diff options
Diffstat (limited to 'drivers/char')
| -rw-r--r-- | drivers/char/hvc_iucv.c | 176 |
1 files changed, 75 insertions, 101 deletions
diff --git a/drivers/char/hvc_iucv.c b/drivers/char/hvc_iucv.c index a23f7e8fba86..ce1a25f779ce 100644 --- a/drivers/char/hvc_iucv.c +++ b/drivers/char/hvc_iucv.c @@ -1,14 +1,15 @@ /* - * hvc_iucv.c - z/VM IUCV back-end for the Hypervisor Console (HVC) + * hvc_iucv.c - z/VM IUCV hypervisor console (HVC) device driver * - * This back-end for HVC provides terminal access via + * This HVC device driver provides terminal access using * z/VM IUCV communication paths. * - * Copyright IBM Corp. 2008. + * Copyright IBM Corp. 2008 * * Author(s): Hendrik Brueckner <brueckner@linux.vnet.ibm.com> */ #define KMSG_COMPONENT "hvc_iucv" +#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt #include <linux/types.h> #include <asm/ebcdic.h> @@ -22,7 +23,7 @@ #include "hvc_console.h" -/* HVC backend for z/VM IUCV */ +/* General device driver settings */ #define HVC_IUCV_MAGIC 0xc9e4c3e5 #define MAX_HVC_IUCV_LINES HVC_ALLOC_TTY_ADAPTERS #define MEMPOOL_MIN_NR (PAGE_SIZE / sizeof(struct iucv_tty_buffer)/4) @@ -35,7 +36,6 @@ #define MSG_TYPE_WINSIZE 0x08 /* Terminal window size update */ #define MSG_TYPE_DATA 0x10 /* Terminal data */ -#define MSG_SIZE(s) ((s) + offsetof(struct iucv_tty_msg, data)) struct iucv_tty_msg { u8 version; /* Message version */ u8 type; /* Message type */ @@ -43,6 +43,7 @@ struct iucv_tty_msg { u16 datalen; /* Payload length */ u8 data[]; /* Payload buffer */ } __attribute__((packed)); +#define MSG_SIZE(s) ((s) + offsetof(struct iucv_tty_msg, data)) enum iucv_state_t { IUCV_DISCONN = 0, @@ -56,7 +57,7 @@ enum tty_state_t { }; struct hvc_iucv_private { - struct hvc_struct *hvc; /* HVC console struct reference */ + struct hvc_struct *hvc; /* HVC struct reference */ u8 srv_name[8]; /* IUCV service name (ebcdic) */ enum iucv_state_t iucv_state; /* IUCV connection status */ enum tty_state_t tty_state; /* TTY status */ @@ -74,7 +75,7 @@ struct hvc_iucv_private { struct iucv_tty_buffer { struct list_head list; /* list pointer */ - struct iucv_message msg; /* store an incoming IUCV message */ + struct iucv_message msg; /* store an IUCV message */ size_t offset; /* data buffer offset */ struct iucv_tty_msg *mbuf; /* buffer to store input/output data */ }; @@ -120,7 +121,7 @@ struct hvc_iucv_private *hvc_iucv_get_private(uint32_t num) } /** - * alloc_tty_buffer() - Returns a new struct iucv_tty_buffer element. + * alloc_tty_buffer() - Return a new struct iucv_tty_buffer element. * @size: Size of the internal buffer used to store data. * @flags: Memory allocation flags passed to mempool. * @@ -128,7 +129,6 @@ struct hvc_iucv_private *hvc_iucv_get_private(uint32_t num) * allocates an internal data buffer with the specified size @size. * Note: The total message size arises from the internal buffer size and the * members of the iucv_tty_msg structure. - * * The function returns NULL if memory allocation has failed. */ static struct iucv_tty_buffer *alloc_tty_buffer(size_t size, gfp_t flags) @@ -157,9 +157,6 @@ static struct iucv_tty_buffer *alloc_tty_buffer(size_t size, gfp_t flags) /** * destroy_tty_buffer() - destroy struct iucv_tty_buffer element. * @bufp: Pointer to a struct iucv_tty_buffer element, SHALL NOT be NULL. - * - * The destroy_tty_buffer() function frees the internal data buffer and returns - * the struct iucv_tty_buffer element back to the mempool for freeing. */ static void destroy_tty_buffer(struct iucv_tty_buffer *bufp) { @@ -169,11 +166,7 @@ static void destroy_tty_buffer(struct iucv_tty_buffer *bufp) /** * destroy_tty_buffer_list() - call destroy_tty_buffer() for each list element. - * @list: List head pointer to a list containing struct iucv_tty_buffer - * elements. - * - * Calls destroy_tty_buffer() for each struct iucv_tty_buffer element in the - * list @list. + * @list: List containing struct iucv_tty_buffer elements. */ static void destroy_tty_buffer_list(struct list_head *list) { @@ -186,24 +179,24 @@ static void destroy_tty_buffer_list(struct list_head *list) } /** - * hvc_iucv_write() - Receive IUCV message write data to HVC console buffer. - * @priv: Pointer to hvc_iucv_private structure. - * @buf: HVC console buffer for writing received terminal data. - * @count: HVC console buffer size. + * hvc_iucv_write() - Receive IUCV message & write data to HVC buffer. + * @priv: Pointer to struct hvc_iucv_private + * @buf: HVC buffer for writing received terminal data. + * @count: HVC buffer size. * @has_more_data: Pointer to an int variable. * * The function picks up pending messages from the input queue and receives * the message data that is then written to the specified buffer @buf. - * If the buffer size @count is less than the data message size, then the + * If the buffer size @count is less than the data message size, the * message is kept on the input queue and @has_more_data is set to 1. - * If the message data has been entirely written, the message is removed from + * If all message data has been written, the message is removed from * the input queue. * * The function returns the number of bytes written to the terminal, zero if * there are no pending data messages available or if there is no established * IUCV path. * If the IUCV path has been severed, then -EPIPE is returned to cause a - * hang up (that is issued by the HVC console layer). + * hang up (that is issued by the HVC layer). */ static int hvc_iucv_write(struct hvc_iucv_private *priv, char *buf, int count, int *has_more_data) @@ -212,12 +205,12 @@ static int hvc_iucv_write(struct hvc_iucv_private *priv, int written; int rc; - /* Immediately return if there is no IUCV connection */ + /* immediately return if there is no IUCV connection */ if (priv->iucv_state == IUCV_DISCONN) return 0; - /* If the IUCV path has been severed, return -EPIPE to inform the - * hvc console layer to hang up the tty device. */ + /* if the IUCV path has been severed, return -EPIPE to inform the + * HVC layer to hang up the tty device. */ if (priv->iucv_state == IUCV_SEVERED) return -EPIPE; @@ -225,7 +218,7 @@ static int hvc_iucv_write(struct hvc_iucv_private *priv, if (list_empty(&priv->tty_inqueue)) return 0; - /* receive a iucv message and flip data to the tty (ldisc) */ + /* receive an iucv message and flip data to the tty (ldisc) */ rb = list_first_entry(&priv->tty_inqueue, struct iucv_tty_buffer, list); written = 0; @@ -268,7 +261,7 @@ static int hvc_iucv_write(struct hvc_iucv_private *priv, case MSG_TYPE_WINSIZE: if (rb->mbuf->datalen != sizeof(struct winsize)) break; - hvc_resize(priv->hvc, *((struct winsize *)rb->mbuf->data)); + hvc_resize(priv->hvc, *((struct winsize *) rb->mbuf->data)); break; case MSG_TYPE_ERROR: /* ignored ... */ @@ -292,10 +285,9 @@ out_written: * @buf: Pointer to a buffer to store data * @count: Size of buffer available for writing * - * The hvc_console thread calls this method to read characters from - * the terminal backend. If an IUCV communication path has been established, - * pending IUCV messages are received and data is copied into buffer @buf - * up to @count bytes. + * The HVC thread calls this method to read characters from the back-end. + * If an IUCV communication path has been established, pending IUCV messages + * are received and data is copied into buffer @buf up to @count bytes. * * Locking: The routine gets called under an irqsave() spinlock; and * the routine locks the struct hvc_iucv_private->lock to call @@ -332,17 +324,17 @@ static int hvc_iucv_get_chars(uint32_t vtermno, char *buf, int count) * @count: Size of buffer and amount of data to send. * * The function queues data for sending. To actually send the buffered data, - * a work queue function is * scheduled (with QUEUE_SNDBUF_DELAY). + * a work queue function is scheduled (with QUEUE_SNDBUF_DELAY). * The function returns the number of data bytes that has been buffered. * * If the device is not connected, data is ignored and the function returns * @count. * If the buffer is full, the function returns 0. - * If an existing IUCV communicaton path has been severed, the function returns - * -EPIPE (can be passed to HVC layer to cause a tty hangup). + * If an existing IUCV communicaton path has been severed, -EPIPE is returned + * (that can be passed to HVC layer to cause a tty hangup). */ static int hvc_iucv_queue(struct hvc_iucv_private *priv, const char *buf, - int count) + int count) { size_t len; @@ -369,12 +361,10 @@ static int hvc_iucv_queue(struct hvc_iucv_private *priv, const char *buf, * hvc_iucv_send() - Send an IUCV message containing terminal data. * @priv: Pointer to struct hvc_iucv_private instance. * - * If an IUCV communication path has been established, the queued data - * for output are sent via an IUCV message. - * - * If there is no IUCV communication path established, the function returns 0. - * If an existing IUCV communicaton path has been severed, the function returns - * -EPIPE. + * If an IUCV communication path has been established, the buffered output data + * is sent via an IUCV message and the number of bytes sent is returned. + * Returns 0 if there is no established IUCV communication path or + * -EPIPE if an existing IUCV communicaton path has been severed. */ static int hvc_iucv_send(struct hvc_iucv_private *priv) { @@ -420,15 +410,14 @@ static int hvc_iucv_send(struct hvc_iucv_private *priv) * hvc_iucv_sndbuf_work() - Send buffered data over IUCV * @work: Work structure. * - * The function sends buffered output data over IUCV and, if necessary, - * reschedules itself if not all buffered data could be sent. + * This work queue function sends buffered output data over IUCV and, + * if not all buffered data could be sent, reschedules itself. */ static void hvc_iucv_sndbuf_work(struct work_struct *work) { struct hvc_iucv_private *priv; priv = container_of(work, struct hvc_iucv_private, sndbuf_work.work); - if (!priv) return; @@ -443,10 +432,8 @@ static void hvc_iucv_sndbuf_work(struct work_struct *work) * @buf: Pointer to an buffer to read data from * @count: Size of buffer available for reading * - * The hvc_console thread calls this method to write characters from - * to the terminal backend. - * The function calls hvc_iucv_send() under the lock of the - * struct hvc_iucv_private instance that corresponds to the tty @vtermno. + * The HVC thread calls this method to write characters to the back-end. + * The function calls hvc_iucv_queue() to queue terminal data for sending. * * Locking: The method gets called under an irqsave() spinlock; and * locks struct hvc_iucv_private->lock. @@ -496,12 +483,8 @@ static int hvc_iucv_notifier_add(struct hvc_struct *hp, int id) } /** - * hvc_iucv_cleanup() - Clean up function if the tty portion is finally closed. + * hvc_iucv_cleanup() - Clean up and reset a z/VM IUCV HVC instance. * @priv: Pointer to the struct hvc_iucv_private instance. - * - * The functions severs the established IUCV communication path (if any), and - * destroy struct iucv_tty_buffer elements from the in- and outqueue. Finally, - * the functions resets the states to TTY_CLOSED and IUCV_DISCONN. */ static void hvc_iucv_cleanup(struct hvc_iucv_private *priv) { @@ -553,22 +536,19 @@ static void flush_sndbuf_sync(struct hvc_iucv_private *priv) } /** - * hvc_iucv_notifier_hangup() - HVC notifier for tty hangups. - * @hp: Pointer to the HVC device (struct hvc_struct) - * @id: Additional data (originally passed to hvc_alloc): the index of an struct - * hvc_iucv_private instance. + * hvc_iucv_notifier_hangup() - HVC notifier for TTY hangups. + * @hp: Pointer to the HVC