[RFC] fix confusion around GFP_* flags and blk_get_request

[RFC] fix confusion around GFP_* flags and blk_get_request

[Christoph Hellwig]

Hi all,

this series sorts out the mess around how we use gfp flags in the
block layer get_request interface.

[PATCH 1/7] scsi/osd: remove the gfp argument to osd_start_request

[Christoph Hellwig]

Always GFP_KERNEL, and keeping it would cause serious complications for
the next change.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/scsi/osd/osd_initiator.c | 24 +++++++++++-------------
 fs/exofs/ore.c                   | 10 +++++-----
 fs/exofs/super.c                 |  2 +-
 include/scsi/osd_initiator.h     |  6 +-----
 4 files changed, 18 insertions(+), 24 deletions(-)

diff --git a/drivers/scsi/osd/osd_initiator.c b/drivers/scsi/osd/osd_initiator.c
index e18877177f1b..f48bae267dc2 100644
--- a/drivers/scsi/osd/osd_initiator.c
+++ b/drivers/scsi/osd/osd_initiator.c
@@ -99,7 +99,7 @@ static int _osd_get_print_system_info(struct osd_dev *od,
 	int nelem = ARRAY_SIZE(get_attrs), a = 0;
 	int ret;
 
-	or = osd_start_request(od, GFP_KERNEL);
+	or = osd_start_request(od);
 	if (!or)
 		return -ENOMEM;
 
@@ -409,16 +409,15 @@ static void _osd_request_free(struct osd_request *or)
 	kfree(or);
 }
 
-struct osd_request *osd_start_request(struct osd_dev *dev, gfp_t gfp)
+struct osd_request *osd_start_request(struct osd_dev *dev)
 {
 	struct osd_request *or;
 
-	or = _osd_request_alloc(gfp);
+	or = _osd_request_alloc(GFP_KERNEL);
 	if (!or)
 		return NULL;
 
 	or->osd_dev = dev;
-	or->alloc_flags = gfp;
 	or->timeout = dev->def_timeout;
 	or->retries = OSD_REQ_RETRIES;
 
@@ -546,7 +545,7 @@ static int _osd_realloc_seg(struct osd_request *or,
 	if (seg->alloc_size >= max_bytes)
 		return 0;
 
-	buff = krealloc(seg->buff, max_bytes, or->alloc_flags);
+	buff = krealloc(seg->buff, max_bytes, GFP_KERNEL);
 	if (!buff) {
 		OSD_ERR("Failed to Realloc %d-bytes was-%d\n", max_bytes,
 			seg->alloc_size);
@@ -728,7 +727,7 @@ static int _osd_req_list_objects(struct osd_request *or,
 		_osd_req_encode_olist(or, list);
 
 	WARN_ON(or->in.bio);
-	bio = bio_map_kern(q, list, len, or->alloc_flags);
+	bio = bio_map_kern(q, list, len, GFP_KERNEL);
 	if (IS_ERR(bio)) {
 		OSD_ERR("!!! Failed to allocate list_objects BIO\n");
 		return PTR_ERR(bio);
@@ -1190,14 +1189,14 @@ static int _req_append_segment(struct osd_request *or,
 			pad_buff = io->pad_buff;
 
 		ret = blk_rq_map_kern(io->req->q, io->req, pad_buff, padding,
-				       or->alloc_flags);
+				       GFP_KERNEL);
 		if (ret)
 			return ret;
 		io->total_bytes += padding;
 	}
 
 	ret = blk_rq_map_kern(io->req->q, io->req, seg->buff, seg->total_bytes,
-			       or->alloc_flags);
+			       GFP_KERNEL);
 	if (ret)
 		return ret;
 
@@ -1564,14 +1563,14 @@ static int _osd_req_finalize_data_integrity(struct osd_request *or,
  * osd_finalize_request and helpers
  */
 static struct request *_make_request(struct request_queue *q, bool has_write,
-			      struct _osd_io_info *oii, gfp_t flags)
+			      struct _osd_io_info *oii)
 {
 	struct request *req;
 	struct bio *bio = oii->bio;
 	int ret;
 
 	req = blk_get_request(q, has_write ? REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN,
-			flags);
+			GFP_KERNEL);
 	if (IS_ERR(req))
 		return req;
 
@@ -1589,13 +1588,12 @@ static struct request *_make_request(struct request_queue *q, bool has_write,
 static int _init_blk_request(struct osd_request *or,
 	bool has_in, bool has_out)
 {
-	gfp_t flags = or->alloc_flags;
 	struct scsi_device *scsi_device = or->osd_dev->scsi_device;
 	struct request_queue *q = scsi_device->request_queue;
 	struct request *req;
 	int ret;
 
-	req = _make_request(q, has_out, has_out ? &or->out : &or->in, flags);
+	req = _make_request(q, has_out, has_out ? &or->out : &or->in);
 	if (IS_ERR(req)) {
 		ret = PTR_ERR(req);
 		goto out;
@@ -1611,7 +1609,7 @@ static int _init_blk_request(struct osd_request *or,
 		or->out.req = req;
 		if (has_in) {
 			/* allocate bidi request */
-			req = _make_request(q, false, &or->in, flags);
+			req = _make_request(q, false, &or->in);
 			if (IS_ERR(req)) {
 				OSD_DEBUG("blk_get_request for bidi failed\n");
 				ret = PTR_ERR(req);
diff --git a/fs/exofs/ore.c b/fs/exofs/ore.c
index 3c6a9c156b7a..ddbf87246898 100644
--- a/fs/exofs/ore.c
+++ b/fs/exofs/ore.c
@@ -790,7 +790,7 @@ int ore_create(struct ore_io_state *ios)
 	for (i = 0; i < ios->oc->numdevs; i++) {
 		struct osd_request *or;
 
-		or = osd_start_request(_ios_od(ios, i), GFP_KERNEL);
+		or = osd_start_request(_ios_od(ios, i));
 		if (unlikely(!or)) {
 			ORE_ERR("%s: osd_start_request failed\n", __func__);
 			ret = -ENOMEM;
@@ -815,7 +815,7 @@ int ore_remove(struct ore_io_state *ios)
 	for (i = 0; i < ios->oc->numdevs; i++) {
 		struct osd_request *or;
 
-		or = osd_start_request(_ios_od(ios, i), GFP_KERNEL);
+		or = osd_start_request(_ios_od(ios, i));
 		if (unlikely(!or)) {
 			ORE_ERR("%s: osd_start_request failed\n", __func__);
 			ret = -ENOMEM;
@@ -847,7 +847,7 @@ static int _write_mirror(struct ore_io_state *ios, int cur_comp)
 		struct ore_per_dev_state *per_dev = &ios->per_dev[cur_comp];
 		struct osd_request *or;
 
-		or = osd_start_request(_ios_od(ios, dev), GFP_KERNEL);
+		or = osd_start_request(_ios_od(ios, dev));
 		if (unlikely(!or)) {
 			ORE_ERR("%s: osd_start_request failed\n", __func__);
 			ret = -ENOMEM;
@@ -966,7 +966,7 @@ int _ore_read_mirror(struct ore_io_state *ios, unsigned cur_comp)
 		return 0; /* Just an empty slot */
 
 	first_dev = per_dev->dev + first_dev % ios->layout->mirrors_p1;
-	or = osd_start_request(_ios_od(ios, first_dev), GFP_KERNEL);
+	or = osd_start_request(_ios_od(ios, first_dev));
 	if (unlikely(!or)) {
 		ORE_ERR("%s: osd_start_request failed\n", __func__);
 		return -ENOMEM;
@@ -1060,7 +1060,7 @@ static int _truncate_mirrors(struct ore_io_state *ios, unsigned cur_comp,
 		struct ore_per_dev_state *per_dev = &ios->per_dev[cur_comp];
 		struct osd_request *or;
 
