Hello Sergey, Sorry for the late review. I don't grab a time to review in detail still but I saw Andrew merged it to mmotm today so at least I should ask somethings now and hope review in detail soon.
On Tue, Mar 03, 2015 at 09:49:44PM +0900, Sergey Senozhatsky wrote: > This patch makes some preparations for dynamic device ADD/REMOVE functionality > via /dev/zram-control interface. > > Remove `zram_devices' array and switch to id-to-pointer translation (idr). > idr doesn't bloat zram struct with additional members, f.e. list_head, yet So are you claiming using of idr is smaller memory footprint than zram included list_head? I hope why you want to use idr for dynamic device management. > still provides ability to match the device_id with the device pointer. > No user-space visible changes. > > Signed-off-by: Sergey Senozhatsky <sergey.senozhat...@gmail.com> > --- > drivers/block/zram/zram_drv.c | 81 > ++++++++++++++++++++++++------------------- > 1 file changed, 46 insertions(+), 35 deletions(-) > > diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c > index 8fc2566..6707b7b 100644 > --- a/drivers/block/zram/zram_drv.c > +++ b/drivers/block/zram/zram_drv.c > @@ -32,12 +32,12 @@ > #include <linux/string.h> > #include <linux/vmalloc.h> > #include <linux/err.h> > +#include <linux/idr.h> > > #include "zram_drv.h" > > -/* Globals */ > +static DEFINE_IDR(zram_index_idr); > static int zram_major; > -static struct zram *zram_devices; > static const char *default_compressor = "lzo"; > > /* Module params (documentation at end) */ > @@ -1061,18 +1061,28 @@ static struct attribute_group zram_disk_attr_group = { > .attrs = zram_disk_attrs, > }; > > -static int create_device(struct zram *zram, int device_id) > +static int zram_add(int device_id) > { > + struct zram *zram; > struct request_queue *queue; > int ret = -ENOMEM; > > + zram = kzalloc(sizeof(struct zram), GFP_KERNEL); > + if (!zram) > + return ret; > + > + ret = idr_alloc(&zram_index_idr, zram, device_id, > + device_id + 1, GFP_KERNEL); > + if (ret < 0) > + goto out_free_dev; > + > init_rwsem(&zram->init_lock); > > queue = blk_alloc_queue(GFP_KERNEL); > if (!queue) { > pr_err("Error allocating disk queue for device %d\n", > device_id); > - goto out; > + goto out_free_idr; > } > > blk_queue_make_request(queue, zram_make_request); > @@ -1141,34 +1151,42 @@ out_free_disk: > put_disk(zram->disk); > out_free_queue: > blk_cleanup_queue(queue); > -out: > +out_free_idr: > + idr_remove(&zram_index_idr, device_id); > +out_free_dev: > + kfree(zram); > return ret; > } > > -static void destroy_devices(unsigned int nr) > +static void zram_remove(struct zram *zram) > { > - struct zram *zram; > - unsigned int i; > - > - for (i = 0; i < nr; i++) { > - zram = &zram_devices[i]; > - /* > - * Remove sysfs first, so no one will perform a disksize > - * store while we destroy the devices > - */ > - sysfs_remove_group(&disk_to_dev(zram->disk)->kobj, > - &zram_disk_attr_group); > + /* > + * Remove sysfs first, so no one will perform a disksize > + * store while we destroy the devices > + */ > + sysfs_remove_group(&disk_to_dev(zram->disk)->kobj, > + &zram_disk_attr_group); > > - zram_reset_device(zram); > + zram_reset_device(zram); > + idr_remove(&zram_index_idr, zram->disk->first_minor); > + blk_cleanup_queue(zram->disk->queue); > + del_gendisk(zram->disk); > + put_disk(zram->disk); > + kfree(zram); > +} > > - blk_cleanup_queue(zram->disk->queue); > - del_gendisk(zram->disk); > - put_disk(zram->disk); > - } > +static int zram_exit_cb(int id, void *ptr, void *data) > +{ > + zram_remove(ptr); > + return 0; > +} > > - kfree(zram_devices); > +static void destroy_devices(void) > +{ > + idr_for_each(&zram_index_idr, &zram_exit_cb, NULL); > + idr_destroy(&zram_index_idr); > unregister_blkdev(zram_major, "zram"); > - pr_info("Destroyed %u device(s)\n", nr); > + pr_info("Destroyed device(s)\n"); > } > > static int __init zram_init(void) > @@ -1187,16 +1205,9 @@ static int __init zram_init(void) > return -EBUSY; > } > > - /* Allocate the device array and initialize each one */ > - zram_devices = kzalloc(num_devices * sizeof(struct zram), GFP_KERNEL); > - if (!zram_devices) { > - unregister_blkdev(zram_major, "zram"); > - return -ENOMEM; > - } > - > for (dev_id = 0; dev_id < num_devices; dev_id++) { > - ret = create_device(&zram_devices[dev_id], dev_id); > - if (ret) > + ret = zram_add(dev_id); > + if (ret != 0) > goto out_error; > } > > @@ -1204,13 +1215,13 @@ static int __init zram_init(void) > return 0; > > out_error: > - destroy_devices(dev_id); > + destroy_devices(); > return ret; > } > > static void __exit zram_exit(void) > { > - destroy_devices(num_devices); > + destroy_devices(); > } > > module_init(zram_init); > -- > 2.3.1.167.g7f4ba4b > -- Kind regards, Minchan Kim -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/