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mm: remove CONFIG_PER_VMA_LOCK ifdefs 

Patch series "Handle most file-backed faults under the VMA lock", v3.

This patchset adds the ability to handle page faults on parts of files
which are already in the page cache without taking the mmap lock.


This patch (of 10):

Provide lock_vma_under_rcu() when CONFIG_PER_VMA_LOCK is not defined to
eliminate ifdefs in the users.

Link: https://lkml.kernel.org/r/20230724185410.1124082-1-willy@infradead.org
Link: https://lkml.kernel.org/r/20230724185410.1124082-2-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Suren Baghdasaryan <surenb@google.com>
Cc: Punit Agrawal <punit.agrawal@bytedance.com>
Cc: Arjun Roy <arjunroy@google.com>
Cc: Eric Dumazet <edumazet@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Matthew Wilcox (Oracle) 2023-07-24 19:54:01 +01:00 committed by Andrew Morton
parent 6935e05255
commit 284e059204
6 changed files with 6 additions and 16 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
arch/arm64/mm/fault.c
View File

@ -587,7 +587,6 @@ static int __kprobes do_page_fault(unsigned long far, unsigned long esr,
perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, addr);
#ifdef CONFIG_PER_VMA_LOCK
if (!(mm_flags & FAULT_FLAG_USER))
goto lock_mmap;
@ -615,7 +614,6 @@ static int __kprobes do_page_fault(unsigned long far, unsigned long esr,
return 0;
}
lock_mmap:
#endif /* CONFIG_PER_VMA_LOCK */
retry:
vma = lock_mm_and_find_vma(mm, addr, regs);

4
arch/powerpc/mm/fault.c
View File

@ -469,7 +469,6 @@ static int ___do_page_fault(struct pt_regs *regs, unsigned long address,
if (is_exec)
flags |= FAULT_FLAG_INSTRUCTION;
#ifdef CONFIG_PER_VMA_LOCK
if (!(flags & FAULT_FLAG_USER))
goto lock_mmap;
@ -501,7 +500,6 @@ static int ___do_page_fault(struct pt_regs *regs, unsigned long address,
return user_mode(regs) ? 0 : SIGBUS;
lock_mmap:
#endif /* CONFIG_PER_VMA_LOCK */
/* When running in the kernel we expect faults to occur only to
* addresses in user space. All other faults represent errors in the
@ -551,9 +549,7 @@ retry:
mmap_read_unlock(current->mm);
#ifdef CONFIG_PER_VMA_LOCK
done:
#endif
if (unlikely(fault & VM_FAULT_ERROR))
return mm_fault_error(regs, address, fault);

4
arch/riscv/mm/fault.c
View File

@ -283,7 +283,6 @@ void handle_page_fault(struct pt_regs *regs)
flags |= FAULT_FLAG_WRITE;
else if (cause == EXC_INST_PAGE_FAULT)
flags |= FAULT_FLAG_INSTRUCTION;
#ifdef CONFIG_PER_VMA_LOCK
if (!(flags & FAULT_FLAG_USER))
goto lock_mmap;
@ -311,7 +310,6 @@ void handle_page_fault(struct pt_regs *regs)
return;
}
lock_mmap:
#endif /* CONFIG_PER_VMA_LOCK */
retry:
vma = lock_mm_and_find_vma(mm, addr, regs);
@ -368,9 +366,7 @@ retry:
mmap_read_unlock(mm);
#ifdef CONFIG_PER_VMA_LOCK
done:
#endif
if (unlikely(fault & VM_FAULT_ERROR)) {
tsk->thread.bad_cause = cause;
mm_fault_error(regs, addr, fault);

2
arch/s390/mm/fault.c
View File

@ -407,7 +407,6 @@ static inline vm_fault_t do_exception(struct pt_regs *regs, int access)
access = VM_WRITE;
if (access == VM_WRITE)
flags |= FAULT_FLAG_WRITE;
#ifdef CONFIG_PER_VMA_LOCK
if (!(flags & FAULT_FLAG_USER))
goto lock_mmap;
vma = lock_vma_under_rcu(mm, address);
@ -432,7 +431,6 @@ static inline vm_fault_t do_exception(struct pt_regs *regs, int access)
goto out;
}
lock_mmap:
#endif /* CONFIG_PER_VMA_LOCK */
mmap_read_lock(mm);
gmap = NULL;

4
arch/x86/mm/fault.c
View File

@ -1328,7 +1328,6 @@ void do_user_addr_fault(struct pt_regs *regs,
}
#endif
#ifdef CONFIG_PER_VMA_LOCK
if (!(flags & FAULT_FLAG_USER))
goto lock_mmap;
@ -1358,7 +1357,6 @@ void do_user_addr_fault(struct pt_regs *regs,
return;
}
lock_mmap:
#endif /* CONFIG_PER_VMA_LOCK */
retry:
vma = lock_mm_and_find_vma(mm, address, regs);
@ -1418,9 +1416,7 @@ retry:
}
mmap_read_unlock(mm);
#ifdef CONFIG_PER_VMA_LOCK
done:
#endif
if (likely(!(fault & VM_FAULT_ERROR)))
return;

6
include/linux/mm.h
View File

@ -742,6 +742,12 @@ static inline void vma_assert_write_locked(struct vm_area_struct *vma) {}
static inline void vma_mark_detached(struct vm_area_struct *vma,
bool detached) {}
static inline struct vm_area_struct *lock_vma_under_rcu(struct mm_struct *mm,
unsigned long address)
{
return NULL;
}
#endif /* CONFIG_PER_VMA_LOCK */
/*