-		or = osd_start_request(_ios_od(ios, cur_comp), GFP_KERNEL);
+		or = osd_start_request(_ios_od(ios, cur_comp));
 		if (unlikely(!or)) {
 			ORE_ERR("%s: osd_start_request failed\n", __func__);
 			return -ENOMEM;
diff --git a/fs/exofs/super.c b/fs/exofs/super.c
index 179cd5c2f52a..719a3152da80 100644
--- a/fs/exofs/super.c
+++ b/fs/exofs/super.c
@@ -229,7 +229,7 @@ void exofs_make_credential(u8 cred_a[OSD_CAP_LEN], const struct osd_obj_id *obj)
 static int exofs_read_kern(struct osd_dev *od, u8 *cred, struct osd_obj_id *obj,
 		    u64 offset, void *p, unsigned length)
 {
-	struct osd_request *or = osd_start_request(od, GFP_KERNEL);
+	struct osd_request *or = osd_start_request(od);
 /*	struct osd_sense_info osi = {.key = 0};*/
 	int ret;
 
diff --git a/include/scsi/osd_initiator.h b/include/scsi/osd_initiator.h
index a29d3086eb56..86a569d008b2 100644
--- a/include/scsi/osd_initiator.h
+++ b/include/scsi/osd_initiator.h
@@ -148,7 +148,6 @@ struct osd_request {
 		u8 *pad_buff;
 	} out, in;
 
-	gfp_t alloc_flags;
 	unsigned timeout;
 	unsigned retries;
 	unsigned sense_len;
@@ -202,14 +201,11 @@ static inline bool osd_req_is_ver1(struct osd_request *or)
  *
  * @osd_dev:    OSD device that holds the scsi-device and default values
  *              that the request is associated with.
- * @gfp:        The allocation flags to use for request allocation, and all
- *              subsequent allocations. This will be stored at
- *              osd_request->alloc_flags, can be changed by user later
  *
  * Allocate osd_request and initialize all members to the
  * default/initial state.
  */
-struct osd_request *osd_start_request(struct osd_dev *od, gfp_t gfp);
+struct osd_request *osd_start_request(struct osd_dev *od);
 
 enum osd_req_options {
 	OSD_REQ_FUA = 0x08,	/* Force Unit Access */
-- 
2.16.3

[PATCH 2/7] block: fix __get_request documentation

[Christoph Hellwig]

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/blk-core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/block/blk-core.c b/block/blk-core.c
index abcb8684ba67..abde22c755ab 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1517,7 +1517,7 @@ static struct request *__get_request(struct request_list *rl, unsigned int op,
  * @bio: bio to allocate request for (can be %NULL)
  * @flags: BLK_MQ_REQ_* flags.
  *
- * Get a free request from @q.  If %__GFP_DIRECT_RECLAIM is set in @gfp_mask,
+ * Get a free request from @q.  If %BLK_MQ_REQ_NOWAIT is set in @flags,
  * this function keeps retrying under memory pressure and fails iff @q is dead.
  *
  * Must be called with @q->queue_lock held and,
-- 
2.16.3

[PATCH 3/7] block: sanitize blk_get_request calling conventions

[Christoph Hellwig]

Switch everyone to blk_get_request_flags, and then rename
blk_get_request_flags to blk_get_request.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/blk-core.c                   | 14 +++-----------
 block/bsg.c                        |  5 ++---
 block/scsi_ioctl.c                 |  8 +++-----
 drivers/block/paride/pd.c          |  2 +-
 drivers/block/pktcdvd.c            |  2 +-
 drivers/block/sx8.c                |  2 +-
 drivers/block/virtio_blk.c         |  2 +-
 drivers/cdrom/cdrom.c              |  2 +-
 drivers/ide/ide-atapi.c            |  2 +-
 drivers/ide/ide-cd.c               |  2 +-
 drivers/ide/ide-cd_ioctl.c         |  2 +-
 drivers/ide/ide-devsets.c          |  2 +-
 drivers/ide/ide-disk.c             |  2 +-
 drivers/ide/ide-ioctls.c           |  4 ++--
 drivers/ide/ide-park.c             |  4 ++--
 drivers/ide/ide-pm.c               |  5 ++---
 drivers/ide/ide-tape.c             |  2 +-
 drivers/ide/ide-taskfile.c         |  2 +-
 drivers/md/dm-mpath.c              |  3 ++-
 drivers/mmc/core/block.c           | 12 +++++-------
 drivers/scsi/osd/osd_initiator.c   |  2 +-
 drivers/scsi/osst.c                |  2 +-
 drivers/scsi/scsi_error.c          |  2 +-
 drivers/scsi/scsi_lib.c            |  2 +-
 drivers/scsi/sg.c                  |  2 +-
 drivers/scsi/st.c                  |  2 +-
 drivers/target/target_core_pscsi.c |  3 +--
 fs/nfsd/blocklayout.c              |  2 +-
 include/linux/blkdev.h             |  5 +----
 29 files changed, 42 insertions(+), 59 deletions(-)

diff --git a/block/blk-core.c b/block/blk-core.c
index abde22c755ab..9002b4b34930 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1606,13 +1606,13 @@ static struct request *blk_old_get_request(struct request_queue *q,
 }
 
 /**
- * blk_get_request_flags - allocate a request
+ * blk_get_request - allocate a request
  * @q: request queue to allocate a request for
  * @op: operation (REQ_OP_*) and REQ_* flags, e.g. REQ_SYNC.
  * @flags: BLK_MQ_REQ_* flags, e.g. BLK_MQ_REQ_NOWAIT.
  */
-struct request *blk_get_request_flags(struct request_queue *q, unsigned int op,
-				      blk_mq_req_flags_t flags)
+struct request *blk_get_request(struct request_queue *q, unsigned int op,
+				blk_mq_req_flags_t flags)
 {
 	struct request *req;
 
@@ -1631,14 +1631,6 @@ struct request *blk_get_request_flags(struct request_queue *q, unsigned int op,
 
 	return req;
 }
-EXPORT_SYMBOL(blk_get_request_flags);
-
-struct request *blk_get_request(struct request_queue *q, unsigned int op,
-				gfp_t gfp_mask)
-{
-	return blk_get_request_flags(q, op, gfp_mask & __GFP_DIRECT_RECLAIM ?
-				     0 : BLK_MQ_REQ_NOWAIT);
-}
 EXPORT_SYMBOL(blk_get_request);
 
 /**
diff --git a/block/bsg.c b/block/bsg.c
index defa06c11858..30876c5fbf15 100644
--- a/block/bsg.c
+++ b/block/bsg.c
@@ -226,8 +226,7 @@ bsg_map_hdr(struct request_queue *q, struct sg_io_v4 *hdr, fmode_t mode)
 		return ERR_PTR(ret);
 
 	rq = blk_get_request(q, hdr->dout_xfer_len ?
-			REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN,
-			GFP_KERNEL);
+			REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN, 0);
 	if (IS_ERR(rq))
 		return rq;
 
@@ -249,7 +248,7 @@ bsg_map_hdr(struct request_queue *q, struct sg_io_v4 *hdr, fmode_t mode)
 			goto out;
 		}
 
-		next_rq = blk_get_request(q, REQ_OP_SCSI_IN, GFP_KERNEL);
+		next_rq = blk_get_request(q, REQ_OP_SCSI_IN, 0);
 		if (IS_ERR(next_rq)) {
 			ret = PTR_ERR(next_rq);
 			goto out;
diff --git a/block/scsi_ioctl.c b/block/scsi_ioctl.c
index 60b471f8621b..04b54f9a4152 100644
--- a/block/scsi_ioctl.c
+++ b/block/scsi_ioctl.c
@@ -321,8 +321,7 @@ static int sg_io(struct request_queue *q, struct gendisk *bd_disk,
 		at_head = 1;
 
 	ret = -ENOMEM;
-	rq = blk_get_request(q, writing ? REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN,
-			GFP_KERNEL);
+	rq = blk_get_request(q, writing ? REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN, 0);
 	if (IS_ERR(rq))
 		return PTR_ERR(rq);
 	req = scsi_req(rq);
@@ -449,8 +448,7 @@ int sg_scsi_ioctl(struct request_queue *q, struct gendisk *disk, fmode_t mode,
 
 	}
 
-	rq = blk_get_request(q, in_len ? REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN,
-			__GFP_RECLAIM);
+	rq = blk_get_request(q, in_len ? REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN, 0);
 	if (IS_ERR(rq)) {
 		err = PTR_ERR(rq);
 		goto error_free_buffer;
@@ -538,7 +536,7 @@ static int __blk_send_generic(struct request_queue *q, struct gendisk *bd_disk,
 	struct request *rq;
 	int err;
 
