Messages in this thread | | | Date | Thu, 29 Jul 2004 13:41:05 -0400 | From | Jeff Garzik <> | Subject | Re: [announce][draft4] HVCS for inclusion in 2.6 tree |
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Ryan Arnold wrote: > +int hvcs_free_partner_info(struct list_head *head) > +{ > + struct hvcs_partner_info *pi; > + struct list_head *element; > + > + if (!head) { > + return -EINVAL; > + }
style: single statements don't want braces
> + while (!list_empty(head)) { > + element = head->next; > + pi = list_entry(element, struct hvcs_partner_info, node); > + list_del(element); > + kfree(pi); > + }
list_for_each()
> + return 0; > +} > +EXPORT_SYMBOL(hvcs_free_partner_info); > + > +/* Helper function for hvcs_get_partner_info */ > +int hvcs_next_partner(unsigned int unit_address, > + unsigned long last_p_partition_ID, > + unsigned long last_p_unit_address, unsigned long *pi_buff) > + > +{ > + long retval; > + retval = plpar_hcall_norets(H_VTERM_PARTNER_INFO, unit_address, > + last_p_partition_ID, > + last_p_unit_address, virt_to_phys(pi_buff)); > + return hvcs_convert(retval); > +} > + > +/* > + * The unit_address parameter is the unit address of the vty-server vdevice > + * in whose partner information the caller is interested. This function > + * uses a pointer to a list_head instance in which to store the partner info. > + * This function returns non-zero on success, or if there is no partner info. > + * > + * Invocation of this function should always be followed by an invocation of > + * hvcs_free_partner_info() using a pointer to the SAME list head instance > + * that was used to store the partner_info list. > + */
since these are exported functions, please use kernel-doc style so that they may be picked up by automated documentation tools
> +int hvcs_get_partner_info(unsigned int unit_address, struct list_head *head, > + unsigned long *pi_buff) > +{ > + /* > + * This is a page sized buffer to be passed to hvcall per invocation. > + * NOTE: the first long returned is unit_address. The second long > + * returned is the partition ID and starting with pi_buff[2] are > + * HVCS_CLC_LENGTH characters, which are diff size than the unsigned > + * long, hence the casting mumbojumbo you see later. > + */ > + unsigned long last_p_partition_ID; > + unsigned long last_p_unit_address; > + struct hvcs_partner_info *next_partner_info = NULL; > + int more = 1; > + int retval; > + > + memset(pi_buff, 0x00, PAGE_SIZE); > + /* invalid parameters */ > + if (!head) > + return -EINVAL; > + > + last_p_partition_ID = last_p_unit_address = ~0UL; > + INIT_LIST_HEAD(head); > + > + if (!pi_buff) > + return -ENOMEM; > + > + do { > + retval = hvcs_next_partner(unit_address, last_p_partition_ID, > + last_p_unit_address, pi_buff); > + if (retval) { > + /* > + * Don't indicate that we've failed if we have > + * any list elements. > + */ > + if (!list_empty(head)) > + return 0; > + return retval; > + } > + > + last_p_partition_ID = pi_buff[0]; > + last_p_unit_address = pi_buff[1]; > + > + /* This indicates that there are no further partners */ > + if (last_p_partition_ID == ~0UL > + && last_p_unit_address == ~0UL) > + break; > + > + /* This is a very small struct and will be freed soon in > + * hvcs_free_partner_info(). */ > + next_partner_info = kmalloc(sizeof(struct hvcs_partner_info), > + GFP_ATOMIC); > + > + if (!next_partner_info) { > + printk(KERN_WARNING "HVCONSOLE: kmalloc() failed to" > + " allocate partner info struct.\n"); > + hvcs_free_partner_info(head); > + return -ENOMEM; > + } > + > + next_partner_info->unit_address > + = (unsigned int)last_p_unit_address; > + next_partner_info->partition_ID > + = (unsigned int)last_p_partition_ID; > + > + /* copy the Null-term char too */ > + strncpy(&next_partner_info->location_code[0], > + (char *)&pi_buff[2], > + strlen((char *)&pi_buff[2]) + 1); > + > + list_add_tail(&(next_partner_info->node), head); > + next_partner_info = NULL; > + > + } while (more); > + > + return 0; > +} > +EXPORT_SYMBOL(hvcs_get_partner_info); > + > +/* > + * If this function is called once and -EINVAL is returned it may > + * indicate that the partner info needs to be refreshed for the > + * target unit address at which point the caller must invoke > + * hvcs_get_partner_info() and then call this function again. If, > + * for a second time, -EINVAL is returned then it indicates that > + * there is probably already a partner connection registered to a > + * different vty-server@ vdevice. It is also possible that a second > + * -EINVAL may indicate that one of the parms is not valid, for > + * instance if the link was removed between the vty-server@ vdevice > + * and the vty@ vdevice that you are trying to open. Don't shoot the > + * messenger. Firmware implemented it this way. > + */ > +int hvcs_register_connection( unsigned int unit_address, > + unsigned int p_partition_ID, unsigned int p_unit_address) > +{ > + long retval; > + retval = plpar_hcall_norets(H_REGISTER_VTERM, unit_address, > + p_partition_ID, p_unit_address); > + return hvcs_convert(retval); > +} > +EXPORT_SYMBOL(hvcs_register_connection); > + > +/* > + * If -EBUSY is returned continue to call this function > + * until 0 is returned. > + */ > +int hvcs_free_connection(unsigned int unit_address) > +{ > + long retval; > + retval = plpar_hcall_norets(H_FREE_VTERM, unit_address); > + return hvcs_convert(retval); > +} > +EXPORT_SYMBOL(hvcs_free_connection);
> +/* > + * The hcall interface involves putting 8 chars into each of two registers. > + * We load up those 2 registers (in arch/ppc64/hvconsole.c) by casting char[16] > + * to long[2]. It would work without __ALIGNED__, but a little (tiny) bit > + * slower because an unaligned load is slower than aligned load. > + */ > +#define __ALIGNED__ __attribute__((__aligned__(8)))
does this definition really belong here?
it also seems like the name would be likely to conflict with some existing symbol.
