dm crypt: add comments to better describe crypto processing logic (54cea3f6) · Commits · 戴 / test

drivers/md/dm-crypt.c

+24 −6

Original line number	Diff line number	Diff line
		/*
		* Copyright (C) 2003 Jana Saout <jana@saout.de>
		* Copyright (C) 2004 Clemens Fruhwirth <clemens@endorphin.org>
		* Copyright (C) 2006-2009 Red Hat, Inc. All rights reserved.
		* Copyright (C) 2006-2015 Red Hat, Inc. All rights reserved.
		* Copyright (C) 2013 Milan Broz <gmazyland@gmail.com>
		*
		* This file is released under the GPL.
		@@ -891,6 +891,11 @@ static void crypt_alloc_req(struct crypt_config *cc,
		ctx->req = mempool_alloc(cc->req_pool, GFP_NOIO);

		ablkcipher_request_set_tfm(ctx->req, cc->tfms[key_index]);

		/*
		* Use REQ_MAY_BACKLOG so a cipher driver internally backlogs
		* requests if driver request queue is full.
		*/
		ablkcipher_request_set_callback(ctx->req,
		CRYPTO_TFM_REQ_MAY_BACKLOG \| CRYPTO_TFM_REQ_MAY_SLEEP,
		kcryptd_async_done, dmreq_of_req(cc, ctx->req));
		@@ -924,24 +929,32 @@ static int crypt_convert(struct crypt_config *cc,
		r = crypt_convert_block(cc, ctx, ctx->req);

		switch (r) {
		/* async */
		/*
		* The request was queued by a crypto driver
		* but the driver request queue is full, let's wait.
		*/
		case -EBUSY:
		wait_for_completion(&ctx->restart);
		reinit_completion(&ctx->restart);
		/* fall through */
		/*
		* The request is queued and processed asynchronously,
		* completion function kcryptd_async_done() will be called.
		*/
		case -EINPROGRESS:
		ctx->req = NULL;
		ctx->cc_sector++;
		continue;

		/* sync */
		/*
		* The request was already processed (synchronously).
		*/
		case 0:
		atomic_dec(&ctx->cc_pending);
		ctx->cc_sector++;
		cond_resched();
		continue;

		/* error */
		/* There was an error while processing the request. */
		default:
		atomic_dec(&ctx->cc_pending);
		return r;
		@@ -1346,6 +1359,11 @@ static void kcryptd_async_done(struct crypto_async_request *async_req,
		struct dm_crypt_io *io = container_of(ctx, struct dm_crypt_io, ctx);
		struct crypt_config *cc = io->cc;

		/*
		* A request from crypto driver backlog is going to be processed now,
		* finish the completion and continue in crypt_convert().
		* (Callback will be called for the second time for this request.)
		*/
		if (error == -EINPROGRESS) {
		complete(&ctx->restart);
		return;

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