cregit-Linux how code gets into the kernel

Release 4.7 drivers/s390/char/monreader.c

/*
 * Character device driver for reading z/VM *MONITOR service records.
 *
 * Copyright IBM Corp. 2004, 2009
 *
 * Author: Gerald Schaefer <gerald.schaefer@de.ibm.com>
 */


#define KMSG_COMPONENT "monreader"

#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/miscdevice.h>
#include <linux/ctype.h>
#include <linux/spinlock.h>
#include <linux/interrupt.h>
#include <linux/poll.h>
#include <linux/device.h>
#include <linux/slab.h>
#include <net/iucv/iucv.h>
#include <asm/uaccess.h>
#include <asm/ebcdic.h>
#include <asm/extmem.h>



#define MON_COLLECT_SAMPLE 0x80

#define MON_COLLECT_EVENT  0x40

#define MON_SERVICE	   "*MONITOR"

#define MON_IN_USE	   0x01

#define MON_MSGLIM	   255


static char mon_dcss_name[9] = "MONDCSS\0";


struct mon_msg {
	
u32 pos;
	
u32 mca_offset;
	
struct iucv_message msg;
	
char msglim_reached;
	
char replied_msglim;
};


struct mon_private {
	
struct iucv_path *path;
	
struct mon_msg *msg_array[MON_MSGLIM];
	
unsigned int   write_index;
	
unsigned int   read_index;
	
atomic_t msglim_count;
	
atomic_t read_ready;
	
atomic_t iucv_connected;
	
atomic_t iucv_severed;
};


static unsigned long mon_in_use = 0;


static unsigned long mon_dcss_start;

static unsigned long mon_dcss_end;

static DECLARE_WAIT_QUEUE_HEAD(mon_read_wait_queue);
static DECLARE_WAIT_QUEUE_HEAD(mon_conn_wait_queue);


static u8 user_data_connect[16] = {
	/* Version code, must be 0x01 for shared mode */
	0x01,
	/* what to collect */
	MON_COLLECT_SAMPLE | MON_COLLECT_EVENT,
	/* DCSS name in EBCDIC, 8 bytes padded with blanks */
	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
	0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
};


static u8 user_data_sever[16] = {
	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
};


static struct device *monreader_device;

/******************************************************************************
 *                             helper functions                               *
 *****************************************************************************/
/*
 * Create the 8 bytes EBCDIC DCSS segment name from
 * an ASCII name, incl. padding
 */

static void dcss_mkname(char *ascii_name, char *ebcdic_name) { int i; for (i = 0; i < 8; i++) { if (ascii_name[i] == '\0') break; ebcdic_name[i] = toupper(ascii_name[i]); } for (; i < 8; i++) ebcdic_name[i] = ' '; ASCEBC(ebcdic_name, 8); }

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PersonTokensPropCommitsCommitProp
gerald schaefergerald schaefer79100.00%1100.00%
Total79100.00%1100.00%


static inline unsigned long mon_mca_start(struct mon_msg *monmsg) { return *(u32 *) &monmsg->msg.rmmsg; }

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gerald schaefergerald schaefer1869.23%150.00%
martin schwidefskymartin schwidefsky830.77%150.00%
Total26100.00%2100.00%


static inline unsigned long mon_mca_end(struct mon_msg *monmsg) { return *(u32 *) &monmsg->msg.rmmsg[4]; }

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gerald schaefergerald schaefer1862.07%150.00%
martin schwidefskymartin schwidefsky1137.93%150.00%
Total29100.00%2100.00%


static inline u8 mon_mca_type(struct mon_msg *monmsg, u8 index) { return *((u8 *) mon_mca_start(monmsg) + monmsg->mca_offset + index); }

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gerald schaefergerald schaefer34100.00%1100.00%
Total34100.00%1100.00%


static inline u32 mon_mca_size(struct mon_msg *monmsg) { return mon_mca_end(monmsg) - mon_mca_start(monmsg) + 1; }