-	rq = blk_get_request(q, REQ_OP_SCSI_OUT, __GFP_RECLAIM);
+	rq = blk_get_request(q, REQ_OP_SCSI_OUT, 0);
 	if (IS_ERR(rq))
 		return PTR_ERR(rq);
 	rq->timeout = BLK_DEFAULT_SG_TIMEOUT;
diff --git a/drivers/block/paride/pd.c b/drivers/block/paride/pd.c
index 27a44b97393a..8961b190e256 100644
--- a/drivers/block/paride/pd.c
+++ b/drivers/block/paride/pd.c
@@ -740,7 +740,7 @@ static int pd_special_command(struct pd_unit *disk,
 {
 	struct request *rq;
 
-	rq = blk_get_request(disk->gd->queue, REQ_OP_DRV_IN, __GFP_RECLAIM);
+	rq = blk_get_request(disk->gd->queue, REQ_OP_DRV_IN, 0);
 	if (IS_ERR(rq))
 		return PTR_ERR(rq);
 
diff --git a/drivers/block/pktcdvd.c b/drivers/block/pktcdvd.c
index c61d20c9f3f8..4880a4a9f52d 100644
--- a/drivers/block/pktcdvd.c
+++ b/drivers/block/pktcdvd.c
@@ -704,7 +704,7 @@ static int pkt_generic_packet(struct pktcdvd_device *pd, struct packet_command *
 	int ret = 0;
 
 	rq = blk_get_request(q, (cgc->data_direction == CGC_DATA_WRITE) ?
-			     REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN, __GFP_RECLAIM);
+			     REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN, 0);
 	if (IS_ERR(rq))
 		return PTR_ERR(rq);
 
diff --git a/drivers/block/sx8.c b/drivers/block/sx8.c
index 08586dc14e85..4d90e5eba2f5 100644
--- a/drivers/block/sx8.c
+++ b/drivers/block/sx8.c
@@ -567,7 +567,7 @@ static struct carm_request *carm_get_special(struct carm_host *host)
 	if (!crq)
 		return NULL;
 
-	rq = blk_get_request(host->oob_q, REQ_OP_DRV_OUT, GFP_KERNEL);
+	rq = blk_get_request(host->oob_q, REQ_OP_DRV_OUT, 0);
 	if (IS_ERR(rq)) {
 		spin_lock_irqsave(&host->lock, flags);
 		carm_put_request(host, crq);
diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index 4a07593c2efd..0617b9922d59 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -298,7 +298,7 @@ static int virtblk_get_id(struct gendisk *disk, char *id_str)
 	struct request *req;
 	int err;
 
-	req = blk_get_request(q, REQ_OP_DRV_IN, GFP_KERNEL);
+	req = blk_get_request(q, REQ_OP_DRV_IN, 0);
 	if (IS_ERR(req))
 		return PTR_ERR(req);
 
diff --git a/drivers/cdrom/cdrom.c b/drivers/cdrom/cdrom.c
index 8327478effd0..4525700c023d 100644
--- a/drivers/cdrom/cdrom.c
+++ b/drivers/cdrom/cdrom.c
@@ -2192,7 +2192,7 @@ static int cdrom_read_cdda_bpc(struct cdrom_device_info *cdi, __u8 __user *ubuf,
 
 		len = nr * CD_FRAMESIZE_RAW;
 
-		rq = blk_get_request(q, REQ_OP_SCSI_IN, GFP_KERNEL);
+		rq = blk_get_request(q, REQ_OP_SCSI_IN, 0);
 		if (IS_ERR(rq)) {
 			ret = PTR_ERR(rq);
 			break;
diff --git a/drivers/ide/ide-atapi.c b/drivers/ide/ide-atapi.c
index 0e6bc631a1ca..8b2b72b93885 100644
--- a/drivers/ide/ide-atapi.c
+++ b/drivers/ide/ide-atapi.c
@@ -92,7 +92,7 @@ int ide_queue_pc_tail(ide_drive_t *drive, struct gendisk *disk,
 	struct request *rq;
 	int error;
 
-	rq = blk_get_request(drive->queue, REQ_OP_DRV_IN, __GFP_RECLAIM);
+	rq = blk_get_request(drive->queue, REQ_OP_DRV_IN, 0);
 	ide_req(rq)->type = ATA_PRIV_MISC;
 	rq->special = (char *)pc;
 
diff --git a/drivers/ide/ide-cd.c b/drivers/ide/ide-cd.c
index 5a8e8e3c22cd..32af6f063cb3 100644
--- a/drivers/ide/ide-cd.c
+++ b/drivers/ide/ide-cd.c
@@ -437,7 +437,7 @@ int ide_cd_queue_pc(ide_drive_t *drive, const unsigned char *cmd,
 		bool delay = false;
 
 		rq = blk_get_request(drive->queue,
-			write ? REQ_OP_DRV_OUT : REQ_OP_DRV_IN,  __GFP_RECLAIM);
+			write ? REQ_OP_DRV_OUT : REQ_OP_DRV_IN, 0);
 		memcpy(scsi_req(rq)->cmd, cmd, BLK_MAX_CDB);
 		ide_req(rq)->type = ATA_PRIV_PC;
 		rq->rq_flags |= rq_flags;
diff --git a/drivers/ide/ide-cd_ioctl.c b/drivers/ide/ide-cd_ioctl.c
index 2acca12b9c94..b1322400887b 100644
--- a/drivers/ide/ide-cd_ioctl.c
+++ b/drivers/ide/ide-cd_ioctl.c
@@ -304,7 +304,7 @@ int ide_cdrom_reset(struct cdrom_device_info *cdi)
 	struct request *rq;
 	int ret;
 
-	rq = blk_get_request(drive->queue, REQ_OP_DRV_IN, __GFP_RECLAIM);
+	rq = blk_get_request(drive->queue, REQ_OP_DRV_IN, 0);
 	ide_req(rq)->type = ATA_PRIV_MISC;
 	rq->rq_flags = RQF_QUIET;
 	blk_execute_rq(drive->queue, cd->disk, rq, 0);
diff --git a/drivers/ide/ide-devsets.c b/drivers/ide/ide-devsets.c
index 4e20747af32e..f4f8afdf8bbe 100644
--- a/drivers/ide/ide-devsets.c
+++ b/drivers/ide/ide-devsets.c
@@ -166,7 +166,7 @@ int ide_devset_execute(ide_drive_t *drive, const struct ide_devset *setting,
 	if (!(setting->flags & DS_SYNC))
 		return setting->set(drive, arg);
 
-	rq = blk_get_request(q, REQ_OP_DRV_IN, __GFP_RECLAIM);
+	rq = blk_get_request(q, REQ_OP_DRV_IN, 0);
 	ide_req(rq)->type = ATA_PRIV_MISC;
 	scsi_req(rq)->cmd_len = 5;
 	scsi_req(rq)->cmd[0] = REQ_DEVSET_EXEC;
diff --git a/drivers/ide/ide-disk.c b/drivers/ide/ide-disk.c
index f1a7c58fe418..e3b4e659082d 100644
--- a/drivers/ide/ide-disk.c
+++ b/drivers/ide/ide-disk.c
@@ -478,7 +478,7 @@ static int set_multcount(ide_drive_t *drive, int arg)
 	if (drive->special_flags & IDE_SFLAG_SET_MULTMODE)
 		return -EBUSY;
 
-	rq = blk_get_request(drive->queue, REQ_OP_DRV_IN, __GFP_RECLAIM);
+	rq = blk_get_request(drive->queue, REQ_OP_DRV_IN, 0);
 	ide_req(rq)->type = ATA_PRIV_TASKFILE;
 
 	drive->mult_req = arg;
diff --git a/drivers/ide/ide-ioctls.c b/drivers/ide/ide-ioctls.c
index 3661abb16a5f..af5119a73689 100644
--- a/drivers/ide/ide-ioctls.c
+++ b/drivers/ide/ide-ioctls.c
@@ -125,7 +125,7 @@ static int ide_cmd_ioctl(ide_drive_t *drive, unsigned long arg)
 	if (NULL == (void *) arg) {
 		struct request *rq;
 
