diff mbox series

[v2,5/7] util/userfaultfd: Return -errno on error

Message ID 20240919134626.166183-6-dave@treblig.org (mailing list archive)
State New
Headers show
Series Migration deadcode removal | expand

Commit Message

Dr. David Alan Gilbert Sept. 19, 2024, 1:46 p.m. UTC 
From: "Dr. David Alan Gilbert" <dave@treblig.org>

Convert (the currently unused) uffd_wakeup, uffd_copy_page and
uffd_zero_page to return -errno on error rather than -1.

That will make it easier to reuse in postcopy.

Signed-off-by: Dr. David Alan Gilbert <dave@treblig.org>
---
 util/userfaultfd.c | 21 ++++++++++++---------
 1 file changed, 12 insertions(+), 9 deletions(-)

Comments

Peter Xu Sept. 19, 2024, 5:46 p.m. UTC | #1 
On Thu, Sep 19, 2024 at 02:46:24PM +0100, dave@treblig.org wrote:
> From: "Dr. David Alan Gilbert" <dave@treblig.org>
> 
> Convert (the currently unused) uffd_wakeup, uffd_copy_page and
> uffd_zero_page to return -errno on error rather than -1.
> 
> That will make it easier to reuse in postcopy.
> 
> Signed-off-by: Dr. David Alan Gilbert <dave@treblig.org>

Reviewed-by: Peter Xu <peterx@redhat.com>
diff mbox series

Patch

diff --git a/util/userfaultfd.c b/util/userfaultfd.c
index 1b2fa949d4..518d5c3586 100644
--- a/util/userfaultfd.c
+++ b/util/userfaultfd.c
@@ -240,7 +240,7 @@  int uffd_change_protection(int uffd_fd, void *addr, uint64_t length,
  * Copy range of source pages to the destination to resolve
  * missing page fault somewhere in the destination range.
  *
- * Returns 0 on success, negative value in case of an error
+ * Returns 0 on success, -errno in case of an error
  *
  * @uffd_fd: UFFD file descriptor
  * @dst_addr: destination base address
@@ -259,10 +259,11 @@  int uffd_copy_page(int uffd_fd, void *dst_addr, void *src_addr,
     uffd_copy.mode = dont_wake ? UFFDIO_COPY_MODE_DONTWAKE : 0;
 
     if (ioctl(uffd_fd, UFFDIO_COPY, &uffd_copy)) {
+        int e = errno;
         error_report("uffd_copy_page() failed: dst_addr=%p src_addr=%p length=%" PRIu64
                 " mode=%" PRIx64 " errno=%i", dst_addr, src_addr,
-                length, (uint64_t) uffd_copy.mode, errno);
-        return -1;
+                length, (uint64_t) uffd_copy.mode, e);
+        return -e;
     }
 
     return 0;
@@ -273,7 +274,7 @@  int uffd_copy_page(int uffd_fd, void *dst_addr, void *src_addr,
  *
  * Fill range pages with zeroes to resolve missing page fault within the range.
  *
- * Returns 0 on success, negative value in case of an error
+ * Returns 0 on success, -errno in case of an error
  *
  * @uffd_fd: UFFD file descriptor
  * @addr: base address
@@ -289,10 +290,11 @@  int uffd_zero_page(int uffd_fd, void *addr, uint64_t length, bool dont_wake)
     uffd_zeropage.mode = dont_wake ? UFFDIO_ZEROPAGE_MODE_DONTWAKE : 0;
 
     if (ioctl(uffd_fd, UFFDIO_ZEROPAGE, &uffd_zeropage)) {
+        int e = errno;
         error_report("uffd_zero_page() failed: addr=%p length=%" PRIu64
                 " mode=%" PRIx64 " errno=%i", addr, length,
-                (uint64_t) uffd_zeropage.mode, errno);
-        return -1;
+                (uint64_t) uffd_zeropage.mode, e);
+        return -e;
     }
 
     return 0;
@@ -306,7 +308,7 @@  int uffd_zero_page(int uffd_fd, void *addr, uint64_t length, bool dont_wake)
  * via UFFD-IO IOCTLs with MODE_DONTWAKE flag set, then after that all waits
  * for the whole memory range are satisfied in a single call to uffd_wakeup().
  *
- * Returns 0 on success, negative value in case of an error
+ * Returns 0 on success, -errno in case of an error
  *
  * @uffd_fd: UFFD file descriptor
  * @addr: base address
@@ -320,9 +322,10 @@  int uffd_wakeup(int uffd_fd, void *addr, uint64_t length)
     uffd_range.len = length;
 
     if (ioctl(uffd_fd, UFFDIO_WAKE, &uffd_range)) {
+        int e = errno;
         error_report("uffd_wakeup() failed: addr=%p length=%" PRIu64 " errno=%i",
-                addr, length, errno);
-        return -1;
+                addr, length, e);
+        return -e;
     }
 
     return 0;