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Add support for ext_pgs mbufs to nfsm_uiombuf().

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This patch uses a slightly different algorithm for the non-ext_pgs case,
where a variable called "mcp" is maintained, pointing to the current
location that mbuf data can be filled into. This avoids use of
mtod(mp, char *) + mp->m_len to calculate the location, since this does
not work for ext_pgs mbufs and I think it makes the algorithm more readable.
This change should not result in semantic changes for the non-ext_pgs case.

This is another in the series of commits that add support to the NFS client
and server for building RPC messages in ext_pgs mbufs with anonymous pages.
This is useful so that the entire mbuf list does not need to be
copied before calling sosend() when NFS over TLS is enabled.

Since ND_EXTPG is never set yet, there is no semantic change at this time.
This commit is contained in:
Rick Macklem 2020-07-08 02:28:08 +00:00
parent 565a5f040f
commit 3eaf03766e
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=363001
1 changed files with 49 additions and 26 deletions
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75
sys/fs/nfsclient/nfs_clcomsubs.c
View File

@ -62,7 +62,7 @@ nfsm_uiombuf(struct nfsrv_descript *nd, struct uio *uiop, int siz)
struct mbuf *mp, *mp2;
int xfer, left, mlen;
int uiosiz, clflg, rem;
char *cp, *tcp;
char *mcp, *tcp;
KASSERT(uiop->uio_iovcnt == 1, ("nfsm_uiotombuf: iovcnt != 1"));
@ -72,41 +72,52 @@ nfsm_uiombuf(struct nfsrv_descript *nd, struct uio *uiop, int siz)
clflg = 0;
rem = NFSM_RNDUP(siz) - siz;
mp = mp2 = nd->nd_mb;
mcp = nd->nd_bpos;
while (siz > 0) {
KASSERT((nd->nd_flag & ND_EXTPG) != 0 || mcp ==
mtod(mp, char *) + mp->m_len, ("nfsm_uiombuf: mcp wrong"));
left = uiop->uio_iov->iov_len;
uiocp = uiop->uio_iov->iov_base;
if (left > siz)
left = siz;
uiosiz = left;
while (left > 0) {
mlen = M_TRAILINGSPACE(mp);
if (mlen == 0) {
if (clflg)
NFSMCLGET(mp, M_WAITOK);
else
NFSMGET(mp);
mp->m_len = 0;
mp2->m_next = mp;
mp2 = mp;
if ((nd->nd_flag & ND_EXTPG) != 0)
mlen = nd->nd_bextpgsiz;
else
mlen = M_TRAILINGSPACE(mp);
if (mlen == 0) {
if ((nd->nd_flag & ND_EXTPG) != 0) {
mp = nfsm_add_ext_pgs(mp,
nd->nd_maxextsiz, &nd->nd_bextpg);
mcp = (char *)(void *)PHYS_TO_DMAP(
mp->m_epg_pa[nd->nd_bextpg]);
nd->nd_bextpgsiz = PAGE_SIZE;
} else {
if (clflg)
NFSMCLGET(mp, M_WAITOK);
else
NFSMGET(mp);
mp->m_len = 0;
mlen = M_TRAILINGSPACE(mp);
mcp = mtod(mp, char *);
mp2->m_next = mp;
mp2 = mp;
}
}
xfer = (left > mlen) ? mlen : left;
#ifdef notdef
/* Not Yet.. */
if (uiop->uio_iov->iov_op != NULL)
(*(uiop->uio_iov->iov_op))
(uiocp, mtod(mp, caddr_t) + mp->m_len,
xfer);
else
#endif
if (uiop->uio_segflg == UIO_SYSSPACE)
NFSBCOPY(uiocp, mtod(mp, caddr_t) + mp->m_len,
xfer);
NFSBCOPY(uiocp, mcp, xfer);
else
copyin(uiocp, mtod(mp, caddr_t) + mp->m_len, xfer);
copyin(uiocp, mcp, xfer);
mp->m_len += xfer;
left -= xfer;
uiocp += xfer;
mcp += xfer;
if ((nd->nd_flag & ND_EXTPG) != 0) {
nd->nd_bextpgsiz -= xfer;
mp->m_epg_last_len += xfer;
}
uiop->uio_offset += xfer;
uiop->uio_resid -= xfer;
}
@ -117,18 +128,30 @@ nfsm_uiombuf(struct nfsrv_descript *nd, struct uio *uiop, int siz)
siz -= uiosiz;
}
if (rem > 0) {
if (rem > M_TRAILINGSPACE(mp)) {
if ((nd->nd_flag & ND_EXTPG) == 0 && rem >
M_TRAILINGSPACE(mp)) {
NFSMGET(mp);
mp->m_len = 0;
mp2->m_next = mp;
mcp = mtod(mp, char *);
} else if ((nd->nd_flag & ND_EXTPG) != 0 && rem >
nd->nd_bextpgsiz) {
mp = nfsm_add_ext_pgs(mp, nd->nd_maxextsiz,
&nd->nd_bextpg);
mcp = (char *)(void *)
PHYS_TO_DMAP(mp->m_epg_pa[nd->nd_bextpg]);
nd->nd_bextpgsiz = PAGE_SIZE;
}
cp = mtod(mp, caddr_t) + mp->m_len;
for (left = 0; left < rem; left++)
*cp++ = '\0';
*mcp++ = '\0';
mp->m_len += rem;
nd->nd_bpos = cp;
nd->nd_bpos = mcp;
if ((nd->nd_flag & ND_EXTPG) != 0) {
nd->nd_bextpgsiz -= rem;
mp->m_epg_last_len += rem;
}
} else
nd->nd_bpos = mtod(mp, caddr_t) + mp->m_len;
nd->nd_bpos = mcp;
nd->nd_mb = mp;
}