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gerald schaefergerald schaefer25100.00%1100.00%
Total25100.00%1100.00%


static inline u32 mon_rec_start(struct mon_msg *monmsg) { return *((u32 *) (mon_mca_start(monmsg) + monmsg->mca_offset + 4)); }

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gerald schaefergerald schaefer33100.00%1100.00%
Total33100.00%1100.00%


static inline u32 mon_rec_end(struct mon_msg *monmsg) { return *((u32 *) (mon_mca_start(monmsg) + monmsg->mca_offset + 8)); }

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gerald schaefergerald schaefer33100.00%1100.00%
Total33100.00%1100.00%


static int mon_check_mca(struct mon_msg *monmsg) { if ((mon_rec_end(monmsg) <= mon_rec_start(monmsg)) || (mon_rec_start(monmsg) < mon_dcss_start) || (mon_rec_end(monmsg) > mon_dcss_end) || (mon_mca_type(monmsg, 0) == 0) || (mon_mca_size(monmsg) % 12 != 0) || (mon_mca_end(monmsg) <= mon_mca_start(monmsg)) || (mon_mca_end(monmsg) > mon_dcss_end) || (mon_mca_start(monmsg) < mon_dcss_start) || ((mon_mca_type(monmsg, 1) == 0) && (mon_mca_type(monmsg, 2) == 0))) return -EINVAL; return 0; }

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gerald schaefergerald schaefer126100.00%1100.00%
Total126100.00%1100.00%


static int mon_send_reply(struct mon_msg *monmsg, struct mon_private *monpriv) { int rc; rc = iucv_message_reply(monpriv->path, &monmsg->msg, IUCV_IPRMDATA, NULL, 0); atomic_dec(&monpriv->msglim_count); if (likely(!monmsg->msglim_reached)) { monmsg->pos = 0; monmsg->mca_offset = 0; monpriv->read_index = (monpriv->read_index + 1) % MON_MSGLIM; atomic_dec(&monpriv->read_ready); } else monmsg->replied_msglim = 1; if (rc) { pr_err("Reading monitor data failed with rc=%i\n", rc); return -EIO; } return 0; }

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PersonTokensPropCommitsCommitProp
gerald schaefergerald schaefer10688.33%250.00%
martin schwidefskymartin schwidefsky1411.67%250.00%
Total120100.00%4100.00%


static void mon_free_mem(struct mon_private *monpriv) { int i; for (i = 0; i < MON_MSGLIM; i++) kfree(monpriv->msg_array[i]); kfree(monpriv); }

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martin schwidefskymartin schwidefsky3890.48%150.00%
gerald schaefergerald schaefer49.52%150.00%
Total42100.00%2100.00%


static struct mon_private *mon_alloc_mem(void) { int i; struct mon_private *monpriv; monpriv = kzalloc(sizeof(struct mon_private), GFP_KERNEL); if (!monpriv) return NULL; for (i = 0; i < MON_MSGLIM; i++) { monpriv->msg_array[i] = kzalloc(sizeof(struct mon_msg), GFP_KERNEL); if (!monpriv->msg_array[i]) { mon_free_mem(monpriv); return NULL; } } return monpriv; }

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PersonTokensPropCommitsCommitProp
gerald schaefergerald schaefer8892.63%133.33%
martin schwidefskymartin schwidefsky55.26%133.33%
eric sesterhenneric sesterhenn22.11%133.33%
Total95100.00%3100.00%


static inline void mon_next_mca(struct mon_msg *monmsg) { if (likely((mon_mca_size(monmsg) - monmsg->mca_offset) == 12)) return; monmsg->mca_offset += 12; monmsg->pos = 0; }

