefile
+++ linux-2.6.11-rc2/lib/Makefile
@@ -25,6 +25,7 @@ obj-$(CONFIG_CRC_CCITT) += crc-ccitt.o
obj-$(CONFIG_CRC32) += crc32.o
obj-$(CONFIG_LIBCRC32C) += libcrc32c.o
obj-$(CONFIG_GENERIC_IOMAP) += iomap.o
+obj-$(CONFIG_QSORT) += qsort.o

obj-$(CONFIG_ZLIB_INFLATE) += zlib_inflate/
obj-$(CONFIG_ZLIB_DEFLATE) += zlib_deflate/
Index: linux-2.6.11-rc2/lib/qsort.c
===================================================================
--- /dev/null
+++ linux-2.6.11-rc2/lib/qsort.c
@@ -0,0 +1,249 @@
+/* Copyright (C) 1991, 1992, 1996, 1997, 1999 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+ Written by Douglas C. Schmidt (schmidt@ics.uci.edu).
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library 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
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, write to the Free
+ Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+ 02111-1307 USA. */
+
+/* If you consider tuning this algorithm, you should consult first:
+ Engineering a sort function; Jon Bentley and M. Douglas McIlroy;
+ Software - Practice and Experience; Vol. 23 (11), 1249-1265, 1993. */
+
+# include <linux/module.h>
+# include <linux/slab.h>
+# include <linux/string.h>
+
+MODULE_LICENSE("GPL");
+
+/* Byte-wise swap two items of size SIZE. */
+#define SWAP(a, b, size) \
+ do \
+ { \
+ register size_t __size = (size); \
+ register char *__a = (a), *__b = (b); \
+ do \
+ { \
+ char __tmp = *__a; \
+ *__a++ = *__b; \
+ *__b++ = __tmp; \
+ } while (--__size > 0); \
+ } while (0)
+
+/* Discontinue quicksort algorithm when partition gets below this size.
+ This particular magic number was chosen to work best on a Sun 4/260. */
+#define MAX_THRESH 4
+
+/* Stack node declarations used to store unfulfilled partition obligations. */
+typedef struct
+ {
+ char *lo;
+ char *hi;
+ } stack_node;
+
+/* The next 5 #defines implement a very fast in-line stack abstraction. */
+/* The stack needs log (total_elements) entries (we could even subtract
+ log(MAX_THRESH)). Since total_elements has type size_t, we get as
+ upper bound for log (total_elements):
+ bits per byte (CHAR_BIT) * sizeof(size_t). */
+#define CHAR_BIT 8
+#define STACK_SIZE (CHAR_BIT * sizeof(size_t))
+#define PUSH(low, high) ((void) ((top->lo = (low)), (top->hi = (high)), ++top))
+#define POP(low, high) ((void) (--top, (low = top->lo), (high = top->hi)))
+#define STACK_NOT_EMPTY (stack < top)
+
+
+/* Order size using quicksort. This implementation incorporates
+ four optimizations discussed in Sedgewick:
+
+ 1. Non-recursive, using an explicit stack of pointer that store the
+ next array partition to sort. To save time, this maximum amount
+ of space required to store an array of SIZE_MAX is allocated on the
+ stack. Assuming a 32-bit (64 bit) integer for size_t, this needs
+ only 32 * sizeof(stack_node) == 256 bytes (for 64 bit: 1024 bytes).
+ Pretty cheap, actually.
+
+ 2. Chose the pivot element using a median-of-three decision tree.
+ This reduces the probability of selecting a bad pivot value and
+ eliminates certain extraneous comparisons.
+
+ 3. Only quicksorts TOTAL_ELEMS / MAX_THRESH partitions, leaving
+ insertion sort to order the MAX_THRESH items within each partition.
+ This is a big win, since insertion sort is faster for small, mostly
+ sorted array segments.
