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lustre: simplify the living hell out of ksocknal_lib_recv_kiov() 

... by using ITER_BVEC recvmsg

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Al Viro 2016-07-23 02:36:59 -04:00 committed by Greg Kroah-Hartman
parent fd25dc3460
commit 28ac4ad0e3
2 changed files with 12 additions and 92 deletions
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6
drivers/staging/lustre/lnet/klnds/socklnd/socklnd.h
View File

@ -86,8 +86,10 @@ struct ksock_sched { /* per scheduler state */
int kss_nconns; /* # connections assigned to
* this scheduler */
struct ksock_sched_info *kss_info; /* owner of it */
struct page *kss_rx_scratch_pgs[LNET_MAX_IOV];
struct kvec kss_scratch_iov[LNET_MAX_IOV];
union {
struct bio_vec kss_scratch_bvec[LNET_MAX_IOV];
struct kvec kss_scratch_iov[LNET_MAX_IOV];
};
};
struct ksock_sched_info {

98
drivers/staging/lustre/lnet/klnds/socklnd/socklnd_lib.c
View File

@ -259,67 +259,11 @@ ksocknal_lib_recv_iov(struct ksock_conn *conn)
return rc;
}
static void
ksocknal_lib_kiov_vunmap(void *addr)
{
if (!addr)
return;
vunmap(addr);
}
static void *
ksocknal_lib_kiov_vmap(lnet_kiov_t *kiov, int niov,
struct kvec *iov, struct page **pages)
{
void *addr;
int nob;
int i;
if (!*ksocknal_tunables.ksnd_zc_recv || !pages)
return NULL;
LASSERT(niov <= LNET_MAX_IOV);
if (niov < 2 ||
niov < *ksocknal_tunables.ksnd_zc_recv_min_nfrags)
return NULL;
for (nob = i = 0; i < niov; i++) {
if ((kiov[i].kiov_offset && i > 0) ||
(kiov[i].kiov_offset + kiov[i].kiov_len != PAGE_SIZE && i < niov - 1))
return NULL;
pages[i] = kiov[i].kiov_page;
nob += kiov[i].kiov_len;
}
addr = vmap(pages, niov, VM_MAP, PAGE_KERNEL);
if (!addr)
return NULL;
iov->iov_base = addr + kiov[0].kiov_offset;
iov->iov_len = nob;
return addr;
}
int
ksocknal_lib_recv_kiov(struct ksock_conn *conn)
{
#if SOCKNAL_SINGLE_FRAG_RX || !SOCKNAL_RISK_KMAP_DEADLOCK
struct kvec scratch;
struct kvec *scratchiov = &scratch;
struct page **pages = NULL;
unsigned int niov = 1;
#else
#ifdef CONFIG_HIGHMEM
#warning "XXX risk of kmap deadlock on multiple frags..."
#endif
struct kvec *scratchiov = conn->ksnc_scheduler->kss_scratch_iov;
struct page **pages = conn->ksnc_scheduler->kss_rx_scratch_pgs;
struct bio_vec *bv = conn->ksnc_scheduler->kss_scratch_bvec;
unsigned int niov = conn->ksnc_rx_nkiov;
#endif
lnet_kiov_t *kiov = conn->ksnc_rx_kiov;
struct msghdr msg = {
.msg_flags = 0
@ -328,44 +272,26 @@ ksocknal_lib_recv_kiov(struct ksock_conn *conn)
int i;
int rc;
void *base;
void *addr;
int sum;
int fragnob;
int n;
/*
* NB we can't trust socket ops to either consume our iovs
* or leave them alone.
*/
addr = ksocknal_lib_kiov_vmap(kiov, niov, scratchiov, pages);
if (addr) {
nob = scratchiov[0].iov_len;
n = 1;
} else {
for (nob = i = 0; i < niov; i++) {
nob += scratchiov[i].iov_len = kiov[i].kiov_len;
scratchiov[i].iov_base = kmap(kiov[i].kiov_page) +
kiov[i].kiov_offset;
}
n = niov;
for (nob = i = 0; i < niov; i++) {
nob += bv[i].bv_len = kiov[i].kiov_len;
bv[i].bv_page = kiov[i].kiov_page;
bv[i].bv_offset = kiov[i].kiov_offset;
}
n = niov;
LASSERT(nob <= conn->ksnc_rx_nob_wanted);
rc = kernel_recvmsg(conn->ksnc_sock, &msg, (struct kvec *)scratchiov,
n, nob, MSG_DONTWAIT);
iov_iter_bvec(&msg.msg_iter, READ | ITER_BVEC, bv, n, nob);
rc = sock_recvmsg(conn->ksnc_sock, &msg, MSG_DONTWAIT);
if (conn->ksnc_msg.ksm_csum) {
for (i = 0, sum = rc; sum > 0; i++, sum -= fragnob) {
LASSERT(i < niov);
/*
* Dang! have to kmap again because I have nowhere to
* stash the mapped address. But by doing it while the
* page is still mapped, the kernel just bumps the map
* count and returns me the address it stashed.
*/
base = kmap(kiov[i].kiov_page) + kiov[i].kiov_offset;
fragnob = kiov[i].kiov_len;
if (fragnob > sum)
@ -377,14 +303,6 @@ ksocknal_lib_recv_kiov(struct ksock_conn *conn)
kunmap(kiov[i].kiov_page);
}
}
if (addr) {
ksocknal_lib_kiov_vunmap(addr);
} else {
for (i = 0; i < niov; i++)
kunmap(kiov[i].kiov_page);
}
return rc;
}