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author | Mike Rapoport <rppt@linux.vnet.ibm.com> | 2017-02-24 14:58:22 -0800 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-02-24 17:46:55 -0800 |
commit | 897ab3e0c49e24b62e2d54d165c7afec6bbca65b (patch) | |
tree | 5fa7e09864d6c959cef33849f6cb10ed04e459e4 /mm/mremap.c | |
parent | 846b1a0f1db065a8479159dd8fecddb1ebf30547 (diff) | |
download | linux-stable-897ab3e0c49e24b62e2d54d165c7afec6bbca65b.tar.gz linux-stable-897ab3e0c49e24b62e2d54d165c7afec6bbca65b.tar.bz2 linux-stable-897ab3e0c49e24b62e2d54d165c7afec6bbca65b.zip |
userfaultfd: non-cooperative: add event for memory unmaps
When a non-cooperative userfaultfd monitor copies pages in the
background, it may encounter regions that were already unmapped.
Addition of UFFD_EVENT_UNMAP allows the uffd monitor to track precisely
changes in the virtual memory layout.
Since there might be different uffd contexts for the affected VMAs, we
first should create a temporary representation for the unmap event for
each uffd context and then notify them one by one to the appropriate
userfault file descriptors.
The event notification occurs after the mmap_sem has been released.
[arnd@arndb.de: fix nommu build]
Link: http://lkml.kernel.org/r/20170203165141.3665284-1-arnd@arndb.de
[mhocko@suse.com: fix nommu build]
Link: http://lkml.kernel.org/r/20170202091503.GA22823@dhcp22.suse.cz
Link: http://lkml.kernel.org/r/1485542673-24387-3-git-send-email-rppt@linux.vnet.ibm.com
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Pavel Emelyanov <xemul@virtuozzo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/mremap.c')
-rw-r--r-- | mm/mremap.c | 23 |
1 files changed, 14 insertions, 9 deletions
diff --git a/mm/mremap.c b/mm/mremap.c index 8779928d6a70..8233b0105c82 100644 --- a/mm/mremap.c +++ b/mm/mremap.c @@ -252,7 +252,8 @@ unsigned long move_page_tables(struct vm_area_struct *vma, static unsigned long move_vma(struct vm_area_struct *vma, unsigned long old_addr, unsigned long old_len, unsigned long new_len, unsigned long new_addr, - bool *locked, struct vm_userfaultfd_ctx *uf) + bool *locked, struct vm_userfaultfd_ctx *uf, + struct list_head *uf_unmap) { struct mm_struct *mm = vma->vm_mm; struct vm_area_struct *new_vma; @@ -341,7 +342,7 @@ static unsigned long move_vma(struct vm_area_struct *vma, if (unlikely(vma->vm_flags & VM_PFNMAP)) untrack_pfn_moved(vma); - if (do_munmap(mm, old_addr, old_len) < 0) { + if (do_munmap(mm, old_addr, old_len, uf_unmap) < 0) { /* OOM: unable to split vma, just get accounts right */ vm_unacct_memory(excess >> PAGE_SHIFT); excess = 0; @@ -417,7 +418,8 @@ static struct vm_area_struct *vma_to_resize(unsigned long addr, static unsigned long mremap_to(unsigned long addr, unsigned long old_len, unsigned long new_addr, unsigned long new_len, bool *locked, - struct vm_userfaultfd_ctx *uf) + struct vm_userfaultfd_ctx *uf, + struct list_head *uf_unmap) { struct mm_struct *mm = current->mm; struct vm_area_struct *vma; @@ -435,12 +437,12 @@ static unsigned long mremap_to(unsigned long addr, unsigned long old_len, if (addr + old_len > new_addr && new_addr + new_len > addr) goto out; - ret = do_munmap(mm, new_addr, new_len); + ret = do_munmap(mm, new_addr, new_len, NULL); if (ret) goto out; if (old_len >= new_len) { - ret = do_munmap(mm, addr+new_len, old_len - new_len); + ret = do_munmap(mm, addr+new_len, old_len - new_len, uf_unmap); if (ret && old_len != new_len) goto out; old_len = new_len; @@ -462,7 +464,8 @@ static unsigned long mremap_to(unsigned long addr, unsigned long old_len, if (offset_in_page(ret)) goto out1; - ret = move_vma(vma, addr, old_len, new_len, new_addr, locked, uf); + ret = move_vma(vma, addr, old_len, new_len, new_addr, locked, uf, + uf_unmap); if (!(offset_in_page(ret))) goto out; out1: @@ -502,6 +505,7 @@ SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len, unsigned long charged = 0; bool locked = false; struct vm_userfaultfd_ctx uf = NULL_VM_UFFD_CTX; + LIST_HEAD(uf_unmap); if (flags & ~(MREMAP_FIXED | MREMAP_MAYMOVE)) return ret; @@ -528,7 +532,7 @@ SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len, if (flags & MREMAP_FIXED) { ret = mremap_to(addr, old_len, new_addr, new_len, - &locked, &uf); + &locked, &uf, &uf_unmap); goto out; } @@ -538,7 +542,7 @@ SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len, * do_munmap does all the needed commit accounting */ if (old_len >= new_len) { - ret = do_munmap(mm, addr+new_len, old_len - new_len); + ret = do_munmap(mm, addr+new_len, old_len - new_len, &uf_unmap); if (ret && old_len != new_len) goto out; ret = addr; @@ -598,7 +602,7 @@ SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len, } ret = move_vma(vma, addr, old_len, new_len, new_addr, - &locked, &uf); + &locked, &uf, &uf_unmap); } out: if (offset_in_page(ret)) { @@ -609,5 +613,6 @@ out: if (locked && new_len > old_len) mm_populate(new_addr + old_len, new_len - old_len); mremap_userfaultfd_complete(&uf, addr, new_addr, old_len); + userfaultfd_unmap_complete(mm, &uf_unmap); return ret; } |