[5/5] [CRYPTO] Optimise kmap calls in crypt()

From: Herbert Xu <herbert@gondor.apana.org.au>
To: Fruhwirth Clemens <clemens@endorphin.org>
Cc: James Morris <jmorris@redhat.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	cryptoapi@lists.logix.cz
Subject: [5/5] [CRYPTO] Optimise kmap calls in crypt()
Date: Mon, 21 Mar 2005 20:53:22 +1100	[thread overview]
Message-ID: <20050321095322.GE23235@gondor.apana.org.au> (raw)
In-Reply-To: <20050321095208.GD23235@gondor.apana.org.au>

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Hi:
 
Perform kmap once (or twice if the buffer is not aligned correctly)
per page in crypt() instead of the current code which does it once
per block.  Consequently it will yield once per page instead of once
per block.

Cheers,
-- 
Visit Openswan at http://www.openswan.org/
Email: Herbert Xu ~{PmV>HI~} <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

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diff -Nru a/crypto/cipher.c b/crypto/cipher.c

--- a/crypto/cipher.c	2005-03-21 18:44:41 +11:00
+++ b/crypto/cipher.c	2005-03-21 18:44:41 +11:00
@@ -117,17 +117,21 @@
 
 		in_place = scatterwalk_samebuf(&walk_in, &walk_out);
 
-		src_p = prepare_src(&walk_in, bsize, tmp_src, in_place);
-		dst_p = prepare_dst(&walk_out, bsize, tmp_dst, in_place);
+		do {
+			src_p = prepare_src(&walk_in, bsize, tmp_src,
+					    in_place);
+			dst_p = prepare_dst(&walk_out, bsize, tmp_dst,
+					    in_place);
 
-		nbytes -= bsize;
+			prfn(tfm, dst_p, src_p, crfn, enc, info);
 
-		prfn(tfm, dst_p, src_p, crfn, enc, info);
+			complete_src(&walk_in, bsize, src_p, in_place);
+			complete_dst(&walk_out, bsize, dst_p, in_place);
 
-		complete_src(&walk_in, bsize, src_p, in_place);
-		scatterwalk_done(&walk_in, 0, nbytes);
+			nbytes -= bsize;
+		} while (nbytes && !scatterwalk_across_pages(&walk_in, bsize));
 
-		complete_dst(&walk_out, bsize, dst_p, in_place);
+		scatterwalk_done(&walk_in, 0, nbytes);
 		scatterwalk_done(&walk_out, 1, nbytes);
 
 		if (!nbytes)