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gerald schaefergerald schaefer43100.00%1100.00%
Total43100.00%1100.00%


static struct mon_msg *mon_next_message(struct mon_private *monpriv) { struct mon_msg *monmsg; if (!atomic_read(&monpriv->read_ready)) return NULL; monmsg = monpriv->msg_array[monpriv->read_index]; if (unlikely(monmsg->replied_msglim)) { monmsg->replied_msglim = 0; monmsg->msglim_reached = 0; monmsg->pos = 0; monmsg->mca_offset = 0; monpriv->read_index = (monpriv->read_index + 1) % MON_MSGLIM; atomic_dec(&monpriv->read_ready); return ERR_PTR(-EOVERFLOW); } return monmsg; }

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gerald schaefergerald schaefer10494.55%150.00%
martin schwidefskymartin schwidefsky65.45%150.00%
Total110100.00%2100.00%

/****************************************************************************** * IUCV handler * *****************************************************************************/
static void mon_iucv_path_complete(struct iucv_path *path, u8 *ipuser) { struct mon_private *monpriv = path->private; atomic_set(&monpriv->iucv_connected, 1); wake_up(&mon_conn_wait_queue); }

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PersonTokensPropCommitsCommitProp
gerald schaefergerald schaefer3075.00%133.33%
martin schwidefskymartin schwidefsky922.50%133.33%
ursula braunursula braun12.50%133.33%
Total40100.00%3100.00%


static void mon_iucv_path_severed(struct iucv_path *path, u8 *ipuser) { struct mon_private *monpriv = path->private; pr_err("z/VM *MONITOR system service disconnected with rc=%i\n", ipuser[0]); iucv_path_sever(path, NULL); atomic_set(&monpriv->iucv_severed, 1); wake_up(&mon_conn_wait_queue); wake_up_interruptible(&mon_read_wait_queue); }

Contributors

PersonTokensPropCommitsCommitProp
gerald schaefergerald schaefer4673.02%250.00%
martin schwidefskymartin schwidefsky1625.40%125.00%
ursula braunursula braun11.59%125.00%
Total63100.00%4100.00%


static void mon_iucv_message_pending(struct iucv_path *path, struct iucv_message *msg) { struct mon_private *monpriv = path->private; memcpy(&monpriv->msg_array[monpriv->write_index]->msg, msg, sizeof(*msg)); if (atomic_inc_return(&monpriv->msglim_count) == MON_MSGLIM) { pr_warn("The read queue for monitor data is full\n"); monpriv->msg_array[monpriv->write_index]->msglim_reached = 1; } monpriv->write_index = (monpriv->write_index + 1) % MON_MSGLIM; atomic_inc(&monpriv->read_ready); wake_up_interruptible(&mon_read_wait_queue); }

Contributors

PersonTokensPropCommitsCommitProp
gerald schaefergerald schaefer9386.11%250.00%
martin schwidefskymartin schwidefsky1412.96%125.00%
joe perchesjoe perches10.93%125.00%
Total108100.00%4100.00%

static struct iucv_handler monreader_iucv_handler = { .path_complete = mon_iucv_path_complete, .path_severed = mon_iucv_path_severed, .message_pending = mon_iucv_message_pending, }; /****************************************************************************** * file operations * *****************************************************************************/
static int mon_open(struct inode *inode, struct file *filp) { struct mon_private *monpriv; int rc; /* * only one user allowed */ rc = -EBUSY; if (test_and_set_bit(MON_IN_USE, &mon_in_use)) goto out; rc = -ENOMEM; monpriv = mon_alloc_mem(); if (!monpriv) goto out_use; /* * Connect to *MONITOR service */ monpriv->path = iucv_path_alloc(MON_MSGLIM, IUCV_IPRMDATA, GFP_KERNEL); if (!monpriv->path) goto out_priv; rc = iucv_path_connect(monpriv->path, &monreader_iucv_handler, MON_SERVICE, NULL, user_data_connect, monpriv); if (rc) { pr_err("Connecting to the z/VM *MONITOR system service " "failed with rc=%i\n", rc); rc = -EIO; goto out_path; } /* * Wait for connection confirmation */ wait_event(mon_conn_wait_queue, atomic_read(&monpriv->iucv_connected) || atomic_read(&monpriv->iucv_severed)); if (atomic_read(&monpriv->iucv_severed)) { atomic_set(&monpriv->iucv_severed, 0); atomic_set(&monpriv->iucv_connected, 0); rc = -EIO; goto out_path; } filp->private_data = monpriv; dev_set_drvdata(monreader_device, monpriv); return nonseekable_open(inode, filp); out_path: iucv_path_free(monpriv->path); out_priv: mon_free_mem(monpriv); out_use: clear_bit(MON_IN_USE, &mon_in_use); out: return rc; }