> +/* Converged location code string length + 1 null terminator */ > +#define CLC_LENGTH 80 > + > +/* > + * How much data can firmware send with each hvc_put_chars()? Maybe this > + * should be moved into an architecture specific area. > + */ > +#define HVCS_BUFF_LEN 16 > + > +/* > + * This is the maximum amount of data we'll let the user send us (hvcs_write) at > + * once in a chunk as a sanity check. > + */ > +#define HVCS_MAX_FROM_USER 4096 > + > +/* > + * Be careful when adding flags to this line discipline. Don't add anything > + * that will cause echoing or we'll go into recursive loop echoing chars back > + * and forth with the console drivers. > + */ > +static struct termios hvcs_tty_termios = { > + .c_iflag = IGNBRK | IGNPAR, > + .c_oflag = OPOST, > + .c_cflag = B38400 | CS8 | CREAD | HUPCL, > + .c_cc = INIT_C_CC > +}; > + > +/* > + * This value is used to take the place of a command line parameter when the > + * module is inserted. It starts as -1 and stays as such if the user doesn't > + * specify a module insmod parameter. If they DO specify one then it is set to > + * the value of the integer passed in. > + */ > +static int hvcs_parm_num_devs = -1; > +module_param(hvcs_parm_num_devs, int, 0); > + > +char hvcs_driver_name[] = "hvcs"; > +char hvcs_device_node[] = "hvcs"; > +char hvcs_driver_string[] > + = "IBM hvcs (Hypervisor Virtual Console Server) Driver"; > + > +/* Status of partner info rescan triggered via sysfs. */ > +static int hvcs_rescan_status = 0;
implicitly rather than explicitly zero statics
> +static struct tty_driver *hvcs_tty_driver; > + > +/* > + * This is used to associate a vty-server, as it is exposed to this driver, with > + * a preallocated tty_struct.index. The dev node and hvcs index numbers are not > + * re-used after device removal otherwise removing and adding a new one would > + * link a /dev/hvcs* entry to a different vty-server than it did before the > + * removal. Incidentally, a newly exposed vty-server will always map to an > + * incrementally higher /dev/hvcs* entry than the last exposed vty-server. > + */ > +static int hvcs_struct_count = -1; > + > +/* > + * Used by the khvcsd to pick up I/O operations when the kernel_thread is > + * already awake but potentially shifted to TASK_INTERRUPTIBLE state. > + */ > +static int hvcs_kicked = 0;
implicitly rather than explicitly zero statics
> +/* Used the the kthread construct for task operations */ > +static struct task_struct *hvcs_task; > + > +/* > + * We allocate this for the use of all of the hvcs_structs when they fetch > + * partner info. > + */ > +static unsigned long *hvcs_pi_buff; > + > +static spinlock_t hvcs_pi_lock;
= SPIN_LOCK_UNLOCKED ?
> +/* One vty-server per hvcs_struct */ > +struct hvcs_struct { > + spinlock_t lock; > + > + /* > + * This index identifies this hvcs device as the complement to a > + * specific tty index. > + */ > + unsigned int index; > + > + struct tty_struct *tty; > + unsigned int open_count; > + > + /* > + * Used to tell the driver kernel_thread what operations need to take > + * place upon this hvcs_struct instance. > + */ > + int todo_mask; > + > + /* > + * This buffer is required so that when hvcs_write_room() reports that > + * it can send HVCS_BUFF_LEN characters that it will buffer the full > + * HVCS_BUFF_LEN characters if need be. This is essential for opost > + * writes since they do not do high level buffering and expect to be > + * able to send what the driver commits to sending buffering > + * [e.g. tab to space conversions in n_tty.c opost()]. > + */ > + char buffer[HVCS_BUFF_LEN]; > + int chars_in_buffer; > + > + /* > + * Any variable below the kobject is valid before a tty is connected and > + * stays valid after the tty is disconnected. These shouldn't be > + * whacked until the koject refcount reaches zero though some entries > + * may be changed via sysfs initiatives. > + */ > + struct kobject kobj; /* ref count & hvcs_struct lifetime */ > + int connected; /* is the vty-server currently connected to a vty? */ > + unsigned int p_unit_address; /* partner unit address */ > + unsigned int p_partition_ID; /* partner partition ID */ > + char p_location_code[CLC_LENGTH]; > + struct list_head next; /* list management */ > + struct vio_dev *vdev; > +}; > + > +/* Required to back map a kobject to its containing object */ > +#define from_kobj(kobj) container_of(kobj, struct hvcs_struct, kobj) > + > +static struct list_head hvcs_structs = LIST_HEAD_INIT(hvcs_structs); > +static spinlock_t hvcs_structs_lock; > + > +static void hvcs_unthrottle(struct tty_struct *tty); > +static void hvcs_throttle(struct tty_struct *tty); > +static irqreturn_t hvcs_handle_interrupt(int irq, void *dev_instance, > + struct pt_regs *regs); > + > +static int hvcs_write(struct tty_struct *tty, int from_user, > + const unsigned char *buf, int count); > +static int hvcs_write_room(struct tty_struct *tty); > +static int hvcs_chars_in_buffer(struct tty_struct *tty); > + > +static int hvcs_has_pi(struct hvcs_struct *hvcsd); > +static void hvcs_set_pi(struct hvcs_partner_info *pi, > + struct hvcs_struct *hvcsd); > +static int hvcs_get_pi(struct hvcs_struct *hvcsd); > +static int hvcs_rescan_devices_list(void); > + > +static int hvcs_partner_connect(struct hvcs_struct *hvcsd); > +static void hvcs_partner_free(struct hvcs_struct *hvcsd); > + > +static int hvcs_enable_device(struct hvcs_struct *hvcsd, > + uint32_t unit_address, unsigned int irq, struct vio_dev *dev); > +static void hvcs_final_close(struct hvcs_struct *hvcsd); > + > +static void destroy_hvcs_struct(struct kobject *kobj); > +static int hvcs_open(struct tty_struct *tty, struct file *filp); > +static void hvcs_close(struct tty_struct *tty, struct file *filp); > +static void hvcs_hangup(struct tty_struct * tty); > + > +static void hvcs_create_device_attrs(struct hvcs_struct *hvcsd); > +static void hvcs_remove_device_attrs(struct vio_dev *vdev); > +static void hvcs_create_driver_attrs(void); > +static void hvcs_remove_driver_attrs(void); > + > +static int __devinit hvcs_probe(struct vio_dev *dev, > + const struct vio_device_id *id); > +static int __devexit hvcs_remove(struct vio_dev *dev); > +static int __init hvcs_module_init(void); > +static void __exit hvcs_module_exit(void); > + > +#define HVCS_SCHED_READ 0x00000001 > +#define HVCS_QUICK_READ 0x00000002 > +#define HVCS_TRY_WRITE 0x00000004 > +#define HVCS_READ_MASK (HVCS_SCHED_READ | HVCS_QUICK_READ) > + > +static void hvcs_kick(void) > +{ > + hvcs_kicked = 1; > + wmb(); > + wake_up_process(hvcs_task); > +}
why not a semaphore or completion?
