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CIFS: Move get_next_mid to ops struct 

Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Pavel Shilovsky <pshilovsky@samba.org>
Signed-off-by: Steve French <sfrench@us.ibm.com>
hifive-unleashed-5.1
Pavel Shilovsky 2012-05-23 14:01:59 +04:00 committed by Steve French
parent 7f0adb53bc
commit 8825736060
7 changed files with 103 additions and 95 deletions
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7
fs/cifs/cifsglob.h
View File

@ -174,6 +174,7 @@ struct smb_version_operations {
void (*add_credits)(struct TCP_Server_Info *, const unsigned int);
void (*set_credits)(struct TCP_Server_Info *, const int);
int * (*get_credits_field)(struct TCP_Server_Info *);
__u64 (*get_next_mid)(struct TCP_Server_Info *);
/* data offset from read response message */
unsigned int (*read_data_offset)(char *);
/* data length from read response message */
@ -399,6 +400,12 @@ set_credits(struct TCP_Server_Info *server, const int val)
server->ops->set_credits(server, val);
}
static inline __u64
get_next_mid(struct TCP_Server_Info *server)
{
return server->ops->get_next_mid(server);
}
/*
* Macros to allow the TCP_Server_Info->net field and related code to drop out
* when CONFIG_NET_NS isn't set.

1
fs/cifs/cifsproto.h
View File

@ -114,7 +114,6 @@ extern int small_smb_init_no_tc(const int smb_cmd, const int wct,
void **request_buf);
extern int CIFS_SessSetup(unsigned int xid, struct cifs_ses *ses,
const struct nls_table *nls_cp);
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,

8
fs/cifs/cifssmb.c
View File

@ -268,7 +268,7 @@ small_smb_init_no_tc(const int smb_command, const int wct,
return rc;
buffer = (struct smb_hdr *)*request_buf;
buffer->Mid = GetNextMid(ses->server);
buffer->Mid = get_next_mid(ses->server);
if (ses->capabilities & CAP_UNICODE)
buffer->Flags2 |= SMBFLG2_UNICODE;
if (ses->capabilities & CAP_STATUS32)
@ -402,7 +402,7 @@ CIFSSMBNegotiate(unsigned int xid, struct cifs_ses *ses)
cFYI(1, "secFlags 0x%x", secFlags);
pSMB->hdr.Mid = GetNextMid(server);
pSMB->hdr.Mid = get_next_mid(server);
pSMB->hdr.Flags2 |= (SMBFLG2_UNICODE | SMBFLG2_ERR_STATUS);
if ((secFlags & CIFSSEC_MUST_KRB5) == CIFSSEC_MUST_KRB5)
@ -782,7 +782,7 @@ CIFSSMBLogoff(const int xid, struct cifs_ses *ses)
return rc;
}
pSMB->hdr.Mid = GetNextMid(ses->server);
pSMB->hdr.Mid = get_next_mid(ses->server);
if (ses->server->sec_mode &
(SECMODE_SIGN_REQUIRED | SECMODE_SIGN_ENABLED))
@ -4762,7 +4762,7 @@ getDFSRetry:
/* server pointer checked in called function,
but should never be null here anyway */
pSMB->hdr.Mid = GetNextMid(ses->server);
pSMB->hdr.Mid = get_next_mid(ses->server);
pSMB->hdr.Tid = ses->ipc_tid;
pSMB->hdr.Uid = ses->Suid;
if (ses->capabilities & CAP_STATUS32)

2
fs/cifs/connect.c
View File

@ -3940,7 +3940,7 @@ CIFSTCon(unsigned int xid, struct cifs_ses *ses,
header_assemble(smb_buffer, SMB_COM_TREE_CONNECT_ANDX,
NULL /*no tid */ , 4 /*wct */ );
smb_buffer->Mid = GetNextMid(ses->server);
smb_buffer->Mid = get_next_mid(ses->server);
smb_buffer->Uid = ses->Suid;
pSMB = (TCONX_REQ *) smb_buffer;
pSMBr = (TCONX_RSP *) smb_buffer_response;

