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ksmbd: Implements sess->ksmbd_chann_list as xarray
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[ Upstream commit 1d9c417 ]

For some ops on channel:
1. lookup_chann_list(), possibly on high frequency.
2. ksmbd_chann_del().

Connection is used as indexing key to lookup channel, in that case,
linear search based on list may suffer a bit for performance.

Implements sess->ksmbd_chann_list as xarray.

Signed-off-by: Dawei Li <set_pte_at@outlook.com>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Stable-dep-of: f5c779b ("ksmbd: fix racy issue from session setup and logoff")
Signed-off-by: Sasha Levin <sashal@kernel.org>
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@gregkh
Dawei Li authored and gregkh committed May 17, 2023
1 parent 3db734e commit 91bbf9c
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Showing 3 changed files with 30 additions and 69 deletions.
61 changes: 24 additions & 37 deletions fs/ksmbd/mgmt/user_session.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -30,15 +30,15 @@ struct ksmbd_session_rpc {

static void free_channel_list(struct ksmbd_session *sess)
{
struct channel *chann, *tmp;
struct channel *chann;
unsigned long index;

write_lock(&sess->chann_lock);
list_for_each_entry_safe(chann, tmp, &sess->ksmbd_chann_list,
chann_list) {
list_del(&chann->chann_list);
xa_for_each(&sess->ksmbd_chann_list, index, chann) {
xa_erase(&sess->ksmbd_chann_list, index);
kfree(chann);
}
write_unlock(&sess->chann_lock);

xa_destroy(&sess->ksmbd_chann_list);
}

static void __session_rpc_close(struct ksmbd_session *sess,
Expand Down Expand Up @@ -190,21 +190,15 @@ int ksmbd_session_register(struct ksmbd_conn *conn,

static int ksmbd_chann_del(struct ksmbd_conn *conn, struct ksmbd_session *sess)
{
struct channel *chann, *tmp;

write_lock(&sess->chann_lock);
list_for_each_entry_safe(chann, tmp, &sess->ksmbd_chann_list,
chann_list) {
if (chann->conn == conn) {
list_del(&chann->chann_list);
kfree(chann);
write_unlock(&sess->chann_lock);
return 0;
}
}
write_unlock(&sess->chann_lock);
struct channel *chann;

chann = xa_erase(&sess->ksmbd_chann_list, (long)conn);
if (!chann)
return -ENOENT;

return -ENOENT;
kfree(chann);

return 0;
}

void ksmbd_sessions_deregister(struct ksmbd_conn *conn)
Expand Down Expand Up @@ -234,7 +228,7 @@ void ksmbd_sessions_deregister(struct ksmbd_conn *conn)
return;

sess_destroy:
if (list_empty(&sess->ksmbd_chann_list)) {
if (xa_empty(&sess->ksmbd_chann_list)) {
xa_erase(&conn->sessions, sess->id);
ksmbd_session_destroy(sess);
}
Expand Down Expand Up @@ -320,6 +314,9 @@ static struct ksmbd_session *__session_create(int protocol)
struct ksmbd_session *sess;
int ret;

if (protocol != CIFDS_SESSION_FLAG_SMB2)
return NULL;

sess = kzalloc(sizeof(struct ksmbd_session), GFP_KERNEL);
if (!sess)
return NULL;
Expand All @@ -329,30 +326,20 @@ static struct ksmbd_session *__session_create(int protocol)

set_session_flag(sess, protocol);
xa_init(&sess->tree_conns);
INIT_LIST_HEAD(&sess->ksmbd_chann_list);
xa_init(&sess->ksmbd_chann_list);
INIT_LIST_HEAD(&sess->rpc_handle_list);
sess->sequence_number = 1;
rwlock_init(&sess->chann_lock);

switch (protocol) {
case CIFDS_SESSION_FLAG_SMB2:
ret = __init_smb2_session(sess);
break;
default:
ret = -EINVAL;
break;
}

ret = __init_smb2_session(sess);
if (ret)
goto error;

ida_init(&sess->tree_conn_ida);

if (protocol == CIFDS_SESSION_FLAG_SMB2) {
down_write(&sessions_table_lock);
hash_add(sessions_table, &sess->hlist, sess->id);
up_write(&sessions_table_lock);
}
down_write(&sessions_table_lock);
hash_add(sessions_table, &sess->hlist, sess->id);
up_write(&sessions_table_lock);

return sess;

error:
Expand Down
4 changes: 1 addition & 3 deletions fs/ksmbd/mgmt/user_session.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -21,7 +21,6 @@ struct ksmbd_file_table;
struct channel {
__u8 smb3signingkey[SMB3_SIGN_KEY_SIZE];
struct ksmbd_conn *conn;
struct list_head chann_list;
};