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PersonTokensPropCommitsCommitProp
gerald schaefergerald schaefer18978.42%350.00%
martin schwidefskymartin schwidefsky4619.09%233.33%
heiko carstensheiko carstens62.49%116.67%
Total241100.00%6100.00%


static int mon_close(struct inode *inode, struct file *filp) { int rc, i; struct mon_private *monpriv = filp->private_data; /* * Close IUCV connection and unregister */ if (monpriv->path) { rc = iucv_path_sever(monpriv->path, user_data_sever); if (rc) pr_warn("Disconnecting the z/VM *MONITOR system service failed with rc=%i\n", rc); iucv_path_free(monpriv->path); } atomic_set(&monpriv->iucv_severed, 0); atomic_set(&monpriv->iucv_connected, 0); atomic_set(&monpriv->read_ready, 0); atomic_set(&monpriv->msglim_count, 0); monpriv->write_index = 0; monpriv->read_index = 0; dev_set_drvdata(monreader_device, NULL); for (i = 0; i < MON_MSGLIM; i++) kfree(monpriv->msg_array[i]); kfree(monpriv); clear_bit(MON_IN_USE, &mon_in_use); return 0; }

Contributors

PersonTokensPropCommitsCommitProp
gerald schaefergerald schaefer16297.59%360.00%
joe perchesjoe perches21.20%120.00%
martin schwidefskymartin schwidefsky21.20%120.00%
Total166100.00%5100.00%


static ssize_t mon_read(struct file *filp, char __user *data, size_t count, loff_t *ppos) { struct mon_private *monpriv = filp->private_data; struct mon_msg *monmsg; int ret; u32 mce_start; monmsg = mon_next_message(monpriv); if (IS_ERR(monmsg)) return PTR_ERR(monmsg); if (!monmsg) { if (filp->f_flags & O_NONBLOCK) return -EAGAIN; ret = wait_event_interruptible(mon_read_wait_queue, atomic_read(&monpriv->read_ready) || atomic_read(&monpriv->iucv_severed)); if (ret) return ret; if (unlikely(atomic_read(&monpriv->iucv_severed))) return -EIO; monmsg = monpriv->msg_array[monpriv->read_index]; } if (!monmsg->pos) monmsg->pos = mon_mca_start(monmsg) + monmsg->mca_offset; if (mon_check_mca(monmsg)) goto reply; /* read monitor control element (12 bytes) first */ mce_start = mon_mca_start(monmsg) + monmsg->mca_offset; if ((monmsg->pos >= mce_start) && (monmsg->pos < mce_start + 12)) { count = min(count, (size_t) mce_start + 12 - monmsg->pos); ret = copy_to_user(data, (void *) (unsigned long) monmsg->pos, count); if (ret) return -EFAULT; monmsg->pos += count; if (monmsg->pos == mce_start + 12) monmsg->pos = mon_rec_start(monmsg); goto out_copy; } /* read records */ if (monmsg->pos <= mon_rec_end(monmsg)) { count = min(count, (size_t) mon_rec_end(monmsg) - monmsg->pos + 1); ret = copy_to_user(data, (void *) (unsigned long) monmsg->pos, count); if (ret) return -EFAULT; monmsg->pos += count; if (monmsg->pos > mon_rec_end(monmsg)) mon_next_mca(monmsg); goto out_copy; } reply: ret = mon_send_reply(monmsg, monpriv); return ret; out_copy: *ppos += count; return count; }

