Re: [PATCH 1/2] staging: lustre: replace uses of class_devno_max by MAX_OBD_DEVICES

[Aya Mahfouz]

On Mon, Oct 17, 2016 at 10:38:31PM +0000, Dilger, Andreas wrote:
> On Oct 17, 2016, at 15:46, Aya Mahfouz <mahfouz.saif.elyazal@xxxxxxxxx> wrote:
> > 
> > class_devno_max is an inline function that returns
> > MAX_OBD_DEVICES. Replace all calls to the function
> > by MAX_OBD_DEVICES.
> 
> Thanks for your patch, but unfortunately it can't be accepted.
> 
> This function was added in preparation of being able to tune the maximum
> number of storage devices dynamically, rather than having to hard code it
> to the maximum possible number of servers that a client can possibly
> connect to.
> 
> While the current maximum of 8192 servers has been enough for current
> filesystems, I'd rather move in the direction of dynamically handling this
> limit rather than re-introducing a hard-coded constant throughout the code.
>
Hello,

I would like to proceed with implementing the function if possible.
Kindly direct me to some starting pointers.

> One comment inline below, if you still want to submit a patch.
> 
> > Signed-off-by: Aya Mahfouz <mahfouz.saif.elyazal@xxxxxxxxx>
> > ---
> > drivers/staging/lustre/lustre/obdclass/class_obd.c |  6 +++---
> > drivers/staging/lustre/lustre/obdclass/genops.c    | 22 +++++++++++-----------
> > .../lustre/lustre/obdclass/linux/linux-module.c    |  6 +++---
> > 3 files changed, 17 insertions(+), 17 deletions(-)
> > 
> > diff --git a/drivers/staging/lustre/lustre/obdclass/class_obd.c b/drivers/staging/lustre/lustre/obdclass/class_obd.c
> > index 2b21675..b775c74 100644
> > --- a/drivers/staging/lustre/lustre/obdclass/class_obd.c
> > +++ b/drivers/staging/lustre/lustre/obdclass/class_obd.c
> > @@ -345,7 +345,7 @@ int class_handle_ioctl(unsigned int cmd, unsigned long arg)
> > 			goto out;
> > 		}
> > 		obd = class_name2obd(data->ioc_inlbuf4);
> > -	} else if (data->ioc_dev < class_devno_max()) {
> > +	} else if (data->ioc_dev < MAX_OBD_DEVICES) {
> > 		obd = class_num2obd(data->ioc_dev);
> > 	} else {
> > 		CERROR("OBD ioctl: No device\n");
> > @@ -498,7 +498,7 @@ static int __init obdclass_init(void)
> > 	}
> > 
> > 	/* This struct is already zeroed for us (static global) */
> > -	for (i = 0; i < class_devno_max(); i++)
> > +	for (i = 0; i < MAX_OBD_DEVICES; i++)
> > 		obd_devs[i] = NULL;
> 
> This block can just be removed entirely.  It used to do something useful,
> but through a series of changes it has become useless.
> 
> Cheers, Andreas
> 
> > 	/* Default the dirty page cache cap to 1/2 of system memory.
> > @@ -548,7 +548,7 @@ static void obdclass_exit(void)
> > 	lustre_unregister_fs();
> > 
> > 	misc_deregister(&obd_psdev);
> > -	for (i = 0; i < class_devno_max(); i++) {
> > +	for (i = 0; i < MAX_OBD_DEVICES; i++) {
> > 		struct obd_device *obd = class_num2obd(i);
> > 
> > 		if (obd && obd->obd_set_up &&
> > diff --git a/drivers/staging/lustre/lustre/obdclass/genops.c b/drivers/staging/lustre/lustre/obdclass/genops.c
> > index 99c2da6..af4fc58 100644
> > --- a/drivers/staging/lustre/lustre/obdclass/genops.c
> > +++ b/drivers/staging/lustre/lustre/obdclass/genops.c
> > @@ -290,7 +290,7 @@ struct obd_device *class_newdev(const char *type_name, const char *name)
> > 	LASSERT(newdev->obd_magic == OBD_DEVICE_MAGIC);
> > 
> > 	write_lock(&obd_dev_lock);
> > -	for (i = 0; i < class_devno_max(); i++) {
> > +	for (i = 0; i < MAX_OBD_DEVICES; i++) {
> > 		struct obd_device *obd = class_num2obd(i);
> > 
> > 		if (obd && (strcmp(name, obd->obd_name) == 0)) {
> > @@ -322,9 +322,9 @@ struct obd_device *class_newdev(const char *type_name, const char *name)
> > 	}
> > 	write_unlock(&obd_dev_lock);
> > 
> > -	if (!result && i >= class_devno_max()) {
> > +	if (!result && i >= MAX_OBD_DEVICES) {
> > 		CERROR("all %u OBD devices used, increase MAX_OBD_DEVICES\n",
> > -		       class_devno_max());
