Author: rmacklem Date: Wed Jun 10 02:51:39 2020 New Revision: 361998 URL: https://svnweb.freebsd.org/changeset/base/361998
Log: Add two functions that create M_EXTPG mbufs with anonymous pages. These two functions are needed by nfs-over-tls, but could also be useful for other purposes. mb_alloc_ext_plus_pages() - Allocates a M_EXTPG mbuf and enough anonymous pages to store "len" data bytes. mb_mapped_to_unmapped() - Copies the data from a list of mapped (non-M_EXTPG) mbufs into a list of M_EXTPG mbufs allocated with anonymous pages. This is roughly the inverse of mb_unmapped_to_ext(). Reviewed by: gallatin Differential Revision: https://reviews.freebsd.org/D25182 Modified: head/sys/kern/kern_mbuf.c head/sys/sys/mbuf.h Modified: head/sys/kern/kern_mbuf.c ============================================================================== --- head/sys/kern/kern_mbuf.c Wed Jun 10 02:50:25 2020 (r361997) +++ head/sys/kern/kern_mbuf.c Wed Jun 10 02:51:39 2020 (r361998) @@ -60,6 +60,7 @@ __FBSDID("$FreeBSD$"); #include <vm/vm_extern.h> #include <vm/vm_kern.h> #include <vm/vm_page.h> +#include <vm/vm_pageout.h> #include <vm/vm_map.h> #include <vm/uma.h> #include <vm/uma_dbg.h> @@ -1536,4 +1537,105 @@ m_snd_tag_destroy(struct m_snd_tag *mst) ifp->if_snd_tag_free(mst); if_rele(ifp); counter_u64_add(snd_tag_count, -1); +} + +/* + * Allocate an mbuf with anonymous external pages. + */ +struct mbuf * +mb_alloc_ext_plus_pages(int len, int how) +{ + struct mbuf *m; + vm_page_t pg; + int i, npgs; + + m = mb_alloc_ext_pgs(how, mb_free_mext_pgs); + if (m == NULL) + return (NULL); + m->m_epg_flags |= EPG_FLAG_ANON; + npgs = howmany(len, PAGE_SIZE); + for (i = 0; i < npgs; i++) { + do { + pg = vm_page_alloc(NULL, 0, VM_ALLOC_NORMAL | + VM_ALLOC_NOOBJ | VM_ALLOC_NODUMP | VM_ALLOC_WIRED); + if (pg == NULL) { + if (how == M_NOWAIT) { + m->m_epg_npgs = i; + m_free(m); + return (NULL); + } + vm_wait(NULL); + } + } while (pg == NULL); + m->m_epg_pa[i] = VM_PAGE_TO_PHYS(pg); + } + m->m_epg_npgs = npgs; + return (m); +} + +/* + * Copy the data in the mbuf chain to a chain of mbufs with anonymous external + * unmapped pages. + * len is the length of data in the input mbuf chain. + * mlen is the maximum number of bytes put into each ext_page mbuf. + */ +struct mbuf * +mb_mapped_to_unmapped(struct mbuf *mp, int len, int mlen, int how, + struct mbuf **mlast) +{ + struct mbuf *m, *mout; + char *pgpos, *mbpos; + int i, mblen, mbufsiz, pglen, xfer; + + if (len == 0) + return (NULL); + mbufsiz = min(mlen, len); + m = mout = mb_alloc_ext_plus_pages(mbufsiz, how); + if (m == NULL) + return (m); + pgpos = (char *)(void *)PHYS_TO_DMAP(m->m_epg_pa[0]); + pglen = PAGE_SIZE; + mblen = 0; + i = 0; + do { + if (pglen == 0) { + if (++i == m->m_epg_npgs) { + m->m_epg_last_len = PAGE_SIZE; + mbufsiz = min(mlen, len); + m->m_next = mb_alloc_ext_plus_pages(mbufsiz, + how); + m = m->m_next; + if (m == NULL) { + m_freem(mout); + return (m); + } + i = 0; + } + pgpos = (char *)(void *)PHYS_TO_DMAP(m->m_epg_pa[i]); + pglen = PAGE_SIZE; + } + while (mblen == 0) { + if (mp == NULL) { + m_freem(mout); + return (NULL); + } + KASSERT((mp->m_flags & M_EXTPG) == 0, + ("mb_copym_ext_pgs: ext_pgs input mbuf")); + mbpos = mtod(mp, char *); + mblen = mp->m_len; + mp = mp->m_next; + } + xfer = min(mblen, pglen); + memcpy(pgpos, mbpos, xfer); + pgpos += xfer; + mbpos += xfer; + pglen -= xfer; + mblen -= xfer; + len -= xfer; + m->m_len += xfer; + } while (len > 0); + m->m_epg_last_len = PAGE_SIZE - pglen; + if (mlast != NULL) + *mlast = m; + return (mout); } Modified: head/sys/sys/mbuf.h ============================================================================== --- head/sys/sys/mbuf.h Wed Jun 10 02:50:25 2020 (r361997) +++ head/sys/sys/mbuf.h Wed Jun 10 02:51:39 2020 (r361998) @@ -741,6 +741,9 @@ void mb_free_ext(struct mbuf *); void mb_free_extpg(struct mbuf *); void mb_free_mext_pgs(struct mbuf *); struct mbuf *mb_alloc_ext_pgs(int, m_ext_free_t); +struct mbuf *mb_alloc_ext_plus_pages(int, int); +struct mbuf *mb_mapped_to_unmapped(struct mbuf *, int, int, int, + struct mbuf **); int mb_unmapped_compress(struct mbuf *m); struct mbuf *mb_unmapped_to_ext(struct mbuf *m); void mb_free_notready(struct mbuf *m, int count); _______________________________________________ svn-src-all@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"