diff options
| -rw-r--r-- | include/linux/fs.h | 3 | ||||
| -rw-r--r-- | include/linux/mm_types.h | 4 | ||||
| -rw-r--r-- | mm/util.c | 119 | ||||
| -rw-r--r-- | mm/vma.h | 2 | ||||
| -rw-r--r-- | tools/testing/vma/include/dup.h | 68 |
5 files changed, 136 insertions, 60 deletions
diff --git a/include/linux/fs.h b/include/linux/fs.h index c390f5c667e3..0bdccfa70b44 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -2058,6 +2058,9 @@ static inline bool can_mmap_file(struct file *file) return true; } +void compat_set_desc_from_vma(struct vm_area_desc *desc, const struct file *file, + const struct vm_area_struct *vma); +int __compat_vma_mmap(struct vm_area_desc *desc, struct vm_area_struct *vma); int compat_vma_mmap(struct file *file, struct vm_area_struct *vma); int __vma_check_mmap_hook(struct vm_area_struct *vma); diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index 91a3db174d78..b702c63bf0e0 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -891,8 +891,8 @@ static __always_inline bool vma_flags_empty(const vma_flags_t *flags) */ struct vm_area_desc { /* Immutable state. */ - const struct mm_struct *const mm; - struct file *const file; /* May vary from vm_file in stacked callers. */ + struct mm_struct *mm; + struct file *file; /* May vary from vm_file in stacked callers. */ unsigned long start; unsigned long end; diff --git a/mm/util.c b/mm/util.c index 9a27d33273fd..5ae20876ef2c 100644 --- a/mm/util.c +++ b/mm/util.c @@ -1163,38 +1163,78 @@ void flush_dcache_folio(struct folio *folio) EXPORT_SYMBOL(flush_dcache_folio); #endif -static int __compat_vma_mmap(struct file *file, struct vm_area_struct *vma) -{ - struct vm_area_desc desc = { - .mm = vma->vm_mm, - .file = file, - .start = vma->vm_start, - .end = vma->vm_end, - - .pgoff = vma->vm_pgoff, - .vm_file = vma->vm_file, - .vma_flags = vma->flags, - .page_prot = vma->vm_page_prot, - - .action.type = MMAP_NOTHING, /* Default */ - }; - struct mmap_action *action = &desc.action; - int err; +/** + * compat_set_desc_from_vma() - assigns VMA descriptor @desc fields from a VMA. + * @desc: A VMA descriptor whose fields need to be set. + * @file: The file object describing the file being mmap()'d. + * @vma: The VMA whose fields we wish to assign to @desc. + * + * This is a compatibility function to allow an mmap() hook to call + * mmap_prepare() hooks when drivers nest these. This function specifically + * allows the construction of a vm_area_desc value, @desc, from a VMA @vma for + * the purposes of doing this. + * + * Once the conversion of drivers is complete this function will no longer be + * required and will be removed. + */ +void compat_set_desc_from_vma(struct vm_area_desc *desc, + const struct file *file, + const struct vm_area_struct *vma) +{ + memset(desc, 0, sizeof(*desc)); - err = vfs_mmap_prepare(file, &desc); - if (err) - return err; + desc->mm = vma->vm_mm; + desc->file = (struct file *)file; + desc->start = vma->vm_start; + desc->end = vma->vm_end; - err = mmap_action_prepare(&desc); - if (err) - return err; + desc->pgoff = vma->vm_pgoff; + desc->vm_file = vma->vm_file; + desc->vma_flags = vma->flags; + desc->page_prot = vma->vm_page_prot; - /* being invoked from .mmap means we don't have to enforce this. */ - action->hide_from_rmap_until_complete = false; + /* Default. */ + desc->action.type = MMAP_NOTHING; +} +EXPORT_SYMBOL(compat_set_desc_from_vma); + +/** + * __compat_vma_mmap() - Similar to compat_vma_mmap(), only it allows + * flexibility as to how the mmap_prepare callback is invoked, which is useful + * for drivers which invoke nested mmap_prepare callbacks in an mmap() hook. + * @desc: A VMA descriptor upon which an mmap_prepare() hook has already been + * executed. + * @vma: The VMA to which @desc should be applied. + * + * The function assumes that you have obtained a VMA descriptor @desc from + * compat_set_desc_from_vma(), and already executed the mmap_prepare() hook upon + * it. + * + * It then performs any specified mmap actions, and invokes the vm_ops->mapped() + * hook if one is present. + * + * See the description of compat_vma_mmap() for more details. + * + * Once the conversion of drivers is complete this function will no longer be + * required and will be removed. + * + * Returns: 0 on success or error. + */ +int __compat_vma_mmap(struct vm_area_desc *desc, + struct vm_area_struct *vma) +{ + int err; - set_vma_from_desc(vma, &desc); - return mmap_action_complete(vma, action); + /* Perform any preparatory tasks for mmap action. */ + err = mmap_action_prepare(desc); + if (err) + return err; + /* Update the VMA from the descriptor. */ + compat_set_vma_from_desc(vma, desc); + /* Complete any specified mmap actions. */ + return mmap_action_complete(vma, &desc->action); } +EXPORT_SYMBOL(__compat_vma_mmap); /** * compat_vma_mmap() - Apply the file's .mmap_prepare() hook to an @@ -1203,10 +1243,10 @@ static int __compat_vma_mmap(struct file *file, struct vm_area_struct *vma) * @vma: The VMA to apply the .mmap_prepare() hook to. * * Ordinarily, .mmap_prepare() is invoked directly upon mmap(). However, certain - * stacked