From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:57813) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dmH9k-0001xb-MW for qemu-devel@nongnu.org; Mon, 28 Aug 2017 06:20:33 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dmH9j-0005zu-L9 for qemu-devel@nongnu.org; Mon, 28 Aug 2017 06:20:32 -0400 Received: from mga04.intel.com ([192.55.52.120]:17236) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dmH9j-0005ys-CR for qemu-devel@nongnu.org; Mon, 28 Aug 2017 06:20:31 -0400 From: Wei Wang Date: Mon, 28 Aug 2017 18:08:30 +0800 Message-Id: <1503914913-28893-3-git-send-email-wei.w.wang@intel.com> In-Reply-To: <1503914913-28893-1-git-send-email-wei.w.wang@intel.com> References: <1503914913-28893-1-git-send-email-wei.w.wang@intel.com> Subject: [Qemu-devel] [PATCH v15 2/5] lib/xbitmap: add xb_find_next_bit() and xb_zero() List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: virtio-dev@lists.oasis-open.org, linux-kernel@vger.kernel.org, qemu-devel@nongnu.org, virtualization@lists.linux-foundation.org, kvm@vger.kernel.org, linux-mm@kvack.org, mst@redhat.com, mhocko@kernel.org, akpm@linux-foundation.org, mawilcox@microsoft.com Cc: david@redhat.com, cornelia.huck@de.ibm.com, mgorman@techsingularity.net, aarcange@redhat.com, amit.shah@redhat.com, pbonzini@redhat.com, willy@infradead.org, wei.w.wang@intel.com, liliang.opensource@gmail.com, yang.zhang.wz@gmail.com, quan.xu@aliyun.com xb_find_next_bit() is used to find the next "1" or "0" bit in the given range. xb_zero() is used to zero the given range of bits. Signed-off-by: Wei Wang Cc: Andrew Morton Cc: Matthew Wilcox Cc: Michal Hocko Cc: Michael S. Tsirkin --- include/linux/xbitmap.h | 3 +++ lib/xbitmap.c | 39 +++++++++++++++++++++++++++++++++++++++ 2 files changed, 42 insertions(+) diff --git a/include/linux/xbitmap.h b/include/linux/xbitmap.h index 25b05ff..0061f7a 100644 --- a/include/linux/xbitmap.h +++ b/include/linux/xbitmap.h @@ -38,6 +38,9 @@ static inline void xb_init(struct xb *xb) int xb_set_bit(struct xb *xb, unsigned long bit); bool xb_test_bit(struct xb *xb, unsigned long bit); void xb_clear_bit(struct xb *xb, unsigned long bit); +void xb_zero(struct xb *xb, unsigned long start, unsigned long end); +unsigned long xb_find_next_bit(struct xb *xb, unsigned long start, + unsigned long end, bool set); /* Check if the xb tree is empty */ static inline bool xb_is_empty(const struct xb *xb) diff --git a/lib/xbitmap.c b/lib/xbitmap.c index 8c55296..b9e2a0c 100644 --- a/lib/xbitmap.c +++ b/lib/xbitmap.c @@ -174,3 +174,42 @@ void xb_preload(gfp_t gfp) } } EXPORT_SYMBOL(xb_preload); + +/** + * xb_zero - zero a range of bits in the xbitmap + * @xb: the xbitmap that the bits reside in + * @start: the start of the range, inclusive + * @end: the end of the range, inclusive + */ +void xb_zero(struct xb *xb, unsigned long start, unsigned long end) +{ + unsigned long i; + + for (i = start; i <= end; i++) + xb_clear_bit(xb, i); +} +EXPORT_SYMBOL(xb_zero); + +/** + * xb_find_next_bit - find next 1 or 0 in the give range of bits + * @xb: the xbitmap that the bits reside in + * @start: the start of the range, inclusive + * @end: the end of the range, inclusive + * @set: the polarity (1 or 0) of the next bit to find + * + * Return the index of the found bit in the xbitmap. If the returned index + * exceeds @end, it indicates that no such bit is found in the given range. + */ +unsigned long xb_find_next_bit(struct xb *xb, unsigned long start, + unsigned long end, bool set) +{ + unsigned long i; + + for (i = start; i <= end; i++) { + if (xb_test_bit(xb, i) == set) + break; + } + + return i; +} +EXPORT_SYMBOL(xb_find_next_bit); -- 2.7.4