-		rq = blk_get_request(drive->queue, REQ_OP_DRV_IN, __GFP_RECLAIM);
+		rq = blk_get_request(drive->queue, REQ_OP_DRV_IN, 0);
 		ide_req(rq)->type = ATA_PRIV_TASKFILE;
 		blk_execute_rq(drive->queue, NULL, rq, 0);
 		err = scsi_req(rq)->result ? -EIO : 0;
@@ -222,7 +222,7 @@ static int generic_drive_reset(ide_drive_t *drive)
 	struct request *rq;
 	int ret = 0;
 
-	rq = blk_get_request(drive->queue, REQ_OP_DRV_IN, __GFP_RECLAIM);
+	rq = blk_get_request(drive->queue, REQ_OP_DRV_IN, 0);
 	ide_req(rq)->type = ATA_PRIV_MISC;
 	scsi_req(rq)->cmd_len = 1;
 	scsi_req(rq)->cmd[0] = REQ_DRIVE_RESET;
diff --git a/drivers/ide/ide-park.c b/drivers/ide/ide-park.c
index 6465bcc7cea6..622f0edb3945 100644
--- a/drivers/ide/ide-park.c
+++ b/drivers/ide/ide-park.c
@@ -32,7 +32,7 @@ static void issue_park_cmd(ide_drive_t *drive, unsigned long timeout)
 	}
 	spin_unlock_irq(&hwif->lock);
 
-	rq = blk_get_request(q, REQ_OP_DRV_IN, __GFP_RECLAIM);
+	rq = blk_get_request(q, REQ_OP_DRV_IN, 0);
 	scsi_req(rq)->cmd[0] = REQ_PARK_HEADS;
 	scsi_req(rq)->cmd_len = 1;
 	ide_req(rq)->type = ATA_PRIV_MISC;
@@ -47,7 +47,7 @@ static void issue_park_cmd(ide_drive_t *drive, unsigned long timeout)
 	 * Make sure that *some* command is sent to the drive after the
 	 * timeout has expired, so power management will be reenabled.
 	 */
-	rq = blk_get_request(q, REQ_OP_DRV_IN, GFP_NOWAIT);
+	rq = blk_get_request(q, REQ_OP_DRV_IN, BLK_MQ_REQ_NOWAIT);
 	if (IS_ERR(rq))
 		goto out;
 
diff --git a/drivers/ide/ide-pm.c b/drivers/ide/ide-pm.c
index ad8a125defdd..59217aa1d1fb 100644
--- a/drivers/ide/ide-pm.c
+++ b/drivers/ide/ide-pm.c
@@ -19,7 +19,7 @@ int generic_ide_suspend(struct device *dev, pm_message_t mesg)
 	}
 
 	memset(&rqpm, 0, sizeof(rqpm));
-	rq = blk_get_request(drive->queue, REQ_OP_DRV_IN, __GFP_RECLAIM);
+	rq = blk_get_request(drive->queue, REQ_OP_DRV_IN, 0);
 	ide_req(rq)->type = ATA_PRIV_PM_SUSPEND;
 	rq->special = &rqpm;
 	rqpm.pm_step = IDE_PM_START_SUSPEND;
@@ -90,8 +90,7 @@ int generic_ide_resume(struct device *dev)
 	}
 
 	memset(&rqpm, 0, sizeof(rqpm));
-	rq = blk_get_request_flags(drive->queue, REQ_OP_DRV_IN,
-				   BLK_MQ_REQ_PREEMPT);
+	rq = blk_get_request(drive->queue, REQ_OP_DRV_IN, BLK_MQ_REQ_PREEMPT);
 	ide_req(rq)->type = ATA_PRIV_PM_RESUME;
 	rq->special = &rqpm;
 	rqpm.pm_step = IDE_PM_START_RESUME;
diff --git a/drivers/ide/ide-tape.c b/drivers/ide/ide-tape.c
index fd57e8ccc47a..66661031f3f1 100644
--- a/drivers/ide/ide-tape.c
+++ b/drivers/ide/ide-tape.c
@@ -854,7 +854,7 @@ static int idetape_queue_rw_tail(ide_drive_t *drive, int cmd, int size)
 	BUG_ON(cmd != REQ_IDETAPE_READ && cmd != REQ_IDETAPE_WRITE);
 	BUG_ON(size < 0 || size % tape->blk_size);
 
-	rq = blk_get_request(drive->queue, REQ_OP_DRV_IN, __GFP_RECLAIM);
+	rq = blk_get_request(drive->queue, REQ_OP_DRV_IN, 0);
 	ide_req(rq)->type = ATA_PRIV_MISC;
 	scsi_req(rq)->cmd[13] = cmd;
 	rq->rq_disk = tape->disk;
diff --git a/drivers/ide/ide-taskfile.c b/drivers/ide/ide-taskfile.c
index abe0822dd429..6308bb0dab50 100644
--- a/drivers/ide/ide-taskfile.c
+++ b/drivers/ide/ide-taskfile.c
@@ -431,7 +431,7 @@ int ide_raw_taskfile(ide_drive_t *drive, struct ide_cmd *cmd, u8 *buf,
 
 	rq = blk_get_request(drive->queue,
 		(cmd->tf_flags & IDE_TFLAG_WRITE) ?
-			REQ_OP_DRV_OUT : REQ_OP_DRV_IN, __GFP_RECLAIM);
+			REQ_OP_DRV_OUT : REQ_OP_DRV_IN, 0);
 	ide_req(rq)->type = ATA_PRIV_TASKFILE;
 
 	/*
diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index 203a0419d2b0..d94ba6f72ff5 100644
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -520,7 +520,8 @@ static int multipath_clone_and_map(struct dm_target *ti, struct request *rq,
 
 	bdev = pgpath->path.dev->bdev;
 	q = bdev_get_queue(bdev);
-	clone = blk_get_request(q, rq->cmd_flags | REQ_NOMERGE, GFP_ATOMIC);
+	clone = blk_get_request(q, rq->cmd_flags | REQ_NOMERGE,
+			BLK_MQ_REQ_NOWAIT);
 	if (IS_ERR(clone)) {
 		/* EBUSY, ENODEV or EWOULDBLOCK: requeue */
 		if (blk_queue_dying(q)) {
diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c
index 02485e310c81..f5fe574e0a98 100644
--- a/drivers/mmc/core/block.c
+++ b/drivers/mmc/core/block.c
@@ -244,7 +244,7 @@ static ssize_t power_ro_lock_store(struct device *dev,
 	mq = &md->queue;
 
 	/* Dispatch locking to the block layer */
-	req = blk_get_request(mq->queue, REQ_OP_DRV_OUT, __GFP_RECLAIM);
+	req = blk_get_request(mq->queue, REQ_OP_DRV_OUT, 0);
 	if (IS_ERR(req)) {
 		count = PTR_ERR(req);
 		goto out_put;
@@ -650,8 +650,7 @@ static int mmc_blk_ioctl_cmd(struct mmc_blk_data *md,
 	 */
 	mq = &md->queue;
 	req = blk_get_request(mq->queue,
-		idata->ic.write_flag ? REQ_OP_DRV_OUT : REQ_OP_DRV_IN,
-		__GFP_RECLAIM);
+		idata->ic.write_flag ? REQ_OP_DRV_OUT : REQ_OP_DRV_IN, 0);
 	if (IS_ERR(req)) {
 		err = PTR_ERR(req);
 		goto cmd_done;
@@ -721,8 +720,7 @@ static int mmc_blk_ioctl_multi_cmd(struct mmc_blk_data *md,
 	 */
 	mq = &md->queue;
 	req = blk_get_request(mq->queue,
-		idata[0]->ic.write_flag ? REQ_OP_DRV_OUT : REQ_OP_DRV_IN,
-		__GFP_RECLAIM);
+		idata[0]->ic.write_flag ? REQ_OP_DRV_OUT : REQ_OP_DRV_IN, 0);
 	if (IS_ERR(req)) {
 		err = PTR_ERR(req);
 		goto cmd_err;
@@ -2750,7 +2748,7 @@ static int mmc_dbg_card_status_get(void *data, u64 *val)
 	int ret;
 
