cregit-Linux how code gets into the kernel

Release 4.18 include/linux/sched/mm.h

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_SCHED_MM_H

#define _LINUX_SCHED_MM_H

#include <linux/kernel.h>
#include <linux/atomic.h>
#include <linux/sched.h>
#include <linux/mm_types.h>
#include <linux/gfp.h>
#include <linux/sync_core.h>

/*
 * Routines for handling mm_structs
 */
extern struct mm_struct *mm_alloc(void);

/**
 * mmgrab() - Pin a &struct mm_struct.
 * @mm: The &struct mm_struct to pin.
 *
 * Make sure that @mm will not get freed even after the owning task
 * exits. This doesn't guarantee that the associated address space
 * will still exist later on and mmget_not_zero() has to be used before
 * accessing it.
 *
 * This is a preferred way to to pin @mm for a longer/unbounded amount
 * of time.
 *
 * Use mmdrop() to release the reference acquired by mmgrab().
 *
 * See also <Documentation/vm/active_mm.rst> for an in-depth explanation
 * of &mm_struct.mm_count vs &mm_struct.mm_users.
 */

static inline void mmgrab(struct mm_struct *mm) { atomic_inc(&mm->mm_count); }

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Ingo Molnar20100.00%1100.00%
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extern void __mmdrop(struct mm_struct *mm);
static inline void mmdrop(struct mm_struct *mm) { /* * The implicit full barrier implied by atomic_dec_and_test() is * required by the membarrier system call before returning to * user-space, after storing to rq->curr. */ if (unlikely(atomic_dec_and_test(&mm->mm_count))) __mmdrop(mm); }

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Andrew Morton31100.00%1100.00%
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/** * mmget() - Pin the address space associated with a &struct mm_struct. * @mm: The address space to pin. * * Make sure that the address space of the given &struct mm_struct doesn't * go away. This does not protect against parts of the address space being * modified or freed, however. * * Never use this function to pin this address space for an * unbounded/indefinite amount of time. * * Use mmput() to release the reference acquired by mmget(). * * See also <Documentation/vm/active_mm.rst> for an in-depth explanation * of &mm_struct.mm_count vs &mm_struct.mm_users. */
static inline void mmget(struct mm_struct *mm) { atomic_inc(&mm->mm_users); }

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Ingo Molnar20100.00%1100.00%
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static inline bool mmget_not_zero(struct mm_struct *mm) { return atomic_inc_not_zero(&mm->mm_users); }

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Ingo Molnar21100.00%1100.00%
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/* mmput gets rid of the mappings and all user-space */ extern void mmput(struct mm_struct *); #ifdef CONFIG_MMU /* same as above but performs the slow path from the async context. Can * be called from the atomic context as well */ void mmput_async(struct mm_struct *); #endif /* Grab a reference to a task's mm, if it is not already going away */ extern struct mm_struct *get_task_mm(struct task_struct *task); /* * Grab a reference to a task's mm, if it is not already going away * and ptrace_may_access with the mode parameter passed to it * succeeds. */ extern struct mm_struct *mm_access(struct task_struct *task, unsigned int mode); /* Remove the current tasks stale references to the old mm_struct */ extern void mm_release(struct task_struct *, struct mm_struct *); #ifdef CONFIG_MEMCG extern void mm_update_next_owner(struct mm_struct *mm); #else
static inline void mm_update_next_owner(struct mm_struct *mm) { }

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#endif /* CONFIG_MEMCG */ #ifdef CONFIG_MMU extern void arch_pick_mmap_layout(struct mm_struct *mm, struct rlimit *rlim_stack); extern unsigned long arch_get_unmapped_area(struct file *, unsigned long, unsigned long, unsigned long, unsigned long); extern unsigned long arch_get_unmapped_area_topdown(struct file *filp, unsigned long addr, unsigned long len, unsigned long pgoff, unsigned long flags); #else
static inline void arch_pick_mmap_layout(struct mm_struct *mm, struct rlimit *rlim_stack) {}