> +static void hvcs_unthrottle(struct tty_struct *tty) > +{ > + struct hvcs_struct *hvcsd = tty->driver_data; > + unsigned long flags; > + > + spin_lock_irqsave(&hvcsd->lock, flags); > + hvcsd->todo_mask |= HVCS_SCHED_READ; > + spin_unlock_irqrestore(&hvcsd->lock, flags); > + hvcs_kick(); > +} > + > +static void hvcs_throttle(struct tty_struct *tty) > +{ > + struct hvcs_struct *hvcsd = tty->driver_data; > + unsigned long flags; > + > + spin_lock_irqsave(&hvcsd->lock, flags); > + vio_disable_interrupts(hvcsd->vdev); > + spin_unlock_irqrestore(&hvcsd->lock, flags); > +} > + > +/* > + * If the device is being removed we don't have to worry about this interrupt > + * handler taking any further interrupts because they are disabled which means > + * the hvcs_struct will always be valid in this handler. > + */ > +static irqreturn_t hvcs_handle_interrupt(int irq, void *dev_instance, > + struct pt_regs *regs) > +{ > + struct hvcs_struct *hvcsd = dev_instance; > + unsigned long flags; > + > + spin_lock_irqsave(&hvcsd->lock, flags); > + vio_disable_interrupts(hvcsd->vdev); > + hvcsd->todo_mask |= HVCS_SCHED_READ; > + spin_unlock_irqrestore(&hvcsd->lock, flags); > + hvcs_kick();
spin_lock_irqsave isn't necessary in interrupt handlers normally
> + return IRQ_HANDLED; > +} > + > +/* This function must be called with the hvcsd->lock held */ > +static void hvcs_try_write(struct hvcs_struct *hvcsd) > +{ > + unsigned int unit_address = hvcsd->vdev->unit_address; > + struct tty_struct *tty = hvcsd->tty; > + int sent; > + > + if (hvcsd->todo_mask & HVCS_TRY_WRITE) { > + /* won't send partial writes */ > + sent = hvc_put_chars(unit_address, > + &hvcsd->buffer[0], > + hvcsd->chars_in_buffer ); > + if (sent > 0) { > + hvcsd->chars_in_buffer = 0; > + wmb(); > + hvcsd->todo_mask &= ~(HVCS_TRY_WRITE); > + wmb();
You are already inside a spinlock, why bother?
> + /* > + * We are still obligated to deliver the data to the > + * hypervisor even if the tty has been closed because > + * we commited to delivering it. But don't try to wake > + * a non-existent tty. > + */ > + if (tty) { > + if ((tty->flags & (1 << TTY_DO_WRITE_WAKEUP)) > + && tty->ldisc.write_wakeup) > + (tty->ldisc.write_wakeup) (tty); > + wake_up_interruptible(&tty->write_wait);
wouldn't just using up() be more simple?
> + } > + } > + } > +} > + > +static int hvcs_io(struct hvcs_struct *hvcsd) > +{ > + unsigned int unit_address; > + struct tty_struct *tty; > + char buf[HVCS_BUFF_LEN] __ALIGNED__; > + unsigned long flags; > + int got; > + int i; > + > + spin_lock_irqsave(&hvcsd->lock, flags); > + > + unit_address = hvcsd->vdev->unit_address; > + tty = hvcsd->tty; > + > + hvcs_try_write(hvcsd); > + > + if (!tty || test_bit(TTY_THROTTLED, &tty->flags)) { > + hvcsd->todo_mask &= ~(HVCS_READ_MASK); > + goto bail; > + } else if (!(hvcsd->todo_mask & (HVCS_READ_MASK))) > + goto bail; > + > + /* remove the read masks */ > + hvcsd->todo_mask &= ~(HVCS_READ_MASK); > + > + if ((tty->flip.count + HVCS_BUFF_LEN) < TTY_FLIPBUF_SIZE) { > + got = hvc_get_chars(unit_address, > + &buf[0], > + HVCS_BUFF_LEN); > + for (i=0;got && i<got;i++) > + tty_insert_flip_char(tty, buf[i], TTY_NORMAL); > + } > + > + /* Give the TTY time to process the data we just sent. */ > + if (got) > + hvcsd->todo_mask |= HVCS_QUICK_READ; > + > + spin_unlock_irqrestore(&hvcsd->lock, flags); > + if (tty->flip.count) { > + /* This is synch because tty->low_latency == 1 */ > + tty_flip_buffer_push(tty); > + } > + > + if (!got) { > + /* Do this _after_ the flip_buffer_push */ > + spin_lock_irqsave(&hvcsd->lock, flags); > + vio_enable_interrupts(hvcsd->vdev); > + spin_unlock_irqrestore(&hvcsd->lock, flags); > + } > + > + return hvcsd->todo_mask; > + > + bail: > + spin_unlock_irqrestore(&hvcsd->lock, flags); > + return hvcsd->todo_mask; > +} > + > +static int khvcsd(void *unused) > +{ > + struct hvcs_struct *hvcsd = NULL; > + struct list_head *element; > + struct list_head *safe_temp; > + int hvcs_todo_mask; > + unsigned long structs_flags; > + > + __set_current_state(TASK_RUNNING); > + > + do { > + hvcs_todo_mask = 0; > + hvcs_kicked = 0; > + wmb(); > + > + spin_lock_irqsave(&hvcs_structs_lock, structs_flags); > + list_for_each_safe(element, safe_temp, &hvcs_structs) { > + hvcsd = list_entry(element, struct hvcs_struct, next); > + hvcs_todo_mask |= hvcs_io(hvcsd); > + } > + spin_unlock_irqrestore(&hvcs_structs_lock, structs_flags); > + > + /* > + * If any of the hvcs adapters want to try a write or quick read > + * don't schedule(), yield a smidgen then execute the hvcs_io > + * thread again for those that want the write. > + */ > + if (hvcs_todo_mask & (HVCS_TRY_WRITE | HVCS_QUICK_READ)) { > + yield(); > + continue; > + } > + > + set_current_state(TASK_INTERRUPTIBLE); > + if (!hvcs_kicked) > + schedule(); > + __set_current_state(TASK_RUNNING);
This is essentially a busy loop.
This thread has no condition to actually block on, which means it is running in a tight loop calling either yield() or schedule(). Not terrible, but it's far better to simply down_interruptible().
