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Message-ID: <20250806203705.2560493-20-dhowells@redhat.com>
Date: Wed, 6 Aug 2025 21:36:40 +0100
From: David Howells <dhowells@...hat.com>
To: Steve French <sfrench@...ba.org>
Cc: David Howells <dhowells@...hat.com>,
Paulo Alcantara <pc@...guebit.org>,
Shyam Prasad N <sprasad@...rosoft.com>,
Tom Talpey <tom@...pey.com>,
Wang Zhaolong <wangzhaolong@...weicloud.com>,
Stefan Metzmacher <metze@...ba.org>,
Mina Almasry <almasrymina@...gle.com>,
linux-cifs@...r.kernel.org,
linux-kernel@...r.kernel.org,
netfs@...ts.linux.dev,
linux-fsdevel@...r.kernel.org
Subject: [RFC PATCH 19/31] cifs: Clean up mid->callback_data and kill off mid->creator
We shouldn't really be pinning a task_struct on the mid_q_struct. Better
to provide a wait queue there and have the waiter wait on it. For
synchronous operations, this allows them to remove themselves from it once
this is absorbed into smb_message and smb_message is generated higher up
the stack. This also gets rid of one of the uses of mid->callback_data.
We can also get rid of the need for callback_data for the Echo command
callback by passing a server pointer down into ->callback() from the
callers (all of which have it available). This can also be used in the
Read and Write callbacks.
We then only need the callback_data for the Read and Write commands - and
in both cases, it points to a cifs_io_subrequest struct. So replace
callback_data with a specifically typed pointer in a union that other users
can be added to as the need arises.
Signed-off-by: David Howells <dhowells@...hat.com>
cc: Steve French <sfrench@...ba.org>
cc: Paulo Alcantara <pc@...guebit.org>
cc: Shyam Prasad N <sprasad@...rosoft.com>
cc: Tom Talpey <tom@...pey.com>
cc: linux-cifs@...r.kernel.org
cc: netfs@...ts.linux.dev
cc: linux-fsdevel@...r.kernel.org
---
fs/smb/client/cifs_debug.c | 3 +--
fs/smb/client/cifsglob.h | 11 ++++++++---
fs/smb/client/cifsproto.h | 2 +-
fs/smb/client/cifstransport.c | 1 -
fs/smb/client/connect.c | 8 ++++----
fs/smb/client/smb2ops.c | 6 +++---
fs/smb/client/smb2pdu.c | 18 +++++++-----------
fs/smb/client/smb2transport.c | 6 ------
fs/smb/client/transport.c | 27 +++++++++++++--------------
9 files changed, 37 insertions(+), 45 deletions(-)
diff --git a/fs/smb/client/cifs_debug.c b/fs/smb/client/cifs_debug.c
index cba30f339d6b..13c569ab3417 100644
--- a/fs/smb/client/cifs_debug.c
+++ b/fs/smb/client/cifs_debug.c
@@ -625,11 +625,10 @@ static int cifs_debug_data_proc_show(struct seq_file *m, void *v)
chan_server->conn_id);
spin_lock(&chan_server->mid_lock);
list_for_each_entry(smb, &chan_server->pending_mid_q, qhead) {
- seq_printf(m, "\n\t\tState: %d com: %d pid: %d cbdata: %p mid %llu",
+ seq_printf(m, "\n\t\tState: %d com: %d pid: %d mid %llu",
smb->mid_state,
smb->command_id,
smb->pid,
- smb->callback_data,
smb->mid);
}
spin_unlock(&chan_server->mid_lock);
diff --git a/fs/smb/client/cifsglob.h b/fs/smb/client/cifsglob.h
index 4173b87bdf0f..14b132fb14e0 100644
--- a/fs/smb/client/cifsglob.h
+++ b/fs/smb/client/cifsglob.h
@@ -1692,7 +1692,8 @@ typedef int (*mid_receive_t)(struct TCP_Server_Info *server,
* - it will be called by cifsd, with no locks held
* - the mid will be removed from any lists
*/
-typedef void (*mid_callback_t)(struct smb_message *smb);
+typedef void (*mid_callback_t)(struct TCP_Server_Info *server,
+ struct smb_message *smb);
/*
* This is the protopyte for mid handle function. This is called once the mid
@@ -1731,11 +1732,17 @@ struct smb_message {
struct smb_message *next; /* Next message in compound */
struct cifs_credits credits; /* Credit requirements for this message */
void *request; /* Pointer to request message body */
+ wait_queue_head_t waitq; /* Wait queue for message events */
refcount_t ref;
