kernel/linux.git/drivers/scsi/sr.c, branch v6.6.148

cdrom, scsi: sr: propagate read-only status to block layer via set_disk_ro()

2026-05-23T11:03:27+00:00

[ Upstream commit 0898a817621a2f0cddca8122d9b974003fe5036d ] The cdrom core never calls set_disk_ro() for a registered device, so BLKROGET on a CD-ROM device always returns 0 (writable), even when the drive has no write capabilities and writes will inevitably fail. This causes problems for userspace that relies on BLKROGET to determine whether a block device is read-only. For example, systemd's loop device setup uses BLKROGET to decide whether to create a loop device with LO_FLAGS_READ_ONLY. Without the read-only flag, writes pass through the loop device to the CD-ROM and fail with I/O errors. systemd-fsck similarly checks BLKROGET to decide whether to run fsck in no-repair mode (-n). The write-capability bits in cdi->mask come from two different sources: CDC_DVD_RAM and CDC_CD_RW are populated by the driver from the MODE SENSE capabilities page (page 0x2A) before register_cdrom() is called, while CDC_MRW_W and CDC_RAM require the MMC GET CONFIGURATION command and were only probed by cdrom_open_write() at device open time. This meant that any attempt to compute the writable state from the full mask at probe time was incorrect, because the GET CONFIGURATION bits were still unset (and cdi->mask is initialized such that capabilities are assumed present). Fix this by factoring the GET CONFIGURATION probing out of cdrom_open_write() into a new exported helper, cdrom_probe_write_features(), and having sr call it from sr_probe() right after get_capabilities() has populated the MODE SENSE bits. register_cdrom() then calls set_disk_ro() based on the full write-capability mask (CDC_DVD_RAM | CDC_MRW_W | CDC_RAM | CDC_CD_RW) so the block layer reflects the drive's actual write support. The feature queries used (CDF_MRW and CDF_RWRT via GET CONFIGURATION with RT=00) report drive-level capabilities that are persistent across media, so a single probe before register_cdrom() is sufficient and the redundant probe at open time is dropped. With set_disk_ro() now accurate, the long-vestigial cd->writeable flag in sr can go: get_capabilities() used to set cd->writeable based on the same four mask bits, but because CDC_MRW_W and CDC_RAM default to "capability present" in cdi->mask and aren't touched by MODE SENSE, the condition that gated cd->writeable was always true, making it unconditionally 1. Replace the corresponding gate in sr_init_command() with get_disk_ro(cd->disk), which turns a previously no-op check into a real one and also catches kernel-internal bio writers that bypass blkdev_write_iter()'s bdev_read_only() check. The sd driver (SCSI disks) does not have this problem because it checks the MODE SENSE Write Protect bit and calls set_disk_ro() accordingly. The sr driver cannot use the same approach because the MMC specification does not define the WP bit in the MODE SENSE device-specific parameter byte for CD-ROM devices. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Daan De Meyer Reviewed-by: Phillip Potter Reviewed-by: Martin K. Petersen Signed-off-by: Phillip Potter Link: https://patch.msgid.link/20260427210139.1400-2-phil@philpotter.co.uk Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

