netdev - [PATCH] net/xdp: use shift instead of 64 bit division

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Message-ID: <20200604214259.GA10835@amd>
Date:   Thu, 4 Jun 2020 23:42:59 +0200
From:   Pavel Machek <pavel@....cz>
To:     bjorn.topel@...el.com, magnus.karlsson@...el.com,
        jonathan.lemon@...il.com, davem@...emloft.net, kuba@...nel.org,
        ast@...nel.org, daniel@...earbox.net, hawk@...nel.org,
        john.fastabend@...il.com, netdev@...r.kernel.org,
        trivial@...nel.org
Subject: [PATCH] net/xdp: use shift instead of 64 bit division

64bit division is kind of expensive, and shift should do the job here.

Signed-off-by: Pavel Machek (CIP) <pavel@...x.de>

---

Now with patch. Sorry about that.

diff --git a/net/xdp/xdp_umem.c b/net/xdp/xdp_umem.c
index 3889bd9aec46..d6c91a43a1ee 100644
--- a/net/xdp/xdp_umem.c
+++ b/net/xdp/xdp_umem.c
@@ -372,7 +372,7 @@ static int xdp_umem_reg(struct xdp_umem *umem, struct xdp_umem_reg *mr)
 	if ((addr + size) < addr)
 		return -EINVAL;
 
-	npgs = div_u64(size, PAGE_SIZE);
+	npgs = size >> PAGE_SHIFT;
 	if (npgs > U32_MAX)
 		return -EINVAL;
 

-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

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