bool sensitive; /* Request contains sensitive data */
bool cancelled; /* T if cancelled */
unsigned int sr_flags; /* Flags passed to send_recv() */
+ /* PDU-type specific data */
+ union {
+ struct cifs_io_subrequest *subreq; /* Read/write subrequest */
+ };
+
/* Queue state */
struct list_head qhead; /* mids waiting on reply from this server */
struct TCP_Server_Info *server; /* server corresponding to this mid */
@@ -1752,8 +1759,6 @@ struct smb_message {
mid_receive_t receive; /* call receive callback */
mid_callback_t callback; /* call completion callback */
mid_handle_t handle; /* call handle mid callback */
- void *callback_data; /* general purpose pointer for callback */
- struct task_struct *creator;
void *resp_buf; /* pointer to received SMB header */
unsigned int resp_buf_size;
int mid_state; /* wish this were enum but can not pass to wait_event */
diff --git a/fs/smb/client/cifsproto.h b/fs/smb/client/cifsproto.h
index fd5fe2723b4a..abae67d83499 100644
--- a/fs/smb/client/cifsproto.h
+++ b/fs/smb/client/cifsproto.h
@@ -83,7 +83,7 @@ extern char *cifs_build_path_to_root(struct smb3_fs_context *ctx,
int add_treename);
extern char *build_wildcard_path_from_dentry(struct dentry *direntry);
char *cifs_build_devname(char *nodename, const char *prepath);
-extern void cifs_wake_up_task(struct smb_message *smb);
+extern void cifs_wake_up_task( struct TCP_Server_Info *server, struct smb_message *smb);
extern int cifs_handle_standard(struct TCP_Server_Info *server,
struct smb_message *smb);
extern char *smb3_fs_context_fullpath(const struct smb3_fs_context *ctx,
diff --git a/fs/smb/client/cifstransport.c b/fs/smb/client/cifstransport.c
index 8cdb9252a37e..1e2a8839d742 100644
--- a/fs/smb/client/cifstransport.c
+++ b/fs/smb/client/cifstransport.c
@@ -60,7 +60,6 @@ alloc_mid(const struct smb_hdr *smb_buffer, struct TCP_Server_Info *server)
* default callback just wakes up the current task.
*/
get_task_struct(current);
- smb->creator = current;
smb->callback = cifs_wake_up_task;
smb->callback_data = current;
diff --git a/fs/smb/client/connect.c b/fs/smb/client/connect.c
index 7a64b070f74b..9bd19dd91d35 100644
--- a/fs/smb/client/connect.c
+++ b/fs/smb/client/connect.c
@@ -334,7 +334,7 @@ cifs_abort_connection(struct TCP_Server_Info *server)
cifs_dbg(FYI, "%s: issuing mid callbacks\n", __func__);
list_for_each_entry_safe(smb, nsmb, &retry_list, qhead) {
list_del_init(&smb->qhead);
- smb->callback(smb);
+ smb->callback(server, smb);
smb_put_message(smb);
}
@@ -917,7 +917,7 @@ is_smb_response(struct TCP_Server_Info *server, unsigned char type)
list_del_init(&smb->qhead);
smb->mid_rc = mid_rc;
smb->mid_state = MID_RC;
- smb->callback(smb);
+ smb->callback(server, smb);
smb_put_message(smb);
}
@@ -1111,7 +1111,7 @@ clean_demultiplex_info(struct TCP_Server_Info *server)
list_for_each_entry_safe(smb, smb2, &dispose_list, qhead) {
cifs_dbg(FYI, "Callback mid %llu\n", smb->mid);
list_del_init(&smb->qhead);
- smb->callback(smb);
+ smb->callback(server, smb);
smb_put_message(smb);
}
/* 1/8th of sec is more than enough time for them to exit */
@@ -1388,7 +1388,7 @@ cifs_demultiplex_thread(void *p)
}
if (!smbs[i]->multiRsp || smbs[i]->multiEnd)
- smbs[i]->callback(smbs[i]);
+ smbs[i]->callback(server, smbs[i]);
smb_put_message(smbs[i]);
} else if (server->ops->is_oplock_break &&
diff --git a/fs/smb/client/smb2ops.c b/fs/smb/client/smb2ops.c
index 835a76169d40..63226bbba3d1 100644
--- a/fs/smb/client/smb2ops.c
+++ b/fs/smb/client/smb2ops.c
@@ -4527,7 +4527,7 @@ handle_read_data(struct TCP_Server_Info *server, struct smb_message *smb,
unsigned int cur_off;
unsigned int cur_page_idx;
unsigned int pad_len;
- struct cifs_io_subrequest *rdata = smb->callback_data;
+ struct cifs_io_subrequest *rdata = smb->subreq;