> + } while (!kthread_should_stop()); > + > + return 0; > +} > + > +static struct vio_device_id hvcs_driver_table[] __devinitdata= { > + {"serial-server", "hvterm2"}, > + { 0, } > +}; > +MODULE_DEVICE_TABLE(vio, hvcs_driver_table); > + > +/* callback when the kboject ref count reaches zero */ > +static void destroy_hvcs_struct(struct kobject *kobj) > +{ > + struct hvcs_struct *hvcsd = from_kobj(kobj); > + struct vio_dev *vdev; > + unsigned long flags; > + > + spin_lock_irqsave(&hvcsd->lock, flags); > + > + /* the list_del poisons the pointers */ > + list_del(&(hvcsd->next)); > + > + if (hvcsd->connected == 1) { > + hvcs_partner_free(hvcsd); > + printk(KERN_INFO "HVCS: Closed vty-server@%X and" > + " partner vty@%X:%d connection.\n", > + hvcsd->vdev->unit_address, > + hvcsd->p_unit_address, > + (unsigned int)hvcsd->p_partition_ID); > + } > + printk(KERN_INFO "HVCS: Destroyed hvcs_struct for vty-server@%X.\n", > + hvcsd->vdev->unit_address); > + > + vdev = hvcsd->vdev; > + hvcsd->vdev = NULL; > + > + hvcsd->p_unit_address = 0; > + hvcsd->p_partition_ID = 0; > + memset(&hvcsd->p_location_code[0], 0x00, CLC_LENGTH); > + > + spin_unlock_irqrestore(&hvcsd->lock, flags); > + > + hvcs_remove_device_attrs(vdev); > + > + kfree(hvcsd); > +} > + > +/* This function must be called with hvcsd->lock held. */ > +static void hvcs_final_close(struct hvcs_struct *hvcsd) > +{ > + vio_disable_interrupts(hvcsd->vdev); > + free_irq(hvcsd->vdev->irq, hvcsd); > + > + hvcsd->todo_mask = 0; > + > + /* These two may be redundant if the operation was a close. */ > + if (hvcsd->tty) { > + hvcsd->tty->driver_data = NULL; > + hvcsd->tty = NULL; > + } > + > + hvcsd->open_count = 0; > + > + memset(&hvcsd->buffer[0], 0x00, HVCS_BUFF_LEN); > + hvcsd->chars_in_buffer = 0; > +} > + > +static struct kobj_type hvcs_kobj_type = { > + .release = destroy_hvcs_struct, > +}; > + > +static int __devinit hvcs_probe( > + struct vio_dev *dev, > + const struct vio_device_id *id) > +{ > + struct hvcs_struct *hvcsd; > + unsigned long structs_flags; > + > + if (!dev || !id) { > + printk(KERN_ERR "HVCS: probed with invalid parameter.\n"); > + return -EPERM; > + } > + > + hvcsd = kmalloc(sizeof(*hvcsd), GFP_KERNEL); > + if (!hvcsd) { > + return -ENODEV; > + }
style
> + /* hvcsd->tty is zeroed out with the memset */ > + memset(hvcsd, 0x00, sizeof(*hvcsd)); > + > + hvcsd->lock = SPIN_LOCK_UNLOCKED; > + /* Automatically incs the refcount the first time */ > + kobject_init(&hvcsd->kobj); > + /* Set up the callback for terminating the hvcs_struct's life */ > + hvcsd->kobj.ktype = &hvcs_kobj_type; > + > + hvcsd->vdev = dev; > + dev->dev.driver_data = hvcsd; > + > + hvcsd->index = ++hvcs_struct_count; > + hvcsd->chars_in_buffer = 0; > + hvcsd->todo_mask = 0; > + hvcsd->connected = 0; > + > + /* > + * This will populate the hvcs_struct's partner info fields for the > + * first time. > + */ > + if (hvcs_get_pi(hvcsd)) { > + printk(KERN_ERR "HVCS: Failed to fetch partner" > + " info for vty-server@%X on device probe.\n", > + hvcsd->vdev->unit_address); > + } > + > + /* > + * If a user app opens a tty that corresponds to this vty-server before > + * the hvcs_struct has been added to the devices list then the user app > + * will get -ENODEV. > + */ > + > + spin_lock_irqsave(&hvcs_structs_lock, structs_flags); > + > + list_add_tail(&(hvcsd->next), &hvcs_structs); > + > + spin_unlock_irqrestore(&hvcs_structs_lock, structs_flags); > + > + hvcs_create_device_attrs(hvcsd); > + > + printk(KERN_INFO "HVCS: Added vty-server@%X.\n", dev->unit_address); > + > + /* > + * DON'T enable interrupts here because there is no user to receive the > + * data. > + */ > + return 0; > +} > + > +static int __devexit hvcs_remove(struct vio_dev *dev) > +{
remove returns an error??? I question the vio API builder...
> + struct hvcs_struct *hvcsd = dev->dev.driver_data; > + unsigned long flags; > + struct kobject *kobjp; > + struct tty_struct *tty; > + > + if (!hvcsd) > + return -ENODEV;
this should be a BUG(), no?
> + /* By this time the vty-server won't be getting any more interrups */ > + > + spin_lock_irqsave(&hvcsd->lock, flags); > + > + tty = hvcsd->tty; > + > + kobjp = &hvcsd->kobj; > + > + spin_unlock_irqrestore(&hvcsd->lock, flags); > + > + /* > + * Let the last holder of this object cause it to be removed, which > + * would probably be tty_hangup below. > + */ > + kobject_put (kobjp); > + > + /* > + * The hangup is a scheduled function which will auto chain call > + * hvcs_hangup. The tty should always be valid at this time unless a > + * simultaneous tty close already cleaned up the hvcs_struct. > + */ > + if (tty) > + tty_hangup(tty); > + > + printk(KERN_INFO "HVCS: vty-server@%X removed from the" > + " vio bus.\n", dev->unit_address); > + return 0; > +}; > + > +static struct vio_driver hvcs_vio_driver = { > + .name = hvcs_driver_name, > + .id_table = hvcs_driver_table, > + .probe = hvcs_probe, > + .remove = hvcs_remove, > +}; > + > +/* Only called from hvcs_get_pi please */ > +static void hvcs_set_pi(struct hvcs_partner_info *pi, struct hvcs_struct *hvcsd) > +{ > + int clclength; > + > + hvcsd->p_unit_address = pi->unit_address; > + hvcsd->p_partition_ID = pi->partition_ID; > + clclength = strlen(&pi->location_code[0]); > + if (clclength > CLC_LENGTH - 1) > + clclength = CLC_LENGTH - 1; > + > + /* copy the null-term char too */ > + strncpy(&hvcsd->p_location_code[0], > + &pi->location_code[0], clclength + 1); > +} > + > +/* > + * Traverse the list and add the partner info that is found to the hvcs_struct > + * struct entry. NOTE: At this time I know that partner info will return a > + * single entry but in the future there may be multiple partner info entries per > + * vty-server and you'll want to zero out that list and reset it. If for some > + * reason you have an old version of this driver but there IS more than one > + * partner info then hvcsd->p_* will hold the last partner info data from the > + * firmware query. A good way to update this code would be to replace the three > + * partner info fields in hvcs_struct with a list of hvcs_partner_info > + * instances. > + * > + * This function must be called with the hvcsd->lock held. > + */ > +static int hvcs_get_pi(struct hvcs_struct *hvcsd) > +{ > + /* struct hvcs_partner_info *head_pi = NULL; */ > + struct hvcs_partner_info *pi = NULL; > + unsigned int unit_address = hvcsd->vdev->unit_address; > + struct list_head head; > + unsigned long flags; > + int retval; > + > + spin_lock_irqsave(&hvcs_pi_lock, flags); > + if (!hvcs_pi_buff) { > + spin_unlock_irqrestore(&hvcs_pi_lock, flags); > + return -EFAULT; > + } > + retval = hvcs_get_partner_info(unit_address, &head, hvcs_pi_buff); > + spin_unlock_irqrestore(&hvcs_pi_lock, flags); > + if (retval) { > + printk(KERN_ERR "HVCS: Failed to fetch partner" > + " info for vty-server@%x.\n", unit_address); > + return retval; > + } > + > + /* nixes the values if the partner vty went away */ > + hvcsd->p_unit_address = 0; > + hvcsd->p_partition_ID = 0; > + > + list_for_each_entry(pi, &head, node) > + hvcs_set_pi(pi, hvcsd); > + > + hvcs_free_partner_info(&head); > + return 0; > +} > + > +/* > + * This function is executed by the driver "rescan" sysfs entry. It shouldn't > + * be executed elsewhere, in order to prevent deadlock issues. > + */ > +static int hvcs_rescan_devices_list(void) > +{ > + struct hvcs_struct *hvcsd = NULL; > + unsigned long flags; > + unsigned long structs_flags; > + > + spin_lock_irqsave(&hvcs_structs_lock, structs_flags); > + > + list_for_each_entry(hvcsd, &hvcs_structs, next) { > + spin_lock_irqsave(&hvcsd->lock, flags); > + hvcs_get_pi(hvcsd); > + spin_unlock_irqrestore(&hvcsd->lock, flags); > + } > + > + spin_unlock_irqrestore(&hvcs_structs_lock, structs_flags);
Isn't this double spin_lock_irqsave rather obviously silly?