 	/* Ask the block layer about the card status */
-	req = blk_get_request(mq->queue, REQ_OP_DRV_IN, __GFP_RECLAIM);
+	req = blk_get_request(mq->queue, REQ_OP_DRV_IN, 0);
 	if (IS_ERR(req))
 		return PTR_ERR(req);
 	req_to_mmc_queue_req(req)->drv_op = MMC_DRV_OP_GET_CARD_STATUS;
@@ -2786,7 +2784,7 @@ static int mmc_ext_csd_open(struct inode *inode, struct file *filp)
 		return -ENOMEM;
 
 	/* Ask the block layer for the EXT CSD */
-	req = blk_get_request(mq->queue, REQ_OP_DRV_IN, __GFP_RECLAIM);
+	req = blk_get_request(mq->queue, REQ_OP_DRV_IN, 0);
 	if (IS_ERR(req)) {
 		err = PTR_ERR(req);
 		goto out_free;
diff --git a/drivers/scsi/osd/osd_initiator.c b/drivers/scsi/osd/osd_initiator.c
index f48bae267dc2..5a33e1ad9881 100644
--- a/drivers/scsi/osd/osd_initiator.c
+++ b/drivers/scsi/osd/osd_initiator.c
@@ -1570,7 +1570,7 @@ static struct request *_make_request(struct request_queue *q, bool has_write,
 	int ret;
 
 	req = blk_get_request(q, has_write ? REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN,
-			GFP_KERNEL);
+			0);
 	if (IS_ERR(req))
 		return req;
 
diff --git a/drivers/scsi/osst.c b/drivers/scsi/osst.c
index 20ec1c01dbd5..2bbe797f8c3d 100644
--- a/drivers/scsi/osst.c
+++ b/drivers/scsi/osst.c
@@ -368,7 +368,7 @@ static int osst_execute(struct osst_request *SRpnt, const unsigned char *cmd,
 	int write = (data_direction == DMA_TO_DEVICE);
 
 	req = blk_get_request(SRpnt->stp->device->request_queue,
-			write ? REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN, GFP_KERNEL);
+			write ? REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN, 0);
 	if (IS_ERR(req))
 		return DRIVER_ERROR << 24;
 
diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
index 946039117bf4..61d280f560df 100644
--- a/drivers/scsi/scsi_error.c
+++ b/drivers/scsi/scsi_error.c
@@ -1937,7 +1937,7 @@ static void scsi_eh_lock_door(struct scsi_device *sdev)
 	 * blk_get_request with GFP_KERNEL (__GFP_RECLAIM) sleeps until a
 	 * request becomes available
 	 */
-	req = blk_get_request(sdev->request_queue, REQ_OP_SCSI_IN, GFP_KERNEL);
+	req = blk_get_request(sdev->request_queue, REQ_OP_SCSI_IN, 0);
 	if (IS_ERR(req))
 		return;
 	rq = scsi_req(req);
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 0dfec0dedd5e..93cb1a9b6671 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -265,7 +265,7 @@ int scsi_execute(struct scsi_device *sdev, const unsigned char *cmd,
 	struct scsi_request *rq;
 	int ret = DRIVER_ERROR << 24;
 
-	req = blk_get_request_flags(sdev->request_queue,
+	req = blk_get_request(sdev->request_queue,
 			data_direction == DMA_TO_DEVICE ?
 			REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN, BLK_MQ_REQ_PREEMPT);
 	if (IS_ERR(req))
diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
index c198b96368dd..0512648ebc8e 100644
--- a/drivers/scsi/sg.c
+++ b/drivers/scsi/sg.c
@@ -1715,7 +1715,7 @@ sg_start_req(Sg_request *srp, unsigned char *cmd)
 	 * does not sleep except under memory pressure.
 	 */
 	rq = blk_get_request(q, hp->dxfer_direction == SG_DXFER_TO_DEV ?
-			REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN, GFP_KERNEL);
+			REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN, 0);
 	if (IS_ERR(rq)) {
 		kfree(long_cmdp);
 		return PTR_ERR(rq);
diff --git a/drivers/scsi/st.c b/drivers/scsi/st.c
index 6c399480783d..a427ce9497be 100644
--- a/drivers/scsi/st.c
+++ b/drivers/scsi/st.c
@@ -545,7 +545,7 @@ static int st_scsi_execute(struct st_request *SRpnt, const unsigned char *cmd,
 
 	req = blk_get_request(SRpnt->stp->device->request_queue,
 			data_direction == DMA_TO_DEVICE ?
-			REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN, GFP_KERNEL);
+			REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN, 0);
 	if (IS_ERR(req))
 		return DRIVER_ERROR << 24;
 	rq = scsi_req(req);
diff --git a/drivers/target/target_core_pscsi.c b/drivers/target/target_core_pscsi.c
index 0d99b242e82e..e0324314ba96 100644
--- a/drivers/target/target_core_pscsi.c
+++ b/drivers/target/target_core_pscsi.c
@@ -984,8 +984,7 @@ pscsi_execute_cmd(struct se_cmd *cmd)
 
 	req = blk_get_request(pdv->pdv_sd->request_queue,
 			cmd->data_direction == DMA_TO_DEVICE ?
-			REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN,
-			GFP_KERNEL);
+			REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN, 0);
 	if (IS_ERR(req)) {
 		pr_err("PSCSI: blk_get_request() failed\n");
 		ret = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
diff --git a/fs/nfsd/blocklayout.c b/fs/nfsd/blocklayout.c
index 70b8bf781fce..a43dfedd69ec 100644
--- a/fs/nfsd/blocklayout.c
+++ b/fs/nfsd/blocklayout.c
@@ -227,7 +227,7 @@ static int nfsd4_scsi_identify_device(struct block_device *bdev,
 	if (!buf)
 		return -ENOMEM;
 
-	rq = blk_get_request(q, REQ_OP_SCSI_IN, GFP_KERNEL);
+	rq = blk_get_request(q, REQ_OP_SCSI_IN, 0);
 	if (IS_ERR(rq)) {
 		error = -ENOMEM;
 		goto out_free_buf;
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 9af3e0f430bc..5193b8bb1feb 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -961,11 +961,8 @@ extern void blk_rq_init(struct request_queue *q, struct request *rq);
 extern void blk_init_request_from_bio(struct request *req, struct bio *bio);
 extern void blk_put_request(struct request *);
 extern void __blk_put_request(struct request_queue *, struct request *);
-extern struct request *blk_get_request_flags(struct request_queue *,
-					     unsigned int op,
-					     blk_mq_req_flags_t flags);
 extern struct request *blk_get_request(struct request_queue *, unsigned int op,
-				       gfp_t gfp_mask);
+				       blk_mq_req_flags_t flags);
 extern void blk_requeue_request(struct request_queue *, struct request *);
 extern int blk_lld_busy(struct request_queue *q);
 extern int blk_rq_prep_clone(struct request *rq, struct request *rq_src,
-- 
2.16.3

Re: [PATCH 3/7] block: sanitize blk_get_request calling conventions

[Hannes Reinecke]

On Mon,  9 Apr 2018 17:39:12 +0200
Christoph Hellwig <hch@lst.de> wrote:

> Switch everyone to blk_get_request_flags, and then rename
> blk_get_request_flags to blk_get_request.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>  block/blk-core.c                   | 14 +++-----------
>  block/bsg.c                        |  5 ++---
>  block/scsi_ioctl.c                 |  8 +++-----
>  drivers/block/paride/pd.c          |  2 +-
>  drivers/block/pktcdvd.c            |  2 +-
>  drivers/block/sx8.c                |  2 +-
>  drivers/block/virtio_blk.c         |  2 +-
>  drivers/cdrom/cdrom.c              |  2 +-
>  drivers/ide/ide-atapi.c            |  2 +-
>  drivers/ide/ide-cd.c               |  2 +-
>  drivers/ide/ide-cd_ioctl.c         |  2 +-
>  drivers/ide/ide-devsets.c          |  2 +-
>  drivers/ide/ide-disk.c             |  2 +-
>  drivers/ide/ide-ioctls.c           |  4 ++--
>  drivers/ide/ide-park.c             |  4 ++--
>  drivers/ide/ide-pm.c               |  5 ++---
>  drivers/ide/ide-tape.c             |  2 +-
>  drivers/ide/ide-taskfile.c         |  2 +-
>  drivers/md/dm-mpath.c              |  3 ++-
>  drivers/mmc/core/block.c           | 12 +++++-------
>  drivers/scsi/osd/osd_initiator.c   |  2 +-
>  drivers/scsi/osst.c                |  2 +-
>  drivers/scsi/scsi_error.c          |  2 +-
>  drivers/scsi/scsi_lib.c            |  2 +-
>  drivers/scsi/sg.c                  |  2 +-
>  drivers/scsi/st.c                  |  2 +-
>  drivers/target/target_core_pscsi.c |  3 +--
>  fs/nfsd/blocklayout.c              |  2 +-
>  include/linux/blkdev.h             |  5 +----
>  29 files changed, 42 insertions(+), 59 deletions(-)
> 
Long overdue.

