[PATCH 12/14] sr: convert to the atomic queue limits API

[Christoph Hellwig <hch@xxxxxx>]

Assign all queue limits through a local queue_limits variable and
queue_limits_commit_update so that we can't race updating them from
multiple places, and free the queue when updating them so that
in-progress I/O submissions don't see half-updated limits.

Also use the chance to clean up variable names to standard ones.

Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Reviewed-by: Damien Le Moal <dlemoal@xxxxxxxxxx>
---
 drivers/scsi/sr.c | 42 +++++++++++++++++++++++++-----------------
 1 file changed, 25 insertions(+), 17 deletions(-)

diff --git a/drivers/scsi/sr.c b/drivers/scsi/sr.c
index 7ab000942b97fc..3f491019103e0c 100644
--- a/drivers/scsi/sr.c
+++ b/drivers/scsi/sr.c
@@ -111,7 +111,7 @@ static struct lock_class_key sr_bio_compl_lkclass;
 static int sr_open(struct cdrom_device_info *, int);
 static void sr_release(struct cdrom_device_info *);
 
-static void get_sectorsize(struct scsi_cd *);
+static int get_sectorsize(struct scsi_cd *);
 static int get_capabilities(struct scsi_cd *);
 
 static unsigned int sr_check_events(struct cdrom_device_info *cdi,
@@ -473,15 +473,15 @@ static blk_status_t sr_init_command(struct scsi_cmnd 
*SCpnt)
        return BLK_STS_IOERR;
 }
 
-static void sr_revalidate_disk(struct scsi_cd *cd)
+static int sr_revalidate_disk(struct scsi_cd *cd)
 {
        struct scsi_sense_hdr sshdr;
 
        /* if the unit is not ready, nothing more to do */
        if (scsi_test_unit_ready(cd->device, SR_TIMEOUT, MAX_RETRIES, &sshdr))
-               return;
+               return 0;
        sr_cd_check(&cd->cdi);
-       get_sectorsize(cd);
+       return get_sectorsize(cd);
 }
 
 static int sr_block_open(struct gendisk *disk, blk_mode_t mode)
@@ -494,13 +494,16 @@ static int sr_block_open(struct gendisk *disk, blk_mode_t 
mode)
                return -ENXIO;
 
        scsi_autopm_get_device(sdev);
-       if (disk_check_media_change(disk))
-               sr_revalidate_disk(cd);
+       if (disk_check_media_change(disk)) {
+               ret = sr_revalidate_disk(cd);
+               if (ret)
+                       goto out;
+       }
 
        mutex_lock(&cd->lock);
        ret = cdrom_open(&cd->cdi, mode);
        mutex_unlock(&cd->lock);
-
+out:
        scsi_autopm_put_device(sdev);
        if (ret)
                scsi_device_put(cd->device);
@@ -685,7 +688,9 @@ static int sr_probe(struct device *dev)
        blk_pm_runtime_init(sdev->request_queue, dev);
 
        dev_set_drvdata(dev, cd);
-       sr_revalidate_disk(cd);
+       error = sr_revalidate_disk(cd);
+       if (error)
+               goto unregister_cdrom;
 
        error = device_add_disk(&sdev->sdev_gendev, disk, NULL);
        if (error)
@@ -714,13 +719,14 @@ static int sr_probe(struct device *dev)
 }
 
 
-static void get_sectorsize(struct scsi_cd *cd)
+static int get_sectorsize(struct scsi_cd *cd)
 {
+       struct request_queue *q = cd->device->request_queue;
        static const u8 cmd[10] = { READ_CAPACITY };
        unsigned char buffer[8] = { };
-       int the_result;
+       struct queue_limits lim;
+       int err;
        int sector_size;
-       struct request_queue *queue;
        struct scsi_failure failure_defs[] = {
                {
                        .result = SCMD_FAILURE_RESULT_ANY,
@@ -736,10 +742,10 @@ static void get_sectorsize(struct scsi_cd *cd)
        };
 
        /* Do the command and wait.. */
-       the_result = scsi_execute_cmd(cd->device, cmd, REQ_OP_DRV_IN, buffer,
+       err = scsi_execute_cmd(cd->device, cmd, REQ_OP_DRV_IN, buffer,
                                      sizeof(buffer), SR_TIMEOUT, MAX_RETRIES,
                                      &exec_args);
-       if (the_result) {
+       if (err) {
                cd->capacity = 0x1fffff;
                sector_size = 2048;     /* A guess, just in case */
        } else {
@@ -789,10 +795,12 @@ static void get_sectorsize(struct scsi_cd *cd)
                set_capacity(cd->disk, cd->capacity);
        }
 
-       queue = cd->device->request_queue;
-       blk_queue_logical_block_size(queue, sector_size);
-
-       return;
+       lim = queue_limits_start_update(q);
+       lim.logical_block_size = sector_size;
+       blk_mq_freeze_queue(q);
+       err = queue_limits_commit_update(q, &lim);
+       blk_mq_unfreeze_queue(q);
+       return err;
 }
 
 static int get_capabilities(struct scsi_cd *cd)
-- 
2.43.0