cregit-Linux how code gets into the kernel

Release 4.10 fs/dlm/midcomms.c

Directory: fs/dlm
**  Copyright (C) Sistina Software, Inc.  1997-2003  All rights reserved.
**  Copyright (C) 2004-2008 Red Hat, Inc.  All rights reserved.
**  This copyrighted material is made available to anyone wishing to use,
**  modify, copy, or redistribute it subject to the terms and conditions
**  of the GNU General Public License v.2.

 * midcomms.c
 * This is the appallingly named "mid-level" comms layer.
 * Its purpose is to take packets from the "real" comms layer,
 * split them up into packets and pass them to the interested
 * part of the locking mechanism.
 * It also takes messages from the locking layer, formats them
 * into packets and sends them to the comms layer.

#include "dlm_internal.h"
#include "lowcomms.h"
#include "config.h"
#include "lock.h"
#include "midcomms.h"

static void copy_from_cb(void *dst, const void *base, unsigned offset, unsigned len, unsigned limit) { unsigned copy = len; if ((copy + offset) > limit) copy = limit - offset; memcpy(dst, base + offset, copy); len -= copy; if (len) memcpy(dst + copy, base, len); }


david teiglanddavid teigland75100.00%1100.00%

/* * Called from the low-level comms layer to process a buffer of * commands. * * Only complete messages are processed here, any "spare" bytes from * the end of a buffer are saved and tacked onto the front of the next * message that comes in. I doubt this will happen very often but we * need to be able to cope with it and I don't want the task to be waiting * for packets to come in when there is useful work to be done. */
int dlm_process_incoming_buffer(int nodeid, const void *base, unsigned offset, unsigned len, unsigned limit) { union { unsigned char __buf[DLM_INBUF_LEN]; /* this is to force proper alignment on some arches */ union dlm_packet p; } __tmp; union dlm_packet *p = &__tmp.p; int ret = 0; int err = 0; uint16_t msglen; uint32_t lockspace; while (len > sizeof(struct dlm_header)) { /* Copy just the header to check the total length. The message may wrap around the end of the buffer back to the start, so we need to use a temp buffer and copy_from_cb. */ copy_from_cb(p, base, offset, sizeof(struct dlm_header), limit); msglen = le16_to_cpu(p->header.h_length); lockspace = p->header.h_lockspace; err = -EINVAL; if (msglen < sizeof(struct dlm_header)) break; if (p->header.h_cmd == DLM_MSG) { if (msglen < sizeof(struct dlm_message)) break; } else { if (msglen < sizeof(struct dlm_rcom)) break; } err = -E2BIG; if (msglen > dlm_config.ci_buffer_size) { log_print("message size %d from %d too big, buf len %d", msglen, nodeid, len); break; } err = 0; /* If only part of the full message is contained in this buffer, then do nothing and wait for lowcomms to call us again later with more data. We return 0 meaning we've consumed none of the input buffer. */ if (msglen > len) break; /* Allocate a larger temp buffer if the full message won't fit in the buffer on the stack (which should work for most ordinary messages). */ if (msglen > sizeof(__tmp) && p == &__tmp.p) { p = kmalloc(dlm_config.ci_buffer_size, GFP_NOFS); if (p == NULL) return ret; } copy_from_cb(p, base, offset, msglen, limit); BUG_ON(lockspace != p->header.h_lockspace); ret += msglen; offset += msglen; offset &= (limit - 1); len -= msglen; dlm_receive_buffer(p, nodeid); } if (p != &__tmp.p) kfree(p); return err ? err : ret; }


david teiglanddavid teigland23574.13%350.00%
al viroal viro6721.14%116.67%
fabio massimo di nittofabio massimo di nitto144.42%116.67%
steven whitehousesteven whitehouse10.32%116.67%

Overall Contributors

david teiglanddavid teigland32779.76%350.00%
al viroal viro6716.34%116.67%
fabio massimo di nittofabio massimo di nitto153.66%116.67%
steven whitehousesteven whitehouse10.24%116.67%
Directory: fs/dlm
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