From: Pratyush Yadav shmem_inode_info::flags can have the VM flags VM_NORESERVE and VM_LOCKED. These are used to suppress pre-accounting or to lock the pages in the inode respectively. Using the VM flags directly makes it difficult to add shmem-specific flags that are unrelated to VM behavior since one would need to find a VM flag not used by shmem and re-purpose it. Introduce SHMEM_F_NORESERVE and SHMEM_F_LOCKED which represent the same information, but their bits are independent of the VM flags. Callers can still pass VM_NORESERVE to shmem_get_inode(), but it gets transformed to the shmem-specific flag internally. No functional changes intended. Signed-off-by: Pratyush Yadav Signed-off-by: Pasha Tatashin --- include/linux/shmem_fs.h | 6 ++++++ mm/shmem.c | 30 +++++++++++++++++------------- 2 files changed, 23 insertions(+), 13 deletions(-) diff --git a/include/linux/shmem_fs.h b/include/linux/shmem_fs.h index 6d0f9c599ff7..923f0da5f6c4 100644 --- a/include/linux/shmem_fs.h +++ b/include/linux/shmem_fs.h @@ -10,6 +10,7 @@ #include #include #include +#include struct swap_iocb; @@ -19,6 +20,11 @@ struct swap_iocb; #define SHMEM_MAXQUOTAS 2 #endif +/* Suppress pre-accounting of the entire object size. */ +#define SHMEM_F_NORESERVE BIT(0) +/* Disallow swapping. */ +#define SHMEM_F_LOCKED BIT(1) + struct shmem_inode_info { spinlock_t lock; unsigned int seals; /* shmem seals */ diff --git a/mm/shmem.c b/mm/shmem.c index e2c76a30802b..8e6b3f003da5 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -175,20 +175,20 @@ static inline struct shmem_sb_info *SHMEM_SB(struct super_block *sb) */ static inline int shmem_acct_size(unsigned long flags, loff_t size) { - return (flags & VM_NORESERVE) ? + return (flags & SHMEM_F_NORESERVE) ? 0 : security_vm_enough_memory_mm(current->mm, VM_ACCT(size)); } static inline void shmem_unacct_size(unsigned long flags, loff_t size) { - if (!(flags & VM_NORESERVE)) + if (!(flags & SHMEM_F_NORESERVE)) vm_unacct_memory(VM_ACCT(size)); } static inline int shmem_reacct_size(unsigned long flags, loff_t oldsize, loff_t newsize) { - if (!(flags & VM_NORESERVE)) { + if (!(flags & SHMEM_F_NORESERVE)) { if (VM_ACCT(newsize) > VM_ACCT(oldsize)) return security_vm_enough_memory_mm(current->mm, VM_ACCT(newsize) - VM_ACCT(oldsize)); @@ -206,7 +206,7 @@ static inline int shmem_reacct_size(unsigned long flags, */ static inline int shmem_acct_blocks(unsigned long flags, long pages) { - if (!(flags & VM_NORESERVE)) + if (!(flags & SHMEM_F_NORESERVE)) return 0; return security_vm_enough_memory_mm(current->mm, @@ -215,7 +215,7 @@ static inline int shmem_acct_blocks(unsigned long flags, long pages) static inline void shmem_unacct_blocks(unsigned long flags, long pages) { - if (flags & VM_NORESERVE) + if (flags & SHMEM_F_NORESERVE) vm_unacct_memory(pages * VM_ACCT(PAGE_SIZE)); } @@ -1588,7 +1588,7 @@ int shmem_writeout(struct folio *folio, struct swap_iocb **plug, int nr_pages; bool split = false; - if ((info->flags & VM_LOCKED) || sbinfo->noswap) + if ((info->flags & SHMEM_F_LOCKED) || sbinfo->noswap) goto redirty; if (!total_swap_pages) @@ -2971,15 +2971,15 @@ int shmem_lock(struct file *file, int lock, struct ucounts *ucounts) * ipc_lock_object() when called from shmctl_do_lock(), * no serialization needed when called from shm_destroy(). */ - if (lock && !(info->flags & VM_LOCKED)) { + if (lock && !(info->flags & SHMEM_F_LOCKED)) { if (!user_shm_lock(inode->i_size, ucounts)) goto out_nomem; - info->flags |= VM_LOCKED; + info->flags |= SHMEM_F_LOCKED; mapping_set_unevictable(file->f_mapping); } - if (!lock && (info->flags & VM_LOCKED) && ucounts) { + if (!lock && (info->flags & SHMEM_F_LOCKED) && ucounts) { user_shm_unlock(inode->i_size, ucounts); - info->flags &= ~VM_LOCKED; + info->flags &= ~SHMEM_F_LOCKED; mapping_clear_unevictable(file->f_mapping); } retval = 0; @@ -3123,7 +3123,9 @@ static struct inode *__shmem_get_inode(struct mnt_idmap *idmap, spin_lock_init(&info->lock); atomic_set(&info->stop_eviction, 0); info->seals = F_SEAL_SEAL; - info->flags = flags & VM_NORESERVE; + info->flags = 0; + if (flags & VM_NORESERVE) + info->flags |= SHMEM_F_NORESERVE; info->i_crtime = inode_get_mtime(inode); info->fsflags = (dir == NULL) ? 0 : SHMEM_I(dir)->fsflags & SHMEM_FL_INHERITED; @@ -5862,8 +5864,10 @@ static inline struct inode *shmem_get_inode(struct mnt_idmap *idmap, /* common code */ static struct file *__shmem_file_setup(struct vfsmount *mnt, const char *name, - loff_t size, unsigned long flags, unsigned int i_flags) + loff_t size, unsigned long vm_flags, + unsigned int i_flags) { + unsigned long flags = (vm_flags & VM_NORESERVE) ? SHMEM_F_NORESERVE : 0; struct inode *inode; struct file *res; @@ -5880,7 +5884,7 @@ static struct file *__shmem_file_setup(struct vfsmount *mnt, const char *name, return ERR_PTR(-ENOMEM); inode = shmem_get_inode(&nop_mnt_idmap, mnt->mnt_sb, NULL, - S_IFREG | S_IRWXUGO, 0, flags); + S_IFREG | S_IRWXUGO, 0, vm_flags); if (IS_ERR(inode)) { shmem_unacct_size(flags, size); return ERR_CAST(inode); -- 2.50.1.565.gc32cd1483b-goog