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

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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: Shuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com>
Reviewed-on: https://review.gerrithub.io/c/spdk/spdk/+/446573
Reviewed-by: Ziye Yang <ziye.yang@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
Reviewed-by: Ben Walker <benjamin.walker@intel.com>
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
This commit is contained in:
Shuhei Matsumoto 2019-03-01 15:05:12 +09:00 committed by Jim Harris
parent fa7dd957ee
commit 4d3a984756
1 changed files with 52 additions and 56 deletions
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100
lib/iscsi/iscsi.c
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@ -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