Commit 4d3a9847 authored by Shuhei Matsumoto's avatar Shuhei Matsumoto Committed by Jim Harris
Browse files

iscsi: Introduce context structure to setup iovec array to flush PDUs 



spdk_iscsi_build_iovs() has the common pattern among segments, and
introduce a temporal context to factor out the common pattern into
a helper function. This will make subsequent patches easier to add
code about DIF strip in spdk_iscsi_build_iovs().

Change-Id: I307d8d0501910071b23a8c0d8eb5e19a4d1684c4
Signed-off-by: default avatarShuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com>
Reviewed-on: https://review.gerrithub.io/c/spdk/spdk/+/446573


Reviewed-by: default avatarZiye Yang <ziye.yang@intel.com>
Reviewed-by: default avatarJim Harris <james.r.harris@intel.com>
Reviewed-by: default avatarBen Walker <benjamin.walker@intel.com>
Tested-by: default avatarSPDK CI Jenkins <sys_sgci@intel.com>
parent fa7dd957

lib/iscsi/iscsi.c

+52 −56
Original line number Diff line number Diff line
@@ -563,16 +563,53 @@ spdk_iscsi_read_pdu(struct spdk_iscsi_conn *conn, struct spdk_iscsi_pdu **_pdu) 
	return 1;

}



struct _iov_ctx {

	struct iovec	*iov;

	int		num_iovs;

	uint32_t	iov_offset;

	int		iovcnt;

	uint32_t	mapped_len;

};



static inline void

_iov_ctx_init(struct _iov_ctx *ctx, struct iovec *iovs, int num_iovs,

	      uint32_t iov_offset)

{

	ctx->iov = iovs;

	ctx->num_iovs = num_iovs;

	ctx->iov_offset = iov_offset;

	ctx->iovcnt = 0;

	ctx->mapped_len = 0;

}



static inline bool

_iov_ctx_set_iov(struct _iov_ctx *ctx, uint8_t *data, uint32_t data_len)

{

	if (ctx->iov_offset >= data_len) {

		ctx->iov_offset -= data_len;

	} else {

		ctx->iov->iov_base = data + ctx->iov_offset;

		ctx->iov->iov_len = data_len - ctx->iov_offset;

		ctx->mapped_len += data_len - ctx->iov_offset;

		ctx->iov_offset = 0;

		ctx->iov++;

		ctx->iovcnt++;

		if (ctx->iovcnt == ctx->num_iovs) {

			return false;

		}

	}



	return true;

}



int

spdk_iscsi_build_iovs(struct spdk_iscsi_conn *conn, struct iovec *iovs, int num_iovs,

		      struct spdk_iscsi_pdu *pdu, uint32_t *_mapped_length)

{

	int iovcnt = 0;

	struct _iov_ctx ctx;

	int enable_digest;

	uint32_t total_ahs_len;

	uint32_t data_len;

	uint32_t iov_offset;

	uint32_t mapped_length = 0;



	if (num_iovs == 0) {

		return 0;
@@ -588,85 +625,44 @@ spdk_iscsi_build_iovs(struct spdk_iscsi_conn *conn, struct iovec *iovs, int num_ 
		enable_digest = 0;

	}



	iov_offset = pdu->writev_offset;

	_iov_ctx_init(&ctx, iovs, num_iovs, pdu->writev_offset);



	/* BHS */

	if (iov_offset >= ISCSI_BHS_LEN) {

		iov_offset -= ISCSI_BHS_LEN;

	} else {

		iovs[iovcnt].iov_base = (uint8_t *)&pdu->bhs + iov_offset;

		iovs[iovcnt].iov_len = ISCSI_BHS_LEN - iov_offset;

		mapped_length += ISCSI_BHS_LEN - iov_offset;

		iov_offset = 0;

		iovcnt++;

		if (iovcnt == num_iovs) {

	if (!_iov_ctx_set_iov(&ctx, (uint8_t *)&pdu->bhs, ISCSI_BHS_LEN)) {

		goto end;

	}

	}

	/* AHS */

	if (total_ahs_len > 0) {

		if (iov_offset >= 4 * total_ahs_len) {

			iov_offset -= 4 * total_ahs_len;

		} else {

			iovs[iovcnt].iov_base = pdu->ahs + iov_offset;

			iovs[iovcnt].iov_len = 4 * total_ahs_len - iov_offset;

			mapped_length += 4 * total_ahs_len - iov_offset;

			iov_offset = 0;

			iovcnt++;

			if (iovcnt == num_iovs) {

		if (!_iov_ctx_set_iov(&ctx, pdu->ahs, 4 * total_ahs_len)) {

			goto end;

		}

	}

	}



	/* Header Digest */

	if (enable_digest && conn->header_digest) {

		if (iov_offset >= ISCSI_DIGEST_LEN) {

			iov_offset -= ISCSI_DIGEST_LEN;

		} else {

			iovs[iovcnt].iov_base = pdu->header_digest + iov_offset;

			iovs[iovcnt].iov_len = ISCSI_DIGEST_LEN - iov_offset;

			mapped_length += ISCSI_DIGEST_LEN - iov_offset;

			iov_offset = 0;

			iovcnt++;

			if (iovcnt == num_iovs) {

		if (!_iov_ctx_set_iov(&ctx, pdu->header_digest, ISCSI_DIGEST_LEN)) {

			goto end;

		}

	}

	}



	/* Data Segment */

	if (data_len > 0) {

		if (iov_offset >= data_len) {

			iov_offset -= data_len;

		} else {

			iovs[iovcnt].iov_base = pdu->data + iov_offset;

			iovs[iovcnt].iov_len = data_len - iov_offset;

			mapped_length += data_len - iov_offset;

			iov_offset = 0;

			iovcnt++;

			if (iovcnt == num_iovs) {

		if (!_iov_ctx_set_iov(&ctx, pdu->data, data_len)) {

			goto end;

		}

	}

	}



	/* Data Digest */

	if (enable_digest && conn->data_digest && data_len != 0) {

		if (iov_offset < ISCSI_DIGEST_LEN) {

			iovs[iovcnt].iov_base = pdu->data_digest + iov_offset;

			iovs[iovcnt].iov_len = ISCSI_DIGEST_LEN - iov_offset;

			mapped_length += ISCSI_DIGEST_LEN - iov_offset;

			iovcnt++;

		}

		_iov_ctx_set_iov(&ctx, pdu->data_digest, ISCSI_DIGEST_LEN);

	}



end:

	if (_mapped_length != NULL) {

		*_mapped_length = mapped_length;

		*_mapped_length = ctx.mapped_len;

	}



	return iovcnt;

	return ctx.iovcnt;

}



static int