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Commit 28ac4ad0 authored by Al Viro's avatar Al Viro Committed by Greg Kroah-Hartman
Browse files

lustre: simplify the living hell out of ksocknal_lib_recv_kiov() 



... by using ITER_BVEC recvmsg

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent fd25dc34

drivers/staging/lustre/lnet/klnds/socklnd/socklnd.h

+4 −2
Original line number Diff line number Diff line
@@ -86,9 +86,11 @@ 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];

	union {

		struct bio_vec          kss_scratch_bvec[LNET_MAX_IOV];

		struct kvec             kss_scratch_iov[LNET_MAX_IOV];

	};

};



struct ksock_sched_info {

	int                     ksi_nthreads_max; /* max allowed threads */

drivers/staging/lustre/lnet/klnds/socklnd/socklnd_lib.c

+8 −90
Original line number Diff line number Diff line
@@ -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;

		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;

}