struct smb2_hdr *shdr = (struct smb2_hdr *)buf;
int length;
bool use_rdma_mr = false;
@@ -4707,7 +4707,7 @@ static void smb2_decrypt_offload(struct work_struct *work)
dw->server->ops->is_network_name_deleted(dw->buf,
dw->server);
- smb->callback(smb);
+ smb->callback(dw->server, smb);
} else {
spin_lock(&dw->server->srv_lock);
if (dw->server->tcpStatus == CifsNeedReconnect) {
@@ -4715,7 +4715,7 @@ static void smb2_decrypt_offload(struct work_struct *work)
smb->mid_state = MID_RETRY_NEEDED;
spin_unlock(&dw->server->mid_lock);
spin_unlock(&dw->server->srv_lock);
- smb->callback(smb);
+ smb->callback(dw->server, smb);
} else {
spin_lock(&dw->server->mid_lock);
smb->mid_state = MID_REQUEST_SUBMITTED;
diff --git a/fs/smb/client/smb2pdu.c b/fs/smb/client/smb2pdu.c
index 6b94da4c1149..8d50036fd028 100644
--- a/fs/smb/client/smb2pdu.c
+++ b/fs/smb/client/smb2pdu.c
@@ -4094,9 +4094,8 @@ SMB2_change_notify(const unsigned int xid, struct cifs_tcon *tcon,
* FIXME: maybe we should consider checking that the reply matches request?
*/
static void
-smb2_echo_callback(struct smb_message *smb)
+smb2_echo_callback(struct TCP_Server_Info *server, struct smb_message *smb)
{
- struct TCP_Server_Info *server = smb->callback_data;
struct smb2_echo_rsp *rsp = (struct smb2_echo_rsp *)smb->resp_buf;
struct cifs_credits credits = { .value = 0, .instance = 0 };
@@ -4298,7 +4297,6 @@ SMB2_echo(struct TCP_Server_Info *server)
smb->request = req;
smb->total_len = total_len;
smb->callback = smb2_echo_callback;
- smb->callback_data = server;
req->hdr.CreditRequest = cpu_to_le16(1);
@@ -4533,12 +4531,11 @@ smb2_new_read_req(void **buf, unsigned int *total_len,
}
static void
-smb2_readv_callback(struct smb_message *smb)
+smb2_readv_callback(struct TCP_Server_Info *server, struct smb_message *smb)
{
- struct cifs_io_subrequest *rdata = smb->callback_data;
+ struct cifs_io_subrequest *rdata = smb->subreq;
struct netfs_inode *ictx = netfs_inode(rdata->rreq->inode);
struct cifs_tcon *tcon = tlink_tcon(rdata->req->cfile->tlink);
- struct TCP_Server_Info *server = rdata->server;
struct smb2_hdr *shdr = (struct smb2_hdr *)rdata->iov[0].iov_base;
struct cifs_credits credits = {
.value = 0,
@@ -4720,7 +4717,7 @@ smb2_async_readv(struct cifs_io_subrequest *rdata)
smb->receive = cifs_readv_receive;
smb->handle = smb3_handle_read_data;
smb->callback = smb2_readv_callback;
- smb->callback_data = rdata;
+ smb->subreq = rdata;
shdr = (struct smb2_hdr *)smb->request;
@@ -4847,11 +4844,10 @@ SMB2_read(const unsigned int xid, struct cifs_io_parms *io_parms,
* workqueue completion task.
*/
static void
-smb2_writev_callback(struct smb_message *smb)
+smb2_writev_callback(struct TCP_Server_Info *server, struct smb_message *smb)
{
- struct cifs_io_subrequest *wdata = smb->callback_data;
+ struct cifs_io_subrequest *wdata = smb->subreq;
struct cifs_tcon *tcon = tlink_tcon(wdata->req->cfile->tlink);
- struct TCP_Server_Info *server = wdata->server;
struct smb2_write_rsp *rsp = (struct smb2_write_rsp *)smb->resp_buf;
struct cifs_credits credits = {
.value = 0,
@@ -5016,7 +5012,7 @@ smb2_async_writev(struct cifs_io_subrequest *wdata)
smb->request = req;
smb->total_len = total_len;
smb->callback = smb2_writev_callback;
- smb->callback_data = wdata;
+ smb->subreq = wdata;
if (smb3_encryption_required(tcon))
flags |= CIFS_TRANSFORM_REQ;
diff --git a/fs/smb/client/smb2transport.c b/fs/smb/client/smb2transport.c
index b02f458e408a..7c60584a8544 100644
--- a/fs/smb/client/smb2transport.c
+++ b/fs/smb/client/smb2transport.c
@@ -759,12 +759,6 @@ static void smb2_init_mid(struct smb_message *smb,
smb->credits_consumed = credits > 0 ? credits : 1;
smb->server = server;
- /*
- * The default is for the mid to be synchronous, so the
- * default callback just wakes up the current task.
