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    SubjectRe: [RFC-v4 11/12] iscsi-target: Add misc utility and debug logic
    On 03/20/2011 04:31 AM, Nicholas A. Bellinger wrote

    > +
    > +/*
    > + * Called with cmd->r2t_lock held.
    > + */
    > +void iscsit_free_r2t(struct iscsi_r2t *r2t, struct iscsi_cmd *cmd)
    > +{
    > + list_del(&r2t->r2t_list);
    > + kmem_cache_free(lio_r2t_cache, r2t);
    > +}
    > +
    > +void iscsit_free_r2ts_from_list(struct iscsi_cmd *cmd)
    > +{
    > + struct iscsi_r2t *r2t, *r2t_tmp;
    > +
    > + spin_lock_bh(&cmd->r2t_lock);
    > + list_for_each_entry_safe(r2t, r2t_tmp,&cmd->cmd_r2t_list, r2t_list) {
    > + list_del(&r2t->r2t_list);
    > + kmem_cache_free(lio_r2t_cache, r2t);

    I think that is iscsit_free_r2t()

    > + }
    > + spin_unlock_bh(&cmd->r2t_lock);
    > +}
    > +
    > +/*
    > + * May be called from interrupt context.


    How does this get called from interrupt context? Is it a real interrupt
    or a soft irq? I could not find the code path.





    > +
    > +struct iscsi_r2t *iscsit_get_holder_for_r2tsn(
    > + struct iscsi_cmd *cmd,
    > + u32 r2t_sn)
    > +{
    > + struct iscsi_r2t *r2t;
    > +
    > + spin_lock_bh(&cmd->r2t_lock);
    > + list_for_each_entry(r2t,&cmd->cmd_r2t_list, r2t_list) {
    > + if (r2t->r2t_sn == r2t_sn)
    > + break;
    > + }
    > + spin_unlock_bh(&cmd->r2t_lock);
    > +
    > + return (r2t) ? r2t : NULL;

    Don't need "( ")".


    > +}
    > +
    > +#define SERIAL_BITS 31
    > +#define MAX_BOUND (u32)2147483647UL
    > +
    > +static inline int serial_lt(u32 x, u32 y)
    > +{
    > + return (x != y)&& (((x< y)&& ((y - x)< MAX_BOUND)) ||
    > + ((x> y)&& ((x - y)> MAX_BOUND)));
    > +}
    > +
    > +static inline int serial_lte(u32 x, u32 y)
    > +{
    > + return (x == y) ? 1 : serial_lt(x, y);
    > +}
    > +
    > +static inline int serial_gt(u32 x, u32 y)
    > +{
    > + return (x != y)&& (((x< y)&& ((y - x)> MAX_BOUND)) ||
    > + ((x> y)&& ((x - y)< MAX_BOUND)));
    > +}
    > +
    > +static inline int serial_gte(u32 x, u32 y)
    > +{
    > + return (x == y) ? 1 : serial_gt(x, y);
    > +}


    You should merged these with libiscsi.c's iscsi_sna_* and put in
    iscsi_proto.h.

    I think this is not iscsi specific is it? It seems like it could go
    someone more generic.



    > +void iscsit_release_cmd_direct(struct iscsi_cmd *cmd)
    > +{
    > + iscsit_free_r2ts_from_list(cmd);
    > + iscsit_free_all_datain_reqs(cmd);
    > +
    > + kfree(cmd->buf_ptr);
    > + kfree(cmd->pdu_list);
    > + kfree(cmd->seq_list);
    > + kfree(cmd->tmr_req);
    > + kfree(cmd->iov_data);
    > +
    > + kmem_cache_free(lio_cmd_cache, cmd);
    > +}
    > +
    > +void __iscsit_release_cmd_to_pool(struct iscsi_cmd *cmd, struct iscsi_session *sess)
    > +{
    > + struct iscsi_conn *conn = cmd->conn;
    > +
    > + iscsit_free_r2ts_from_list(cmd);
    > + iscsit_free_all_datain_reqs(cmd);
    > +
    > + kfree(cmd->buf_ptr);
    > + kfree(cmd->pdu_list);
    > + kfree(cmd->seq_list);
    > + kfree(cmd->tmr_req);
    > + kfree(cmd->iov_data);
    > +
    > + if (conn) {
    > + iscsit_remove_cmd_from_immediate_queue(cmd, conn);
    > + iscsit_remove_cmd_from_response_queue(cmd, conn);
    > + }
    > +
    > + kmem_cache_free(lio_cmd_cache, cmd);
    > +}

    sess is not used and I could not figure the _to_pool part of the name.

