diff options
| -rw-r--r-- | include/linux/mm.h | 1 | ||||
| -rw-r--r-- | mm/gup.c | 33 | ||||
| -rw-r--r-- | mm/hugetlb.c | 5 |
3 files changed, 34 insertions, 5 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h index 8bbcccbc5565..3c84f4e48cd7 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -2958,6 +2958,7 @@ struct page *follow_page(struct vm_area_struct *vma, unsigned long address, #define FOLL_SPLIT_PMD 0x20000 /* split huge pmd before returning */ #define FOLL_PIN 0x40000 /* pages must be released via unpin_user_page */ #define FOLL_FAST_ONLY 0x80000 /* gup_fast: prevent fall-back to slow gup */ +#define FOLL_INTERRUPTIBLE 0x100000 /* allow interrupts from generic signals */ /* * FOLL_PIN and FOLL_LONGTERM may be used in various combinations with each @@ -989,8 +989,17 @@ static int faultin_page(struct vm_area_struct *vma, fault_flags |= FAULT_FLAG_WRITE; if (*flags & FOLL_REMOTE) fault_flags |= FAULT_FLAG_REMOTE; - if (locked) + if (locked) { fault_flags |= FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE; + /* + * FAULT_FLAG_INTERRUPTIBLE is opt-in. GUP callers must set + * FOLL_INTERRUPTIBLE to enable FAULT_FLAG_INTERRUPTIBLE. + * That's because some callers may not be prepared to + * handle early exits caused by non-fatal signals. + */ + if (*flags & FOLL_INTERRUPTIBLE) + fault_flags |= FAULT_FLAG_INTERRUPTIBLE; + } if (*flags & FOLL_NOWAIT) fault_flags |= FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_RETRY_NOWAIT; if (*flags & FOLL_TRIED) { @@ -1392,6 +1401,22 @@ retry: EXPORT_SYMBOL_GPL(fixup_user_fault); /* + * GUP always responds to fatal signals. When FOLL_INTERRUPTIBLE is + * specified, it'll also respond to generic signals. The caller of GUP + * that has FOLL_INTERRUPTIBLE should take care of the GUP interruption. + */ +static bool gup_signal_pending(unsigned int flags) +{ + if (fatal_signal_pending(current)) + return true; + + if (!(flags & FOLL_INTERRUPTIBLE)) + return false; + + return signal_pending(current); +} + +/* * Please note that this function, unlike __get_user_pages will not * return 0 for nr_pages > 0 without FOLL_NOWAIT */ @@ -1472,11 +1497,11 @@ retry: * Repeat on the address that fired VM_FAULT_RETRY * with both FAULT_FLAG_ALLOW_RETRY and * FAULT_FLAG_TRIED. Note that GUP can be interrupted - * by fatal signals, so we need to check it before we + * by fatal signals of even common signals, depending on + * the caller's request. So we need to check it before we * start trying again otherwise it can loop forever. */ - - if (fatal_signal_pending(current)) { + if (gup_signal_pending(flags)) { if (!pages_done) pages_done = -EINTR; break; diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 546df97c31e4..b5ed54f760bb 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -6285,9 +6285,12 @@ long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma, fault_flags |= FAULT_FLAG_WRITE; else if (unshare) fault_flags |= FAULT_FLAG_UNSHARE; - if (locked) + if (locked) { fault_flags |= FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE; + if (flags & FOLL_INTERRUPTIBLE) + fault_flags |= FAULT_FLAG_INTERRUPTIBLE; + } if (flags & FOLL_NOWAIT) fault_flags |= FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_RETRY_NOWAIT; |