hulk inclusion category: bugfix bugzilla: https://gitee.com/openeuler/release-management/issues/ID5CMS -------------------------------- To store per-process data, introducing a prefetch_mm_data. There are three important member in this struct. For prefetch_mm_data.items, this is a prefetch item array. We can use file descriptor value to index to its prefetch item. For prefetch_mm_data.events, it serves in epoll_ctl(). We use this buffer to copy ready fd-list from user. For prefetch_mm_data.mmu_notifier, in my test, when redis is being killed or exit abnormally. It will cause memleak since we has no chance to free the buffer page in prefetch_mm_data.items. To open a window for each process to free their resources, just use this mmu_notifier to register a callback in MMU. Fixes: ccb8cd0c6313 ("xcall2.0: Introduce xcall epollwait prefetch feature") Signed-off-by: Xinyu Zheng <zhengxinyu6@huawei.com> --- drivers/staging/xcall/prefetch.c | 131 ++++++++++++++++++++----------- 1 file changed, 87 insertions(+), 44 deletions(-) diff --git a/drivers/staging/xcall/prefetch.c b/drivers/staging/xcall/prefetch.c index c49f44edaf38..324eff618101 100644 --- a/drivers/staging/xcall/prefetch.c +++ b/drivers/staging/xcall/prefetch.c @@ -17,13 +17,13 @@ #include <asm/xcall.h> -#define MAX_FD 100 +#define MAX_FD 1024 #define XCALL_CACHE_PAGE_ORDER 2 #define XCALL_CACHE_BUF_SIZE ((1 << XCALL_CACHE_PAGE_ORDER) * PAGE_SIZE) -#define current_prefetch_items() \ - ((struct prefetch_item *) \ +#define current_prefetch_mm_data() \ + ((struct prefetch_mm_data *) \ ((((struct xcall_area *)(current->mm->xcall))->sys_call_data)[__NR_epoll_pwait])) static DEFINE_PER_CPU_ALIGNED(unsigned long, xcall_cache_hit); @@ -33,6 +33,9 @@ static struct workqueue_struct *rc_work; static struct cpumask xcall_mask; struct proc_dir_entry *xcall_proc_dir, *prefetch_dir, *xcall_mask_dir; +static struct list_head prefetch_mm_data_to_delete; +static spinlock_t prefetch_mm_delete_lock; + enum cache_state { XCALL_CACHE_NONE = 0, XCALL_CACHE_PREFETCH, @@ -53,6 +56,13 @@ struct prefetch_item { loff_t pos; }; +struct prefetch_mm_data { + struct prefetch_item items[MAX_FD]; + struct epoll_event events[MAX_FD]; + struct mmu_notifier mmu_notifier; + struct list_head list; +}; + static ssize_t xcall_mask_proc_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) { @@ -140,6 +150,17 @@ static const struct proc_ops xcall_prefetch_fops = { .proc_release = single_release }; +static inline struct prefetch_item *get_pfi(unsigned int fd) +{ + struct prefetch_item *pfis = NULL; + + if (fd >= MAX_FD || !current_prefetch_mm_data()) + return NULL; + + pfis = (struct prefetch_item *)current_prefetch_mm_data(); + return pfis + fd; +} + static inline bool transition_state(struct prefetch_item *pfi, enum cache_state old, enum cache_state new) { @@ -202,36 +223,53 @@ static int get_async_prefetch_cpu(struct prefetch_item *pfi) static void prefetch_pfi_release(struct mmu_notifier *mn, struct mm_struct *mm) { + struct prefetch_mm_data *private_data = + container_of(mn, struct prefetch_mm_data, mmu_notifier); struct xcall_area *area = mm_xcall_area(mm); struct