block: Kill gfp_t argument of blkdev_report_zones()

Only GFP_KERNEL and GFP_NOIO are used with blkdev_report_zones(). In
preparation of using vmalloc() for large report buffer and zone array
allocations used by this function, remove its "gfp_t gfp_mask" argument
and rely on the caller context to use memalloc_noio_save/restore() where
necessary (block layer zone revalidation and dm-zoned I/O error path).

Reviewed-by: Christoph Hellwig <[e-mail]>
Reviewed-by: Martin K. Petersen <[e-mail]>
Signed-off-by: Damien Le Moal <[e-mail]>
Signed-off-by: Jens Axboe <[e-mail]>

block/blk-zoned.c

···
 #include <linux/rbtree.h>
 #include <linux/blkdev.h>
 #include <linux/blk-mq.h>
+#include <linux/sched/mm.h>
 
 #include "blk.h"
 
···
 }
 
 static int blk_report_zones(struct gendisk *disk, sector_t sector,
-			    struct blk_zone *zones, unsigned int *nr_zones,
-			    gfp_t gfp_mask)
+			    struct blk_zone *zones, unsigned int *nr_zones)
 {
 	struct request_queue *q = disk->queue;
 	unsigned int z = 0, n, nrz = *nr_zones;
···
 
 	while (z < nrz && sector < capacity) {
 		n = nrz - z;
-		ret = disk->fops->report_zones(disk, sector, &zones[z], &n,
-					       gfp_mask);
+		ret = disk->fops->report_zones(disk, sector, &zones[z], &n);
 		if (ret)
 			return ret;
 		if (!n)
···
  * @sector:	Sector from which to report zones
  * @zones:	Array of zone structures where to return the zones information
  * @nr_zones:	Number of zone structures in the zone array
- * @gfp_mask:	Memory allocation flags (for bio_alloc)
  *
  * Description:
  *    Get zone information starting from the zone containing @sector.
  *    The number of zone information reported may be less than the number
  *    requested by @nr_zones. The number of zones actually reported is
  *    returned in @nr_zones.
+ *    The caller must use memalloc_noXX_save/restore() calls to control
+ *    memory allocations done within this function (zone array and command
+ *    buffer allocation by the device driver).
  */
 int blkdev_report_zones(struct block_device *bdev, sector_t sector,
-			struct blk_zone *zones, unsigned int *nr_zones,
-			gfp_t gfp_mask)
+			struct blk_zone *zones, unsigned int *nr_zones)
 {
 	struct request_queue *q = bdev_get_queue(bdev);
 	unsigned int i, nrz;
···
 	nrz = min(*nr_zones,
 		  __blkdev_nr_zones(q, bdev->bd_part->nr_sects - sector));
 	ret = blk_report_zones(bdev->bd_disk, get_start_sect(bdev) + sector,
-			       zones, &nrz, gfp_mask);
+			       zones, &nrz);
 	if (ret)
 		return ret;
 
···
 	if (!zones)
 		return -ENOMEM;
 
-	ret = blkdev_report_zones(bdev, rep.sector,
-				  zones, &rep.nr_zones,
-				  GFP_KERNEL);
+	ret = blkdev_report_zones(bdev, rep.sector, zones, &rep.nr_zones);
 	if (ret)
 		goto out;
 
···
 	unsigned long *seq_zones_wlock = NULL, *seq_zones_bitmap = NULL;
 	unsigned int i, rep_nr_zones = 0, z = 0, nrz;
 	struct blk_zone *zones = NULL;
+	unsigned int noio_flag;
 	sector_t sector = 0;
 	int ret = 0;
 
···
 		q->nr_zones = nr_zones;
 		return 0;
 	}
+
+	/*
+	 * Ensure that all memory allocations in this context are done as
+	 * if GFP_NOIO was specified.
+	 */
+	noio_flag = memalloc_noio_save();
 
 	if (!blk_queue_is_zoned(q) || !nr_zones) {
 		nr_zones = 0;
···
 
 	while (z < nr_zones) {
 		nrz = min(nr_zones - z, rep_nr_zones);
-		ret = blk_report_zones(disk, sector, zones, &nrz, GFP_NOIO);
+		ret = blk_report_zones(disk, sector, zones, &nrz);
 		if (ret)
 			goto out;
 		if (!nrz)
···
 	blk_mq_unfreeze_queue(q);
 
