On Thu, 31 May 2012 16:50:52 +0400
Pavel Shilovsky <pshilovsky@xxxxxxxxx> wrote:
> Reviewed-by: Jeff Layton <jlayton@xxxxxxxxxx>
> Signed-off-by: Pavel Shilovsky <pshilovsky@xxxxxxxxx>
> ---
> fs/cifs/cifsglob.h | 7 ++++
> fs/cifs/cifsproto.h | 1 -
> fs/cifs/cifssmb.c | 8 ++--
> fs/cifs/connect.c | 2 +-
> fs/cifs/misc.c | 89 +--------------------------------------------------
> fs/cifs/smb1ops.c | 89 +++++++++++++++++++++++++++++++++++++++++++++++++++
> fs/cifs/transport.c | 2 +-
> 7 files changed, 103 insertions(+), 95 deletions(-)
>
> diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
> index 20350a9..6df0cbe 100644
> --- a/fs/cifs/cifsglob.h
> +++ b/fs/cifs/cifsglob.h
> @@ -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.
> diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
> index 5ec21ec..0a6cbfe 100644
> --- a/fs/cifs/cifsproto.h
> +++ b/fs/cifs/cifsproto.h
> @@ -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,
> diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c
> index b5ad716..5b40073 100644
> --- a/fs/cifs/cifssmb.c
> +++ b/fs/cifs/cifssmb.c
> @@ -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)
> diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
> index 3647b1a..78db68a 100644
> --- a/fs/cifs/connect.c
> +++ b/fs/cifs/connect.c
> @@ -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;
> diff --git a/fs/cifs/misc.c b/fs/cifs/misc.c
> index e2552d2..557506a 100644
> --- a/fs/cifs/misc.c
> +++ b/fs/cifs/misc.c
> @@ -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;
> diff --git a/fs/cifs/smb1ops.c b/fs/cifs/smb1ops.c
> index d9d615f..6dec38f 100644
> --- a/fs/cifs/smb1ops.c
> +++ b/fs/cifs/smb1ops.c
> @@ -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,
> diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c
> index 1b36ffe..3097ee5 100644
> --- a/fs/cifs/transport.c
> +++ b/fs/cifs/transport.c
> @@ -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);
Not sure we need the get_next_mid() wrapper, but this looks fine.
Reviewed-by: Jeff Layton <jlayton@xxxxxxxxx>
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