device (struct hvc_struct) + * @id: Additional data (originally passed to hvc_alloc): + * the index of an struct hvc_iucv_private instance. * - * This routine notifies the HVC backend that a tty hangup (carrier loss, + * This routine notifies the HVC back-end that a tty hangup (carrier loss, * virtual or otherwise) has occured. - * - * The HVC backend for z/VM IUCV ignores virtual hangups (vhangup()), to keep - * an existing IUCV communication path established. + * The z/VM IUCV HVC device driver ignores virtual hangups (vhangup()) + * to keep an existing IUCV communication path established. * (Background: vhangup() is called from user space (by getty or login) to * disable writing to the tty by other applications). - * - * If the tty has been opened (e.g. getty) and an established IUCV path has been - * severed (we caused the tty hangup in that case), then the functions invokes - * hvc_iucv_cleanup() to clean up. + * If the tty has been opened and an established IUCV path has been severed + * (we caused the tty hangup), the function calls hvc_iucv_cleanup(). * * Locking: struct hvc_iucv_private->lock */ @@ -584,10 +564,8 @@ static void hvc_iucv_notifier_hangup(struct hvc_struct *hp, int id) spin_lock_bh(&priv->lock); /* NOTE: If the hangup was scheduled by ourself (from the iucv - * path_servered callback [IUCV_SEVERED]), then we have to - * finally clean up the tty backend structure and set state to - * TTY_CLOSED. - * + * path_servered callback [IUCV_SEVERED]), we have to clean up + * our structure and to set state to TTY_CLOSED. * If the tty was hung up otherwise (e.g. vhangup()), then we * ignore this hangup and keep an established IUCV path open... * (...the reason is that we are not able to connect back to the @@ -605,10 +583,9 @@ static void hvc_iucv_notifier_hangup(struct hvc_struct *hp, int id) * @id: Additional data (originally passed to hvc_alloc): * the index of an struct hvc_iucv_private instance. * - * This routine notifies the HVC backend that the last tty device file - * descriptor has been closed. - * The function calls hvc_iucv_cleanup() to clean up the struct hvc_iucv_private - * instance. + * This routine notifies the HVC back-end that the last tty device fd has been + * closed. The function calls hvc_iucv_cleanup() to clean up the struct + * hvc_iucv_private instance. * * Locking: struct hvc_iucv_private->lock */ @@ -640,20 +617,18 @@ static void hvc_iucv_notifier_del(struct hvc_struct *hp, int id) /** * hvc_iucv_path_pending() - IUCV handler to process a connection request. * @path: Pending path (struct iucv_path) - * @ipvmid: Originator z/VM system identifier + * @ipvmid: z/VM system identifier of originator * @ipuser: User specified data for this path * (AF_IUCV: port/service name and originator port) * - * The function uses the @ipuser data to check to determine if the pending - * path belongs to a terminal managed by this HVC backend. - * If the check is successful, then an additional check is done to ensure - * that a terminal cannot be accessed multiple times (only one connection - * to a terminal is allowed). In that particular case, the pending path is - * severed. If it is the first connection, the pending path is accepted and - * associated to the struct hvc_iucv_private. The iucv state is updated to - * reflect that a communication path has been established. + * The function uses the @ipuser data to determine if the pending path belongs + * to a terminal managed by this device driver. + * If the path belongs to this driver, ensure that the terminal is not accessed + * multiple times (only one connection to a terminal is allowed). + * If the terminal is not yet connected, the pending path is accepted and is + * associated to the appropriate struct hvc_iucv_private instance. * - * Returns 0 if the path belongs to a terminal managed by the this HVC backend; + * Returns 0 if @path belongs to a terminal managed by the this device driver; * otherwise returns -ENODEV in order to dispatch this path to other handlers. * * Locking: struct hvc_iucv_private->lock @@ -672,7 +647,6 @@ static int hvc_iucv_path_pending(struct iucv_path *path, priv = hvc_iucv_table[i]; break; } - if (!priv) return -ENODEV; @@ -719,8 +693,7 @@ out_path_handled: * sets the iucv state to IUCV_SEVERED for the associated struct * hvc_iucv_private instance. Later, the IUCV_SEVERED state triggers a tty * hangup (hvc_iucv_get_chars() / hvc_iucv_write()). - * - * If tty portion of the HVC is closed then clean up the outqueue in addition. + * If tty portion of the HVC is closed, clean up the outqueue. * * Locking: struct hvc_iucv_private->lock */ @@ -755,9 +728,9 @@ static void hvc_iucv_path_severed(struct iucv_path *path, u8 ipuser[16]) * @path: Pending path (struct iucv_path) * @msg: Pointer to the IUCV message * - * The function stores an incoming message on the input queue for later + * The function puts an incoming message on the input queue for later * processing (by hvc_iucv_get_chars() / hvc_iucv_write()). - * However, if the tty has not yet been opened, the message is rejected. + * If the tty has not yet been opened, the message is rejected. * * Locking: struct hvc_iucv_private->lock */ @@ -773,6 +746,7 @@ static void hvc_iucv_msg_pending(struct iucv_path *path, return; } + spin_lock(&priv->lock); /* reject messages if tty has not yet been opened */ @@ -791,7 +765,7 @@ static void hvc_iucv_msg_pending(struct iucv_path *path, list_add_tail(&rb->list, &priv->tty_inqueue); - hvc_kick(); /* wake up hvc console thread */ + hvc_kick(); /* wake up hvc thread */ unlock_return: spin_unlock(&priv->lock); @@ -802,10 +776,10 @@ unlock_return: * @path: Pending path (struct iucv_path) * @msg: Pointer to the IUCV message * - * The function is called upon completion of message delivery and the - * message is removed from the outqueue. Additional delivery information - * can be found in msg->audit: rejected messages (0x040000 (IPADRJCT)) and - * purged messages (0x010000 (IPADPGNR)). + * The function is called upon completion of message delivery to remove the + * message from the outqueue. Additional delivery information can be found + * msg->audit: rejected messages (0x040000 (IPADRJCT)), and + * purged messages (0x010000 (IPADPGNR)). * * Locking: struct hvc_iucv_private->lock */ @@ -841,8 +815,8 @@ static struct hv_ops hvc_iucv_ops = { * hvc_iucv_alloc() - Allocates a new struct hvc_iucv_private instance * @id: hvc_iucv_table index * - * This function allocates a new hvc_iucv_private struct and put the - * instance into hvc_iucv_table at index @id. + * This function allocates a new hvc_iucv_private structure and stores + * the instance in hvc_iucv_table at index @id. * Returns 0 on success; otherwise non-zero. */ static int __init hvc_iucv_alloc(int id) @@ -867,7 +841,7 @@ static int __init hvc_iucv_alloc(int id) return -ENOMEM; } - /* Finally allocate hvc */ + /* finally allocate hvc */ priv->hvc = hvc_alloc(HVC_IUCV_MAGIC + id, /* PAGE_SIZE */ HVC_IUCV_MAGIC + id, &hvc_iucv_ops, 256); if (IS_ERR(priv->hvc)) { @@ -877,7 +851,7 @@ static int __init hvc_iucv_alloc(int id) return rc; } - /* kick khvcd thread; instead of using polling */ + /* notify HVC thread instead of using polling */ priv->hvc->irq_requested = 1; /* setup iucv related information */ @@ -890,7 +864,7 @@ static int __init hvc_iucv_alloc(int id) } /** - * hvc_iucv_init() - Initialization of HVC backend for z/VM IUCV + * hvc_iucv_init() - z/VM IUCV HVC device driver initialization */ static int __init hvc_iucv_init(void) { @@ -929,7 +903,7 @@ static int __init hvc_iucv_init(void) rc = hvc_iucv_alloc(i); if (rc) { pr_err("Creating a new HVC terminal device " - "failed with error code=%d\n", rc); + "failed with error code=%d\n", rc); goto out_error_hvc; } } |