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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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