+
+ 4. The larger of the two sub-partitions is always pushed onto the
+ stack first, with the algorithm then concentrating on the
+ smaller partition. This *guarantees* no more than log (total_elems)
+ stack size is needed (actually O(1) in this case)! */
+
+void
+qsort(void *const pbase, size_t total_elems, size_t size,
+ int(*cmp)(const void *,const void *))
+{
+ register char *base_ptr = (char *) pbase;
+
+ const size_t max_thresh = MAX_THRESH * size;
+
+ if (total_elems == 0)
+ /* Avoid lossage with unsigned arithmetic below. */
+ return;
+
+ if (total_elems > MAX_THRESH)
+ {
+ char *lo = base_ptr;
+ char *hi = &lo[size * (total_elems - 1)];
+ stack_node stack[STACK_SIZE];
+ stack_node *top = stack + 1;
+
+ while (STACK_NOT_EMPTY)
+ {
+ char *left_ptr;
+ char *right_ptr;
+
+ /* Select median value from among LO, MID, and HI. Rearrange
+ LO and HI so the three values are sorted. This lowers the
+ probability of picking a pathological pivot value and
+ skips a comparison for both the LEFT_PTR and RIGHT_PTR in
+ the while loops. */
+
+ char *mid = lo + size * ((hi - lo) / size >> 1);
+
+ if ((*cmp) ((void *) mid, (void *) lo) < 0)
+ SWAP (mid, lo, size);
+ if ((*cmp) ((void *) hi, (void *) mid) < 0)
+ SWAP (mid, hi, size);
+ else
+ goto jump_over;
+ if ((*cmp) ((void *) mid, (void *) lo) < 0)
+ SWAP (mid, lo, size);
+ jump_over:;
+
+ left_ptr = lo + size;
+ right_ptr = hi - size;
+
+ /* Here's the famous ``collapse the walls'' section of quicksort.
+ Gotta like those tight inner loops! They are the main reason
+ that this algorithm runs much faster than others. */
+ do
+ {
+ while ((*cmp) ((void *) left_ptr, (void *) mid) < 0)
+ left_ptr += size;
+
+ while ((*cmp) ((void *) mid, (void *) right_ptr) < 0)
+ right_ptr -= size;
+
+ if (left_ptr < right_ptr)
+ {
+ SWAP (left_ptr, right_ptr, size);
+ if (mid == left_ptr)
+ mid = right_ptr;
+ else if (mid == right_ptr)
+ mid = left_ptr;
+ left_ptr += size;
+ right_ptr -= size;
+ }
+ else if (left_ptr == right_ptr)
+ {
+ left_ptr += size;
+ right_ptr -= size;
+ break;
+ }
+ }
+ while (left_ptr <= right_ptr);
+
+ /* Set up pointers for next iteration. First determine whether
+ left and right partitions are below the threshold size. If so,
+ ignore one or both. Otherwise, push the larger partition's
+ bounds on the stack and continue sorting the smaller one. */
+
+ if ((size_t) (right_ptr - lo) <= max_thresh)
+ {
+ if ((size_t) (hi - left_ptr) <= max_thresh)
+ /* Ignore both small partitions. */
+ POP (lo, hi);
+ else
+ /* Ignore small left partition. */
+ lo = left_ptr;
+ }
+ else if ((size_t) (hi - left_ptr) <= max_thresh)
+ /* Ignore small right partition. */
+ hi = right_ptr;
+ else if ((right_ptr - lo) > (hi - left_ptr))
+ {
+ /* Push larger left partition indices. */
+ PUSH (lo, right_ptr);
+ lo = left_ptr;
+ }
+ else
+ {
+ /* Push larger right partition indices. */
+ PUSH (left_ptr, hi);
+ hi = right_ptr;
+ }
+ }
+ }
+
+ /* Once the BASE_PTR array is partially sorted by quicksort the rest
+ is completely sorted using insertion sort, since this is efficient
+ for partitions below MAX_THRESH size. BASE_PTR points to the beginning
+ of the array to sort, and END_PTR points at the very last element in
+ the array (*not* one beyond it!). */
+
+ {
+ char *end_ptr = &base_ptr[size * (total_elems - 1)];
+ char *tmp_ptr = base_ptr;
+ char *thresh = min(end_ptr, base_ptr + max_thresh);
+ register char *run_ptr;
+
+ /* Find smallest element in first threshold and place it at the
+ array's beginning. This is the smallest array element,
+ and the operation speeds up insertion sort's inner loop. */
+
+ for (run_ptr = tmp_ptr + size; run_ptr <= thresh; run_ptr += size)
+ if ((*cmp) ((void *) run_ptr, (void *) tmp_ptr) < 0)
+ tmp_ptr = run_ptr;
+
+ if (tmp_ptr != base_ptr)
+ SWAP (tmp_ptr, base_ptr, size);
+
+ /* Insertion sort, running from left-hand-side up to right-hand-side. */
+
+ run_ptr = base_ptr + size;
+ while ((run_ptr += size) <= end_ptr)
+ {
+ tmp_ptr = run_ptr - size;
+ while ((*cmp) ((void *) run_ptr, (void *) tmp_ptr) < 0)
+ tmp_ptr -= size;
+
+ tmp_ptr += size;
+ if (tmp_ptr != run_ptr)
+ {
+ char *trav;
+
+ trav = run_ptr + size;
+ while (--trav >= run_ptr)
+ {
+ char c = *trav;
+ char *hi, *lo;
+
+ for (hi = lo = trav; (lo -= size) >= tmp_ptr; hi = lo)
+ *hi = *lo;
+ *hi = c;
+ }
+ }
+ }
+ }
+}
+EXPORT_SYMBOL(qsort);
Index: linux-2.6.11-rc2/fs/xfs/support/qsort.c
===================================================================
--- linux-2.6.11-rc2.orig/fs/xfs/support/qsort.c
+++ /dev/null
@@ -1,155 +0,0 @@
-/*
- * Copyright (c) 1992, 1993
- * The Regents of the University of California. All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- * 2. 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.