 out:
+	memalloc_noio_restore(noio_flag);
+
 	free_pages((unsigned long)zones,
 		   get_order(rep_nr_zones * sizeof(struct blk_zone)));
 	kfree(seq_zones_wlock);

drivers/block/null_blk.h

···
 int null_zone_init(struct nullb_device *dev);
 void null_zone_exit(struct nullb_device *dev);
 int null_zone_report(struct gendisk *disk, sector_t sector,
-		     struct blk_zone *zones, unsigned int *nr_zones,
-		     gfp_t gfp_mask);
+		     struct blk_zone *zones, unsigned int *nr_zones);
 void null_zone_write(struct nullb_cmd *cmd, sector_t sector,
 			unsigned int nr_sectors);
 void null_zone_reset(struct nullb_cmd *cmd, sector_t sector);

drivers/block/null_blk_zoned.c

···
 }
 
 int null_zone_report(struct gendisk *disk, sector_t sector,
-		     struct blk_zone *zones, unsigned int *nr_zones,
-		     gfp_t gfp_mask)
+		     struct blk_zone *zones, unsigned int *nr_zones)
 {
 	struct nullb *nullb = disk->private_data;
 	struct nullb_device *dev = nullb->dev;

drivers/md/dm-flakey.c

···
 
 #ifdef CONFIG_BLK_DEV_ZONED
 static int flakey_report_zones(struct dm_target *ti, sector_t sector,
-			       struct blk_zone *zones, unsigned int *nr_zones,
-			       gfp_t gfp_mask)
+			       struct blk_zone *zones, unsigned int *nr_zones)
 {
 	struct flakey_c *fc = ti->private;
 	int ret;
 
 	/* Do report and remap it */
 	ret = blkdev_report_zones(fc->dev->bdev, flakey_map_sector(ti, sector),
-				  zones, nr_zones, gfp_mask);
+				  zones, nr_zones);
 	if (ret != 0)
 		return ret;
 

drivers/md/dm-linear.c

···
 
 #ifdef CONFIG_BLK_DEV_ZONED
 static int linear_report_zones(struct dm_target *ti, sector_t sector,
-			       struct blk_zone *zones, unsigned int *nr_zones,
-			       gfp_t gfp_mask)
+			       struct blk_zone *zones, unsigned int *nr_zones)
 {
 	struct linear_c *lc = (struct linear_c *) ti->private;
 	int ret;
 
 	/* Do report and remap it */
 	ret = blkdev_report_zones(lc->dev->bdev, linear_map_sector(ti, sector),
-				  zones, nr_zones, gfp_mask);
+				  zones, nr_zones);
 	if (ret != 0)
 		return ret;
 

drivers/md/dm-zoned-metadata.c

···
 
 #include <linux/module.h>
 #include <linux/crc32.h>
+#include <linux/sched/mm.h>
 
 #define	DM_MSG_PREFIX		"zoned metadata"
 
···
 	while (sector < dev->capacity) {
 		/* Get zone information */
 		nr_blkz = DMZ_REPORT_NR_ZONES;
-		ret = blkdev_report_zones(dev->bdev, sector, blkz,
-					  &nr_blkz, GFP_KERNEL);
+		ret = blkdev_report_zones(dev->bdev, sector, blkz, &nr_blkz);
 		if (ret) {
 			dmz_dev_err(dev, "Report zones failed %d", ret);
 			goto out;
···
 static int dmz_update_zone(struct dmz_metadata *zmd, struct dm_zone *zone)
 {
 	unsigned int nr_blkz = 1;
+	unsigned int noio_flag;
 	struct blk_zone blkz;
 	int ret;
 