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gerald schaefergerald schaefer25565.05%150.00%
martin schwidefskymartin schwidefsky13734.95%150.00%
Total392100.00%2100.00%


static unsigned int mon_poll(struct file *filp, struct poll_table_struct *p) { struct mon_private *monpriv = filp->private_data; poll_wait(filp, &mon_read_wait_queue, p); if (unlikely(atomic_read(&monpriv->iucv_severed))) return POLLERR; if (atomic_read(&monpriv->read_ready)) return POLLIN | POLLRDNORM; return 0; }

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gerald schaefergerald schaefer70100.00%1100.00%
Total70100.00%1100.00%

static const struct file_operations mon_fops = { .owner = THIS_MODULE, .open = &mon_open, .release = &mon_close, .read = &mon_read, .poll = &mon_poll, .llseek = noop_llseek, }; static struct miscdevice mon_dev = { .name = "monreader", .fops = &mon_fops, .minor = MISC_DYNAMIC_MINOR, }; /****************************************************************************** * suspend / resume * *****************************************************************************/
static int monreader_freeze(struct device *dev) { struct mon_private *monpriv = dev_get_drvdata(dev); int rc; if (!monpriv) return 0; if (monpriv->path) { rc = iucv_path_sever(monpriv->path, user_data_sever); if (rc) pr_warn("Disconnecting the z/VM *MONITOR system service failed with rc=%i\n", rc); iucv_path_free(monpriv->path); } atomic_set(&monpriv->iucv_severed, 0); atomic_set(&monpriv->iucv_connected, 0); atomic_set(&monpriv->read_ready, 0); atomic_set(&monpriv->msglim_count, 0); monpriv->write_index = 0; monpriv->read_index = 0; monpriv->path = NULL; return 0; }

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PersonTokensPropCommitsCommitProp
gerald schaefergerald schaefer12596.15%133.33%
martin schwidefskymartin schwidefsky32.31%133.33%
joe perchesjoe perches21.54%133.33%
Total130100.00%3100.00%


static int monreader_thaw(struct device *dev) { struct mon_private *monpriv = dev_get_drvdata(dev); int rc; if (!monpriv) return 0; rc = -ENOMEM; monpriv->path = iucv_path_alloc(MON_MSGLIM, IUCV_IPRMDATA, GFP_KERNEL); if (!monpriv->path) goto out; rc = iucv_path_connect(monpriv->path, &monreader_iucv_handler, MON_SERVICE, NULL, user_data_connect, monpriv); if (rc) { pr_err("Connecting to the z/VM *MONITOR system service " "failed with rc=%i\n", rc); goto out_path; } wait_event(mon_conn_wait_queue, atomic_read(&monpriv->iucv_connected) || atomic_read(&monpriv->iucv_severed)); if (atomic_read(&monpriv->iucv_severed)) goto out_path; return 0; out_path: rc = -EIO; iucv_path_free(monpriv->path); monpriv->path = NULL; out: atomic_set(&monpriv->iucv_severed, 1); return rc; }

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gerald schaefergerald schaefer16698.22%150.00%
martin schwidefskymartin schwidefsky31.78%150.00%
Total169100.00%2100.00%


static int monreader_restore(struct device *dev) { int rc; segment_unload(mon_dcss_name); rc = segment_load(mon_dcss_name, SEGMENT_SHARED, &mon_dcss_start, &mon_dcss_end); if (rc < 0) { segment_warning(rc, mon_dcss_name); panic("fatal monreader resume error: no monitor dcss\n"); } return monreader_thaw(dev); }