filesystems invoke a nested mmap hook of an underlying file. + * stacked drivers invoke a nested mmap hook of an underlying file. * - * Until all filesystems are converted to use .mmap_prepare(), we must be - * conservative and continue to invoke these stacked filesystems using the + * Until all drivers are converted to use .mmap_prepare(), we must be + * conservative and continue to invoke these stacked drivers using the * deprecated .mmap() hook. * * However we have a problem if the underlying file system possesses an @@ -1217,14 +1257,27 @@ static int __compat_vma_mmap(struct file *file, struct vm_area_struct *vma) * establishes a struct vm_area_desc descriptor, passes to the underlying * .mmap_prepare() hook and applies any changes performed by it. * - * Once the conversion of filesystems is complete this function will no longer - * be required and will be removed. + * Once the conversion of drivers is complete this function will no longer be + * required and will be removed. * * Returns: 0 on success or error. */ int compat_vma_mmap(struct file *file, struct vm_area_struct *vma) { - return __compat_vma_mmap(file, vma); + struct vm_area_desc desc; + struct mmap_action *action; + int err; + + compat_set_desc_from_vma(&desc, file, vma); + err = vfs_mmap_prepare(file, &desc); + if (err) + return err; + action = &desc.action; + + /* being invoked from .mmmap means we don't have to enforce this. */ + action->hide_from_rmap_until_complete = false; + + return __compat_vma_mmap(&desc, vma); } EXPORT_SYMBOL(compat_vma_mmap); @@ -300,7 +300,7 @@ static inline int vma_iter_store_gfp(struct vma_iterator *vmi, * f_op->mmap() but which might have an underlying file system which implements * f_op->mmap_prepare(). */ -static inline void set_vma_from_desc(struct vm_area_struct *vma, +static inline void compat_set_vma_from_desc(struct vm_area_struct *vma, struct vm_area_desc *desc) { /* diff --git a/tools/testing/vma/include/dup.h b/tools/testing/vma/include/dup.h index b31207bbe10d..ecd47d0f7d17 100644 --- a/tools/testing/vma/include/dup.h +++ b/tools/testing/vma/include/dup.h @@ -519,8 +519,8 @@ enum vma_operation { */ struct vm_area_desc { /* Immutable state. */ - const struct mm_struct *const mm; - struct file *const file; /* May vary from vm_file in stacked callers. */ + struct mm_struct *mm; + struct file *file; /* May vary from vm_file in stacked callers. */ unsigned long start; unsigned long end; @@ -1278,50 +1278,70 @@ static inline void vma_set_anonymous(struct vm_area_struct *vma) } /* Declared in vma.h. */ -static inline void set_vma_from_desc(struct vm_area_struct *vma, +static inline void compat_set_vma_from_desc(struct vm_area_struct *vma, struct vm_area_desc *desc); -static inline int vfs_mmap_prepare(struct file *file, struct vm_area_desc *desc) +static inline void compat_set_desc_from_vma(struct vm_area_desc *desc, + const struct file *file, + const struct vm_area_struct *vma) { - return file->f_op->mmap_prepare(desc); + memset(desc, 0, sizeof(*desc)); + + desc->mm = vma->vm_mm; + desc->file = (struct file *)file; + desc->start = vma->vm_start; + desc->end = vma->vm_end; + + desc->pgoff = vma->vm_pgoff; + desc->vm_file = vma->vm_file; + desc->vma_flags = vma->flags; + desc->page_prot = vma->vm_page_prot; + + /* Default. */ + desc->action.type = MMAP_NOTHING; } -static inline unsigned long vma_pages(struct vm_area_struct *vma) +static inline unsigned long vma_pages(const struct vm_area_struct *vma) { return (vma->vm_end - vma->vm_start) >> PAGE_SHIFT; } -static inline int compat_vma_mmap(struct file *file, struct vm_area_struct *vma) +static inline int vfs_mmap_prepare(struct file *file, struct vm_area_desc *desc) { - struct vm_area_desc desc = { - .mm = vma->vm_mm, - .file = file, - .start = vma->vm_start, - .end = vma->vm_end, - - .pgoff = vma->vm_pgoff, - .vm_file = vma->vm_file, - .vma_flags = vma->flags, - .page_prot = vma->vm_page_prot, + return file->f_op->mmap_prepare(desc); +} - .action.type = MMAP_NOTHING, /* Default */ - }; - struct mmap_action *action = &desc.action; +static inline int __compat_vma_mmap(struct vm_area_desc *desc, + struct vm_area_struct *vma) +{ int err; - err = vfs_mmap_prepare(file, &desc); + /* Perform any preparatory tasks for mmap action. */ + err = mmap_action_prepare(desc); if (err) return err; + /* Update the VMA from the descriptor. */ + compat_set_vma_from_desc(vma, desc); + /* Complete any specified mmap actions. */ + return mmap_action_complete(vma, &desc->action); +} - err = mmap_action_prepare(&desc); +static inline int compat_vma_mmap(struct file *file, struct vm_area_struct *vma) +{ + struct vm_area_desc desc; + struct mmap_action *action; + int err; + + compat_set_desc_from_vma(&desc, file, vma); + err = vfs_mmap_prepare(file, &desc); if (err) return err; + action = &desc.action; /* being invoked from .mmmap means we don't have to enforce this. */ action->hide_from_rmap_until_complete = false; - set_vma_from_desc(vma, &desc); - return mmap_action_complete(vma, action); + return __compat_vma_mmap(&desc, vma); } static inline void vma_iter_init(struct vma_iterator *vmi, |