Reviewed-by: Hannes Reinecke <hare@suse.com>

Cheers,

Hannes

[PATCH 4/7] block: pass explicit gfp_t to get_request

[Christoph Hellwig]

blk_old_get_request already has it at hand, and in blk_queue_bio, which
is the fast path, it is constant.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/blk-core.c          | 14 +++++++-------
 drivers/scsi/scsi_error.c |  4 ----
 2 files changed, 7 insertions(+), 11 deletions(-)

diff --git a/block/blk-core.c b/block/blk-core.c
index 9002b4b34930..16ff472233ba 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1333,6 +1333,7 @@ int blk_update_nr_requests(struct request_queue *q, unsigned int nr)
  * @op: operation and flags
  * @bio: bio to allocate request for (can be %NULL)
  * @flags: BLQ_MQ_REQ_* flags
+ * @gfp_mask: allocator flags
  *
  * Get a free request from @q.  This function may fail under memory
  * pressure or if @q is dead.
@@ -1342,7 +1343,7 @@ int blk_update_nr_requests(struct request_queue *q, unsigned int nr)
  * Returns request pointer on success, with @q->queue_lock *not held*.
  */
 static struct request *__get_request(struct request_list *rl, unsigned int op,
-				     struct bio *bio, blk_mq_req_flags_t flags)
+		struct bio *bio, blk_mq_req_flags_t flags, gfp_t gfp_mask)
 {
 	struct request_queue *q = rl->q;
 	struct request *rq;
@@ -1351,8 +1352,6 @@ static struct request *__get_request(struct request_list *rl, unsigned int op,
 	struct io_cq *icq = NULL;
 	const bool is_sync = op_is_sync(op);
 	int may_queue;
-	gfp_t gfp_mask = flags & BLK_MQ_REQ_NOWAIT ? GFP_ATOMIC :
-			 __GFP_DIRECT_RECLAIM;
 	req_flags_t rq_flags = RQF_ALLOCED;
 
 	lockdep_assert_held(q->queue_lock);
@@ -1516,6 +1515,7 @@ static struct request *__get_request(struct request_list *rl, unsigned int op,
  * @op: operation and flags
  * @bio: bio to allocate request for (can be %NULL)
  * @flags: BLK_MQ_REQ_* flags.
+ * @gfp: allocator flags
  *
  * Get a free request from @q.  If %BLK_MQ_REQ_NOWAIT is set in @flags,
  * this function keeps retrying under memory pressure and fails iff @q is dead.
@@ -1525,7 +1525,7 @@ static struct request *__get_request(struct request_list *rl, unsigned int op,
  * Returns request pointer on success, with @q->queue_lock *not held*.
  */
 static struct request *get_request(struct request_queue *q, unsigned int op,
-				   struct bio *bio, blk_mq_req_flags_t flags)
+		struct bio *bio, blk_mq_req_flags_t flags, gfp_t gfp)
 {
 	const bool is_sync = op_is_sync(op);
 	DEFINE_WAIT(wait);
@@ -1537,7 +1537,7 @@ static struct request *get_request(struct request_queue *q, unsigned int op,
 
 	rl = blk_get_rl(q, bio);	/* transferred to @rq on success */
 retry:
-	rq = __get_request(rl, op, bio, flags);
+	rq = __get_request(rl, op, bio, flags, gfp);
 	if (!IS_ERR(rq))
 		return rq;
 
@@ -1591,7 +1591,7 @@ static struct request *blk_old_get_request(struct request_queue *q,
 	if (ret)
 		return ERR_PTR(ret);
 	spin_lock_irq(q->queue_lock);
-	rq = get_request(q, op, NULL, flags);
+	rq = get_request(q, op, NULL, flags, gfp_mask);
 	if (IS_ERR(rq)) {
 		spin_unlock_irq(q->queue_lock);
 		blk_queue_exit(q);
@@ -2057,7 +2057,7 @@ static blk_qc_t blk_queue_bio(struct request_queue *q, struct bio *bio)
 	 * Returns with the queue unlocked.
 	 */
 	blk_queue_enter_live(q);
-	req = get_request(q, bio->bi_opf, bio, 0);
+	req = get_request(q, bio->bi_opf, bio, 0, __GFP_DIRECT_RECLAIM);
 	if (IS_ERR(req)) {
 		blk_queue_exit(q);
 		__wbt_done(q->rq_wb, wb_acct);
diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
index 61d280f560df..b36e73090018 100644
--- a/drivers/scsi/scsi_error.c
+++ b/drivers/scsi/scsi_error.c
@@ -1933,10 +1933,6 @@ static void scsi_eh_lock_door(struct scsi_device *sdev)
 	struct request *req;
 	struct scsi_request *rq;
 
-	/*
-	 * blk_get_request with GFP_KERNEL (__GFP_RECLAIM) sleeps until a
-	 * request becomes available
-	 */
 	req = blk_get_request(sdev->request_queue, REQ_OP_SCSI_IN, 0);
 	if (IS_ERR(req))
 		return;
-- 
2.16.3

Re: [PATCH 4/7] block: pass explicit gfp_t to get_request

[Hannes Reinecke]

On Mon,  9 Apr 2018 17:39:13 +0200
Christoph Hellwig <hch@lst.de> wrote:

> blk_old_get_request already has it at hand, and in blk_queue_bio,
> which is the fast path, it is constant.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>  block/blk-core.c          | 14 +++++++-------
>  drivers/scsi/scsi_error.c |  4 ----
>  2 files changed, 7 insertions(+), 11 deletions(-)
> 
Reviewed-by: Hannes Reinecke <hare@suse.com>

Cheers,

Hannes

[PATCH 5/7] block: use GFP_NOIO instead of __GFP_DIRECT_RECLAIM

[Christoph Hellwig]

We just can't do I/O when doing block layer requests allocations,
so use GFP_NOIO instead of the even more limited __GFP_DIRECT_RECLAIM.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/blk-core.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/block/blk-core.c b/block/blk-core.c
index 16ff472233ba..432923751551 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1578,8 +1578,7 @@ static struct request *blk_old_get_request(struct request_queue *q,
 				unsigned int op, blk_mq_req_flags_t flags)
 {
 	struct request *rq;
-	gfp_t gfp_mask = flags & BLK_MQ_REQ_NOWAIT ? GFP_ATOMIC :
-			 __GFP_DIRECT_RECLAIM;
+	gfp_t gfp_mask = flags & BLK_MQ_REQ_NOWAIT ? GFP_ATOMIC : GFP_NOIO;
 	int ret = 0;
 
 	WARN_ON_ONCE(q->mq_ops);
@@ -2057,7 +2056,7 @@ static blk_qc_t blk_queue_bio(struct request_queue *q, struct bio *bio)
 	 * Returns with the queue unlocked.
 	 */
 	blk_queue_enter_live(q);
-	req = get_request(q, bio->bi_opf, bio, 0, __GFP_DIRECT_RECLAIM);
+	req = get_request(q, bio->bi_opf, bio, 0, GFP_NOIO);
 	if (IS_ERR(req)) {
 		blk_queue_exit(q);
 		__wbt_done(q->rq_wb, wb_acct);
-- 
2.16.3

Re: [PATCH 5/7] block: use GFP_NOIO instead of __GFP_DIRECT_RECLAIM

[Hannes Reinecke]

On Mon,  9 Apr 2018 17:39:14 +0200
Christoph Hellwig <hch@lst.de> wrote:

