[PATCH] softmmu/physmem: Use qemu_madvise

[Andrew Deason]

We have a thin wrapper around madvise, called qemu_madvise, which
provides consistent behavior for the !CONFIG_MADVISE case, and works
around some platform-specific quirks (some platforms only provide
posix_madvise, and some don't offer all 'advise' types). This specific
caller of madvise has never used it, tracing back to its original
introduction in commit e0b266f01dd2 ("migration_completion: Take
current state").

Call qemu_madvise here, to follow the same logic as all of our other
madvise callers. This slightly changes the behavior for
!CONFIG_MADVISE (EINVAL instead of ENOSYS, and a slightly different
error message), but this is now more consistent with other callers
that use qemu_madvise.

Signed-off-by: Andrew Deason <adeason@sinenomine.net>
---
Looking at the history of commits that touch this madvise() call, it
doesn't _look_ like there's any reason to be directly calling madvise vs
qemu_advise (I don't see anything mentioned), but I'm not sure.

 softmmu/physmem.c | 12 ++----------
 1 file changed, 2 insertions(+), 10 deletions(-)

diff --git a/softmmu/physmem.c b/softmmu/physmem.c
index 43ae70fbe2..900c692b5e 100644
--- a/softmmu/physmem.c
+++ b/softmmu/physmem.c
@@ -3584,40 +3584,32 @@ int ram_block_discard_range(RAMBlock *rb, uint64_t 
start, size_t length)
                          rb->idstr, start, length, ret);
             goto err;
 #endif
         }
         if (need_madvise) {
             /* For normal RAM this causes it to be unmapped,
              * for shared memory it causes the local mapping to disappear
              * and to fall back on the file contents (which we just
              * fallocate'd away).
              */
-#if defined(CONFIG_MADVISE)
             if (qemu_ram_is_shared(rb) && rb->fd < 0) {
-                ret = madvise(host_startaddr, length, QEMU_MADV_REMOVE);
+                ret = qemu_madvise(host_startaddr, length, QEMU_MADV_REMOVE);
             } else {
-                ret = madvise(host_startaddr, length, QEMU_MADV_DONTNEED);
+                ret = qemu_madvise(host_startaddr, length, QEMU_MADV_DONTNEED);
             }
             if (ret) {
                 ret = -errno;
                 error_report("ram_block_discard_range: Failed to discard range 
"
                              "%s:%" PRIx64 " +%zx (%d)",
                              rb->idstr, start, length, ret);
                 goto err;
             }
-#else
-            ret = -ENOSYS;
-            error_report("ram_block_discard_range: MADVISE not available"
-                         "%s:%" PRIx64 " +%zx (%d)",
-                         rb->idstr, start, length, ret);
-            goto err;
-#endif
         }
         trace_ram_block_discard_range(rb->idstr, host_startaddr, length,
                                       need_madvise, need_fallocate, ret);
     } else {
         error_report("ram_block_discard_range: Overrun block '%s' (%" PRIu64
                      "/%zx/" RAM_ADDR_FMT")",
                      rb->idstr, start, length, rb->max_length);
     }
 
 err:
-- 
2.11.0