    This is not some sort of mistake, right? iscsit_release_cmd_direct and
    __iscsit_release_cmd_to_pool look alike except for the conn check
    related code. Did you mean to merge those functions?



    > +
    > +void iscsit_release_cmd_to_pool(struct iscsi_cmd *cmd)
    > +{
    > + if (!cmd->conn&& !cmd->sess) {
    > + iscsit_release_cmd_direct(cmd);
    > + } else {
    > + __iscsit_release_cmd_to_pool(cmd, (cmd->conn) ?
    > + cmd->conn->sess : cmd->sess);
    > + }
    > +}
    > +
    > +/*
    > + * Routine to pack an ordinary (LINUX) LUN 32-bit number
    > + * into an 8-byte LUN structure
    > + * (see SAM-2, Section 4.12.3 page 39)
    > + * Thanks to UNH for help with this :-).
    > + */
    > +inline u64 iscsit_pack_lun(unsigned int lun)
    > +{
    > + u64 result;
    > +
    > + result = ((lun& 0xff)<< 8); /* LSB of lun into byte 1 big-endian */
    > +
    > + if (0) {
    > + /* use flat space addressing method, SAM-2 Section 4.12.4
    > + - high-order 2 bits of byte 0 are 01
    > + - low-order 6 bits of byte 0 are MSB of the lun
    > + - all 8 bits of byte 1 are LSB of the lun
    > + - all other bytes (2 thru 7) are 0
    > + */
    > + result |= 0x40 | ((lun>> 8)& 0x3f);
    > + }
    > + /* else use peripheral device addressing method, Sam-2 Section 4.12.5
    > + - high-order 2 bits of byte 0 are 00
    > + - low-order 6 bits of byte 0 are all 0
    > + - all 8 bits of byte 1 are the lun
    > + - all other bytes (2 thru 7) are 0
    > + */
    > +
    > + return cpu_to_le64(result);
    > +}

    Is this int_to_scsilun?


    > +
    > +/*
    > + * Routine to pack an 8-byte LUN structure into a ordinary (LINUX) 32-bit
    > + * LUN number (see SAM-2, Section 4.12.3 page 39)
    > + * Thanks to UNH for help with this :-).
    > + */
    > +inline u32 iscsit_unpack_lun(unsigned char *lun_ptr)
    > +{
    > + u32 result, temp;
    > +
    > + result = *(lun_ptr+1); /* LSB of lun from byte 1 big-endian */
    > +
    > + switch (temp = ((*lun_ptr)>>6)) { /* high 2 bits of byte 0 big-endian */
    > + case 0: /* peripheral device addressing method, Sam-2 Section 4.12.5
    > + - high-order 2 bits of byte 0 are 00
    > + - low-order 6 bits of byte 0 are all 0
    > + - all 8 bits of byte 1 are the lun
    > + - all other bytes (2 thru 7) are 0
    > + */
    > + if (*lun_ptr != 0) {
    > + printk(KERN_ERR "Illegal Byte 0 in LUN peripheral"
    > + " device addressing method %u, expected 0\n",
    > + *lun_ptr);
    > + }
    > + break;
    > + case 1: /* flat space addressing method, SAM-2 Section 4.12.4
    > + - high-order 2 bits of byte 0 are 01
    > + - low-order 6 bits of byte 0 are MSB of the lun
    > + - all 8 bits of byte 1 are LSB of the lun
    > + - all other bytes (2 thru 7) are 0
    > + */
    > + result += ((*lun_ptr)& 0x3f)<< 8;
    > + break;
    > + default: /* (extended) logical unit addressing */
    > + printk(KERN_ERR "Unimplemented LUN addressing method %u, "
    > + "PDA method used instead\n", temp);
    > + break;
    > + }
    > +
    > + return result;
    > +}


    scsilun_to_int?