> > +		       MAX_OBD_DEVICES);
> > 		result = ERR_PTR(-EOVERFLOW);
> > 		goto out;
> > 	}
> > @@ -372,7 +372,7 @@ int class_name2dev(const char *name)
> > 		return -1;
> > 
> > 	read_lock(&obd_dev_lock);
> > -	for (i = 0; i < class_devno_max(); i++) {
> > +	for (i = 0; i < MAX_OBD_DEVICES; i++) {
> > 		struct obd_device *obd = class_num2obd(i);
> > 
> > 		if (obd && strcmp(name, obd->obd_name) == 0) {
> > @@ -397,7 +397,7 @@ struct obd_device *class_name2obd(const char *name)
> > {
> > 	int dev = class_name2dev(name);
> > 
> > -	if (dev < 0 || dev > class_devno_max())
> > +	if (dev < 0 || dev > MAX_OBD_DEVICES)
> > 		return NULL;
> > 	return class_num2obd(dev);
> > }
> > @@ -408,7 +408,7 @@ int class_uuid2dev(struct obd_uuid *uuid)
> > 	int i;
> > 
> > 	read_lock(&obd_dev_lock);
> > -	for (i = 0; i < class_devno_max(); i++) {
> > +	for (i = 0; i < MAX_OBD_DEVICES; i++) {
> > 		struct obd_device *obd = class_num2obd(i);
> > 
> > 		if (obd && obd_uuid_equals(uuid, &obd->obd_uuid)) {
> > @@ -435,7 +435,7 @@ struct obd_device *class_num2obd(int num)
> > {
> > 	struct obd_device *obd = NULL;
> > 
> > -	if (num < class_devno_max()) {
> > +	if (num < MAX_OBD_DEVICES) {
> > 		obd = obd_devs[num];
> > 		if (!obd)
> > 			return NULL;
> > @@ -463,7 +463,7 @@ struct obd_device *class_find_client_obd(struct obd_uuid *tgt_uuid,
> > 	int i;
> > 
> > 	read_lock(&obd_dev_lock);
> > -	for (i = 0; i < class_devno_max(); i++) {
> > +	for (i = 0; i < MAX_OBD_DEVICES; i++) {
> > 		struct obd_device *obd = class_num2obd(i);
> > 
> > 		if (!obd)
> > @@ -496,13 +496,13 @@ struct obd_device *class_devices_in_group(struct obd_uuid *grp_uuid, int *next)
> > 
> > 	if (!next)
> > 		i = 0;
> > -	else if (*next >= 0 && *next < class_devno_max())
> > +	else if (*next >= 0 && *next < MAX_OBD_DEVICES)
> > 		i = *next;
> > 	else
> > 		return NULL;
> > 
> > 	read_lock(&obd_dev_lock);
> > -	for (; i < class_devno_max(); i++) {
> > +	for (; i < MAX_OBD_DEVICES; i++) {
> > 		struct obd_device *obd = class_num2obd(i);
> > 
> > 		if (!obd)
> > @@ -533,7 +533,7 @@ int class_notify_sptlrpc_conf(const char *fsname, int namelen)
> > 	LASSERT(namelen > 0);
> > 
> > 	read_lock(&obd_dev_lock);
> > -	for (i = 0; i < class_devno_max(); i++) {
> > +	for (i = 0; i < MAX_OBD_DEVICES; i++) {
> > 		obd = class_num2obd(i);
> > 
> > 		if (!obd || obd->obd_set_up == 0 || obd->obd_stopping)
> > diff --git a/drivers/staging/lustre/lustre/obdclass/linux/linux-module.c b/drivers/staging/lustre/lustre/obdclass/linux/linux-module.c
> > index 33342bf..ca5b466 100644
> > --- a/drivers/staging/lustre/lustre/obdclass/linux/linux-module.c
> > +++ b/drivers/staging/lustre/lustre/obdclass/linux/linux-module.c
> > @@ -228,7 +228,7 @@ static ssize_t health_show(struct kobject *kobj, struct attribute *attr,
> > 		return sprintf(buf, "LBUG\n");
> > 
> > 	read_lock(&obd_dev_lock);
> > -	for (i = 0; i < class_devno_max(); i++) {
> > +	for (i = 0; i < MAX_OBD_DEVICES; i++) {
> > 		struct obd_device *obd;
> > 
> > 		obd = class_num2obd(i);
> > @@ -326,7 +326,7 @@ static struct attribute *lustre_attrs[] = {
> > 
> > static void *obd_device_list_seq_start(struct seq_file *p, loff_t *pos)
> > {
> > -	if (*pos >= class_devno_max())
> > +	if (*pos >= MAX_OBD_DEVICES)
> > 		return NULL;
> > 
> > 	return pos;
> > @@ -339,7 +339,7 @@ static void obd_device_list_seq_stop(struct seq_file *p, void *v)
> > static void *obd_device_list_seq_next(struct seq_file *p, void *v, loff_t *pos)
> > {
> > 	++*pos;
> > -	if (*pos >= class_devno_max())
> > +	if (*pos >= MAX_OBD_DEVICES)
> > 		return NULL;
> > 
> > 	return pos;
> > -- 
> > 2.5.0
> > 
> > 
> > -- 
> > Kind Regards,
> > Aya Saif El-yazal Mahfouz
> > _______________________________________________
> > lustre-devel mailing list
> > lustre-devel@xxxxxxxxxxxxxxxx
> > http://lists.lustre.org/listinfo.cgi/lustre-devel-lustre.org
> 

-- 
Kind Regards,
Aya Saif El-yazal Mahfouz