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-rw-r--r--fs/dlm/midcomms.c136
1 files changed, 53 insertions, 83 deletions
diff --git a/fs/dlm/midcomms.c b/fs/dlm/midcomms.c
index 921322d133e3..fde3a6afe4be 100644
--- a/fs/dlm/midcomms.c
+++ b/fs/dlm/midcomms.c
@@ -22,114 +22,84 @@
* into packets and sends them to the comms layer.
*/
+#include <asm/unaligned.h>
+
#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);
-}
-
/*
* 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)
+int dlm_process_incoming_buffer(int nodeid, unsigned char *buf, int len)
{
- 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;
+ const unsigned char *ptr = buf;
+ const struct dlm_header *hd;
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;
+ int ret = 0;
- 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;
+ while (len >= sizeof(struct dlm_header)) {
+ hd = (struct dlm_header *)ptr;
+
+ /* no message should be more than this otherwise we
+ * cannot deliver this message to upper layers
+ */
+ msglen = get_unaligned_le16(&hd->h_length);
+ if (msglen > DEFAULT_BUFFER_SIZE) {
+ log_print("received invalid length header: %u, will abort message parsing",
+ msglen);
+ return -EBADMSG;
}
- 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. */
+ /* caller will take care that leftover
+ * will be parsed next call with more data
+ */
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;
- }
+ switch (hd->h_cmd) {
+ case DLM_MSG:
+ if (msglen < sizeof(struct dlm_message)) {
+ log_print("dlm msg too small: %u, will skip this message",
+ msglen);
+ goto skip;
+ }
- copy_from_cb(p, base, offset, msglen, limit);
+ break;
+ case DLM_RCOM:
+ if (msglen < sizeof(struct dlm_rcom)) {
+ log_print("dlm rcom msg too small: %u, will skip this message",
+ msglen);
+ goto skip;
+ }
- BUG_ON(lockspace != p->header.h_lockspace);
+ break;
+ default:
+ log_print("unsupported h_cmd received: %u, will skip this message",
+ hd->h_cmd);
+ goto skip;
+ }
+ /* for aligned memory access, we just copy current message
+ * to begin of the buffer which contains already parsed buffer
+ * data and should provide align access for upper layers
+ * because the start address of the buffer has a aligned
+ * address. This memmove can be removed when the upperlayer
+ * is capable of unaligned memory access.
+ */
+ memmove(buf, ptr, msglen);
+ dlm_receive_buffer((union dlm_packet *)buf, nodeid);
+
+skip:
ret += msglen;
- offset += msglen;
- offset &= (limit - 1);
len -= msglen;
-
- dlm_receive_buffer(p, nodeid);
+ ptr += msglen;
}
- if (p != &__tmp.p)
- kfree(p);
-
- return err ? err : ret;
+ return ret;
}