    > +
    > +int iscsit_check_session_usage_count(struct iscsi_session *sess)
    > +{
    > + spin_lock_bh(&sess->session_usage_lock);
    > + if (atomic_read(&sess->session_usage_count)) {
    > + atomic_set(&sess->session_waiting_on_uc, 1);
    > + spin_unlock_bh(&sess->session_usage_lock);
    > + if (in_interrupt())
    > + return 2;
    > +
    > + wait_for_completion(&sess->session_waiting_on_uc_comp);
    > + return 1;
    > + }
    > + spin_unlock_bh(&sess->session_usage_lock);
    > +
    > + return 0;
    > +}
    > +
    > +void iscsit_dec_session_usage_count(struct iscsi_session *sess)
    > +{
    > + spin_lock_bh(&sess->session_usage_lock);
    > + atomic_dec(&sess->session_usage_count);
    > +
    > + if (!atomic_read(&sess->session_usage_count)&&
    > + atomic_read(&sess->session_waiting_on_uc))
    > + complete(&sess->session_waiting_on_uc_comp);
    > +
    > + spin_unlock_bh(&sess->session_usage_lock);
    > +}
    > +
    > +void iscsit_inc_session_usage_count(struct iscsi_session *sess)
    > +{
    > + spin_lock_bh(&sess->session_usage_lock);
    > + atomic_inc(&sess->session_usage_count);
    > + spin_unlock_bh(&sess->session_usage_lock);
    > +}



    It seems strange for the session_usage_count and waiting_on_uc to be
    atomic and accessed under the spin lock. I think you normally do one or
    the other.



    > +
    > +unsigned char *iscsit_ntoa(u32 ip)
    > +{
    > + static unsigned char buf[18];
    > +
    > + memset(buf, 0, 18);
    > + sprintf(buf, "%u.%u.%u.%u", ((ip>> 24)& 0xff), ((ip>> 16)& 0xff),
    > + ((ip>> 8)& 0xff), (ip& 0xff));
    > +
    > + return buf;
    > +}

    Nothing is using this. Remove.


    > +
    > +void iscsit_ntoa2(unsigned char *buf, u32 ip)
    > +{
    > + memset(buf, 0, 18);
    > + sprintf(buf, "%u.%u.%u.%u", ((ip>> 24)& 0xff), ((ip>> 16)& 0xff),
    > + ((ip>> 8)& 0xff), (ip& 0xff));
    > +}

    I think we have a function like this already.


    If not, I think this should be:

    sprintf(buf, "%pI4",

    What s up with ipv6 btw? That uses %pI6.


    > +
    > +#define NS_INT16SZ 2
    > +#define NS_INADDRSZ 4
    > +#define NS_IN6ADDRSZ 16
    > +
    > +/* const char *
    > + * inet_ntop4(src, dst, size)
    > + * format an IPv4 address
    > + * return:
    > + * `dst' (as a const)
    > + * notes:
    > + * (1) uses no statics
    > + * (2) takes a unsigned char* not an in_addr as input
    > + * author:
    > + * Paul Vixie, 1996.
    > + */
    > +static const char *iscsit_ntop4(


    Only used by iscsit_ntop6


    > +/* const char *
    > + * isc_inet_ntop6(src, dst, size)
    > + * convert IPv6 binary address into presentation (printable) format
    > + * author:
    > + * Paul Vixie, 1996.
    > + */
    > +const char *iscsit_ntop6(const unsigned char *src, char *dst, size_t size)
    > +{


    Not used.


    > +
    > +/* int
    > + * inet_pton4(src, dst)
    > + * like inet_aton() but without all the hexadecimal and shorthand.
    > + * return:
    > + * 1 if `src' is a valid dotted quad, else 0.
    > + * notice:
    > + * does not touch `dst' unless it's returning 1.
    > + * author:
    > + * Paul Vixie, 1996.
    > + */
    > +static int iscsit_pton4(const char *src, unsigned char *dst)
    > +{



    Only used by inet_pton6

    > +
    > +/* int
    > + * inet_pton6(src, dst)
    > + * convert presentation level address to network order binary form.
    > + * return:
    > + * 1 if `src' is a valid [RFC1884 2.2] address, else 0.
    > + * notice:
    > + * (1) does not touch `dst' unless it's returning 1.
    > + * (2) :: in a full address is silently ignored.
    > + * credit:
    > + * inspired by Mark Andrews.
    > + * author:
    > + * Paul Vixie, 1996.
    > + */
    > +int iscsit_pton6(const char *src, unsigned char *dst)
    > +{
    > + static const char xdigits_l[] = "0123456789abcdef",



    Not used.

    I think if you needed these functions then they should go into some
    network code. There were not specific to a iscsi target were they.