> We just can't do I/O when doing block layer requests allocations,
> so use GFP_NOIO instead of the even more limited __GFP_DIRECT_RECLAIM.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>  block/blk-core.c | 5 ++---
>  1 file changed, 2 insertions(+), 3 deletions(-)
> 

Reviewed-by: Hannes Reinecke <hare@suse.com>

Cheers,

Hannes

[PATCH 6/7] block: consistently use GFP_NOIO instead of __GFP_NORECLAIM

[Christoph Hellwig]

Same numerical value (for now at least), but a much better documentation
of intent.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/scsi_ioctl.c               |  2 +-
 drivers/block/drbd/drbd_bitmap.c |  3 ++-
 drivers/block/pktcdvd.c          |  2 +-
 drivers/ide/ide-tape.c           |  2 +-
 drivers/ide/ide-taskfile.c       |  2 +-
 drivers/scsi/scsi_lib.c          |  2 +-
 fs/direct-io.c                   |  4 ++--
 kernel/power/swap.c              | 14 +++++++-------
 8 files changed, 16 insertions(+), 15 deletions(-)

diff --git a/block/scsi_ioctl.c b/block/scsi_ioctl.c
index 04b54f9a4152..533f4aee8567 100644
--- a/block/scsi_ioctl.c
+++ b/block/scsi_ioctl.c
@@ -499,7 +499,7 @@ int sg_scsi_ioctl(struct request_queue *q, struct gendisk *disk, fmode_t mode,
 		break;
 	}
 
-	if (bytes && blk_rq_map_kern(q, rq, buffer, bytes, __GFP_RECLAIM)) {
+	if (bytes && blk_rq_map_kern(q, rq, buffer, bytes, GFP_NOIO)) {
 		err = DRIVER_ERROR << 24;
 		goto error;
 	}
diff --git a/drivers/block/drbd/drbd_bitmap.c b/drivers/block/drbd/drbd_bitmap.c
index 9f4e6f502b84..d82237d534cf 100644
--- a/drivers/block/drbd/drbd_bitmap.c
+++ b/drivers/block/drbd/drbd_bitmap.c
@@ -1014,7 +1014,8 @@ static void bm_page_io_async(struct drbd_bm_aio_ctx *ctx, int page_nr) __must_ho
 	bm_set_page_unchanged(b->bm_pages[page_nr]);
 
 	if (ctx->flags & BM_AIO_COPY_PAGES) {
-		page = mempool_alloc(drbd_md_io_page_pool, __GFP_HIGHMEM|__GFP_RECLAIM);
+		page = mempool_alloc(drbd_md_io_page_pool,
+				GFP_NOIO | __GFP_HIGHMEM);
 		copy_highpage(page, b->bm_pages[page_nr]);
 		bm_store_page_idx(page, page_nr);
 	} else
diff --git a/drivers/block/pktcdvd.c b/drivers/block/pktcdvd.c
index 4880a4a9f52d..ccfcf544830f 100644
--- a/drivers/block/pktcdvd.c
+++ b/drivers/block/pktcdvd.c
@@ -710,7 +710,7 @@ static int pkt_generic_packet(struct pktcdvd_device *pd, struct packet_command *
 
 	if (cgc->buflen) {
 		ret = blk_rq_map_kern(q, rq, cgc->buffer, cgc->buflen,
-				      __GFP_RECLAIM);
+				      GFP_NOIO);
 		if (ret)
 			goto out;
 	}
diff --git a/drivers/ide/ide-tape.c b/drivers/ide/ide-tape.c
index 66661031f3f1..62c1a19a9aed 100644
--- a/drivers/ide/ide-tape.c
+++ b/drivers/ide/ide-tape.c
@@ -862,7 +862,7 @@ static int idetape_queue_rw_tail(ide_drive_t *drive, int cmd, int size)
 
 	if (size) {
 		ret = blk_rq_map_kern(drive->queue, rq, tape->buf, size,
-				      __GFP_RECLAIM);
+				      GFP_NOIO);
 		if (ret)
 			goto out_put;
 	}
diff --git a/drivers/ide/ide-taskfile.c b/drivers/ide/ide-taskfile.c
index 6308bb0dab50..c034cd965831 100644
--- a/drivers/ide/ide-taskfile.c
+++ b/drivers/ide/ide-taskfile.c
@@ -442,7 +442,7 @@ int ide_raw_taskfile(ide_drive_t *drive, struct ide_cmd *cmd, u8 *buf,
 	 */
 	if (nsect) {
 		error = blk_rq_map_kern(drive->queue, rq, buf,
-					nsect * SECTOR_SIZE, __GFP_RECLAIM);
+					nsect * SECTOR_SIZE, GFP_NOIO);
 		if (error)
 			goto put_req;
 	}
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 93cb1a9b6671..33d3bfa3e8ea 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -273,7 +273,7 @@ int scsi_execute(struct scsi_device *sdev, const unsigned char *cmd,
 	rq = scsi_req(req);
 
 	if (bufflen &&	blk_rq_map_kern(sdev->request_queue, req,
-					buffer, bufflen, __GFP_RECLAIM))
+					buffer, bufflen, GFP_NOIO))
 		goto out;
 
 	rq->cmd_len = COMMAND_SIZE(cmd[0]);
diff --git a/fs/direct-io.c b/fs/direct-io.c
index 874607bb6e02..093fb54cd316 100644
--- a/fs/direct-io.c
+++ b/fs/direct-io.c
@@ -432,8 +432,8 @@ dio_bio_alloc(struct dio *dio, struct dio_submit *sdio,
 	struct bio *bio;
 
 	/*
-	 * bio_alloc() is guaranteed to return a bio when called with
-	 * __GFP_RECLAIM and we request a valid number of vectors.
+	 * bio_alloc() is guaranteed to return a bio when allowed to sleep and
+	 * we request a valid number of vectors.
 	 */
 	bio = bio_alloc(GFP_KERNEL, nr_vecs);
 
diff --git a/kernel/power/swap.c b/kernel/power/swap.c
index 11b4282c2d20..1efcb5b0c3ed 100644
--- a/kernel/power/swap.c
+++ b/kernel/power/swap.c
@@ -269,7 +269,7 @@ static int hib_submit_io(int op, int op_flags, pgoff_t page_off, void *addr,
 	struct bio *bio;
 	int error = 0;
 
-	bio = bio_alloc(__GFP_RECLAIM | __GFP_HIGH, 1);
+	bio = bio_alloc(GFP_NOIO | __GFP_HIGH, 1);
 	bio->bi_iter.bi_sector = page_off * (PAGE_SIZE >> 9);
 	bio_set_dev(bio, hib_resume_bdev);
 	bio_set_op_attrs(bio, op, op_flags);
@@ -376,7 +376,7 @@ static int write_page(void *buf, sector_t offset, struct hib_bio_batch *hb)
 		return -ENOSPC;
 
 	if (hb) {
-		src = (void *)__get_free_page(__GFP_RECLAIM | __GFP_NOWARN |
+		src = (void *)__get_free_page(GFP_NOIO | __GFP_NOWARN |
 		                              __GFP_NORETRY);
 		if (src) {
 			copy_page(src, buf);
@@ -384,7 +384,7 @@ static int write_page(void *buf, sector_t offset, struct hib_bio_batch *hb)
 			ret = hib_wait_io(hb); /* Free pages */
 			if (ret)
 				return ret;
-			src = (void *)__get_free_page(__GFP_RECLAIM |
+			src = (void *)__get_free_page(GFP_NOIO |
 			                              __GFP_NOWARN |
 			                              __GFP_NORETRY);
 			if (src) {
@@ -691,7 +691,7 @@ static int save_image_lzo(struct swap_map_handle *handle,
 	nr_threads = num_online_cpus() - 1;
 	nr_threads = clamp_val(nr_threads, 1, LZO_THREADS);
 