- * 3. Neither the name of the University nor the names of its contributors
- * may be used to endorse or promote products derived from this software
- * without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
- * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
- * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
- * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
- * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
- * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
- * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
- * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
- * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- */
-
-#include <linux/kernel.h>
-#include <linux/string.h>
-
-/*
- * Qsort routine from Bentley & McIlroy's "Engineering a Sort Function".
- */
-#define swapcode(TYPE, parmi, parmj, n) { \
- long i = (n) / sizeof (TYPE); \
- register TYPE *pi = (TYPE *) (parmi); \
- register TYPE *pj = (TYPE *) (parmj); \
- do { \
- register TYPE t = *pi; \
- *pi++ = *pj; \
- *pj++ = t; \
- } while (--i > 0); \
-}
-
-#define SWAPINIT(a, es) swaptype = ((char *)a - (char *)0) % sizeof(long) || \
- es % sizeof(long) ? 2 : es == sizeof(long)? 0 : 1;
-
-static __inline void
-swapfunc(char *a, char *b, int n, int swaptype)
-{
- if (swaptype <= 1)
- swapcode(long, a, b, n)
- else
- swapcode(char, a, b, n)
-}
-
-#define swap(a, b) \
- if (swaptype == 0) { \
- long t = *(long *)(a); \
- *(long *)(a) = *(long *)(b); \
- *(long *)(b) = t; \
- } else \
- swapfunc(a, b, es, swaptype)
-
-#define vecswap(a, b, n) if ((n) > 0) swapfunc(a, b, n, swaptype)
-
-static __inline char *
-med3(char *a, char *b, char *c, int (*cmp)(const void *, const void *))
-{
- return cmp(a, b) < 0 ?
- (cmp(b, c) < 0 ? b : (cmp(a, c) < 0 ? c : a ))
- :(cmp(b, c) > 0 ? b : (cmp(a, c) < 0 ? a : c ));
-}
-
-void
-qsort(void *aa, size_t n, size_t es, int (*cmp)(const void *, const void *))
-{
- char *pa, *pb, *pc, *pd, *pl, *pm, *pn;
- int d, r, swaptype, swap_cnt;
- register char *a = aa;
-
-loop: SWAPINIT(a, es);
- swap_cnt = 0;
- if (n < 7) {
- for (pm = (char *)a + es; pm < (char *) a + n * es; pm += es)
- for (pl = pm; pl > (char *) a && cmp(pl - es, pl) > 0;
- pl -= es)
- swap(pl, pl - es);
- return;
- }
- pm = (char *)a + (n / 2) * es;
- if (n > 7) {
- pl = (char *)a;
- pn = (char *)a + (n - 1) * es;
- if (n > 40) {
- d = (n / 8) * es;
- pl = med3(pl, pl + d, pl + 2 * d, cmp);
- pm = med3(pm - d, pm, pm + d, cmp);
- pn = med3(pn - 2 * d, pn - d, pn, cmp);
- }
- pm = med3(pl, pm, pn, cmp);
- }
- swap(a, pm);
- pa = pb = (char *)a + es;
-
- pc = pd = (char *)a + (n - 1) * es;
- for (;;) {
- while (pb <= pc && (r = cmp(pb, a)) <= 0) {
- if (r == 0) {
- swap_cnt = 1;
- swap(pa, pb);
- pa += es;
- }
- pb += es;
- }
- while (pb <= pc && (r = cmp(pc, a)) >= 0) {
- if (r == 0) {
- swap_cnt = 1;
- swap(pc, pd);
- pd -= es;
- }
- pc -= es;
- }
- if (pb > pc)
- break;
- swap(pb, pc);
- swap_cnt = 1;
- pb += es;
- pc -= es;
- }
- if (swap_cnt == 0) { /* Switch to insertion sort */
- for (pm = (char *) a + es; pm < (char *) a + n * es; pm += es)
- for (pl = pm; pl > (char *) a && cmp(pl - es, pl) > 0;
- pl -= es)
- swap(pl, pl - es);
- return;
- }
-
- pn = (char *)a + n * es;
