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* s390/gup: handle zero nr_pages case correctlyHeiko Carstens2013-10-241-1/+1
| | | | | | | | | | | If [__]get_user_pages_fast() gets called with nr_pages == 0, the current code would walk the page tables and pin as many pages until the first invalid pte (or the kernel crashed while writing struct page pointers to the pages array). So let's handle at least the nr_pages == 0 case correctly and exit early. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* s390/gup: reduce code duplication between [__]get_user_pages_fast functionsHeiko Carstens2013-10-241-58/+23
| | | | | | | | | Just call __get_user_pages_fast() from get_user_pages_fast() like powerpc. This saves a lot of duplicated code. Reviewed-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* s390/mm: cleanup page table definitionsMartin Schwidefsky2013-08-221-3/+3
| | | | | | | | | | | | | Improve the encoding of the different pte types and the naming of the page, segment table and region table bits. Due to the different pte encoding the hugetlbfs primitives need to be adapted as well. To improve compatability with common code make the huge ptes use the encoding of normal ptes. The conversion between the pte and pmd encoding for a huge pte is done with set_huge_pte_at and huge_ptep_get. Overall the code is now easier to understand. Reviewed-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* s390/gup: fix access_ok() usage in __get_user_pages_fast()Heiko Carstens2012-11-131-2/+1
| | | | | | | | | | | | | access_ok() returns always "true" on s390. Therefore all access_ok() invocations are rather pointless. However when walking page tables we need to make sure that everything is within bounds of the ASCE limit of the task's address space. So remove the access_ok() call and add the same check we have in get_user_pages_fast(). Reviewed-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* s390/gup: add missing TASK_SIZE check to get_user_pages_fast()Heiko Carstens2012-11-131-1/+1
| | | | | | | | | | | | | | When walking page tables we need to make sure that everything is within bounds of the ASCE limit of the task's address space. Otherwise we might calculate e.g. a pud pointer which is not within a pud and dereference it. So check against TASK_SIZE (which is the ASCE limit) before walking page tables. Reviewed-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> Cc: stable@vger.kernel.org Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* s390/mm: use pmd_large() instead of pmd_huge()Gerald Schaefer2012-10-261-1/+1
| | | | | | | | | Without CONFIG_HUGETLB_PAGE, pmd_huge() will always return 0. So pmd_large() should be used instead in places where both transparent huge pages and hugetlbfs pages can occur. Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* thp, s390: thp splitting backend for s390Gerald Schaefer2012-10-091-1/+10
| | | | | | | | | | | | | | | | | | | This patch is part of the architecture backend for thp on s390. It provides the functions related to thp splitting, including serialization against gup. Unlike other archs, pmdp_splitting_flush() cannot use a tlb flushing operation to serialize against gup on s390, because that wouldn't be stopped by the disabled IRQs. So instead, smp_call_function() is called with an empty function, which will have the expected effect. Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Hugh Dickins <hughd@google.com> Cc: Hillf Danton <dhillf@gmail.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* s390/mm: implement __get_user_pages_fast()Gerald Schaefer2012-09-261-0/+37
| | | | | | | | This patch introduces the __get_user_pages_fast() function on s390, which will be needed with CONFIG_TRANSPARENT_HUGEPAGE and futex. Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* thp: share get_huge_page_tail()Andrea Arcangeli2011-11-021-11/+0
| | | | | | | | | | | | | | | | | | | This avoids duplicating the function in every arch gup_fast. Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <jweiner@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: David Gibson <david@gibson.dropbear.id.au> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: David Miller <davem@davemloft.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* s390: gup_huge_pmd() return 0 if pte changesAndrea Arcangeli2011-11-021-10/+11
| | | | | | | | | | | | | | | | | | | | | s390 didn't return 0 in that case, if it's rolling back the *nr pointer it should also return zero to avoid adding pages to the array at the wrong offset. Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <jweiner@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: David Gibson <david@gibson.dropbear.id.au> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: David Miller <davem@davemloft.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* s390: gup_huge_pmd() support THP tail recountingAndrea Arcangeli2011-11-021-1/+23
| | | | | | | | | | | | | | | | | | | | Up to this point the code assumed old refcounting for hugepages (pre-thp). This updates the code directly to the thp mapcount tail page refcounting. Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <jweiner@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: David Gibson <david@gibson.dropbear.id.au> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: David Miller <davem@davemloft.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [S390] fix get_user_pages_fastMartin Schwidefsky2010-11-101-4/+3
| | | | | | | The check for the _PAGE_RO bit in get_user_pages_fast for write==1 is the wrong way around. It must not be set for the fast path. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* [S390] lockless get_user_pages_fast()Martin Schwidefsky2010-10-251-0/+225
Implement get_user_pages_fast without locking in the fastpath on s390. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
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