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Memory we use to submit for IO needs strict alignment to the underlying driver contraints. Worst case, this is 512 bytes. Given that all allocations for IO are always a power of 2 multiple of 512 bytes, the kernel heap provides natural alignment for objects of these sizes and that suffices. Until, of course, memory debugging of some kind is turned on (e.g. red zones, poisoning, KASAN) and then the alignment of the heap objects is thrown out the window. Then we get weird IO errors and data corruption problems because drivers don't validate alignment and do the wrong thing when passed unaligned memory buffers in bios. TO fix this, introduce kmem_alloc_io(), which will guaranteeat least 512 byte alignment of buffers for IO, even if memory debugging options are turned on. It is assumed that the minimum allocation size will be 512 bytes, and that sizes will be power of 2 mulitples of 512 bytes. Use this everywhere we allocate buffers for IO. This no longer fails with log recovery errors when KASAN is enabled due to the brd driver not handling unaligned memory buffers: # mkfs.xfs -f /dev/ram0 ; mount /dev/ram0 /mnt/test Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
131 lines
3.0 KiB
C
131 lines
3.0 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (c) 2000-2005 Silicon Graphics, Inc.
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* All Rights Reserved.
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*/
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#ifndef __XFS_SUPPORT_KMEM_H__
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#define __XFS_SUPPORT_KMEM_H__
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#include <linux/slab.h>
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#include <linux/sched.h>
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#include <linux/mm.h>
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#include <linux/vmalloc.h>
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/*
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* General memory allocation interfaces
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*/
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typedef unsigned __bitwise xfs_km_flags_t;
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#define KM_NOFS ((__force xfs_km_flags_t)0x0004u)
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#define KM_MAYFAIL ((__force xfs_km_flags_t)0x0008u)
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#define KM_ZERO ((__force xfs_km_flags_t)0x0010u)
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/*
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* We use a special process flag to avoid recursive callbacks into
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* the filesystem during transactions. We will also issue our own
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* warnings, so we explicitly skip any generic ones (silly of us).
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*/
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static inline gfp_t
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kmem_flags_convert(xfs_km_flags_t flags)
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{
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gfp_t lflags;
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BUG_ON(flags & ~(KM_NOFS|KM_MAYFAIL|KM_ZERO));
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lflags = GFP_KERNEL | __GFP_NOWARN;
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if (flags & KM_NOFS)
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lflags &= ~__GFP_FS;
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/*
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* Default page/slab allocator behavior is to retry for ever
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* for small allocations. We can override this behavior by using
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* __GFP_RETRY_MAYFAIL which will tell the allocator to retry as long
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* as it is feasible but rather fail than retry forever for all
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* request sizes.
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*/
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if (flags & KM_MAYFAIL)
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lflags |= __GFP_RETRY_MAYFAIL;
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if (flags & KM_ZERO)
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lflags |= __GFP_ZERO;
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return lflags;
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}
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extern void *kmem_alloc(size_t, xfs_km_flags_t);
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extern void *kmem_alloc_io(size_t size, int align_mask, xfs_km_flags_t flags);
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extern void *kmem_alloc_large(size_t size, xfs_km_flags_t);
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extern void *kmem_realloc(const void *, size_t, xfs_km_flags_t);
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static inline void kmem_free(const void *ptr)
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{
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kvfree(ptr);
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}
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static inline void *
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kmem_zalloc(size_t size, xfs_km_flags_t flags)
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{
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return kmem_alloc(size, flags | KM_ZERO);
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}
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static inline void *
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kmem_zalloc_large(size_t size, xfs_km_flags_t flags)
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{
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return kmem_alloc_large(size, flags | KM_ZERO);
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}
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/*
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* Zone interfaces
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*/
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#define KM_ZONE_HWALIGN SLAB_HWCACHE_ALIGN
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#define KM_ZONE_RECLAIM SLAB_RECLAIM_ACCOUNT
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#define KM_ZONE_SPREAD SLAB_MEM_SPREAD
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#define KM_ZONE_ACCOUNT SLAB_ACCOUNT
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#define kmem_zone kmem_cache
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#define kmem_zone_t struct kmem_cache
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static inline kmem_zone_t *
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kmem_zone_init(int size, char *zone_name)
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{
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return kmem_cache_create(zone_name, size, 0, 0, NULL);
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}
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static inline kmem_zone_t *
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kmem_zone_init_flags(int size, char *zone_name, slab_flags_t flags,
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void (*construct)(void *))
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{
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return kmem_cache_create(zone_name, size, 0, flags, construct);
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}
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static inline void
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kmem_zone_free(kmem_zone_t *zone, void *ptr)
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{
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kmem_cache_free(zone, ptr);
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}
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static inline void
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kmem_zone_destroy(kmem_zone_t *zone)
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{
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kmem_cache_destroy(zone);
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}
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extern void *kmem_zone_alloc(kmem_zone_t *, xfs_km_flags_t);
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static inline void *
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kmem_zone_zalloc(kmem_zone_t *zone, xfs_km_flags_t flags)
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{
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return kmem_zone_alloc(zone, flags | KM_ZERO);
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}
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static inline struct page *
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kmem_to_page(void *addr)
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{
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if (is_vmalloc_addr(addr))
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return vmalloc_to_page(addr);
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return virt_to_page(addr);
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}
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#endif /* __XFS_SUPPORT_KMEM_H__ */
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