linux/mm
Vasily Tarasov f772b3d9ca block: blk_max_pfn is somtimes wrong
There is a small problem in handling page bounce.

At the moment blk_max_pfn equals max_pfn, which is in fact not maximum
possible _number_ of a page frame, but the _amount_ of page frames.  For
example for the 32bit x86 node with 4Gb RAM, max_pfn = 0x100000, but not
0xFFFF.

request_queue structure has a member q->bounce_pfn and queue needs bounce
pages for the pages _above_ this limit.  This routine is handled by
blk_queue_bounce(), where the following check is produced:

	if (q->bounce_pfn >= blk_max_pfn)
		return;

Assume, that a driver has set q->bounce_pfn to 0xFFFF, but blk_max_pfn
equals 0x10000.  In such situation the check above fails and for each bio
we always fall down for iterating over pages tied to the bio.

I want to notice, that for quite a big range of device drivers (ide, md,
...) such problem doesn't happen because they use BLK_BOUNCE_ANY for
bounce_pfn.  BLK_BOUNCE_ANY is defined as blk_max_pfn << PAGE_SHIFT, and
then the check above doesn't fail.  But for other drivers, which obtain
reuired value from drivers, it fails.  For example sata_nv uses
ATA_DMA_MASK or dev->dma_mask.

I propose to use (max_pfn - 1) for blk_max_pfn.  And the same for
blk_max_low_pfn.  The patch also cleanses some checks related with
bounce_pfn.

