From 3f602d2724b1f7d2d27ddcd7963a040a5890fd16 Mon Sep 17 00:00:00 2001 From: Pavel Emelyanov Date: Fri, 4 Sep 2015 15:46:34 -0700 Subject: [PATCH] userfaultfd: Rename uffd_api.bits into .features This is (seems to be) the minimal thing that is required to unblock standard uffd usage from the non-cooperative one. Now more bits can be added to the features field indicating e.g. UFFD_FEATURE_FORK and others needed for the latter use-case. Signed-off-by: Pavel Emelyanov Signed-off-by: Andrea Arcangeli Cc: Sanidhya Kashyap Cc: zhang.zhanghailiang@huawei.com Cc: "Kirill A. Shutemov" Cc: Andres Lagar-Cavilla Cc: Dave Hansen Cc: Paolo Bonzini Cc: Rik van Riel Cc: Mel Gorman Cc: Andy Lutomirski Cc: Hugh Dickins Cc: Peter Feiner Cc: "Dr. David Alan Gilbert" Cc: Johannes Weiner Cc: "Huangpeng (Peter)" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/userfaultfd.c | 4 ++-- include/uapi/linux/userfaultfd.h | 12 +++++++++--- 2 files changed, 11 insertions(+), 5 deletions(-) diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c index 9bc256d1a143..0756d97b0666 100644 --- a/fs/userfaultfd.c +++ b/fs/userfaultfd.c @@ -884,7 +884,7 @@ static int userfaultfd_api(struct userfaultfd_ctx *ctx, goto out; } /* careful not to leak info, we only read the first 8 bytes */ - uffdio_api.bits = UFFD_API_BITS; + uffdio_api.features = UFFD_API_FEATURES; uffdio_api.ioctls = UFFD_API_IOCTLS; ret = -EFAULT; if (copy_to_user(buf, &uffdio_api, sizeof(uffdio_api))) @@ -941,7 +941,7 @@ static void userfaultfd_show_fdinfo(struct seq_file *m, struct file *f) * protocols: aa:... bb:... */ seq_printf(m, "pending:\t%lu\ntotal:\t%lu\nAPI:\t%Lx:%x:%Lx\n", - pending, total, UFFD_API, UFFD_API_BITS, + pending, total, UFFD_API, UFFD_API_FEATURES, UFFD_API_IOCTLS|UFFD_API_RANGE_IOCTLS); } #endif diff --git a/include/uapi/linux/userfaultfd.h b/include/uapi/linux/userfaultfd.h index 09c2e2a8c9d6..330206016249 100644 --- a/include/uapi/linux/userfaultfd.h +++ b/include/uapi/linux/userfaultfd.h @@ -12,8 +12,8 @@ #include #define UFFD_API ((__u64)0xAA) -/* FIXME: add "|UFFD_BIT_WP" to UFFD_API_BITS after implementing it */ -#define UFFD_API_BITS (UFFD_BIT_WRITE) +/* FIXME: add "|UFFD_FEATURE_WP" to UFFD_API_FEATURES after implementing it */ +#define UFFD_API_FEATURES (UFFD_FEATURE_WRITE_BIT) #define UFFD_API_IOCTLS \ ((__u64)1 << _UFFDIO_REGISTER | \ (__u64)1 << _UFFDIO_UNREGISTER | \ @@ -53,12 +53,18 @@ #define UFFD_BIT_WP (1<<1) /* handle_userfault() reason VM_UFFD_WP */ #define UFFD_BITS 2 /* two above bits used for UFFD_BIT_* mask */ +/* + * Features reported in uffdio_api.features field + */ +#define UFFD_FEATURE_WRITE_BIT (1<<0) /* Corresponds to UFFD_BIT_WRITE */ +#define UFFD_FEATURE_WP_BIT (1<<1) /* Corresponds to UFFD_BIT_WP */ + struct uffdio_api { /* userland asks for an API number */ __u64 api; /* kernel answers below with the available features for the API */ - __u64 bits; + __u64 features; __u64 ioctls; }; -- 2.20.1