89
fs/cifs/misc.c
View File

@ -212,93 +212,6 @@ cifs_small_buf_release(void *buf_to_free)
return;
}
/*
* 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)
{
__u64 mid = 0;
__u16 last_mid, cur_mid;
bool collision;
spin_lock(&GlobalMid_Lock);
/* 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 (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 == cur_mid &&
mid_entry->mid_state == MID_REQUEST_SUBMITTED) {
/* This mid is in use, try a different one */
collision = true;
break;
}
}
/*
* if we have more than 32k mids in the list, then something
* is very wrong. Possibly a local user is trying to DoS the
* box by issuing long-running calls and SIGKILL'ing them. If
* we get to 2^16 mids then we're in big trouble as this
* function could loop forever.
*
* Go ahead and assign out the mid in this situation, but force
* an eventual reconnect to clean out the pending_mid_q.
*/
if (num_mids > 32768)
server->tcpStatus = CifsNeedReconnect;
if (!collision) {
mid = (__u64)cur_mid;
server->CurrentMid = mid;
break;
}
cur_mid++;
}
spin_unlock(&GlobalMid_Lock);
return mid;
}
/* NB: MID can not be set if treeCon not passed in, in that
case it is responsbility of caller to set the mid */
void
@ -334,7 +247,7 @@ header_assemble(struct smb_hdr *buffer, char smb_command /* command */ ,
/* Uid is not converted */
buffer->Uid = treeCon->ses->Suid;
buffer->Mid = GetNextMid(treeCon->ses->server);
buffer->Mid = get_next_mid(treeCon->ses->server);
}
if (treeCon->Flags & SMB_SHARE_IS_IN_DFS)
buffer->Flags2 |= SMBFLG2_DFS;

89
fs/cifs/smb1ops.c
View File

@ -125,6 +125,94 @@ cifs_get_credits_field(struct TCP_Server_Info *server)
return &server->credits;
}
/*
* 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.
*/
static __u64
cifs_get_next_mid(struct TCP_Server_Info *server)
{
__u64 mid = 0;
__u16 last_mid, cur_mid;
bool collision;
spin_lock(&GlobalMid_Lock);
/* 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 (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 == cur_mid &&
mid_entry->mid_state == MID_REQUEST_SUBMITTED) {
/* This mid is in use, try a different one */
collision = true;
break;
}
}
/*
* if we have more than 32k mids in the list, then something
* is very wrong. Possibly a local user is trying to DoS the
* box by issuing long-running calls and SIGKILL'ing them. If
* we get to 2^16 mids then we're in big trouble as this
* function could loop forever.
*
* Go ahead and assign out the mid in this situation, but force
* an eventual reconnect to clean out the pending_mid_q.
*/
if (num_mids > 32768)
server->tcpStatus = CifsNeedReconnect;
if (!collision) {
mid = (__u64)cur_mid;
server->CurrentMid = mid;
break;
}
cur_mid++;
}
spin_unlock(&GlobalMid_Lock);
return mid;
}
struct smb_version_operations smb1_operations = {
.send_cancel = send_nt_cancel,
.compare_fids = cifs_compare_fids,
@ -133,6 +221,7 @@ struct smb_version_operations smb1_operations = {
.add_credits = cifs_add_credits,
.set_credits = cifs_set_credits,
.get_credits_field = cifs_get_credits_field,
.get_next_mid = cifs_get_next_mid,
.read_data_offset = cifs_read_data_offset,
.read_data_length = cifs_read_data_length,
.map_error = map_smb_to_linux_error,

2
fs/cifs/transport.c
View File

@ -779,7 +779,7 @@ send_lock_cancel(const unsigned int xid, struct cifs_tcon *tcon,
pSMB->LockType = LOCKING_ANDX_CANCEL_LOCK|LOCKING_ANDX_LARGE_FILES;
pSMB->Timeout = 0;
pSMB->hdr.Mid = GetNextMid(ses->server);
pSMB->hdr.Mid = get_next_mid(ses->server);
return SendReceive(xid, ses, in_buf, out_buf,
&bytes_returned, 0);