Merge tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi

2023-06-30T18:57:07+00:00

Pull SCSI updates from James Bottomley: "Updates to the usual drivers (ufs, pm80xx, libata-scsi, smartpqi, lpfc, qla2xxx). We have a couple of major core changes impacting other systems: - Command Duration Limits, which spills into block and ATA - block level Persistent Reservation Operations, which touches block, nvme, target and dm Both of these are added with merge commits containing a cover letter explaining what's going on" * tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: (187 commits) scsi: core: Improve warning message in scsi_device_block() scsi: core: Replace scsi_target_block() with scsi_block_targets() scsi: core: Don't wait for quiesce in scsi_device_block() scsi: core: Don't wait for quiesce in scsi_stop_queue() scsi: core: Merge scsi_internal_device_block() and device_block() scsi: sg: Increase number of devices scsi: bsg: Increase number of devices scsi: qla2xxx: Remove unused nvme_ls_waitq wait queue scsi: ufs: ufs-pci: Add support for Intel Arrow Lake scsi: sd: sd_zbc: Use PAGE_SECTORS_SHIFT scsi: ufs: wb: Add explicit flush_threshold sysfs attribute scsi: ufs: ufs-qcom: Switch to the new ICE API scsi: ufs: dt-bindings: qcom: Add ICE phandle scsi: ufs: ufs-mediatek: Set UFSHCD_QUIRK_MCQ_BROKEN_RTC quirk scsi: ufs: ufs-mediatek: Set UFSHCD_QUIRK_MCQ_BROKEN_INTR quirk scsi: ufs: core: Add host quirk UFSHCD_QUIRK_MCQ_BROKEN_RTC scsi: ufs: core: Add host quirk UFSHCD_QUIRK_MCQ_BROKEN_INTR scsi: ufs: core: Remove dedicated hwq for dev command scsi: ufs: core: mcq: Fix the incorrect OCS value for the device command scsi: ufs: dt-bindings: samsung,exynos: Drop unneeded quotes ...

block: replace fmode_t with a block-specific type for block open flags

2023-06-12T14:04:05+00:00

The only overlap between the block open flags mapped into the fmode_t and other uses of fmode_t are FMODE_READ and FMODE_WRITE. Define a new blk_mode_t instead for use in blkdev_get_by_{dev,path}, ->open and ->ioctl and stop abusing fmode_t. Signed-off-by: Christoph Hellwig Acked-by: Jack Wang [rnbd] Reviewed-by: Hannes Reinecke Reviewed-by: Christian Brauner Link: https://lore.kernel.org/r/20230608110258.189493-28-hch@lst.de Signed-off-by: Jens Axboe

scsi: replace the fmode_t argument to scsi_ioctl with a simple bool

2023-06-12T14:04:04+00:00

Instead of passing a fmode_t and only checking it for FMODE_WRITE, pass a bool open_for_write to prepare for callers that won't have the fmode_t. Signed-off-by: Christoph Hellwig Reviewed-by: Martin K. Petersen Reviewed-by: Hannes Reinecke Acked-by: Christian Brauner Link: https://lore.kernel.org/r/20230608110258.189493-20-hch@lst.de Signed-off-by: Jens Axboe

block: remove the unused mode argument to ->release

2023-06-12T14:04:04+00:00

The mode argument to the ->release block_device_operation is never used, so remove it. Signed-off-by: Christoph Hellwig Reviewed-by: Hannes Reinecke Acked-by: Christian Brauner Acked-by: Jack Wang [rnbd] Link: https://lore.kernel.org/r/20230608110258.189493-10-hch@lst.de Signed-off-by: Jens Axboe

block: pass a gendisk to ->open

2023-06-12T14:04:04+00:00

->open is only called on the whole device. Make that explicit by passing a gendisk instead of the block_device. Signed-off-by: Christoph Hellwig Reviewed-by: Hannes Reinecke Acked-by: Christian Brauner Acked-by: Jack Wang [rnbd] Link: https://lore.kernel.org/r/20230608110258.189493-9-hch@lst.de Signed-off-by: Jens Axboe

block: pass a gendisk on bdev_check_media_change

2023-06-12T14:04:03+00:00

bdev_check_media_change should only ever be called for the whole device. Pass a gendisk to make that explicit and rename the function to disk_check_media_change. Signed-off-by: Christoph Hellwig Reviewed-by: Hannes Reinecke Acked-by: Christian Brauner Link: https://lore.kernel.org/r/20230608110258.189493-8-hch@lst.de Signed-off-by: Jens Axboe

cdrom: remove the unused mode argument to cdrom_release

2023-06-12T14:04:03+00:00

Signed-off-by: Christoph Hellwig Reviewed-by: Phillip Potter Reviewed-by: Hannes Reinecke Acked-by: Christian Brauner Link: https://lore.kernel.org/r/20230608110258.189493-7-hch@lst.de Signed-off-by: Jens Axboe

cdrom: remove the unused mode argument to cdrom_ioctl

2023-06-12T14:04:03+00:00

cdrom: remove the unused bdev argument to cdrom_open

2023-06-12T14:04:03+00:00