scsi: core: Add a no_highmem flag to struct Scsi_Host

While we really should be killing the block layer bounce buffering ASAP, I
even more urgently need to stop the drivers to fiddle with the limits from
->slave_configure.  Add a no_highmem flag to the Scsi_Host to centralize
this setting and switch the remaining four drivers that use block layer
bounce buffering to it.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20240409143748.980206-7-hch@lst.deReviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: John Garry <john.g.garry@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/aha152x.c

@@ -746,6 +746,7 @@ struct Scsi_Host *aha152x_probe_one(struct aha152x_setup *setup)
 	/* need to have host registered before triggering any interrupt */
 	list_add_tail(&HOSTDATA(shpnt)->host_list, &aha152x_host_list);
 
+	shpnt->no_highmem = true;
 	shpnt->io_port   = setup->io_port;
 	shpnt->n_io_port = IO_RANGE;
 	shpnt->irq       = setup->irq;
@@ -2940,12 +2941,6 @@ static int aha152x_show_info(struct seq_file *m, struct Scsi_Host *shpnt)
 	return 0;
 }
 
-static int aha152x_adjust_queue(struct scsi_device *device)
-{
-	blk_queue_bounce_limit(device->request_queue, BLK_BOUNCE_HIGH);
-	return 0;
-}
-
 static const struct scsi_host_template aha152x_driver_template = {
 	.module				= THIS_MODULE,
 	.name				= AHA152X_REVID,
@@ -2961,7 +2956,6 @@ static const struct scsi_host_template aha152x_driver_template = {
 	.this_id			= 7,
 	.sg_tablesize			= SG_ALL,
 	.dma_boundary			= PAGE_SIZE - 1,
-	.slave_alloc			= aha152x_adjust_queue,
 	.cmd_size			= sizeof(struct aha152x_cmd_priv),
 };
 

drivers/scsi/imm.c

@@ -1100,16 +1100,6 @@ static int device_check(imm_struct *dev, bool autodetect)
 	return -ENODEV;
 }
 
-/*
- * imm cannot deal with highmem, so this causes all IO pages for this host
- * to reside in low memory (hence mapped)
- */
-static int imm_adjust_queue(struct scsi_device *device)
-{
-	blk_queue_bounce_limit(device->request_queue, BLK_BOUNCE_HIGH);
-	return 0;
-}
-
 static const struct scsi_host_template imm_template = {
 	.module			= THIS_MODULE,
 	.proc_name		= "imm",
@@ -1123,7 +1113,6 @@ static const struct scsi_host_template imm_template = {
 	.this_id		= 7,
 	.sg_tablesize		= SG_ALL,
 	.can_queue		= 1,
-	.slave_alloc		= imm_adjust_queue,
 	.cmd_size		= sizeof(struct scsi_pointer),
 };
 
@@ -1235,6 +1224,7 @@ static int __imm_attach(struct parport *pb)
 	host = scsi_host_alloc(&imm_template, sizeof(imm_struct *));
 	if (!host)
 		goto out1;
+	host->no_highmem = true;
 	host->io_port = pb->base;
 	host->n_io_port = ports;
 	host->dma_channel = -1;

drivers/scsi/ppa.c

@@ -986,12 +986,6 @@ static int device_check(ppa_struct *dev, bool autodetect)
 	return -ENODEV;
 }
 
-static int ppa_adjust_queue(struct scsi_device *device)
-{
-	blk_queue_bounce_limit(device->request_queue, BLK_BOUNCE_HIGH);
-	return 0;
-}
-
 static const struct scsi_host_template ppa_template = {
 	.module			= THIS_MODULE,
 	.proc_name		= "ppa",
@@ -1005,7 +999,6 @@ static const struct scsi_host_template ppa_template = {
 	.this_id		= -1,
 	.sg_tablesize		= SG_ALL,
 	.can_queue		= 1,
-	.slave_alloc		= ppa_adjust_queue,
 	.cmd_size		= sizeof(struct scsi_pointer),
 };
 
@@ -1111,6 +1104,7 @@ static int __ppa_attach(struct parport *pb)
 	host = scsi_host_alloc(&ppa_template, sizeof(ppa_struct *));
 	if (!host)
 		goto out1;
+	host->no_highmem = true;
 	host->io_port = pb->base;
 	host->n_io_port = ports;
 	host->dma_channel = -1;

drivers/scsi/scsi_lib.c

@@ -1995,6 +1995,9 @@ void scsi_init_limits(struct Scsi_Host *shost, struct queue_limits *lim)
 	 */
 	lim->dma_alignment = max(4, dma_get_cache_alignment()) - 1;
 
+	if (shost->no_highmem)
+		lim->bounce = BLK_BOUNCE_HIGH;
+
 	dma_set_seg_boundary(dev, shost->dma_boundary);
 	dma_set_max_seg_size(dev, shost->max_segment_size);
 }

drivers/usb/storage/scsiglue.c

@@ -40,7 +40,6 @@
 #include <scsi/scsi_eh.h>
 
 #include "usb.h"
-#include <linux/usb/hcd.h>
 #include "scsiglue.h"
 #include "debug.h"
 #include "transport.h"
@@ -130,15 +129,6 @@ static int slave_configure(struct scsi_device *sdev)
 		min_t(size_t, queue_max_hw_sectors(sdev->request_queue),
 		      dma_max_mapping_size(dev) >> SECTOR_SHIFT));
 
-	/*
-	 * Some USB host controllers can't do DMA; they have to use PIO.
-	 * For such controllers we need to make sure the block layer sets
-	 * up bounce buffers in addressable memory.
-	 */
-	if (!hcd_uses_dma(bus_to_hcd(us->pusb_dev->bus)) ||
-			(bus_to_hcd(us->pusb_dev->bus)->localmem_pool != NULL))
-		blk_queue_bounce_limit(sdev->request_queue, BLK_BOUNCE_HIGH);
-
 	/*
 	 * We can't put these settings in slave_alloc() because that gets
 	 * called before the device type is known.  Consequently these

drivers/usb/storage/usb.c

@@ -47,6 +47,7 @@
 #include <scsi/scsi_device.h>
 
 #include "usb.h"
+#include <linux/usb/hcd.h>
 #include "scsiglue.h"
 #include "transport.h"
 #include "protocol.h"
@@ -961,6 +962,15 @@ int usb_stor_probe1(struct us_data **pus,
 	if (result)
 		goto BadDevice;
 
+	/*
+	 * Some USB host controllers can't do DMA; they have to use PIO.
+	 * For such controllers we need to make sure the block layer sets
+	 * up bounce buffers in addressable memory.
+	 */
+	if (!hcd_uses_dma(bus_to_hcd(us->pusb_dev->bus)) ||
+	    bus_to_hcd(us->pusb_dev->bus)->localmem_pool)
+		host->no_highmem = true;
+
 	/* Get the unusual_devs entries and the descriptors */
 	result = get_device_info(us, id, unusual_dev);
 	if (result)

include/scsi/scsi_host.h

@@ -665,6 +665,8 @@ struct Scsi_Host {
 	/* The transport requires the LUN bits NOT to be stored in CDB[1] */
 	unsigned no_scsi2_lun_in_cdb:1;
 
+	unsigned no_highmem:1;
+
 	/*
 	 * Optional work queue to be utilized by the transport
 	 */