prefetch_item *prefetch_items = NULL; int i; - prefetch_items = xchg(&area->sys_call_data[__NR_epoll_pwait], NULL); - if (!prefetch_items) - return; - + private_data = xchg(&area->sys_call_data[__NR_epoll_pwait], NULL); + prefetch_items = (struct prefetch_item *)private_data->items; for (i = 0; i < MAX_FD; i++) { cancel_work_sync(&prefetch_items[i].work); if (prefetch_items[i].cache_pages) __free_pages(prefetch_items[i].cache_pages, XCALL_CACHE_PAGE_ORDER); prefetch_items[i].cache = NULL; } - kfree(prefetch_items); + spin_lock(&prefetch_mm_delete_lock); + list_add_tail(&private_data->list, &prefetch_mm_data_to_delete); + spin_unlock(&prefetch_mm_delete_lock); +} + +static void xcall_mmu_notifier_free(struct mmu_notifier *mn) +{ + kfree(container_of(mn, struct prefetch_mm_data, mmu_notifier)); +} + +static void xcall_prefetch_mm_free(void) +{ + struct prefetch_mm_data *private_data, *tmp; + + spin_lock(&prefetch_mm_delete_lock); + list_for_each_entry_safe(private_data, tmp, &prefetch_mm_data_to_delete, list) { + list_del(&private_data->list); + mmu_notifier_put(&private_data->mmu_notifier); + } + spin_unlock(&prefetch_mm_delete_lock); } static struct mmu_notifier_ops xcall_mmu_notifier_ops = { .release = prefetch_pfi_release, -}; - -static struct mmu_notifier xcall_mmu_notifier = { - .ops = &xcall_mmu_notifier_ops, + .free_notifier = xcall_mmu_notifier_free, }; static void xcall_cancel_work(unsigned int fd) { - struct prefetch_item *pfi = current_prefetch_items() + fd; + struct prefetch_item *pfi = NULL; - if (fd < MAX_FD && pfi->file) + pfi = get_pfi(fd); + if (pfi && pfi->file) cancel_work_sync(&pfi->work); } @@ -301,11 +339,8 @@ static inline int xcall_read_begin(unsigned int fd, char __user *buf, size_t cou { struct prefetch_item *pfi = NULL; - if (fd >= MAX_FD || !current_prefetch_items()) - return -EAGAIN; - - pfi = current_prefetch_items() + fd; - if (!pfi->file) + pfi = get_pfi(fd); + if (!pfi || !pfi->file) return -EAGAIN; return xcall_read(pfi, buf, count); @@ -315,11 +350,8 @@ static inline void xcall_read_end(unsigned int fd) { struct prefetch_item *pfi = NULL; - if (fd >= MAX_FD || !current_prefetch_items()) - return; - - pfi = current_prefetch_items() + fd; - if (!pfi->file) + pfi = get_pfi(fd); + if (!pfi || !pfi->file) return; transition_state(pfi, XCALL_CACHE_CANCEL, XCALL_CACHE_NONE); @@ -330,24 +362,24 @@ static long __do_sys_epoll_create(struct pt_regs *regs) long ret; int i; struct xcall_area *area = mm_xcall_area(current->mm); + struct prefetch_mm_data *private_data = NULL; struct prefetch_item *items = NULL; ret = default_sys_call_table()[__NR_epoll_create1](regs); if (ret < 0) return ret; - - if (current_prefetch_items()) + if (current_prefetch_mm_data()) return ret; - items = kcalloc(MAX_FD, sizeof(struct prefetch_item), GFP_KERNEL); - if (!items) - return -ENOMEM; - - if (cmpxchg(&area->sys_call_data[__NR_epoll_pwait], NULL, items)) { - kfree(items); + private_data = kmalloc(sizeof(struct prefetch_mm_data), GFP_KERNEL); + if (!private_data) + return ret; + if (cmpxchg(&area->sys_call_data[__NR_epoll_pwait], NULL, private_data)) { + kfree(private_data); return