- r = min(pa - (char *)a, pb - pa);
- vecswap(a, pb - r, r);
- r = min((long)(pd - pc), (long)(pn - pd - es));
- vecswap(pb, pn - r, r);
- if ((r = pb - pa) > es)
- qsort(a, r / es, es, cmp);
- if ((r = pd - pc) > es) {
- /* Iterate rather than recurse to save stack space */
- a = pn - r;
- n = r / es;
- goto loop;
- }
-/* qsort(pn - r, r / es, es, cmp);*/
-}
Index: linux-2.6.11-rc2/fs/xfs/Makefile
===================================================================
--- linux-2.6.11-rc2.orig/fs/xfs/Makefile
+++ linux-2.6.11-rc2/fs/xfs/Makefile
@@ -142,7 +142,6 @@ xfs-y += $(addprefix linux-2.6/, \
xfs-y += $(addprefix support/, \
debug.o \
move.o \
- qsort.o \
uuid.o)

xfs-$(CONFIG_XFS_TRACE) += support/ktrace.o
Index: linux-2.6.11-rc2/fs/xfs/support/qsort.h
===================================================================
--- linux-2.6.11-rc2.orig/fs/xfs/support/qsort.h
+++ /dev/null
@@ -1,41 +0,0 @@
-/*
- * Copyright (c) 2000-2002 Silicon Graphics, Inc. All Rights Reserved.
- *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of version 2 of the GNU General Public License as
- * published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it would be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
- *
- * Further, this software is distributed without any warranty that it is
- * free of the rightful claim of any third person regarding infringement
- * or the like. Any license provided herein, whether implied or
- * otherwise, applies only to this software file. Patent licenses, if
- * any, provided herein do not apply to combinations of this program with
- * other software, or any other product whatsoever.
- *
- * You should have received a copy of the GNU General Public License along
- * with this program; if not, write the Free Software Foundation, Inc., 59
- * Temple Place - Suite 330, Boston MA 02111-1307, USA.
- *
- * Contact information: Silicon Graphics, Inc., 1600 Amphitheatre Pkwy,
- * Mountain View, CA 94043, or:
- *
- * http://www.sgi.com
- *
- * For further information regarding this notice, see:
- *
- * http://oss.sgi.com/projects/GenInfo/SGIGPLNoticeExplan/
- */
-
-#ifndef QSORT_H
-#define QSORT_H
-
-extern void qsort (void *const pbase,
- size_t total_elems,
- size_t size,
- int (*cmp)(const void *, const void *));
-
-#endif
Index: linux-2.6.11-rc2/fs/xfs/linux-2.6/xfs_linux.h
===================================================================
--- linux-2.6.11-rc2.orig/fs/xfs/linux-2.6/xfs_linux.h
+++ linux-2.6.11-rc2/fs/xfs/linux-2.6/xfs_linux.h
@@ -64,7 +64,6 @@
#include <sema.h>
#include <time.h>

-#include <support/qsort.h>
#include <support/ktrace.h>
#include <support/debug.h>
#include <support/move.h>
Index: linux-2.6.11-rc2/fs/Kconfig
===================================================================
--- linux-2.6.11-rc2.orig/fs/Kconfig
+++ linux-2.6.11-rc2/fs/Kconfig
@@ -306,6 +306,7 @@ config FS_POSIX_ACL

config XFS_FS
tristate "XFS filesystem support"
+ select QSORT
help
XFS is a high performance journaling filesystem which originated
on the SGI IRIX platform. It is completely multi-threaded, can
--
Andreas Gruenbacher <agruen@suse.de>
SUSE Labs, SUSE LINUX PRODUCTS GMBH

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