Continuation of multi page mbuf redesign from r359919.

The following series of patches addresses three things:

Now that array of pages is embedded into mbuf, we no longer need
separate structure to pass around, so struct mbuf_ext_pgs is an
artifact of the first implementation. And struct mbuf_ext_pgs_data
is a crutch to accomodate the main idea r359919 with minimal churn.

Also, M_EXT of type EXT_PGS are just a synonym of M_NOMAP.

The namespace for the newfeature is somewhat inconsistent and
sometimes has a lengthy prefixes. In these patches we will
gradually bring the namespace to "m_epg" prefix for all mbuf
fields and most functions.

Step 1 of 4:

 o Anonymize mbuf_ext_pgs_data, embed in m_ext
 o Embed mbuf_ext_pgs
 o Start documenting all this entanglement

Reviewed by:	gallatin
Differential Revision:	https://reviews.freebsd.org/D24598

1 files changed, 3 insertions, 3 deletions

diff --git a/sys/kern/kern_sendfile.c b/sys/kern/kern_sendfile.c
index 93029e765cfd..ed5be9cc0f8e 100644
--- a/sys/kern/kern_sendfile.c
+++ b/sys/kern/kern_sendfile.c
@@ -203,7 +203,7 @@ sendfile_free_mext_pg(struct mbuf *m)
 	for (i = 0; i < ext_pgs->npgs; i++) {
 		if (cache_last && i == ext_pgs->npgs - 1)
 			flags = 0;
-		pg = PHYS_TO_VM_PAGE(ext_pgs->m_epg_pa[i]);
+		pg = PHYS_TO_VM_PAGE(m->m_epg_pa[i]);
 		vm_page_release(pg, flags);
 	}
 
@@ -1046,11 +1046,11 @@ retry_space:
 					ext_pgs->nrdy++;
 				}
 
-				ext_pgs->m_epg_pa[ext_pgs_idx] = VM_PAGE_TO_PHYS(pga);
+				m0->m_epg_pa[ext_pgs_idx] = VM_PAGE_TO_PHYS(pga);
 				ext_pgs->npgs++;
 				xfs = xfsize(i, npages, off, space);
 				ext_pgs->last_pg_len = xfs;
-				MBUF_EXT_PGS_ASSERT_SANITY(ext_pgs);
+				MBUF_EXT_PGS_ASSERT_SANITY(m0);
 				mtail->m_len += xfs;
 				mtail->m_ext.ext_size += PAGE_SIZE;
 				continue;