    > +
    > + return NULL;
    > +}
    > +
    > +void iscsit_check_conn_usage_count(struct iscsi_conn *conn)
    > +{
    > + spin_lock_bh(&conn->conn_usage_lock);
    > + if (atomic_read(&conn->conn_usage_count)) {
    > + atomic_set(&conn->conn_waiting_on_uc, 1);
    > + spin_unlock_bh(&conn->conn_usage_lock);
    > +
    > + wait_for_completion(&conn->conn_waiting_on_uc_comp);
    > + return;
    > + }
    > + spin_unlock_bh(&conn->conn_usage_lock);
    > +}
    > +
    > +void iscsit_dec_conn_usage_count(struct iscsi_conn *conn)
    > +{
    > + spin_lock_bh(&conn->conn_usage_lock);
    > + atomic_dec(&conn->conn_usage_count);
    > +
    > + if (!atomic_read(&conn->conn_usage_count)&&
    > + atomic_read(&conn->conn_waiting_on_uc))
    > + complete(&conn->conn_waiting_on_uc_comp);
    > +
    > + spin_unlock_bh(&conn->conn_usage_lock);
    > +}
    > +
    > +void iscsit_inc_conn_usage_count(struct iscsi_conn *conn)
    > +{
    > + spin_lock_bh(&conn->conn_usage_lock);
    > + atomic_inc(&conn->conn_usage_count);
    > + spin_unlock_bh(&conn->conn_usage_lock);
    > +}

    Something about atomics and always being accessed under a lock. I think
    this happens in other places too.

    Could this also be done with krefs?



    > +
    > +int iscsit_check_for_active_network_device(struct iscsi_conn *conn)
    > +{
    > + struct net_device *net_dev;
    > +
    > + if (!conn->net_if) {
    > + printk(KERN_ERR "struct iscsi_conn->net_if is NULL for CID:"
    > + " %hu\n", conn->cid);
    > + return 0;
    > + }
    > + net_dev = conn->net_if;
    > +
    > + return netif_carrier_ok(net_dev);
    > +}
    > +
    > +static void iscsit_handle_netif_timeout(unsigned long data)
    > +{
    > + struct iscsi_conn *conn = (struct iscsi_conn *) data;
    > +
    > + iscsit_inc_conn_usage_count(conn);
    > +
    > + spin_lock_bh(&conn->netif_lock);
    > + if (conn->netif_timer_flags& ISCSI_TF_STOP) {
    > + spin_unlock_bh(&conn->netif_lock);
    > + iscsit_dec_conn_usage_count(conn);
    > + return;
    > + }
    > + conn->netif_timer_flags&= ~ISCSI_TF_RUNNING;
    > +
    > + if (iscsit_check_for_active_network_device((void *)conn)) {
    > + iscsit_start_netif_timer(conn);
    > + spin_unlock_bh(&conn->netif_lock);
    > + iscsit_dec_conn_usage_count(conn);
    > + return;
    > + }
    > +
    > + printk(KERN_ERR "Detected PHY loss on Network Interface: %s for iSCSI"
    > + " CID: %hu on SID: %u\n", conn->net_dev, conn->cid,
    > + conn->sess->sid);
    > +
    > + spin_unlock_bh(&conn->netif_lock);
    > +
    > + iscsit_cause_connection_reinstatement(conn, 0);
    > + iscsit_dec_conn_usage_count(conn);
    > +}


    I think instead of polling the device you can use
    register_netdevice_notifier. See fcoe.c for an example.



    > +
    > +static inline int iscsit_do_rx_data(
    > + struct iscsi_conn *conn,
    > + struct iscsi_data_count *count)
    > +{



    > +
    > + while (total_rx< data) {
    > + oldfs = get_fs();
    > + set_fs(get_ds());
    > +
    > + conn->sock->sk->sk_allocation = GFP_ATOMIC;


    I do not think you need GFP_ATOMIC. If you cannot sleep then I think you
    are in trouble below, because you pass in MSG_WAITALL.

    I think since this is the target side you can use GFP_KERNEL. Target
    mode should not have the same allocation swinging around on you
    dependency problem like a initiator does, does it?

    If it does at least use GFP_NOIO (I think iscsi_tcp.c should be using
    GFP_NOIO and not GFP_ATOMIC).

    And I think we are supposed to be using kernel_recvmsg. It does the
    get/set_ds stuff for you.


    > + rx_loop = sock_recvmsg(conn->sock,&msg,
    > + (data - total_rx), MSG_WAITALL);
    > +




    > +static inline int iscsit_do_tx_data(
    > + struct iscsi_conn *conn,
    > + struct iscsi_data_count *count)
    > +{



    > +
    > + while (total_tx< data) {
    > + oldfs = get_fs();
    > + set_fs(get_ds());
    > +
    > + conn->sock->sk->sk_allocation = GFP_ATOMIC;

    Same comment as the recv side. I think you can also move this and set it
    in one place.

