CIFS: Expand CurrentMid field
While in CIFS/SMB we have 16 bit mid, in SMB2 it is 64 bit.
Convert the existing field to 64 bit and mask off higher bits
for CIFS/SMB.
Signed-off-by: Pavel Shilovsky <piastry@etersoft.ru>
diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index a403398..b213458 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -282,7 +282,7 @@
vcnumbers */
int capabilities; /* allow selective disabling of caps by smb sess */
int timeAdj; /* Adjust for difference in server time zone in sec */
- __u16 CurrentMid; /* multiplex id - rotating counter */
+ __u64 CurrentMid; /* multiplex id - rotating counter */
char cryptkey[CIFS_CRYPTO_KEY_SIZE]; /* used by ntlm, ntlmv2 etc */
/* 16th byte of RFC1001 workstation name is always null */
char workstation_RFC1001_name[RFC1001_NAME_LEN_WITH_NULL];
diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
index 05f0a2e..95ee5a6 100644
--- a/fs/cifs/cifsproto.h
+++ b/fs/cifs/cifsproto.h
@@ -115,7 +115,7 @@
void **request_buf);
extern int CIFS_SessSetup(unsigned int xid, struct cifs_ses *ses,
const struct nls_table *nls_cp);
-extern __u16 GetNextMid(struct TCP_Server_Info *server);
+extern __u64 GetNextMid(struct TCP_Server_Info *server);
extern struct timespec cifs_NTtimeToUnix(__le64 utc_nanoseconds_since_1601);
extern u64 cifs_UnixTimeToNT(struct timespec);
extern struct timespec cnvrtDosUnixTm(__le16 le_date, __le16 le_time,
diff --git a/fs/cifs/misc.c b/fs/cifs/misc.c
index dc61dff2..d2ccce8 100644
--- a/fs/cifs/misc.c
+++ b/fs/cifs/misc.c
@@ -213,54 +213,61 @@
}
/*
- Find a free multiplex id (SMB mid). Otherwise there could be
- mid collisions which might cause problems, demultiplexing the
- wrong response to this request. Multiplex ids could collide if
- one of a series requests takes much longer than the others, or
- if a very large number of long lived requests (byte range
- locks or FindNotify requests) are pending. No more than
- 64K-1 requests can be outstanding at one time. If no
- mids are available, return zero. A future optimization
- could make the combination of mids and uid the key we use
- to demultiplex on (rather than mid alone).
- In addition to the above check, the cifs demultiplex
- code already used the command code as a secondary
- check of the frame and if signing is negotiated the
- response would be discarded if the mid were the same
- but the signature was wrong. Since the mid is not put in the
- pending queue until later (when it is about to be dispatched)
- we do have to limit the number of outstanding requests
- to somewhat less than 64K-1 although it is hard to imagine
- so many threads being in the vfs at one time.
-*/
-__u16 GetNextMid(struct TCP_Server_Info *server)
+ * Find a free multiplex id (SMB mid). Otherwise there could be
+ * mid collisions which might cause problems, demultiplexing the
+ * wrong response to this request. Multiplex ids could collide if
+ * one of a series requests takes much longer than the others, or
+ * if a very large number of long lived requests (byte range
+ * locks or FindNotify requests) are pending. No more than
+ * 64K-1 requests can be outstanding at one time. If no
+ * mids are available, return zero. A future optimization
+ * could make the combination of mids and uid the key we use
+ * to demultiplex on (rather than mid alone).
+ * In addition to the above check, the cifs demultiplex
+ * code already used the command code as a secondary
+ * check of the frame and if signing is negotiated the
+ * response would be discarded if the mid were the same
+ * but the signature was wrong. Since the mid is not put in the
+ * pending queue until later (when it is about to be dispatched)
+ * we do have to limit the number of outstanding requests
+ * to somewhat less than 64K-1 although it is hard to imagine
+ * so many threads being in the vfs at one time.
+ */
+__u64 GetNextMid(struct TCP_Server_Info *server)
{
- __u16 mid = 0;
- __u16 last_mid;
+ __u64 mid = 0;
+ __u16 last_mid, cur_mid;
bool collision;
spin_lock(&GlobalMid_Lock);
- last_mid = server->CurrentMid; /* we do not want to loop forever */
- server->CurrentMid++;
- /* This nested loop looks more expensive than it is.
- In practice the list of pending requests is short,
- fewer than 50, and the mids are likely to be unique
- on the first pass through the loop unless some request
- takes longer than the 64 thousand requests before it
- (and it would also have to have been a request that
- did not time out) */
- while (server->CurrentMid != last_mid) {
+
+ /* mid is 16 bit only for CIFS/SMB */
+ cur_mid = (__u16)((server->CurrentMid) & 0xffff);
+ /* we do not want to loop forever */
+ last_mid = cur_mid;
+ cur_mid++;
+
+ /*
+ * This nested loop looks more expensive than it is.
+ * In practice the list of pending requests is short,
+ * fewer than 50, and the mids are likely to be unique
+ * on the first pass through the loop unless some request
+ * takes longer than the 64 thousand requests before it
+ * (and it would also have to have been a request that
+ * did not time out).
+ */
+ while (cur_mid != last_mid) {
struct mid_q_entry *mid_entry;
unsigned int num_mids;
collision = false;
- if (server->CurrentMid == 0)
- server->CurrentMid++;
+ if (cur_mid == 0)
+ cur_mid++;
num_mids = 0;
list_for_each_entry(mid_entry, &server->pending_mid_q, qhead) {
++num_mids;
- if (mid_entry->mid == server->CurrentMid &&
+ if (mid_entry->mid == cur_mid &&
mid_entry->midState == MID_REQUEST_SUBMITTED) {
/* This mid is in use, try a different one */
collision = true;
@@ -282,10 +289,11 @@
server->tcpStatus = CifsNeedReconnect;
if (!collision) {
- mid = server->CurrentMid;
+ mid = (__u64)cur_mid;
+ server->CurrentMid = mid;
break;
}
- server->CurrentMid++;
+ cur_mid++;
}
spin_unlock(&GlobalMid_Lock);
return mid;