-	page = (void *)__get_free_page(__GFP_RECLAIM | __GFP_HIGH);
+	page = (void *)__get_free_page(GFP_NOIO | __GFP_HIGH);
 	if (!page) {
 		pr_err("Failed to allocate LZO page\n");
 		ret = -ENOMEM;
@@ -989,7 +989,7 @@ static int get_swap_reader(struct swap_map_handle *handle,
 		last = tmp;
 
 		tmp->map = (struct swap_map_page *)
-			   __get_free_page(__GFP_RECLAIM | __GFP_HIGH);
+			   __get_free_page(GFP_NOIO | __GFP_HIGH);
 		if (!tmp->map) {
 			release_swap_reader(handle);
 			return -ENOMEM;
@@ -1261,8 +1261,8 @@ static int load_image_lzo(struct swap_map_handle *handle,
 
 	for (i = 0; i < read_pages; i++) {
 		page[i] = (void *)__get_free_page(i < LZO_CMP_PAGES ?
-						  __GFP_RECLAIM | __GFP_HIGH :
-						  __GFP_RECLAIM | __GFP_NOWARN |
+						  GFP_NOIO | __GFP_HIGH :
+						  GFP_NOIO | __GFP_NOWARN |
 						  __GFP_NORETRY);
 
 		if (!page[i]) {
-- 
2.16.3

Re: [PATCH 6/7] block: consistently use GFP_NOIO instead of __GFP_NORECLAIM

[Matthew Wilcox]

On Mon, Apr 09, 2018 at 05:39:15PM +0200, Christoph Hellwig wrote:
> Same numerical value (for now at least), but a much better documentation
> of intent.

> @@ -499,7 +499,7 @@ int sg_scsi_ioctl(struct request_queue *q, struct gendisk *disk, fmode_t mode,
>  		break;
>  	}
>  
> -	if (bytes && blk_rq_map_kern(q, rq, buffer, bytes, __GFP_RECLAIM)) {
> +	if (bytes && blk_rq_map_kern(q, rq, buffer, bytes, GFP_NOIO)) {

We don't seem to have grabbed any locks between the line which allocates
memory using GFP_USER (line 446) and here, so I don't see why we should
prohibit I/O?

Re: [PATCH 6/7] block: consistently use GFP_NOIO instead of __GFP_NORECLAIM

[Christoph Hellwig]

On Mon, Apr 09, 2018 at 09:03:54AM -0700, Matthew Wilcox wrote:
> > @@ -499,7 +499,7 @@ int sg_scsi_ioctl(struct request_queue *q, struct gendisk *disk, fmode_t mode,
> >  		break;
> >  	}
> >  
> > -	if (bytes && blk_rq_map_kern(q, rq, buffer, bytes, __GFP_RECLAIM)) {
> > +	if (bytes && blk_rq_map_kern(q, rq, buffer, bytes, GFP_NOIO)) {
> 
> We don't seem to have grabbed any locks between the line which allocates
> memory using GFP_USER (line 446) and here, so I don't see why we should
> prohibit I/O?

No change of behavior for this patch.  If you care deeply about using
GFP_KERNEL here send an incremental patch that I can add to the end of
the series.

Re: [PATCH 6/7] block: consistently use GFP_NOIO instead of __GFP_NORECLAIM

[Hannes Reinecke]

On Mon,  9 Apr 2018 17:39:15 +0200
Christoph Hellwig <hch@lst.de> wrote:

> Same numerical value (for now at least), but a much better
> documentation of intent.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>  block/scsi_ioctl.c               |  2 +-
>  drivers/block/drbd/drbd_bitmap.c |  3 ++-
>  drivers/block/pktcdvd.c          |  2 +-
>  drivers/ide/ide-tape.c           |  2 +-
>  drivers/ide/ide-taskfile.c       |  2 +-
>  drivers/scsi/scsi_lib.c          |  2 +-
>  fs/direct-io.c                   |  4 ++--
>  kernel/power/swap.c              | 14 +++++++-------
>  8 files changed, 16 insertions(+), 15 deletions(-)
> 
Reviewed-by: Hannes Reinecke <hare@suse.com>

Cheers,

Hannes

[PATCH 7/7] block: use GFP_KERNEL for allocations from blk_get_request

[Christoph Hellwig]

blk_get_request is used for pass-through style I/O and thus doesn't need
GFP_NOIO.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/blk-core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/block/blk-core.c b/block/blk-core.c
index 432923751551..253a869558f9 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1578,7 +1578,7 @@ static struct request *blk_old_get_request(struct request_queue *q,
 				unsigned int op, blk_mq_req_flags_t flags)
 {
 	struct request *rq;
-	gfp_t gfp_mask = flags & BLK_MQ_REQ_NOWAIT ? GFP_ATOMIC : GFP_NOIO;
+	gfp_t gfp_mask = flags & BLK_MQ_REQ_NOWAIT ? GFP_ATOMIC : GFP_KERNEL;
 	int ret = 0;
 
 	WARN_ON_ONCE(q->mq_ops);
-- 
2.16.3

Re: [PATCH 7/7] block: use GFP_KERNEL for allocations from blk_get_request

[Matthew Wilcox]

On Mon, Apr 09, 2018 at 05:39:16PM +0200, Christoph Hellwig wrote:
> blk_get_request is used for pass-through style I/O and thus doesn't need
> GFP_NOIO.

Obviously GFP_KERNEL is a big improvement over GFP_NOIO!  But can we take
it all the way to GFP_USER, if this is always done in the ioctl path
(which it seems to be, except for nfsd, which presumably won't have
a cpuset memory allocation policy ... and if it did, the admin might
appreciate it honouring said policy).

> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>  block/blk-core.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/block/blk-core.c b/block/blk-core.c
> index 432923751551..253a869558f9 100644
> --- a/block/blk-core.c
> +++ b/block/blk-core.c
> @@ -1578,7 +1578,7 @@ static struct request *blk_old_get_request(struct request_queue *q,
>  				unsigned int op, blk_mq_req_flags_t flags)
>  {
>  	struct request *rq;
> -	gfp_t gfp_mask = flags & BLK_MQ_REQ_NOWAIT ? GFP_ATOMIC : GFP_NOIO;
> +	gfp_t gfp_mask = flags & BLK_MQ_REQ_NOWAIT ? GFP_ATOMIC : GFP_KERNEL;
>  	int ret = 0;
>  
>  	WARN_ON_ONCE(q->mq_ops);
> -- 
> 2.16.3
> 

Re: [PATCH 7/7] block: use GFP_KERNEL for allocations from blk_get_request

[Christoph Hellwig]

On Mon, Apr 09, 2018 at 09:52:03AM -0700, Matthew Wilcox wrote:
> On Mon, Apr 09, 2018 at 05:39:16PM +0200, Christoph Hellwig wrote:
> > blk_get_request is used for pass-through style I/O and thus doesn't need
> > GFP_NOIO.
> 
> Obviously GFP_KERNEL is a big improvement over GFP_NOIO!  But can we take
> it all the way to GFP_USER, if this is always done in the ioctl path
> (which it seems to be, except for nfsd, which presumably won't have
> a cpuset memory allocation policy ... and if it did, the admin might
> appreciate it honouring said policy).

GFP_USER claims to be for allocations mapped into userspace, and except
for a few outliers that is how we use it.  I see no reason to change
that here.

Re: [PATCH 7/7] block: use GFP_KERNEL for allocations from blk_get_request

[Hannes Reinecke]

On Mon,  9 Apr 2018 17:39:16 +0200
Christoph Hellwig <hch@lst.de> wrote:

> blk_get_request is used for pass-through style I/O and thus doesn't
> need GFP_NOIO.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>  block/blk-core.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/block/blk-core.c b/block/blk-core.c
> index 432923751551..253a869558f9 100644
> --- a/block/blk-core.c
> +++ b/block/blk-core.c
> @@ -1578,7 +1578,7 @@ static struct request
> *blk_old_get_request(struct request_queue *q, unsigned int op,
> blk_mq_req_flags_t flags) {
>  	struct request *rq;
> -	gfp_t gfp_mask = flags & BLK_MQ_REQ_NOWAIT ? GFP_ATOMIC :
> GFP_NOIO;
> +	gfp_t gfp_mask = flags & BLK_MQ_REQ_NOWAIT ? GFP_ATOMIC :
> GFP_KERNEL; int ret = 0;
>  
>  	WARN_ON_ONCE(q->mq_ops);

Reviewed-by: Hannes Reinecke <hare@suse.com>

Cheers,

Hannes