    And I think we are supposed to be using kernel_sendmsg. That will also
    do the get/set_fs stuff for you.


    > + tx_loop = sock_sendmsg(conn->sock,&msg, (data - total_tx));
    > +
    > + set_fs(oldfs);
    > +







    > +extern int iscsit_build_sendtargets_response(struct iscsi_cmd *cmd)
    > +{
    > + char *ip, *payload = NULL;
    > + struct iscsi_conn *conn = cmd->conn;
    > + struct iscsi_portal_group *tpg;
    > + struct iscsi_tiqn *tiqn;
    > + struct iscsi_tpg_np *tpg_np;
    > + int buffer_len, end_of_buf = 0, len = 0, payload_len = 0;
    > + unsigned char buf[256];
    > + unsigned char buf_ipv4[IPV4_BUF_SIZE];
    > +
    > + buffer_len = (conn->conn_ops->MaxRecvDataSegmentLength> 32768) ?
    > + 32768 : conn->conn_ops->MaxRecvDataSegmentLength;
    > +
    > + payload = kzalloc(buffer_len, GFP_KERNEL);
    > + if (!payload) {
    > + printk(KERN_ERR "Unable to allocate memory for sendtargets"
    > + " response.\n");
    > + return -1;
    > + }
    > +
    > + spin_lock(&tiqn_lock);
    > + list_for_each_entry(tiqn,&g_tiqn_list, tiqn_list) {
    > + memset(buf, 0, 256);
    > +
    > + len = sprintf(buf, "TargetName=%s", tiqn->tiqn);
    > + len += 1;
    > +
    > + if ((len + payload_len)> buffer_len) {
    > + spin_unlock(&tiqn->tiqn_tpg_lock);
    > + end_of_buf = 1;
    > + goto eob;
    > + }
    > + memcpy((void *)payload + payload_len, buf, len);
    > + payload_len += len;
    > +
    > + spin_lock(&tiqn->tiqn_tpg_lock);
    > + list_for_each_entry(tpg,&tiqn->tiqn_tpg_list, tpg_list) {
    > +
    > + spin_lock(&tpg->tpg_state_lock);
    > + if ((tpg->tpg_state == TPG_STATE_FREE) ||
    > + (tpg->tpg_state == TPG_STATE_INACTIVE)) {
    > + spin_unlock(&tpg->tpg_state_lock);
    > + continue;
    > + }
    > + spin_unlock(&tpg->tpg_state_lock);
    > +
    > + spin_lock(&tpg->tpg_np_lock);
    > + list_for_each_entry(tpg_np,&tpg->tpg_gnp_list,
    > + tpg_np_list) {
    > + memset(buf, 0, 256);
    > +
    > + if (tpg_np->tpg_np->np_sockaddr.ss_family == AF_INET6) {
    > + ip =&tpg_np->tpg_np->np_ipv6[0];


    Is ip supposed to be a string with the ip address in it? If so is that
    right? Is np_ipv6 a string with the ip address in human readable format,
    but below np_ipv4 is the integer representation then you convert it.


    > + } else {
    > + memset(buf_ipv4, 0, IPV4_BUF_SIZE);
    > + iscsit_ntoa2(buf_ipv4,
    > + tpg_np->tpg_np->np_ipv4);
    > + ip =&buf_ipv4[0];
    > + }
    > +
    > + len = sprintf(buf, "TargetAddress="
    > + "%s%s%s:%hu,%hu",
    > + (tpg_np->tpg_np->np_sockaddr.ss_family == AF_INET6) ?
    > + "[" : "", ip,
    > + (tpg_np->tpg_np->np_sockaddr.ss_family == AF_INET6) ?
    > + "]" : "", tpg_np->tpg_np->np_port,
    > + tpg->tpgt);
    > + len += 1;
    > +
    > + if ((len + payload_len)> buffer_len) {
    > + spin_unlock(&tpg->tpg_np_lock);
    > + spin_unlock(&tiqn->tiqn_tpg_lock);
    > + end_of_buf = 1;
    > + goto eob;
    > + }
    > +
    > + memcpy((void *)payload + payload_len, buf, len);
    > + payload_len += len;
    > + }
    > + spin_unlock(&tpg->tpg_np_lock);
    > + }
    > + spin_unlock(&tiqn->tiqn_tpg_lock);
    > +eob:
    > + if (end_of_buf)
    > + break;
    > + }
    > + spin_unlock(&tiqn_lock);
    > +
    > + cmd->buf_ptr = payload;


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