/* * CDDL HEADER START * * The contents of this file are subject to the terms of the * Common Development and Distribution License, Version 1.0 only * (the "License"). You may not use this file except in compliance * with the License. * * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE * or http://www.opensolaris.org/os/licensing. * See the License for the specific language governing permissions * and limitations under the License. * * When distributing Covered Code, include this CDDL HEADER in each * file and include the License file at usr/src/OPENSOLARIS.LICENSE. * If applicable, add the following below this CDDL HEADER, with the * fields enclosed by brackets "[]" replaced with your own identifying * information: Portions Copyright [yyyy] [name of copyright owner] * * CDDL HEADER END */ /* * Copyright 2004 Sun Microsystems, Inc. All rights reserved. * Use is subject to license terms. */ #include <sys/types.h> #include <sys/kmem.h> #include <sys/bitmap.h> #include <sys/stream.h> #include <sys/strsubr.h> #define _SUN_TPI_VERSION 2 #include <sys/tihdr.h> #include <sys/suntpi.h> /* * Hash table parameters for tpi_provinfo_table. */ #define TPI_HASH_BITS 4 #define TPI_NHASH (1 << TPI_HASH_BITS) /* * Use the first element in the key for the hash. */ #define TPI_HASH(p) ((((uintptr_t *)p)[0] >> tpi_hashshift) % TPI_NHASH) /* * SAMESTR is a very confusing name. LAST_QUEUE is introduced for readability. */ #define LAST_QUEUE(q) (!SAMESTR(q)) static tpi_provinfo_t *tpi_provinfo_table[TPI_NHASH]; static kmutex_t tpi_provinfo_lock; static int tpi_hashshift; /* * In most cases there is some transport provider (like tcp or udp) below * transport user (like timod or sockets). However, it is possible to construct * stream without transport provider (e.g. by pushing timod into FIFO). It is * hardly of any use, but this condition was observed with sparcv9 abi tests. * To count for such special case, a special tpi_nullprov static data is * provided to cache information about such degenerated null-transport case. */ static tpi_provinfo_t tpi_nullprov; /* Placeholder for null transport */ /* * Initialise the TPI support routines. Called from strinit(). */ void tpi_init() { mutex_init(&tpi_provinfo_lock, NULL, MUTEX_DEFAULT, NULL); /* * Calculate the right shift for hashing a tpi_provinfo_t. */ tpi_hashshift = highbit(sizeof (tpi_provinfo_t)); } /* * Generate a downstream signature given the write-side queue. It * passes back the size of the generated key in *keylenp. This routine * cannot multithread as it returns a pointer to a static data item. * * There is no way (in the current module loading infrastructure) to * _absolutely_ guarantee that the key below uniquely identifies an * arrangement of modules and drivers. A module _might_ be unloaded and * another module _might_ be loaded such that the qi_minfo is at _exactly_ * same kernel address, and then it _might_ be placed in a transport * provider stream in exactly the same configuration (modules above and * below all identical) - but it would take quite a few coincidences * and modules loading and unloading does not usually happen n times a * second... */ static void * tpi_makekey(queue_t *q, size_t *keylenp) { static uintptr_t *key = NULL; int i; ASSERT(q != NULL); ASSERT(MUTEX_HELD(&tpi_provinfo_lock)); /* assert this queue is write queue and qprocson() is called before */ ASSERT((q->q_flag & QREADR) == 0); ASSERT(q->q_next != NULL); /* * This can be global because tpi_makekey is called with * tpi_provinfo_lock. */ if (key == NULL) key = kmem_alloc((nstrpush + 1) * sizeof (uintptr_t), KM_SLEEP); ASSERT(key != NULL); /* * Go down q_next to the driver, but no further. We use the qi_minfo * because we can find in from the queue and it is a stable part of * any driver/module infrastructure. */ for (i = 0; !LAST_QUEUE(q) && (q = q->q_next) != NULL; ++i) { ASSERT(i < nstrpush + 1); key[i] = (uintptr_t)q->q_qinfo->qi_minfo; } /* * Allocate the actual key with the proper length, and pass it * all back. */ *keylenp = i * sizeof (uintptr_t); return ((void *)key); } /* * Find an existing provider entry given a queue pointer, or allocate a * new empty entry if not found. Because this routine calls kmem_alloc * with KM_SLEEP, and because it traverses the q_next pointers of a stream * it must be called with a proper user context and within a perimeter * which protects the STREAM e.g. an open routine. This routine always * returns a valid pointer. */ tpi_provinfo_t * tpi_findprov(queue_t *q) { void *key; size_t keylen; tpi_provinfo_t **tpp; mutex_enter(&tpi_provinfo_lock); /* * Must hold tpi_provinfo_lock since tpi_makekey() returns a pointer * to static data. */ key = tpi_makekey(WR(q), &keylen); if (keylen == 0) { /* there is nothing below us, return special nullprov entry */ mutex_exit(&tpi_provinfo_lock); return (&tpi_nullprov); } /* * Look for an existing entry, or the place to put a new one. */ for (tpp = &tpi_provinfo_table[TPI_HASH(key)]; *tpp != NULL; tpp = &(*tpp)->tpi_next) { if ((*tpp)->tpi_keylen == keylen && bcmp((*tpp)->tpi_key, key, keylen) == 0) { mutex_exit(&tpi_provinfo_lock); return (*tpp); } } /* * Allocate and fill in the new tpi_provinfo_t. */ *tpp = kmem_zalloc(sizeof (tpi_provinfo_t), KM_SLEEP); (*tpp)->tpi_key = kmem_alloc(keylen, KM_SLEEP); bcopy(key, (*tpp)->tpi_key, keylen); (*tpp)->tpi_keylen = keylen; mutex_init(&(*tpp)->tpi_lock, NULL, MUTEX_DEFAULT, NULL); mutex_exit(&tpi_provinfo_lock); return (*tpp); } /* * Allocate a TPI ACK reusing the old message if possible. */ mblk_t * tpi_ack_alloc(mblk_t *mp, size_t size, uchar_t db_type, t_scalar_t prim) { mblk_t *omp = mp; if ((mp = reallocb(mp, size, 0)) == NULL) { freemsg(omp); return (NULL); } if (mp->b_cont != NULL) { freemsg(mp->b_cont); mp->b_cont = NULL; } mp->b_datap->db_type = db_type; mp->b_wptr = mp->b_rptr + size; ((union T_primitives *)mp->b_rptr)->type = prim; return (mp); }
