From 79eb597cba06c435b72f220e9d426ae413fc2579 Mon Sep 17 00:00:00 2001 From: Daniel Jordan Date: Tue, 16 Jul 2019 16:30:54 -0700 Subject: mm: add account_locked_vm utility function locked_vm accounting is done roughly the same way in five places, so unify them in a helper. Include the helper's caller in the debug print to distinguish between callsites. Error codes stay the same, so user-visible behavior does too. The one exception is that the -EPERM case in tce_account_locked_vm is removed because Alexey has never seen it triggered. [daniel.m.jordan@oracle.com: v3] Link: http://lkml.kernel.org/r/20190529205019.20927-1-daniel.m.jordan@oracle.com [sfr@canb.auug.org.au: fix mm/util.c] Link: http://lkml.kernel.org/r/20190524175045.26897-1-daniel.m.jordan@oracle.com Signed-off-by: Daniel Jordan Signed-off-by: Stephen Rothwell Tested-by: Alexey Kardashevskiy Acked-by: Alex Williamson Cc: Alan Tull Cc: Alex Williamson Cc: Benjamin Herrenschmidt Cc: Christoph Lameter Cc: Christophe Leroy Cc: Davidlohr Bueso Cc: Jason Gunthorpe Cc: Mark Rutland Cc: Michael Ellerman Cc: Moritz Fischer Cc: Paul Mackerras Cc: Steve Sistare Cc: Wu Hao Cc: Ira Weiny Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/util.c | 75 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 75 insertions(+) (limited to 'mm/util.c') diff --git a/mm/util.c b/mm/util.c index 68575a315dc5..e6351a80f248 100644 --- a/mm/util.c +++ b/mm/util.c @@ -7,6 +7,7 @@ #include #include #include +#include #include #include #include @@ -300,6 +301,80 @@ void arch_pick_mmap_layout(struct mm_struct *mm, struct rlimit *rlim_stack) } #endif +/** + * __account_locked_vm - account locked pages to an mm's locked_vm + * @mm: mm to account against + * @pages: number of pages to account + * @inc: %true if @pages should be considered positive, %false if not + * @task: task used to check RLIMIT_MEMLOCK + * @bypass_rlim: %true if checking RLIMIT_MEMLOCK should be skipped + * + * Assumes @task and @mm are valid (i.e. at least one reference on each), and + * that mmap_sem is held as writer. + * + * Return: + * * 0 on success + * * -ENOMEM if RLIMIT_MEMLOCK would be exceeded. + */ +int __account_locked_vm(struct mm_struct *mm, unsigned long pages, bool inc, + struct task_struct *task, bool bypass_rlim) +{ + unsigned long locked_vm, limit; + int ret = 0; + + lockdep_assert_held_write(&mm->mmap_sem); + + locked_vm = mm->locked_vm; + if (inc) { + if (!bypass_rlim) { + limit = task_rlimit(task, RLIMIT_MEMLOCK) >> PAGE_SHIFT; + if (locked_vm + pages > limit) + ret = -ENOMEM; + } + if (!ret) + mm->locked_vm = locked_vm + pages; + } else { + WARN_ON_ONCE(pages > locked_vm); + mm->locked_vm = locked_vm - pages; + } + + pr_debug("%s: [%d] caller %ps %c%lu %lu/%lu%s\n", __func__, task->pid, + (void *)_RET_IP_, (inc) ? '+' : '-', pages << PAGE_SHIFT, + locked_vm << PAGE_SHIFT, task_rlimit(task, RLIMIT_MEMLOCK), + ret ? " - exceeded" : ""); + + return ret; +} +EXPORT_SYMBOL_GPL(__account_locked_vm); + +/** + * account_locked_vm - account locked pages to an mm's locked_vm + * @mm: mm to account against, may be NULL + * @pages: number of pages to account + * @inc: %true if @pages should be considered positive, %false if not + * + * Assumes a non-NULL @mm is valid (i.e. at least one reference on it). + * + * Return: + * * 0 on success, or if mm is NULL + * * -ENOMEM if RLIMIT_MEMLOCK would be exceeded. + */ +int account_locked_vm(struct mm_struct *mm, unsigned long pages, bool inc) +{ + int ret; + + if (pages == 0 || !mm) + return 0; + + down_write(&mm->mmap_sem); + ret = __account_locked_vm(mm, pages, inc, current, + capable(CAP_IPC_LOCK)); + up_write(&mm->mmap_sem); + + return ret; +} +EXPORT_SYMBOL_GPL(account_locked_vm); + unsigned long vm_mmap_pgoff(struct file *file, unsigned long addr, unsigned long len, unsigned long prot, unsigned long flag, unsigned long pgoff) -- cgit v1.2.3-58-ga151