ret; } + items = private_data->items; for (i = 0; i < MAX_FD; i++) { items[i].cache_pages = alloc_pages(GFP_KERNEL_ACCOUNT | __GFP_ZERO, XCALL_CACHE_PAGE_ORDER); @@ -364,7 +396,12 @@ static long __do_sys_epoll_create(struct pt_regs *regs) items[i].file = NULL; set_prefetch_numa_cpu(&items[i]); } - mmu_notifier_register(&xcall_mmu_notifier, current->mm); + + memset(private_data->events, 0, sizeof(private_data->events)); + INIT_LIST_HEAD(&private_data->list); + private_data->mmu_notifier.ops = &xcall_mmu_notifier_ops; + mmu_notifier_register(&private_data->mmu_notifier, current->mm); + xcall_prefetch_mm_free(); return ret; } @@ -377,13 +414,13 @@ static long __do_sys_epoll_ctl(struct pt_regs *regs) long ret; ret = default_sys_call_table()[__NR_epoll_ctl](regs); - if (ret || fd >= MAX_FD) + if (ret) return ret; - if (!current_prefetch_items()) + pfi = get_pfi(fd); + if (!pfi) return ret; - pfi = current_prefetch_items() + fd; switch (op) { case EPOLL_CTL_ADD: file = fget(fd); @@ -393,8 +430,6 @@ static long __do_sys_epoll_ctl(struct pt_regs *regs) cmpxchg(&pfi->file, NULL, file); fput(file); break; - - break; case EPOLL_CTL_DEL: xcall_cancel_work(fd); break; @@ -407,7 +442,8 @@ static long __do_sys_epoll_pwait(struct pt_regs *regs) { void __user *buf = (void *)regs->regs[1]; struct prefetch_item *pfi = NULL; - struct epoll_event events[MAX_FD] = {0}; + struct prefetch_mm_data *private_data = NULL; + struct epoll_event *events = NULL; int i, fd, cpu, prefetch_task_num; long ret; @@ -415,9 +451,12 @@ static long __do_sys_epoll_pwait(struct pt_regs *regs) if (ret <= 0) return ret; - if (!current_prefetch_items()) + if (!current_prefetch_mm_data()) return ret; + private_data = current_prefetch_mm_data(); + events = private_data->events; + prefetch_task_num = ret > MAX_FD ? MAX_FD : ret; if (copy_from_user(events, buf, prefetch_task_num * sizeof(struct epoll_event))) return ret; @@ -427,7 +466,7 @@ static long __do_sys_epoll_pwait(struct pt_regs *regs) if (!(events[i].events & EPOLLIN) || fd >= MAX_FD) continue; - pfi = current_prefetch_items() + fd; + pfi = get_pfi(fd); if (!(pfi->file) || !(pfi->file->f_mode & FMODE_READ)) continue; if (atomic_read(&pfi->state) != XCALL_CACHE_NONE) @@ -446,11 +485,11 @@ static long __do_sys_close(struct pt_regs *regs) struct file *pfi_old_file = NULL; struct file *pfi_new_file = NULL; - if (!current_prefetch_items()) + pfi = get_pfi(fd); + if (!pfi) return default_sys_call_table()[__NR_close](regs); - pfi = current_prefetch_items() + fd; - if (fd < MAX_FD && pfi->file) { + if (pfi && pfi->file) { pfi_old_file = pfi->file; pfi_new_file = cmpxchg(&pfi->file, pfi_old_file, NULL); if (pfi_new_file == pfi_old_file) { @@ -551,6 +590,8 @@ static int __init xcall_prefetch_init(void) if (ret) goto remove_dir; + INIT_LIST_HEAD(&prefetch_mm_data_to_delete); + spin_lock_init(&prefetch_mm_delete_lock); return ret; remove_dir: @@ -575,6 +616,8 @@ static void __exit xcall_prefetch_exit(void) proc_remove(xcall_proc_dir); xcall_prog_unregister(&xcall_prefetch_prog); + xcall_prefetch_mm_free(); + mmu_notifier_synchronize(); } module_init(xcall_prefetch_init); -- 2.34.1