linux/include, branch v2.6.28.1

mm: fix assertion

2009-01-18T18:44:06Z

commit 18e6959c385f3edf3991fa6662a53dac4eb10d5b upstream. This assertion is incorrect for lockless pagecache. By definition if we have an unpinned page that we are trying to take a speculative reference to, it may become the tail of a compound page at any time (if it is freed, then reallocated as a compound page). It was still a valid assertion for the vmscan.c LRU isolation case, but it doesn't seem incredibly helpful... if somebody wants it, they can put it back directly where it applies in the vmscan code. Signed-off-by: Nick Piggin Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

mm lockless pagecache barrier fix

2009-01-18T18:44:04Z

commit e8c82c2e23e3527e0c9dc195e432c16784d270fa upstream. An XFS workload showed up a bug in the lockless pagecache patch. Basically it would go into an "infinite" loop, although it would sometimes be able to break out of the loop! The reason is a missing compiler barrier in the "increment reference count unless it was zero" case of the lockless pagecache protocol in the gang lookup functions. This would cause the compiler to use a cached value of struct page pointer to retry the operation with, rather than reload it. So the page might have been removed from pagecache and freed (refcount==0) but the lookup would not correctly notice the page is no longer in pagecache, and keep attempting to increment the refcount and failing, until the page gets reallocated for something else. This isn't a data corruption because the condition will be detected if the page has been reallocated. However it can result in a lockup. Linus points out that ACCESS_ONCE is also required in that pointer load, even if it's absence is not causing a bug on our particular build. The most general way to solve this is just to put an rcu_dereference in radix_tree_deref_slot. Assembly of find_get_pages, before: .L220: movq (%rbx), %rax #* ivtmp.1162, tmp82 movq (%rax), %rdi #, prephitmp.1149 .L218: testb $1, %dil #, prephitmp.1149 jne .L217 #, testq %rdi, %rdi # prephitmp.1149 je .L203 #, cmpq $-1, %rdi #, prephitmp.1149 je .L217 #, movl 8(%rdi), %esi # ._count.counter, c testl %esi, %esi # c je .L218 #, after: .L212: movq (%rbx), %rax #* ivtmp.1109, tmp81 movq (%rax), %rdi #, ret testb $1, %dil #, ret jne .L211 #, testq %rdi, %rdi # ret je .L197 #, cmpq $-1, %rdi #, ret je .L211 #, movl 8(%rdi), %esi # ._count.counter, c testl %esi, %esi # c je .L212 #, (notice the obvious infinite loop in the first example, if page->count remains 0) Signed-off-by: Nick Piggin Reviewed-by: Paul E. McKenney Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

System call wrappers part 33

2009-01-18T18:44:01Z

commit 2b66421995d2e93c9d1a0111acf2581f8529c6e5 upstream. Signed-off-by: Heiko Carstens Signed-off-by: Greg Kroah-Hartman

System call wrappers part 32

2009-01-18T18:44:01Z

commit d4e82042c4cfa87a7d51710b71f568fe80132551 upstream. Signed-off-by: Heiko Carstens Signed-off-by: Greg Kroah-Hartman

powerpc: Enable syscall wrappers for 64-bit

2009-01-18T18:43:52Z

commit ee6a093222549ac0c72cfd296c69fa5e7d6daa34 upstream. This enables the use of syscall wrappers to do proper sign extension for 64-bit programs. Signed-off-by: Benjamin Herrenschmidt Signed-off-by: Heiko Carstens Signed-off-by: Greg Kroah-Hartman

System call wrapper infrastructure

2009-01-18T18:43:52Z

commit 1a94bc34768e463a93cb3751819709ab0ea80a01 upstream. From: Martin Schwidefsky By selecting HAVE_SYSCALL_WRAPPERS architectures can activate system call wrappers in order to sign extend system call arguments. All architectures where the ABI defines that the caller of a function has to perform sign extension probably need this. Reported-by: Christian Borntraeger Acked-by: Ralf Baechle Signed-off-by: Martin Schwidefsky Signed-off-by: Heiko Carstens Signed-off-by: Greg Kroah-Hartman

Rename old_readdir to sys_old_readdir

2009-01-18T18:43:51Z

commit e55380edf68796d75bf41391a781c68ee678587d upstream. This way it matches the generic system call name convention. Signed-off-by: Heiko Carstens Signed-off-by: Greg Kroah-Hartman

Convert all system calls to return a long

2009-01-18T18:43:50Z

commit 2ed7c03ec17779afb4fcfa3b8c61df61bd4879ba upstream. Convert all system calls to return a long. This should be a NOP since all converted types should have the same size anyway. With the exception of sys_exit_group which returned void. But that doesn't matter since the system call doesn't return. Signed-off-by: Heiko Carstens Signed-off-by: Greg Kroah-Hartman

Move compat system call declarations to compat header file

2009-01-18T18:43:50Z

commit 4c696ba7982501d43dea11dbbaabd2aa8a19cc42 upstream. Move declarations to correct header file. Signed-off-by: Heiko Carstens Signed-off-by: Greg Kroah-Hartman

inotify: fix type errors in interfaces

2009-01-18T18:43:49Z

commit 4ae8978cf92a96257cd8998a49e781be83571d64 upstream. The problems lie in the types used for some inotify interfaces, both at the kernel level and at the glibc level. This mail addresses the kernel problem. I will follow up with some suggestions for glibc changes. For the sys_inotify_rm_watch() interface, the type of the 'wd' argument is currently 'u32', it should be '__s32' . That is Robert's suggestion, and is consistent with the other declarations of watch descriptors in the kernel source, in particular, the inotify_event structure in include/linux/inotify.h: struct inotify_event { __s32 wd; /* watch descriptor */ __u32 mask; /* watch mask */ __u32 cookie; /* cookie to synchronize two events */ __u32 len; /* length (including nulls) of name */ char name[0]; /* stub for possible name */ }; The patch makes the changes needed for inotify_rm_watch(). Signed-off-by: Michael Kerrisk Cc: Robert Love Cc: Vegard Nossum Cc: Ulrich Drepper Signed-off-by: Andrew Morton Signed-off-by: Al Viro Signed-off-by: Greg Kroah-Hartman