> + return 0; > +} > + > +/* > + * Farm this off into its own function because it could be more complex once > + * multiple partners support is added. This function should be called with > + * the hvcsd->lock held. > + */ > +static int hvcs_has_pi(struct hvcs_struct *hvcsd) > +{ > + if ((!hvcsd->p_unit_address) || (!hvcsd->p_partition_ID)) > + return 0; > + return 1; > +} > + > +/* > + * NOTE: It is possible that the super admin removed a partner vty and then > + * added a different vty as the new partner. > + * > + * This function must be called with the hvcsd->lock held. > + */ > +static int hvcs_partner_connect(struct hvcs_struct *hvcsd) > +{ > + int retval; > + unsigned int unit_address = hvcsd->vdev->unit_address; > + > + /* > + * If there wasn't any pi when the device was added it doesn't meant > + * there isn't any now. This driver isn't notified when a new partner > + * vty is added to a vty-server so we discover changes on our own. > + * Please see comments in hvcs_register_connection() for justification > + * of this bizarre code. > + */ > + retval = hvcs_register_connection(unit_address, > + hvcsd->p_partition_ID, > + hvcsd->p_unit_address); > + if (!retval) { > + hvcsd->connected = 1; > + return 0; > + } else if (retval != -EINVAL) > + return retval; > + > + /* > + * As per the spec re-get the pi and try again if -EINVAL after the > + * first connection attempt. > + */ > + if (hvcs_get_pi(hvcsd)) > + return -ENOMEM; > + > + if (!hvcs_has_pi(hvcsd)) > + return -ENODEV; > + > + retval = hvcs_register_connection(unit_address, > + hvcsd->p_partition_ID, > + hvcsd->p_unit_address); > + if (retval != -EINVAL) { > + hvcsd->connected = 1; > + return retval; > + } > + > + /* > + * EBUSY is the most likely scenario though the vty could have been > + * removed or there really could be an hcall error due to the parameter > + * data but thanks to ambiguous firmware return codes we can't really > + * tell. > + */ > + printk(KERN_INFO "HVCS: vty-server or partner" > + " vty is busy. Try again later.\n"); > + return -EBUSY; > +} > + > +/* This function must be called with the hvcsd->lock held */ > +static void hvcs_partner_free(struct hvcs_struct *hvcsd) > +{ > + int retval; > + do { > + retval = hvcs_free_connection(hvcsd->vdev->unit_address); > + } while (retval == -EBUSY); > + hvcsd->connected = 0; > +} > + > +/* This helper function must be called WITHOUT the hvcsd->lock held */ > +static int hvcs_enable_device(struct hvcs_struct *hvcsd, uint32_t unit_address, > + unsigned int irq, struct vio_dev *vdev) > +{ > + unsigned long flags; > + > + /* > + * It is possible that the vty-server was removed between the time that > + * the conn was registered and now. > + */ > + if (!request_irq(irq, &hvcs_handle_interrupt, > + SA_INTERRUPT, "ibmhvcs", hvcsd)) { > + /* > + * It is possible the vty-server was removed after the irq was > + * requested but before we have time to enable interrupts. > + */ > + if (vio_enable_interrupts(vdev) == H_Success) > + return 0; > + else { > + printk(KERN_ERR "HVCS: int enable failed for" > + " vty-server@%X.\n", unit_address); > + free_irq(irq, hvcsd); > + } > + } else > + printk(KERN_ERR "HVCS: irq req failed for" > + " vty-server@%X.\n", unit_address);
propagate return value from request_irq()
> + spin_lock_irqsave(&hvcsd->lock, flags); > + hvcs_partner_free(hvcsd); > + spin_unlock_irqrestore(&hvcsd->lock, flags); > + > + return -ENODEV; > + > +} > + > +/* > + * This always increments the kobject ref count if the call is successful. > + * Please remember to dec when you are done with the instance. > + * > + * NOTICE: Do NOT hold either the hvcs_struct.lock or hvcs_structs_lock when > + * calling this function or you will get deadlock. > + */ > +struct hvcs_struct *hvcs_get_by_index(int index) > +{ > + struct hvcs_struct *hvcsd = NULL; > + struct list_head *element; > + struct list_head *safe_temp; > + unsigned long flags; > + unsigned long structs_flags; > + > + spin_lock_irqsave(&hvcs_structs_lock, structs_flags); > + /* We can immediately discard OOB requests */ > + if (index >= 0 && index < HVCS_MAX_SERVER_ADAPTERS) { > + list_for_each_safe(element, safe_temp, &hvcs_structs) { > + hvcsd = list_entry(element, struct hvcs_struct, next); > + spin_lock_irqsave(&hvcsd->lock, flags); > + if (hvcsd->index == index) { > + kobject_get(&hvcsd->kobj); > + spin_unlock_irqrestore(&hvcsd->lock, flags); > + spin_unlock_irqrestore(&hvcs_structs_lock, > + structs_flags); > + return hvcsd; > + } > + spin_unlock_irqrestore(&hvcsd->lock, flags); > + } > + hvcsd = NULL; > + } > + > + spin_unlock_irqrestore(&hvcs_structs_lock, structs_flags);
another spin_lock_irqsave() inside spin_lock_irqsave()
> + return hvcsd; > +} > + > +/* > + * This is invoked via the tty_open interface when a user app connects to the > + * /dev node. > + */ > +static int hvcs_open(struct tty_struct *tty, struct file *filp) > +{ > + struct hvcs_struct *hvcsd = NULL; > + int retval = 0; > + unsigned long flags; > + unsigned int irq; > + struct vio_dev *vdev; > + unsigned long unit_address; > + > + if (tty->driver_data) > + goto fast_open; > + > + /* > + * Is there a vty-server that shares the same index? > + * This function increments the kobject index. > + */ > + if (!(hvcsd = hvcs_get_by_index(tty->index))) { > + printk(KERN_WARNING "HVCS: open failed, no index.\n"); > + return -ENODEV; > + } > + > + spin_lock_irqsave(&hvcsd->lock, flags); > + > + if (hvcsd->connected == 0) > + if ((retval = hvcs_partner_connect(hvcsd))) > + goto error_release; > + > + hvcsd->open_count = 1; > + hvcsd->tty = tty; > + tty->driver_data = hvcsd; > + > + /* > + * Set this driver to low latency so that we actually have a chance at > + * catching a throttled TTY after we flip_buffer_push. Otherwise the > + * flush_to_async may not execute until after the kernel_thread has > + * yielded and resumed the next flip_buffer_push resulting in data > + * loss. > + */ > + tty->low_latency = 1; > + > + memset(&hvcsd->buffer[0], 0x3F, HVCS_BUFF_LEN); > + > + /* > + * Save these in the spinlock for the enable operations that need them > + * outside of the spinlock. > + */ > + irq = hvcsd->vdev->irq; > + vdev = hvcsd->vdev; > + unit_address = hvcsd->vdev->unit_address; > + > + hvcsd->todo_mask |= HVCS_SCHED_READ; > + spin_unlock_irqrestore(&hvcsd->lock, flags); > + > + /* > + * This must be done outside of the spinlock because it requests irqs > + * and will grab the spinlcok and free the connection if it fails. > + */ > + if ((hvcs_enable_device(hvcsd, unit_address, irq, vdev))) { > + kobject_put(&hvcsd->kobj); > + printk(KERN_WARNING "HVCS: enable device failed.\n"); > + return -ENODEV; > + }
propagate return value?
