[PATCH v11 18/34] scsi: sd: Fix sshdr use in sd_suspend_common

Mike Christie
2023-09-05T23:22:34Z

If scsi_execute_cmd returns < 0, it doesn't initialize the sshdr, so we
shouldn't access the sshdr. If it returns 0, then the cmd executed
successfully, so there is no need to check the sshdr. sd_sync_cache will
only access the sshdr if it's been setup because it calls
scsi_status_is_check_condition before accessing it. However, the
sd_sync_cache caller, sd_suspend_common, does not check.

sd_suspend_common is only checking for ILLEGAL_REQUEST which it's using
to determine if the command is supported. If it's not it just ignores
the error. So to fix its sshdr use this patch just moves that check to
sd_sync_cache where it converts ILLEGAL_REQUEST to success/0.
sd_suspend_common was ignoring that error and sd_shutdown doesn't check
for errors so there will be no behavior changes.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
drivers/scsi/sd.c | 53 ++++++++++++++++++++---------------------------
1 file changed, 23 insertions(+), 30 deletions(-)

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index f5e6b5cc762f..1f6cc24d633b 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -1564,24 +1564,21 @@ static unsigned int sd_check_events(struct gendisk *disk, unsigned int clearing)
return disk_changed ? DISK_EVENT_MEDIA_CHANGE : 0;
}

-static int sd_sync_cache(struct scsi_disk *sdkp, struct scsi_sense_hdr *sshdr)
+static int sd_sync_cache(struct scsi_disk *sdkp)
{
int retries, res;
struct scsi_device *sdp = sdkp->device;
const int timeout = sdp->request_queue->rq_timeout
* SD_FLUSH_TIMEOUT_MULTIPLIER;
- struct scsi_sense_hdr my_sshdr;
+ struct scsi_sense_hdr sshdr;
const struct scsi_exec_args exec_args = {
.req_flags = BLK_MQ_REQ_PM,
- /* caller might not be interested in sense, but we need it */
- .sshdr = sshdr ? : &my_sshdr,
+ .sshdr = &sshdr,
};

if (!scsi_device_online(sdp))
return -ENODEV;

- sshdr = exec_args.sshdr;
-
for (retries = 3; retries > 0; --retries) {
unsigned char cmd[16] = { 0 };

@@ -1606,15 +1603,23 @@ static int sd_sync_cache(struct scsi_disk *sdkp, struct scsi_sense_hdr *sshdr)
return res;

if (scsi_status_is_check_condition(res) &&
- scsi_sense_valid(sshdr)) {
- sd_print_sense_hdr(sdkp, sshdr);
+ scsi_sense_valid(&sshdr)) {
+ sd_print_sense_hdr(sdkp, &sshdr);

/* we need to evaluate the error return */
- if (sshdr->asc == 0x3a || /* medium not present */
- sshdr->asc == 0x20 || /* invalid command */
- (sshdr->asc == 0x74 && sshdr->ascq == 0x71)) /* drive is password locked */
+ if (sshdr.asc == 0x3a || /* medium not present */
+ sshdr.asc == 0x20 || /* invalid command */
+ (sshdr.asc == 0x74 && sshdr.ascq == 0x71)) /* drive is password locked */
/* this is no error here */
return 0;
+ /*
+ * This drive doesn't support sync and there's not much
+ * we can do because this is called during shutdown
+ * or suspend so just return success so those operations
+ * can proceed.
+ */
+ if (sshdr.sense_key == ILLEGAL_REQUEST)
+ return 0;
}

switch (host_byte(res)) {
@@ -3816,7 +3821,7 @@ static void sd_shutdown(struct device *dev)

if (sdkp->WCE && sdkp->media_present) {
sd_printk(KERN_NOTICE, sdkp, "Synchronizing SCSI cache\n");
- sd_sync_cache(sdkp, NULL);
+ sd_sync_cache(sdkp);
}

if (system_state != SYSTEM_RESTART && sdkp->device->manage_start_stop) {
@@ -3828,7 +3833,6 @@ static void sd_shutdown(struct device *dev)
static int sd_suspend_common(struct device *dev, bool ignore_stop_errors)
{
struct scsi_disk *sdkp = dev_get_drvdata(dev);
- struct scsi_sense_hdr sshdr;
int ret = 0;

if (!sdkp) /* E.g.: runtime suspend following sd_remove() */
@@ -3837,24 +3841,13 @@ static int sd_suspend_common(struct device *dev, bool ignore_stop_errors)
if (sdkp->WCE && sdkp->media_present) {
if (!sdkp->device->silence_suspend)
sd_printk(KERN_NOTICE, sdkp, "Synchronizing SCSI cache\n");
- ret = sd_sync_cache(sdkp, &sshdr);
-
- if (ret) {
- /* ignore OFFLINE device */
- if (ret == -ENODEV)
- return 0;
-
- if (!scsi_sense_valid(&sshdr) ||
- sshdr.sense_key != ILLEGAL_REQUEST)
- return ret;
+ ret = sd_sync_cache(sdkp);
+ /* ignore OFFLINE device */
+ if (ret == -ENODEV)
+ return 0;

- /*
- * sshdr.sense_key == ILLEGAL_REQUEST means this drive
- * doesn't support sync. There's not much to do and
- * suspend shouldn't fail.
- */
- ret = 0;
- }
+ if (ret)
+ return ret;
}

if (sdkp->device->manage_start_stop) {
--
2.34.1