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gerald schaefergerald schaefer60100.00%1100.00%
Total60100.00%1100.00%

static const struct dev_pm_ops monreader_pm_ops = { .freeze = monreader_freeze, .thaw = monreader_thaw, .restore = monreader_restore, }; static struct device_driver monreader_driver = { .name = "monreader", .bus = &iucv_bus, .pm = &monreader_pm_ops, }; /****************************************************************************** * module init/exit * *****************************************************************************/
static int __init mon_init(void) { int rc; if (!MACHINE_IS_VM) { pr_err("The z/VM *MONITOR record device driver cannot be " "loaded without z/VM\n"); return -ENODEV; } /* * Register with IUCV and connect to *MONITOR service */ rc = iucv_register(&monreader_iucv_handler, 1); if (rc) { pr_err("The z/VM *MONITOR record device driver failed to " "register with IUCV\n"); return rc; } rc = driver_register(&monreader_driver); if (rc) goto out_iucv; monreader_device = kzalloc(sizeof(struct device), GFP_KERNEL); if (!monreader_device) { rc = -ENOMEM; goto out_driver; } dev_set_name(monreader_device, "monreader-dev"); monreader_device->bus = &iucv_bus; monreader_device->parent = iucv_root; monreader_device->driver = &monreader_driver; monreader_device->release = (void (*)(struct device *))kfree; rc = device_register(monreader_device); if (rc) { put_device(monreader_device); goto out_driver; } rc = segment_type(mon_dcss_name); if (rc < 0) { segment_warning(rc, mon_dcss_name); goto out_device; } if (rc != SEG_TYPE_SC) { pr_err("The specified *MONITOR DCSS %s does not have the " "required type SC\n", mon_dcss_name); rc = -EINVAL; goto out_device; } rc = segment_load(mon_dcss_name, SEGMENT_SHARED, &mon_dcss_start, &mon_dcss_end); if (rc < 0) { segment_warning(rc, mon_dcss_name); rc = -EINVAL; goto out_device; } dcss_mkname(mon_dcss_name, &user_data_connect[8]); /* * misc_register() has to be the last action in module_init(), because * file operations will be available right after this. */ rc = misc_register(&mon_dev); if (rc < 0 ) goto out; return 0; out: segment_unload(mon_dcss_name); out_device: device_unregister(monreader_device); out_driver: driver_unregister(&monreader_driver); out_iucv: iucv_unregister(&monreader_iucv_handler, 1); return rc; }

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PersonTokensPropCommitsCommitProp
gerald schaefergerald schaefer22470.66%440.00%
martin schwidefskymartin schwidefsky8526.81%440.00%
peter senna tschudinpeter senna tschudin72.21%110.00%
sebastian ottsebastian ott10.32%110.00%
Total317100.00%10100.00%


static void __exit mon_exit(void) { segment_unload(mon_dcss_name); misc_deregister(&mon_dev); device_unregister(monreader_device); driver_unregister(&monreader_driver); iucv_unregister(&monreader_iucv_handler, 1); return; }

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PersonTokensPropCommitsCommitProp
gerald schaefergerald schaefer3280.00%266.67%
martin schwidefskymartin schwidefsky820.00%133.33%
Total40100.00%3100.00%

module_init(mon_init); module_exit(mon_exit); module_param_string(mondcss, mon_dcss_name, 9, 0444); MODULE_PARM_DESC(mondcss, "Name of DCSS segment to be used for *MONITOR " "service, max. 8 chars. Default is MONDCSS"); MODULE_AUTHOR("Gerald Schaefer <geraldsc@de.ibm.com>"); MODULE_DESCRIPTION("Character device driver for reading z/VM " "monitor service records."); MODULE_LICENSE("GPL");

Overall Contributors

PersonTokensPropCommitsCommitProp
gerald schaefergerald schaefer259585.11%627.27%
martin schwidefskymartin schwidefsky42113.81%627.27%
peter senna tschudinpeter senna tschudin70.23%14.55%
heiko carstensheiko carstens60.20%14.55%
joe perchesjoe perches50.16%14.55%
arnd bergmannarnd bergmann50.16%14.55%
tejun heotejun heo30.10%14.55%
eric sesterhenneric sesterhenn20.07%14.55%
ursula braunursula braun20.07%14.55%
arjan van de venarjan van de ven10.03%14.55%
sebastian ottsebastian ott10.03%14.55%
alexey dobriyanalexey dobriyan10.03%14.55%
Total3049100.00%22100.00%
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