> + goto open_success; > + > +fast_open: > + hvcsd = tty->driver_data; > + > + spin_lock_irqsave(&hvcsd->lock, flags); > + if (!kobject_get(&hvcsd->kobj)) { > + spin_unlock_irqrestore(&hvcsd->lock, flags); > + printk(KERN_ERR "HVCS: Kobject of open" > + " hvcs doesn't exist.\n"); > + return -EFAULT; /* Is this the right return value? */ > + } > + > + hvcsd->open_count++; > + > + hvcsd->todo_mask |= HVCS_SCHED_READ; > + spin_unlock_irqrestore(&hvcsd->lock, flags); > +open_success: > + hvcs_kick(); > + > + printk(KERN_INFO "HVCS: vty-server@%X opened.\n", > + hvcsd->vdev->unit_address ); > + > + return 0; > + > +error_release: > + spin_unlock_irqrestore(&hvcsd->lock, flags); > + kobject_put(&hvcsd->kobj); > + > + printk(KERN_WARNING "HVCS: HVCS partner connect failed.\n"); > + return retval; > +} > + > +static void hvcs_close(struct tty_struct *tty, struct file *filp) > +{ > + struct hvcs_struct *hvcsd; > + unsigned long flags; > + struct kobject *kobjp; > + > + /* > + * Is someone trying to close the file associated with this device after > + * we have hung up? If so tty->driver_data wouldn't be valid. > + */ > + if (tty_hung_up_p(filp)) > + return; > + > + /* > + * No driver_data means that this close was probably issued after a > + * failed hvcs_open by the tty layer's release_dev() api and we can just > + * exit cleanly. > + */ > + if (!tty->driver_data) > + return; > + > + hvcsd = tty->driver_data; > + > + spin_lock_irqsave(&hvcsd->lock, flags); > + if (--hvcsd->open_count == 0) { > + > + /* > + * This line is important because it tells hvcs_open that this > + * device needs to be re-configured the next time hvcs_open is > + * called. > + */ > + hvcsd->tty->driver_data = NULL; > + > + /* > + * NULL this early so that the kernel_thread doesn't try to > + * execute any operations on the TTY even though it is obligated > + * to deliver any pending I/O to the hypervisor. > + */ > + hvcsd->tty = NULL; > + > + /* > + * Block the close until all the buffered data has been > + * delivered. > + */ > + while(hvcsd->chars_in_buffer) { > + spin_unlock_irqrestore(&hvcsd->lock, flags); > + > + /* > + * Give the kernel thread the hvcs_struct so that it can > + * try to deliver the remaining data but block the close > + * operation by spinning in this function so that other > + * tty operations have to wait. > + */ > + yield(); > + spin_lock_irqsave(&hvcsd->lock, flags); > + } > + > + hvcs_final_close(hvcsd); > + > + } else if (hvcsd->open_count < 0) { > + printk(KERN_ERR "HVCS: vty-server@%X open_count: %d" > + " is missmanaged.\n", > + hvcsd->vdev->unit_address, hvcsd->open_count); > + } > + kobjp = &hvcsd->kobj; > + spin_unlock_irqrestore(&hvcsd->lock, flags); > + > + kobject_put(kobjp); > +} > + > +static void hvcs_hangup(struct tty_struct * tty) > +{ > + struct hvcs_struct *hvcsd = tty->driver_data; > + unsigned long flags; > + int temp_open_count; > + struct kobject *kobjp; > + > + spin_lock_irqsave(&hvcsd->lock, flags); > + /* Preserve this so that we know how many kobject refs to put */ > + temp_open_count = hvcsd->open_count; > + > + /* > + * Don't kobject put inside the spinlock because the destruction > + * callback may use the spinlock and it may get called before the > + * spinlock has been released. Get a pointer to the kobject and > + * kobject_put on that instead. > + */ > + kobjp = &hvcsd->kobj; > + > + /* Calling this will drop any buffered data on the floor. */ > + hvcs_final_close(hvcsd); > + > + spin_unlock_irqrestore(&hvcsd->lock, flags); > + > + /* > + * We need to kobject_put() for every open_count we have since the > + * tty_hangup() function doesn't invoke a close per open connection on a > + * non-console device. > + */ > + while(temp_open_count) { > + --temp_open_count; > + /* > + * The final put will trigger destruction of the hvcs_struct. > + * NOTE: If this hangup was signaled from user space then the > + * final put will never happen. > + */ > + kobject_put(kobjp); > + } > +} > + > +/* > + * NOTE: This is almost always from_user since user level apps interact with the > + * /dev nodes. I'm trusting that if hvcs_write gets called and interrupted by > + * hvcs_remove (which removes the target device and executes tty_hangup()) that > + * tty_hangup will allow hvcs_write time to complete execution before it > + * terminates our device. > + */ > +static int hvcs_write(struct tty_struct *tty, int from_user, > + const unsigned char *buf, int count) > +{ > + struct hvcs_struct *hvcsd = tty->driver_data; > + unsigned int unit_address; > + unsigned char *charbuf; > + unsigned long flags; > + int total_sent = 0; > + int tosend = 0; > + int result = 0; > + > + /* > + * If they don't check the return code off of their open they may > + * attempt this even if there is no connected device. > + */ > + if (!hvcsd) > + return -ENODEV; > + > + /* Reasonable size to prevent user level flooding */ > + if (count > HVCS_MAX_FROM_USER) { > + printk(KERN_WARNING "HVCS write: count being truncated to" > + " HVCS_MAX_FROM_USER.\n"); > + count = HVCS_MAX_FROM_USER; > + } > + > + if (!from_user) > + charbuf = (unsigned char *)buf; > + else { > + charbuf = kmalloc(count, GFP_KERNEL); > + if (!charbuf) { > + printk(KERN_WARNING "HVCS: write -ENOMEM.\n"); > + return -ENOMEM; > + } > + > + if (copy_from_user(charbuf, buf, count)) { > + kfree(charbuf); > + printk(KERN_WARNING "HVCS: write -EFAULT.