kernel/linux.git/drivers/cdrom, branch v5.15.209

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

2026-06-01T15:35:41+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

scsi: sr: cdrom: Move cdrom_read_cdda_bpc() into the sr driver

2021-07-31T02:13:09+00:00

cdrom_read_cdda_bpc() relies on sending SCSI command to the low level driver using a REQ_OP_SCSI_IN request. This isn't generic block layer functionality, so move the actual low-level code into the sr driver and call it through a new read_cdda_bpc method in the cdrom_device_ops structure. With this the CDROM code does not have to pull in scsi_normalize_sense() and depend on CONFIG_SCSI_COMMON. Link: https://lore.kernel.org/r/20210730072752.GB23847%40lst.de Tested-by: Anders Roxell Signed-off-by: Christoph Hellwig Signed-off-by: Martin K. Petersen

scsi: cdrom: Remove the call to scsi_cmd_blk_ioctl() from cdrom_ioctl()

2021-07-29T02:24:25+00:00

Only the sr driver can handle SCSI passthrough requests, so move the call to scsi_cmd_blk_ioctl() there. Link: https://lore.kernel.org/r/20210724072033.1284840-9-hch@lst.de Signed-off-by: Christoph Hellwig Signed-off-by: Martin K. Petersen

block: remove REQ_OP_SCSI_{IN,OUT}

2021-06-30T21:34:19+00:00

With the legacy IDE driver gone drivers now use either REQ_OP_DRV_* or REQ_OP_SCSI_*, so unify the two concepts of passthrough requests into a single one. Reviewed-by: Chaitanya Kulkarni Signed-off-by: Christoph Hellwig Signed-off-by: Jens Axboe

gdrom: use blk_mq_alloc_disk

2021-06-11T17:53:03+00:00

Use the blk_mq_alloc_disk API to simplify the gendisk and request_queue allocation. Signed-off-by: Christoph Hellwig Reviewed-by: Chaitanya Kulkarni Link: https://lore.kernel.org/r/20210602065345.355274-15-hch@lst.de Signed-off-by: Jens Axboe

cdrom: gdrom: initialize global variable at init time

2021-05-13T16:58:44+00:00

As Peter points out, if we were to disconnect and then reconnect this driver from a device, the "global" state of the device would contain odd values and could cause problems. Fix this up by just initializing the whole thing to 0 at probe() time. Ideally this would be a per-device variable, but given the age and the total lack of users of it, that would require a lot of s/./->/g changes for really no good reason. Reported-by: Peter Rosin Cc: Jens Axboe Reviewed-by: Peter Rosin Link: https://lore.kernel.org/r/YJP2j6AU82MqEY2M@kroah.com Signed-off-by: Greg Kroah-Hartman

cdrom: gdrom: deallocate struct gdrom_unit fields in remove_gdrom

2021-05-13T15:33:32+00:00

The fields, "toc" and "cd_info", of "struct gdrom_unit gd" are allocated in "probe_gdrom()". Prevent a memory leak by making sure "gd.cd_info" is deallocated in the "remove_gdrom()" function. Also prevent double free of the field "gd.toc" by moving it from the module's exit function to "remove_gdrom()". This is because, in "probe_gdrom()", the function makes sure to deallocate "gd.toc" in case of any errors, so the exit function invoked later would again free "gd.toc". The patch also maintains consistency by deallocating the above mentioned fields in "remove_gdrom()" along with another memory allocated field "gd.disk". Suggested-by: Jens Axboe Cc: Peter Rosin Cc: stable Signed-off-by: Atul Gopinathan Link: https://lore.kernel.org/r/20210503115736.2104747-28-gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman

Revert "gdrom: fix a memory leak bug"

2021-05-13T15:33:30+00:00

This reverts commit 093c48213ee37c3c3ff1cf5ac1aa2a9d8bc66017. Because of recent interactions with developers from @umn.edu, all commits from them have been recently re-reviewed to ensure if they were correct or not. Upon review, this commit was found to be incorrect for the reasons below, so it must be reverted. It will be fixed up "correctly" in a later kernel change. Because of this, all submissions from this group must be reverted from the kernel tree and will need to be re-reviewed again to determine if they actually are a valid fix. Until that work is complete, remove this change to ensure that no problems are being introduced into the codebase. Cc: Wenwen Wang Cc: Peter Rosin Cc: Jens Axboe Fixes: 093c48213ee3 ("gdrom: fix a memory leak bug") Cc: stable Link: https://lore.kernel.org/r/20210503115736.2104747-27-gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman

gdrom: fix compilation error

2021-04-12T01:32:06+00:00

Use the right name for the struct request variable that removes the following compilation error :- make --silent --keep-going --jobs=8 O=/home/tuxbuild/.cache/tuxmake/builds/1/tmp ARCH=sh CROSS_COMPILE=sh4-linux-gnu- 'CC=sccache sh4-linux-gnu-gcc' 'HOSTCC=sccache gcc' In file included from /builds/linux/include/linux/scatterlist.h:9, from /builds/linux/include/linux/dma-mapping.h:10, from /builds/linux/drivers/cdrom/gdrom.c:16: /builds/linux/drivers/cdrom/gdrom.c: In function 'gdrom_readdisk_dma': /builds/linux/drivers/cdrom/gdrom.c:586:61: error: 'rq' undeclared (first use in this function) 586 | __raw_writel(page_to_phys(bio_page(req->bio)) + bio_offset(rq->bio), | ^~ Fixes: 1d2c82001a5f ("gdrom: support highmem") Reported-by: Naresh Kamboju Tested-by: Naresh Kamboju Signed-off-by: Chaitanya Kulkarni Signed-off-by: Jens Axboe

gdrom: support highmem

2021-04-06T15:29:36+00:00

The gdrom driver only has a single reference to the virtual address of the bio data, and uses that only to get the physical address. Switch to deriving the physical address from the page directly and thus avoid bounce buffering highmem data. Signed-off-by: Christoph Hellwig Link: https://lore.kernel.org/r/20210406061648.811275-1-hch@lst.de Signed-off-by: Jens Axboe