Signed-off-by: Vasily Tarasov <vtaras@openvz.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2007-03-27 08:52:47 +02:00
..
allocpercpu.c [PATCH] Allow NULL pointers in percpu_free 2006-12-07 08:39:22 -08:00
backing-dev.c [PATCH] nfs: fix congestion control 2007-03-16 19:25:05 -07:00
bootmem.c [PATCH] remove EXPORT_UNUSED_SYMBOL'ed symbols 2006-12-07 08:39:44 -08:00
bounce.c block: blk_max_pfn is somtimes wrong 2007-03-27 08:52:47 +02:00
fadvise.c [PATCH] mm: change uses of f_{dentry,vfsmnt} to use f_path 2006-12-08 08:28:43 -08:00
filemap_xip.c [PATCH] mm: mremap correct rmap accounting 2007-01-30 08:33:32 -08:00
filemap.c [PATCH] dio: invalidate clean pages before dio write 2007-03-16 19:25:04 -07:00
filemap.h Remove all inclusions of <linux/config.h> 2006-10-04 03:38:54 -04:00
fremap.c [PATCH] mm: more rmap debugging 2006-12-22 08:55:49 -08:00
highmem.c [PATCH] Use ZVC for free_pages 2007-02-11 10:51:17 -08:00
hugetlb.c [PATCH] hugetlb: preserve hugetlb pte dirty state 2007-02-09 09:25:46 -08:00
internal.h [PATCH] mm: VM_BUG_ON 2006-09-26 08:48:44 -07:00
Kconfig [PATCH] Set CONFIG_ZONE_DMA for arches with GENERIC_ISA_DMA 2007-02-11 10:51:19 -08:00
madvise.c [PATCH] mm: fix madvise infinine loop 2007-03-16 19:25:04 -07:00
Makefile [PATCH] separate bdi congestion functions from queue congestion functions 2006-10-20 10:26:35 -07:00
memory_hotplug.c [PATCH] Fix sparsemem on Cell 2007-01-11 18:18:20 -08:00
memory.c [PATCH] Add NOPFN_REFAULT result from vm_ops->nopfn() 2007-02-12 09:48:27 -08:00
mempolicy.c [PATCH] Page migration: Fix vma flag checking 2007-03-05 07:57:51 -08:00
mempool.c [PATCH] Numerous fixes to kernel-doc info in source files. 2007-02-11 10:51:32 -08:00
migrate.c [PATCH] Page migration: Fix vma flag checking 2007-03-05 07:57:51 -08:00
mincore.c [PATCH] mincore: vma crossing fix 2007-02-15 09:57:03 -08:00
mlock.c [PATCH] mlock cleanup 2006-12-07 08:39:22 -08:00
mmap.c [PATCH] Bug in MM_RB debugging 2007-03-01 14:53:38 -08:00
mmzone.c [PATCH] remove EXPORT_UNUSED_SYMBOL'ed symbols 2006-12-07 08:39:44 -08:00
mprotect.c [PATCH] paravirt: lazy mmu mode hooks.patch 2006-10-01 00:39:33 -07:00
mremap.c [PATCH] mm: mremap correct rmap accounting 2007-01-30 08:33:32 -08:00
msync.c [PATCH] mm: msync() cleanup 2006-09-26 08:48:45 -07:00
nommu.c [PATCH] NOMMU: make SYSV SHM nattch work correctly 2007-03-22 19:39:06 -07:00
oom_kill.c [PATCH] oom fix: prevent oom from killing a process with children/sibling unkillable 2007-03-16 19:25:06 -07:00
page_alloc.c [PATCH] Rename PG_checked to PG_owner_priv_1 2007-03-01 14:53:37 -08:00
page_io.c [PATCH] swsusp: use block device offsets to identify swap locations 2006-12-07 08:39:27 -08:00
page-writeback.c [PATCH] throttle_vm_writeout(): don't loop on GFP_NOFS and GFP_NOIO allocations 2007-03-01 14:53:38 -08:00
pdflush.c [PATCH] Add include/linux/freezer.h and move definitions from sched.h 2006-12-07 08:39:27 -08:00
prio_tree.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
readahead.c [PATCH] Drop __get_zone_counts() 2007-02-11 10:51:18 -08:00
rmap.c [PATCH] adapt page_lock_anon_vma() to PREEMPT_RCU 2007-03-01 14:53:39 -08:00
shmem_acl.c [PATCH] Fix typos in mm/shmem_acl.c 2006-10-11 11:14:23 -07:00
shmem.c [PATCH] shmem and simple const super_operations 2007-03-05 07:57:51 -08:00
slab.c [PATCH] kernel-doc fixes for 2.6.20-git15 (non-drivers) 2007-03-01 14:53:37 -08:00
slob.c [PATCH] MM: SLOB is broken by recent cleanup of slab.h 2006-12-30 10:56:42 -08:00
sparse.c [PATCH] numa node ids are int, page_to_nid and zone_to_nid should return int 2006-12-07 08:39:23 -08:00
swap_state.c [PATCH] lockdep: locking init debugging improvement 2006-07-03 15:27:02 -07:00
swap.c [PATCH] hotplug CPU: clean up hotcpu_notifier() use 2006-12-07 08:39:39 -08:00
swapfile.c [PATCH] swsusp: Do not fail if resume device is not set 2007-01-05 23:55:22 -08:00
thrash.c [PATCH] make mm/thrash.c:global_faults static 2006-12-07 08:39:22 -08:00
tiny-shmem.c [PATCH] mm/{,tiny-}shmem.c cleanups 2007-03-01 14:53:35 -08:00
truncate.c [PATCH] VM: invalidate_inode_pages2_range() should not exit early 2007-03-01 14:53:39 -08:00
util.c [PATCH] slab: clean up leak tracking ifdefs a little bit 2006-10-04 07:55:13 -07:00
vmalloc.c [PATCH] Numerous fixes to kernel-doc info in source files. 2007-02-11 10:51:32 -08:00
vmscan.c [PATCH] throttle_vm_writeout(): don't loop on GFP_NOFS and GFP_NOIO allocations 2007-03-01 14:53:38 -08:00
vmstat.c [PATCH] optional ZONE_DMA: optional ZONE_DMA in the VM 2007-02-11 10:51:18 -08:00