\n"); > + return -EFAULT; > + } > + } > + > + spin_lock_irqsave(&hvcsd->lock, flags); > + > + /* > + * Somehow an open succedded but the device was removed or the > + * connection terminated between the vty-server and partner vty during > + * the middle of a write operation? This is a crummy place to do this > + * but we want to keep it all in the spinlock. > + */ > + if (hvcsd->open_count <= 0) { > + spin_unlock_irqrestore(&hvcsd->lock, flags); > + if (from_user) > + kfree(charbuf); > + return -ENODEV; > + } > + > + unit_address = hvcsd->vdev->unit_address; > + > + while (count > 0) { > + tosend = min(count, (HVCS_BUFF_LEN - hvcsd->chars_in_buffer)); > + /* > + * No more space, this probably means that the last call to > + * hvcs_write() didn't succeed and the buffer was filled up. > + */ > + if (!tosend) > + break; > + > + memcpy(&hvcsd->buffer[hvcsd->chars_in_buffer], > + &charbuf[total_sent], > + tosend); > + > + hvcsd->chars_in_buffer += tosend; > + > + result = 0; > + > + /* > + * If this is true then we don't want to try writing to the > + * hypervisor because that is the kernel_threads job now. We'll > + * just add to the buffer. > + */ > + if (!(hvcsd->todo_mask & HVCS_TRY_WRITE)) > + /* won't send partial writes */ > + result = hvc_put_chars(unit_address, > + &hvcsd->buffer[0], > + hvcsd->chars_in_buffer); > + > + /* > + * Since we know we have enough room in hvcsd->buffer for > + * tosend we record that it was sent regardless of whether the > + * hypervisor actually took it because we have it buffered. > + */ > + total_sent+=tosend; > + count-=tosend; > + if (result == 0) { > + hvcsd->todo_mask |= HVCS_TRY_WRITE; > + hvcs_kick(); > + break; > + } > + > + hvcsd->chars_in_buffer = 0; > + /* > + * Test after the chars_in_buffer reset otherwise this could > + * deadlock our writes if hvc_put_chars fails. > + */ > + if (result < 0) > + break; > + } > + > + spin_unlock_irqrestore(&hvcsd->lock, flags); > + if (from_user) > + kfree(charbuf); > + > + if (result == -1) > + return -EIO; > + else > + return total_sent; > +} > + > +/* > + * This is really asking how much can we guarentee that we can send or that we > + * absolutely WILL BUFFER if we can't send it. This driver MUST honor the > + * return value, hence the reason for hvcs_struct buffering. > + */ > +static int hvcs_write_room(struct tty_struct *tty) > +{ > + struct hvcs_struct *hvcsd = tty->driver_data; > + unsigned long flags; > + int retval; > + > + if (!hvcsd || hvcsd->open_count <= 0) > + return 0; > + > + spin_lock_irqsave(&hvcsd->lock, flags); > + retval = HVCS_BUFF_LEN - hvcsd->chars_in_buffer; > + spin_unlock_irqrestore(&hvcsd->lock, flags); > + return retval; > +} > + > +static int hvcs_chars_in_buffer(struct tty_struct *tty) > +{ > + struct hvcs_struct *hvcsd = tty->driver_data; > + unsigned long flags; > + int retval; > + > + spin_lock_irqsave(&hvcsd->lock, flags); > + retval = hvcsd->chars_in_buffer; > + spin_unlock_irqrestore(&hvcsd->lock, flags); > + return retval; > +} > + > +static struct tty_operations hvcs_ops = { > + .open = hvcs_open, > + .close = hvcs_close, > + .hangup = hvcs_hangup, > + .write = hvcs_write, > + .write_room = hvcs_write_room, > + .chars_in_buffer = hvcs_chars_in_buffer, > + .unthrottle = hvcs_unthrottle, > + .throttle = hvcs_throttle, > +}; > + > +static int __init hvcs_module_init(void) > +{ > + int rc; > + int num_ttys_to_alloc; > + > + printk(KERN_INFO "Initializing %s\n", hvcs_driver_string); > + > + /* Has the user specified an overload with an insmod param? */ > + if (hvcs_parm_num_devs <= 0 || > + (hvcs_parm_num_devs > HVCS_MAX_SERVER_ADAPTERS)) { > + num_ttys_to_alloc = HVCS_DEFAULT_SERVER_ADAPTERS; > + } else > + num_ttys_to_alloc = hvcs_parm_num_devs; > + > + hvcs_tty_driver = alloc_tty_driver(num_ttys_to_alloc); > + if (!hvcs_tty_driver) > + return -ENOMEM; > + > + hvcs_tty_driver->owner = THIS_MODULE; > + > + hvcs_tty_driver->driver_name = hvcs_driver_name; > + hvcs_tty_driver->name = hvcs_device_node; > + > + /* > + * We'll let the system assign us a major number, indicated by leaving > + * it blank. > + */ > + > + hvcs_tty_driver->minor_start = HVCS_MINOR_START; > + hvcs_tty_driver->type = TTY_DRIVER_TYPE_SYSTEM; > + > + /* > + * We role our own so that we DONT ECHO. We can't echo because the > + * device we are connecting to already echoes by default and this would > + * throw us into a horrible recursive echo-echo-echo loop. > + */ > + hvcs_tty_driver->init_termios = hvcs_tty_termios; > + hvcs_tty_driver->flags = TTY_DRIVER_REAL_RAW; > + > + tty_set_operations(hvcs_tty_driver, &hvcs_ops); > + > + /* > + * The following call will result in sysfs entries that denote the > + * dynamically assigned major and minor numbers for our devices. > + */ > + if (tty_register_driver(hvcs_tty_driver)) { > + printk(KERN_ERR "HVCS: registration " > + " as a tty driver failed.\n"); > + put_tty_driver(hvcs_tty_driver); > + return rc; > + } > + > + hvcs_structs_lock = SPIN_LOCK_UNLOCKED; > + > + hvcs_pi_lock = SPIN_LOCK_UNLOCKED; > + hvcs_pi_buff = kmalloc(PAGE_SIZE, GFP_KERNEL);
check return value
> + hvcs_task = kthread_run(khvcsd, NULL, "khvcsd"); > + if (IS_ERR(hvcs_task)) { > + printk("khvcsd creation failed. Driver not loaded.\n"); > + kfree(hvcs_pi_buff); > + put_tty_driver(hvcs_tty_driver); > + return -EIO; > + } > + > + rc = vio_register_driver(&hvcs_vio_driver); > + /* > + * This needs to be done AFTER the vio_register_driver() call or else > + * the kobjects won't be initialized properly. > + */ > + hvcs_create_driver_attrs();
Are you sure about all this?? The whole order of initialization looks wrong.
What happens if someone opens a tty before vio_register_driver() is finished?
