Hi Bernard,
+/*
+ * siw_0copy_tx()
+ *
+ * Pushes list of pages to TCP socket. If pages from multiple
+ * SGE's, all referenced pages of each SGE are pushed in one
+ * shot.
+ */
+static int siw_0copy_tx(struct socket *s, struct page **page,
+ struct siw_sge *sge, unsigned int offset,
+ unsigned int size)
+{
siw_zcopy_tx is a better name
+ int i = 0, sent = 0, rv;
+ int sge_bytes = min(sge->length - offset, size);
+
+ offset = (sge->laddr + offset) & ~PAGE_MASK;
+
+ while (sent != size) {
+
+ rv = siw_tcp_sendpages(s, &page[i], offset, sge_bytes);
+ if (rv >= 0) {
+ sent += rv;
+ if (size == sent || sge_bytes > rv)
+ break;
+
+ i += PAGE_ALIGN(sge_bytes + offset) >> PAGE_SHIFT;
+ sge++;
+ sge_bytes = min(sge->length, size - sent);
+ offset = sge->laddr & ~PAGE_MASK;
+ } else {
+ sent = rv;
+ break;
+ }
+ }
+ return sent;
+}
+
+#define MAX_TRAILER (MPA_CRC_SIZE + 4)
+
+/*
+ * siw_tx_hdt() tries to push a complete packet to TCP where all
+ * packet fragments are referenced by the elements of one iovec.
+ * For the data portion, each involved page must be referenced by
+ * one extra element. All sge's data can be non-aligned to page
+ * boundaries. Two more elements are referencing iWARP header
+ * and trailer:
+ * MAX_ARRAY = 64KB/PAGE_SIZE + 1 + (2 * (SIW_MAX_SGE - 1) + HDR + TRL
+ */
+#define MAX_ARRAY ((0xffff / PAGE_SIZE) + 1 + (2 * (SIW_MAX_SGE - 1) + 2))
+
+/*
+ * Write out iov referencing hdr, data and trailer of current FPDU.
+ * Update transmit state dependent on write return status
+ */
+static int siw_tx_hdt(struct siw_iwarp_tx *c_tx, struct socket *s)
+{
+ struct siw_wqe *wqe = &c_tx->wqe_active;
+ struct siw_sge *sge = &wqe->sqe.sge[c_tx->sge_idx],
+ *first_sge = sge;
+ union siw_mem_resolved *mem = &wqe->mem[c_tx->sge_idx];
+ struct siw_mr *mr = NULL;
+
+ struct kvec iov[MAX_ARRAY];
+ struct page *page_array[MAX_ARRAY];
+ struct msghdr msg = {.msg_flags = MSG_DONTWAIT|MSG_EOR};
+
Have you considered using iov_iter's for all the send and receive
routines? IMO, This code is very hard to review mostly because it
doesn't use any of the kernel services for file (and socket) I/O.
For example, no one said an MR needs to hold a real page_vec like its HW
fellows, it can easily hold kvec and iov_iter to describe the page
vector which in turn would be used to process rdma writes/reads.
My impression is that it would greatly simplify the entire code and make
it much more maintainable...
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