From f5fba0976a2841e2f4033a01076161ce2ede0477 Mon Sep 17 00:00:00 2001 From: Natanael Copa Date: Tue, 29 Apr 2014 14:34:12 +0200 Subject: [PATCH 4/6] vhost: replace ffsl with ctzl Avoid using the GNU extesion ffsl which is not implemented in musl libc. The atomic_xchg() means we know that vhost_log_chunk_t will never be larger than the 'long' type, so ctzl() is always sufficient. See also commit fbeadf50 (bitops: unify bitops_ffsl with the one in host-utils.h, call it bitops_ctzl) on why ctzl should be used instead of ffsl. Signed-off-by: Natanael Copa --- hw/virtio/vhost.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c index 9e336ad..f62cfaf 100644 --- a/hw/virtio/vhost.c +++ b/hw/virtio/vhost.c @@ -41,7 +41,6 @@ static void vhost_dev_sync_region(struct vhost_dev *dev, for (;from < to; ++from) { vhost_log_chunk_t log; - int bit; /* We first check with non-atomic: much cheaper, * and we expect non-dirty to be the common case. */ if (!*from) { @@ -51,12 +50,11 @@ static void vhost_dev_sync_region(struct vhost_dev *dev, /* Data must be read atomically. We don't really need barrier semantics * but it's easier to use atomic_* than roll our own. */ log = atomic_xchg(from, 0); - while ((bit = sizeof(log) > sizeof(int) ? - ffsll(log) : ffs(log))) { + while (log) { + int bit = ctzl(log); hwaddr page_addr; hwaddr section_offset; hwaddr mr_offset; - bit -= 1; page_addr = addr + bit * VHOST_LOG_PAGE; section_offset = page_addr - section->offset_within_address_space; mr_offset = section_offset + section->offset_within_region; -- 1.9.2