> + printk(KERN_INFO "HVCS: driver module inserted.\n"); > + > + return rc; > +} > + > +static void __exit hvcs_module_exit(void) > +{ > + unsigned long flags; > + > + /* > + * This driver receives hvcs_remove callbacks for each device upon > + * module removal. > + */ > + > + /* > + * This synchronous operation will wake the khvcsd kthread if it is > + * asleep and will return when khvcsd has terminated. > + */ > + kthread_stop(hvcs_task); > + > + spin_lock_irqsave(&hvcs_pi_lock, flags); > + kfree(hvcs_pi_buff); > + hvcs_pi_buff = NULL; > + spin_unlock_irqrestore(&hvcs_pi_lock, flags); > + > + hvcs_remove_driver_attrs(); > + > + vio_unregister_driver(&hvcs_vio_driver); > + > + tty_unregister_driver(hvcs_tty_driver); > + > + put_tty_driver(hvcs_tty_driver); > + > + printk(KERN_INFO "HVCS: driver module removed.\n"); > +} > + > +module_init(hvcs_module_init); > +module_exit(hvcs_module_exit); > + > +static inline struct hvcs_struct *from_vio_dev(struct vio_dev *viod) > +{ > + return viod->dev.driver_data; > +} > +/* The sysfs interface for the driver and devices */ > + > +static ssize_t hvcs_partner_vtys_show(struct device *dev, char *buf) > +{ > + struct vio_dev *viod = to_vio_dev(dev); > + struct hvcs_struct *hvcsd = from_vio_dev(viod); > + unsigned long flags; > + int retval; > + > + spin_lock_irqsave(&hvcsd->lock, flags); > + retval = sprintf(buf, "%X\n", hvcsd->p_unit_address); > + spin_unlock_irqrestore(&hvcsd->lock, flags); > + return retval; > +} > +static DEVICE_ATTR(partner_vtys, S_IRUGO, hvcs_partner_vtys_show, NULL); > + > +static ssize_t hvcs_partner_clcs_show(struct device *dev, char *buf) > +{ > + struct vio_dev *viod = to_vio_dev(dev); > + struct hvcs_struct *hvcsd = from_vio_dev(viod); > + unsigned long flags; > + int retval; > + > + spin_lock_irqsave(&hvcsd->lock, flags); > + retval = sprintf(buf, "%s\n", &hvcsd->p_location_code[0]); > + spin_unlock_irqrestore(&hvcsd->lock, flags); > + return retval; > +} > +static DEVICE_ATTR(partner_clcs, S_IRUGO, hvcs_partner_clcs_show, NULL); > + > +static ssize_t hvcs_current_vty_store(struct device *dev, const char * buf, > + size_t count) > +{ > + /* > + * Don't need this feature at the present time because firmware doesn't > + * yet support multiple partners. > + */ > + printk(KERN_INFO "HVCS: Denied current_vty change: -EPERM.\n"); > + return -EPERM; > +} > + > +static ssize_t hvcs_current_vty_show(struct device *dev, char *buf) > +{ > + struct vio_dev *viod = to_vio_dev(dev); > + struct hvcs_struct *hvcsd = from_vio_dev(viod); > + unsigned long flags; > + int retval; > + > + spin_lock_irqsave(&hvcsd->lock, flags); > + retval = sprintf(buf, "%s\n", &hvcsd->p_location_code[0]); > + spin_unlock_irqrestore(&hvcsd->lock, flags); > + return retval; > +} > + > +static DEVICE_ATTR(current_vty, > + S_IRUGO | S_IWUSR, hvcs_current_vty_show, hvcs_current_vty_store); > + > +static ssize_t hvcs_vterm_state_store(struct device *dev, const char *buf, > + size_t count) > +{ > + struct vio_dev *viod = to_vio_dev(dev); > + struct hvcs_struct *hvcsd = from_vio_dev(viod); > + unsigned long flags; > + > + /* writing a '0' to this sysfs entry will result in the disconnect. */ > + if (simple_strtol(buf, NULL, 0) != 0) > + return -EINVAL; > + > + spin_lock_irqsave(&hvcsd->lock, flags); > + > + if (hvcsd->open_count > 0) { > + spin_unlock_irqrestore(&hvcsd->lock, flags); > + printk(KERN_INFO "HVCS: vterm state unchanged. " > + "The hvcs device node is still in use.\n"); > + return -EPERM; > + } > + > + if (hvcsd->connected == 0) { > + spin_unlock_irqrestore(&hvcsd->lock, flags); > + printk(KERN_INFO "HVCS: vterm state unchanged. The" > + " vty-server is not connected to a vty.\n"); > + return -EPERM; > + } > + > + hvcs_partner_free(hvcsd); > + printk(KERN_INFO "HVCS: Closed vty-server@%X and" > + " partner vty@%X:%d connection.\n", > + hvcsd->vdev->unit_address, > + hvcsd->p_unit_address, > + (unsigned int)hvcsd->p_partition_ID); > + > + spin_unlock_irqrestore(&hvcsd->lock, flags); > + return count; > +} > + > +static ssize_t hvcs_vterm_state_show(struct device *dev, char *buf) > +{ > + struct vio_dev *viod = to_vio_dev(dev); > + struct hvcs_struct *hvcsd = from_vio_dev(viod); > + unsigned long flags; > + int retval; > + > + spin_lock_irqsave(&hvcsd->lock, flags); > + retval = sprintf(buf, "%d\n", hvcsd->connected); > + spin_unlock_irqrestore(&hvcsd->lock, flags); > + return retval; > +} > +static DEVICE_ATTR(vterm_state, S_IRUGO | S_IWUSR, > + hvcs_vterm_state_show, hvcs_vterm_state_store); > + > +static struct attribute *hvcs_attrs[] = { > + &dev_attr_partner_vtys.attr, > + &dev_attr_partner_clcs.attr, > + &dev_attr_current_vty.attr, > + &dev_attr_vterm_state.attr, > + NULL, > +}; > + > +static struct attribute_group hvcs_attr_group = { > + .attrs = hvcs_attrs, > +}; > + > +static void hvcs_create_device_attrs(struct hvcs_struct *hvcsd) > +{ > + struct vio_dev *vdev = hvcsd->vdev; > + sysfs_create_group(&vdev->dev.kobj, &hvcs_attr_group); > +} > + > +static void hvcs_remove_device_attrs(struct vio_dev *vdev) > +{ > + sysfs_remove_group(&vdev->dev.kobj, &hvcs_attr_group); > +} > + > +static ssize_t hvcs_rescan_show(struct device_driver *ddp, char *buf) > +{ > + /* A 1 means it is updating, a 0 means it is done updating */ > + return snprintf(buf, PAGE_SIZE, "%d\n", hvcs_rescan_status); > +} > + > +static ssize_t hvcs_rescan_store(struct device_driver *ddp, const char * buf, > + size_t count) > +{ > + if ((simple_strtol(buf, NULL, 0) != 1) > + && (hvcs_rescan_status != 0)) > + return -EINVAL; > + > + hvcs_rescan_status = 1; > + printk(KERN_INFO "HVCS: rescanning partner info for all" > + " vty-servers.\n"); > + hvcs_rescan_devices_list(); > + hvcs_rescan_status = 0; > + return count; > +} > +static DRIVER_ATTR(rescan, > + S_IRUGO | S_IWUSR, hvcs_rescan_show, hvcs_rescan_store); > + > +static void hvcs_create_driver_attrs(void) > +{ > + struct device_driver *driverfs = &(hvcs_vio_driver.driver); > + driver_create_file(driverfs, &driver_attr_rescan); > +} > + > +static void hvcs_remove_driver_attrs(void) > +{ > + struct device_driver *driverfs = &(hvcs_vio_driver.driver); > + driver_remove_file(driverfs, &driver_attr_rescan); > +}
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