mm/mlock: prepare params outside critical region
All mlock related syscalls prepare lock limits, lengths and start parameters with the mmap_sem held. Move this logic outside of the critical region. For the case of mlock, continue incrementing the amount already locked by mm->locked_vm with the rwsem taken. Signed-off-by: Davidlohr Bueso <davidlohr@hp.com> Cc: Rik van Riel <riel@redhat.com> Reviewed-by: Michel Lespinasse <walken@google.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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1 changed files with 11 additions and 7 deletions
18
mm/mlock.c
18
mm/mlock.c
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@ -709,19 +709,21 @@ SYSCALL_DEFINE2(mlock, unsigned long, start, size_t, len)
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lru_add_drain_all(); /* flush pagevec */
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down_write(¤t->mm->mmap_sem);
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len = PAGE_ALIGN(len + (start & ~PAGE_MASK));
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start &= PAGE_MASK;
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locked = len >> PAGE_SHIFT;
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locked += current->mm->locked_vm;
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lock_limit = rlimit(RLIMIT_MEMLOCK);
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lock_limit >>= PAGE_SHIFT;
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locked = len >> PAGE_SHIFT;
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down_write(¤t->mm->mmap_sem);
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locked += current->mm->locked_vm;
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/* check against resource limits */
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if ((locked <= lock_limit) || capable(CAP_IPC_LOCK))
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error = do_mlock(start, len, 1);
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up_write(¤t->mm->mmap_sem);
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if (!error)
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error = __mm_populate(start, len, 0);
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@ -732,11 +734,13 @@ SYSCALL_DEFINE2(munlock, unsigned long, start, size_t, len)
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{
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int ret;
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down_write(¤t->mm->mmap_sem);
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len = PAGE_ALIGN(len + (start & ~PAGE_MASK));
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start &= PAGE_MASK;
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down_write(¤t->mm->mmap_sem);
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ret = do_mlock(start, len, 0);
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up_write(¤t->mm->mmap_sem);
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return ret;
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}
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@ -781,12 +785,12 @@ SYSCALL_DEFINE1(mlockall, int, flags)
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if (flags & MCL_CURRENT)
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lru_add_drain_all(); /* flush pagevec */
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down_write(¤t->mm->mmap_sem);
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lock_limit = rlimit(RLIMIT_MEMLOCK);
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lock_limit >>= PAGE_SHIFT;
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ret = -ENOMEM;
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down_write(¤t->mm->mmap_sem);
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if (!(flags & MCL_CURRENT) || (current->mm->total_vm <= lock_limit) ||
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capable(CAP_IPC_LOCK))
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ret = do_mlockall(flags);
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