struct preauth_session {
Expand Down Expand Up @@ -50,8 +49,7 @@ struct ksmbd_session {
char sess_key[CIFS_KEY_SIZE];

struct hlist_node hlist;
rwlock_t chann_lock;
struct list_head ksmbd_chann_list;
struct xarray ksmbd_chann_list;
struct xarray tree_conns;
struct ida tree_conn_ida;
struct list_head rpc_handle_list;
Expand Down
34 changes: 5 additions & 29 deletions fs/ksmbd/smb2pdu.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -74,14 +74,7 @@ static inline bool check_session_id(struct ksmbd_conn *conn, u64 id)

struct channel *lookup_chann_list(struct ksmbd_session *sess, struct ksmbd_conn *conn)
{
struct channel *chann;

list_for_each_entry(chann, &sess->ksmbd_chann_list, chann_list) {
if (chann->conn == conn)
return chann;
}

return NULL;
return xa_load(&sess->ksmbd_chann_list, (long)conn);
}

/**
Expand Down Expand Up @@ -592,6 +585,7 @@ static void destroy_previous_session(struct ksmbd_conn *conn,
struct ksmbd_session *prev_sess = ksmbd_session_lookup_slowpath(id);
struct ksmbd_user *prev_user;
struct channel *chann;
long index;

if (!prev_sess)
return;
Expand All @@ -605,10 +599,8 @@ static void destroy_previous_session(struct ksmbd_conn *conn,
return;

prev_sess->state = SMB2_SESSION_EXPIRED;
write_lock(&prev_sess->chann_lock);
list_for_each_entry(chann, &prev_sess->ksmbd_chann_list, chann_list)
xa_for_each(&prev_sess->ksmbd_chann_list, index, chann)
chann->conn->status = KSMBD_SESS_EXITING;
write_unlock(&prev_sess->chann_lock);
}

/**
Expand Down Expand Up @@ -1520,19 +1512,14 @@ static int ntlm_authenticate(struct ksmbd_work *work)

binding_session:
if (conn->dialect >= SMB30_PROT_ID) {
read_lock(&sess->chann_lock);
chann = lookup_chann_list(sess, conn);
read_unlock(&sess->chann_lock);
if (!chann) {
chann = kmalloc(sizeof(struct channel), GFP_KERNEL);
if (!chann)
return -ENOMEM;

chann->conn = conn;
INIT_LIST_HEAD(&chann->chann_list);
write_lock(&sess->chann_lock);
list_add(&chann->chann_list, &sess->ksmbd_chann_list);
write_unlock(&sess->chann_lock);
xa_store(&sess->ksmbd_chann_list, (long)conn, chann, GFP_KERNEL);
}
}

Expand Down Expand Up @@ -1606,19 +1593,14 @@ static int krb5_authenticate(struct ksmbd_work *work)
}

if (conn->dialect >= SMB30_PROT_ID) {
read_lock(&sess->chann_lock);
chann = lookup_chann_list(sess, conn);
read_unlock(&sess->chann_lock);
if (!chann) {
chann = kmalloc(sizeof(struct channel), GFP_KERNEL);
if (!chann)
return -ENOMEM;

chann->conn = conn;
INIT_LIST_HEAD(&chann->chann_list);
write_lock(&sess->chann_lock);
list_add(&chann->chann_list, &sess->ksmbd_chann_list);
write_unlock(&sess->chann_lock);
xa_store(&sess->ksmbd_chann_list, (long)conn, chann, GFP_KERNEL);
}
}

Expand Down Expand Up @@ -8428,14 +8410,11 @@ int smb3_check_sign_req(struct ksmbd_work *work)
if (le16_to_cpu(hdr->Command) == SMB2_SESSION_SETUP_HE) {
signing_key = work->sess->smb3signingkey;
} else {
read_lock(&work->sess->chann_lock);
chann = lookup_chann_list(work->sess, conn);
if (!chann) {
read_unlock(&work->sess->chann_lock);
return 0;
}
signing_key = chann->smb3signingkey;
read_unlock(&work->sess->chann_lock);
}

if (!signing_key) {
Expand Down Expand Up @@ -8495,14 +8474,11 @@ void smb3_set_sign_rsp(struct ksmbd_work *work)
le16_to_cpu(hdr->Command) == SMB2_SESSION_SETUP_HE) {
signing_key = work->sess->smb3signingkey;
} else {
read_lock(&work->sess->chann_lock);
chann = lookup_chann_list(work->sess, work->conn);
if (!chann) {
read_unlock(&work->sess->chann_lock);
return;
}
signing_key = chann->smb3signingkey;
read_unlock(&work->sess->chann_lock);
}

if (!signing_key)
Expand Down

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