-	/* Get zone information from disk */
+	/*
+	 * Get zone information from disk. Since blkdev_report_zones() uses
+	 * GFP_KERNEL by default for memory allocations, set the per-task
+	 * PF_MEMALLOC_NOIO flag so that all allocations are done as if
+	 * GFP_NOIO was specified.
+	 */
+	noio_flag = memalloc_noio_save();
 	ret = blkdev_report_zones(zmd->dev->bdev, dmz_start_sect(zmd, zone),
-				  &blkz, &nr_blkz, GFP_NOIO);
+				  &blkz, &nr_blkz);
+	memalloc_noio_restore(noio_flag);
 	if (!nr_blkz)
 		ret = -EIO;
 	if (ret) {

drivers/md/dm.c

···
 }
 
 static int dm_blk_report_zones(struct gendisk *disk, sector_t sector,
-			       struct blk_zone *zones, unsigned int *nr_zones,
-			       gfp_t gfp_mask)
+			       struct blk_zone *zones, unsigned int *nr_zones)
 {
 #ifdef CONFIG_BLK_DEV_ZONED
 	struct mapped_device *md = disk->private_data;
···
 	 * So there is no need to loop here trying to fill the entire array
 	 * of zones.
 	 */
-	ret = tgt->type->report_zones(tgt, sector, zones,
-				      nr_zones, gfp_mask);
+	ret = tgt->type->report_zones(tgt, sector, zones, nr_zones);
 
 out:
 	dm_put_live_table(md, srcu_idx);

drivers/scsi/sd.h

···
 extern void sd_zbc_complete(struct scsi_cmnd *cmd, unsigned int good_bytes,
 			    struct scsi_sense_hdr *sshdr);
 extern int sd_zbc_report_zones(struct gendisk *disk, sector_t sector,
-			       struct blk_zone *zones, unsigned int *nr_zones,
-			       gfp_t gfp_mask);
+			       struct blk_zone *zones, unsigned int *nr_zones);
 
 #else /* CONFIG_BLK_DEV_ZONED */
 

drivers/scsi/sd_zbc.c

···
  * @sector: Start 512B sector of the report
  * @zones: Array of zone descriptors
  * @nr_zones: Number of descriptors in the array
- * @gfp_mask: Memory allocation mask
  *
  * Execute a report zones command on the target disk.
  */
 int sd_zbc_report_zones(struct gendisk *disk, sector_t sector,
-			struct blk_zone *zones, unsigned int *nr_zones,
-			gfp_t gfp_mask)
+			struct blk_zone *zones, unsigned int *nr_zones)
 {
 	struct scsi_disk *sdkp = scsi_disk(disk);
 	unsigned int i, buflen, nrz = *nr_zones;
···
 	 */
 	buflen = min(queue_max_hw_sectors(disk->queue) << 9,
 		     roundup((nrz + 1) * 64, 512));
-	buf = kmalloc(buflen, gfp_mask);
+	buf = kmalloc(buflen, GFP_KERNEL);
 	if (!buf)
 		return -ENOMEM;
 

fs/f2fs/super.c

···
 	while (zones && sector < nr_sectors) {
 
 		nr_zones = F2FS_REPORT_NR_ZONES;
-		err = blkdev_report_zones(bdev, sector,
-					  zones, &nr_zones,
-					  GFP_KERNEL);
+		err = blkdev_report_zones(bdev, sector, zones, &nr_zones);
 		if (err)
 			break;
 		if (!nr_zones) {

include/linux/blkdev.h

···
 extern unsigned int blkdev_nr_zones(struct block_device *bdev);
 extern int blkdev_report_zones(struct block_device *bdev,
 			       sector_t sector, struct blk_zone *zones,
-			       unsigned int *nr_zones, gfp_t gfp_mask);
+			       unsigned int *nr_zones);
 extern int blkdev_reset_zones(struct block_device *bdev, sector_t sectors,
 			      sector_t nr_sectors, gfp_t gfp_mask);
 extern int blk_revalidate_disk_zones(struct gendisk *disk);
···
 	/* this callback is with swap_lock and sometimes page table lock held */
 	void (*swap_slot_free_notify) (struct block_device *, unsigned long);
 	int (*report_zones)(struct gendisk *, sector_t sector,
-			    struct blk_zone *zones, unsigned int *nr_zones,
-			    gfp_t gfp_mask);
+			    struct blk_zone *zones, unsigned int *nr_zones);
 	struct module *owner;
 	const struct pr_ops *pr_ops;
 };

include/linux/device-mapper.h

···
 
 typedef int (*dm_report_zones_fn) (struct dm_target *ti, sector_t sector,
 				   struct blk_zone *zones,
-				   unsigned int *nr_zones,
-				   gfp_t gfp_mask);
+				   unsigned int *nr_zones);
 
 /*
  * These iteration functions are typically used to check (and combine)