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Ingo Molnar1168.75%150.00%
Kees Cook531.25%150.00%
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#endif
static inline bool in_vfork(struct task_struct *tsk) { bool ret; /* * need RCU to access ->real_parent if CLONE_VM was used along with * CLONE_PARENT. * * We check real_parent->mm == tsk->mm because CLONE_VFORK does not * imply CLONE_VM * * CLONE_VFORK can be used with CLONE_PARENT/CLONE_THREAD and thus * ->real_parent is not necessarily the task doing vfork(), so in * theory we can't rely on task_lock() if we want to dereference it. * * And in this case we can't trust the real_parent->mm == tsk->mm * check, it can be false negative. But we do not care, if init or * another oom-unkillable task does this it should blame itself. */ rcu_read_lock(); ret = tsk->vfork_done && tsk->real_parent->mm == tsk->mm; rcu_read_unlock(); return ret; }

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Ingo Molnar41100.00%1100.00%
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/* * Applies per-task gfp context to the given allocation flags. * PF_MEMALLOC_NOIO implies GFP_NOIO * PF_MEMALLOC_NOFS implies GFP_NOFS */
static inline gfp_t current_gfp_context(gfp_t flags) { /* * NOIO implies both NOIO and NOFS and it is a weaker context * so always make sure it makes precendence */ if (unlikely(current->flags & PF_MEMALLOC_NOIO)) flags &= ~(__GFP_IO | __GFP_FS); else if (unlikely(current->flags & PF_MEMALLOC_NOFS)) flags &= ~__GFP_FS; return flags; }

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Ingo Molnar3262.75%150.00%
Michal Hocko1937.25%150.00%
Total51100.00%2100.00%

#ifdef CONFIG_LOCKDEP extern void __fs_reclaim_acquire(void); extern void __fs_reclaim_release(void); extern void fs_reclaim_acquire(gfp_t gfp_mask); extern void fs_reclaim_release(gfp_t gfp_mask); #else
static inline void __fs_reclaim_acquire(void) { }

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Omar Sandoval8100.00%1100.00%
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static inline void __fs_reclaim_release(void) { }

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Omar Sandoval8100.00%1100.00%
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static inline void fs_reclaim_acquire(gfp_t gfp_mask) { }

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Peter Zijlstra9100.00%1100.00%
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static inline void fs_reclaim_release(gfp_t gfp_mask) { }

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Peter Zijlstra9100.00%1100.00%
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#endif /** * memalloc_noio_save - Marks implicit GFP_NOIO allocation scope. * * This functions marks the beginning of the GFP_NOIO allocation scope. * All further allocations will implicitly drop __GFP_IO flag and so * they are safe for the IO critical section from the allocation recursion * point of view. Use memalloc_noio_restore to end the scope with flags * returned by this function. * * This function is safe to be used from any context. */
static inline unsigned int memalloc_noio_save(void) { unsigned int flags = current->flags & PF_MEMALLOC_NOIO; current->flags |= PF_MEMALLOC_NOIO; return flags; }

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Ingo Molnar29100.00%1100.00%
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/** * memalloc_noio_restore - Ends the implicit GFP_NOIO scope. * @flags: Flags to restore. * * Ends the implicit GFP_NOIO scope started by memalloc_noio_save function. * Always make sure that that the given flags is the return value from the * pairing memalloc_noio_save call. */
static inline void memalloc_noio_restore(unsigned int flags) { current->flags = (current->flags & ~PF_MEMALLOC_NOIO) | flags; }

