Revision 475049809977bf3975d78f2d2fd992e19ce2d59e authored by Roel Kluin on 10 March 2009, 19:55:45 UTC, committed by Linus Torvalds on 10 March 2009, 22:55:10 UTC
get_nid_for_pfn() returns int Presumably the (nid < 0) case has never happened. We do know that it is happening on one system while creating a symlink for a memory section so it should also happen on the same system if unregister_mem_sect_under_nodes() were called to remove the same symlink. The test was actually added in response to a problem with an earlier version reported by Yasunori Goto where one or more of the leading pages of a memory section on the 2nd node of one of his systems was uninitialized because I believe they coincided with a memory hole. That earlier version did not ignore uninitialized pages and determined the nid by considering only the 1st page of each memory section. This caused the symlink to the 1st memory section on the 2nd node to be incorrectly created in /sys/devices/system/node/node0 instead of /sys/devices/system/node/node1. The problem was fixed by adding the test to skip over uninitialized pages. I suspect we have not seen any reports of the non-removal of a symlink due to the incorrect declaration of the nid variable in unregister_mem_sect_under_nodes() because - systems where a memory section could have an uninitialized range of leading pages are probably rare. - memory remove is probably not done very frequently on the systems that are capable of demonstrating the problem. - lingering symlink(s) that should have been removed may have simply gone unnoticed. [garyhade@us.ibm.com: wrote changelog] Signed-off-by: Roel Kluin <roel.kluin@gmail.com> Cc: Gary Hade <garyhade@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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raid6altivec.uc
/* -*- linux-c -*- ------------------------------------------------------- *
*
* Copyright 2002-2004 H. Peter Anvin - All Rights Reserved
*
* This program 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, Inc., 53 Temple Place Ste 330,
* Bostom MA 02111-1307, USA; either version 2 of the License, or
* (at your option) any later version; incorporated herein by reference.
*
* ----------------------------------------------------------------------- */
/*
* raid6altivec$#.c
*
* $#-way unrolled portable integer math RAID-6 instruction set
*
* This file is postprocessed using unroll.pl
*
* <benh> hpa: in process,
* you can just "steal" the vec unit with enable_kernel_altivec() (but
* bracked this with preempt_disable/enable or in a lock)
*/
#include "raid6.h"
#ifdef CONFIG_ALTIVEC
#include <altivec.h>
#ifdef __KERNEL__
# include <asm/system.h>
# include <asm/cputable.h>
#endif
/*
* This is the C data type to use. We use a vector of
* signed char so vec_cmpgt() will generate the right
* instruction.
*/
typedef vector signed char unative_t;
#define NBYTES(x) ((vector signed char) {x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x})
#define NSIZE sizeof(unative_t)
/*
* The SHLBYTE() operation shifts each byte left by 1, *not*
* rolling over into the next byte
*/
static inline __attribute_const__ unative_t SHLBYTE(unative_t v)
{
return vec_add(v,v);
}
/*
* The MASK() operation returns 0xFF in any byte for which the high
* bit is 1, 0x00 for any byte for which the high bit is 0.
*/
static inline __attribute_const__ unative_t MASK(unative_t v)
{
unative_t zv = NBYTES(0);
/* vec_cmpgt returns a vector bool char; thus the need for the cast */
return (unative_t)vec_cmpgt(zv, v);
}
/* This is noinline to make damned sure that gcc doesn't move any of the
Altivec code around the enable/disable code */
static void noinline
raid6_altivec$#_gen_syndrome_real(int disks, size_t bytes, void **ptrs)
{
u8 **dptr = (u8 **)ptrs;
u8 *p, *q;
int d, z, z0;
unative_t wd$$, wq$$, wp$$, w1$$, w2$$;
unative_t x1d = NBYTES(0x1d);
z0 = disks - 3; /* Highest data disk */
p = dptr[z0+1]; /* XOR parity */
q = dptr[z0+2]; /* RS syndrome */
for ( d = 0 ; d < bytes ; d += NSIZE*$# ) {
wq$$ = wp$$ = *(unative_t *)&dptr[z0][d+$$*NSIZE];
for ( z = z0-1 ; z >= 0 ; z-- ) {
wd$$ = *(unative_t *)&dptr[z][d+$$*NSIZE];
wp$$ = vec_xor(wp$$, wd$$);
w2$$ = MASK(wq$$);
w1$$ = SHLBYTE(wq$$);
w2$$ = vec_and(w2$$, x1d);
w1$$ = vec_xor(w1$$, w2$$);
wq$$ = vec_xor(w1$$, wd$$);
}
*(unative_t *)&p[d+NSIZE*$$] = wp$$;
*(unative_t *)&q[d+NSIZE*$$] = wq$$;
}
}
static void raid6_altivec$#_gen_syndrome(int disks, size_t bytes, void **ptrs)
{
preempt_disable();
enable_kernel_altivec();
raid6_altivec$#_gen_syndrome_real(disks, bytes, ptrs);
preempt_enable();
}
int raid6_have_altivec(void);
#if $# == 1
int raid6_have_altivec(void)
{
/* This assumes either all CPUs have Altivec or none does */
# ifdef __KERNEL__
return cpu_has_feature(CPU_FTR_ALTIVEC);
# else
return 1;
# endif
}
#endif
const struct raid6_calls raid6_altivec$# = {
raid6_altivec$#_gen_syndrome,
raid6_have_altivec,
"altivecx$#",
0
};
#endif /* CONFIG_ALTIVEC */
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