- */
- smb->creator = get_task_struct(current);
-
atomic_inc(&mid_count);
trace_smb3_cmd_enter(le32_to_cpu(shdr->Id.SyncId.TreeId),
le64_to_cpu(shdr->SessionId),
diff --git a/fs/smb/client/transport.c b/fs/smb/client/transport.c
index 042f689bbf52..7a4788b54a07 100644
--- a/fs/smb/client/transport.c
+++ b/fs/smb/client/transport.c
@@ -49,8 +49,9 @@ struct smb_message *smb_message_alloc(enum smb2_command cmd, gfp_t gfp)
* callback just wakes up the current task.
*/
smb->callback = cifs_wake_up_task;
- smb->callback_data = current;
smb->mid_state = MID_REQUEST_ALLOCATED;
+
+ init_waitqueue_head(&smb->waitq);
}
return smb;
}
@@ -84,11 +85,11 @@ void smb_put_messages(struct smb_message *smb)
}
void
-cifs_wake_up_task(struct smb_message *smb)
+cifs_wake_up_task(struct TCP_Server_Info *server, struct smb_message *smb)
{
if (smb->mid_state == MID_RESPONSE_RECEIVED)
smb->mid_state = MID_RESPONSE_READY;
- wake_up_process(smb->callback_data);
+ wake_up_all(&smb->waitq);
}
static void smb_clear_mid(struct smb_message *smb, struct TCP_Server_Info *server)
@@ -163,7 +164,6 @@ static void smb_clear_mid(struct smb_message *smb, struct TCP_Server_Info *serve
}
}
#endif
- put_task_struct(smb->creator);
}
static bool discard_message(struct TCP_Server_Info *server, struct smb_message *smb)
@@ -817,7 +817,7 @@ int wait_for_response(struct TCP_Server_Info *server, struct smb_message *smb)
if (smb->sr_flags & CIFS_INTERRUPTIBLE_WAIT)
sleep_state = TASK_INTERRUPTIBLE;
- error = wait_event_state(server->response_q,
+ error = wait_event_state(smb->waitq,
smb->mid_state != MID_REQUEST_SUBMITTED &&
smb->mid_state != MID_RESPONSE_RECEIVED,
(sleep_state | TASK_FREEZABLE_UNSAFE));
@@ -948,9 +948,8 @@ int cifs_sync_mid_result(struct smb_message *smb, struct TCP_Server_Info *server
}
static void
-cifs_compound_callback(struct smb_message *smb)
+cifs_compound_callback(struct TCP_Server_Info *server, struct smb_message *smb)
{
- struct TCP_Server_Info *server = smb->server;
struct cifs_credits credits = {
.value = server->ops->get_credits(smb),
.instance = server->reconnect_instance,
@@ -963,16 +962,16 @@ cifs_compound_callback(struct smb_message *smb)
}
static void
-cifs_compound_last_callback(struct smb_message *smb)
+cifs_compound_last_callback(struct TCP_Server_Info *server, struct smb_message *smb)
{
- cifs_compound_callback(smb);
- cifs_wake_up_task(smb);
+ cifs_compound_callback(server, smb);
+ cifs_wake_up_task(server, smb);
}
static void
-cifs_cancelled_callback(struct smb_message *smb)
+cifs_cancelled_callback(struct TCP_Server_Info *server, struct smb_message *smb)
{
- cifs_compound_callback(smb);
+ cifs_compound_callback(server, smb);
}
/*
@@ -1352,7 +1351,7 @@ __cifs_readv_discard(struct TCP_Server_Info *server, struct smb_message *smb,
static int
cifs_readv_discard(struct TCP_Server_Info *server, struct smb_message *smb)
{
- struct cifs_io_subrequest *rdata = smb->callback_data;
+ struct cifs_io_subrequest *rdata = smb->subreq;
return __cifs_readv_discard(server, smb, rdata->result);
}
@@ -1362,7 +1361,7 @@ cifs_readv_receive(struct TCP_Server_Info *server, struct smb_message *smb)
{
int length, len;
unsigned int data_offset, data_len;
- struct cifs_io_subrequest *rdata = smb->callback_data;
+ struct cifs_io_subrequest *rdata = smb->subreq;
char *buf = server->smallbuf;
unsigned int buflen = server->pdu_size + HEADER_PREAMBLE_SIZE(server);
bool use_rdma_mr = false;
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