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Ingo Molnar26100.00%1100.00%
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/** * memalloc_nofs_save - Marks implicit GFP_NOFS allocation scope. * * This functions marks the beginning of the GFP_NOFS allocation scope. * All further allocations will implicitly drop __GFP_FS flag and so * they are safe for the FS critical section from the allocation recursion * point of view. Use memalloc_nofs_restore to end the scope with flags * returned by this function. * * This function is safe to be used from any context. */
static inline unsigned int memalloc_nofs_save(void) { unsigned int flags = current->flags & PF_MEMALLOC_NOFS; current->flags |= PF_MEMALLOC_NOFS; return flags; }

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Michal Hocko29100.00%1100.00%
Total29100.00%1100.00%

/** * memalloc_nofs_restore - Ends the implicit GFP_NOFS scope. * @flags: Flags to restore. * * Ends the implicit GFP_NOFS scope started by memalloc_nofs_save function. * Always make sure that that the given flags is the return value from the * pairing memalloc_nofs_save call. */
static inline void memalloc_nofs_restore(unsigned int flags) { current->flags = (current->flags & ~PF_MEMALLOC_NOFS) | flags; }

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Michal Hocko26100.00%1100.00%
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static inline unsigned int memalloc_noreclaim_save(void) { unsigned int flags = current->flags & PF_MEMALLOC; current->flags |= PF_MEMALLOC; return flags; }

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Vlastimil Babka29100.00%1100.00%
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static inline void memalloc_noreclaim_restore(unsigned int flags) { current->flags = (current->flags & ~PF_MEMALLOC) | flags; }

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Vlastimil Babka26100.00%1100.00%
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#ifdef CONFIG_MEMBARRIER enum { MEMBARRIER_STATE_PRIVATE_EXPEDITED_READY = (1U << 0), MEMBARRIER_STATE_PRIVATE_EXPEDITED = (1U << 1), MEMBARRIER_STATE_GLOBAL_EXPEDITED_READY = (1U << 2), MEMBARRIER_STATE_GLOBAL_EXPEDITED = (1U << 3), MEMBARRIER_STATE_PRIVATE_EXPEDITED_SYNC_CORE_READY = (1U << 4), MEMBARRIER_STATE_PRIVATE_EXPEDITED_SYNC_CORE = (1U << 5), }; enum { MEMBARRIER_FLAG_SYNC_CORE = (1U << 0), }; #ifdef CONFIG_ARCH_HAS_MEMBARRIER_CALLBACKS #include <asm/membarrier.h> #endif
static inline void membarrier_mm_sync_core_before_usermode(struct mm_struct *mm) { if (likely(!(atomic_read(&mm->membarrier_state) & MEMBARRIER_STATE_PRIVATE_EXPEDITED_SYNC_CORE))) return; sync_core_before_usermode(); }

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Mathieu Desnoyers34100.00%1100.00%
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static inline void membarrier_execve(struct task_struct *t) { atomic_set(&t->mm->membarrier_state, 0); }

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Mathieu Desnoyers24100.00%1100.00%
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#else #ifdef CONFIG_ARCH_HAS_MEMBARRIER_CALLBACKS
static inline void membarrier_arch_switch_mm(struct mm_struct *prev, struct mm_struct *next, struct task_struct *tsk) { }

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Mathieu Desnoyers21100.00%1100.00%
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#endif
static inline void membarrier_execve(struct task_struct *t) { }

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Mathieu Desnoyers11100.00%1100.00%
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static inline void membarrier_mm_sync_core_before_usermode(struct mm_struct *mm) { }

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Mathieu Desnoyers11100.00%1100.00%
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#endif #endif /* _LINUX_SCHED_MM_H */

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Ingo Molnar39146.44%834.78%
Mathieu Desnoyers18622.09%417.39%
Michal Hocko799.38%28.70%
Vlastimil Babka556.53%14.35%
Peter Zijlstra414.87%14.35%
Andrew Morton333.92%28.70%
Omar Sandoval303.56%14.35%
Sherry Yang141.66%14.35%
Kees Cook101.19%14.35%
Mike Rapoport20.24%14.35%
Greg Kroah-Hartman10.12%14.35%
Total842100.00%23100.00%
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