On Wed, 25 May 2011, Jens Axboe wrote:
> I don't think we can move it earlier, we essentially have to do the
> check at both ends. The "normal" IO path would see that the queue is
> dead and error the IO, but this is an internal setup that sets up the
> request and then adds it to the stored queue pointer. So it needs to
> check this state one way or the other. I think the above fix with the
> sdev_alive() will be good enough.
>
If I understood it right we need checks in both places (kind of makes
sense as the device could be gone *after* we checked in ioctl function and
before the request queue was dereferenced). So here is the ioctl check
with a helper function for state check that Linus asked for.
Signed-off-by: Parag Warudkar <parag.lkml@xxxxxxxxx>
diff --git a/drivers/scsi/scsi_ioctl.c b/drivers/scsi/scsi_ioctl.c
index d9564fb..8615e63 100644
--- a/drivers/scsi/scsi_ioctl.c
+++ b/drivers/scsi/scsi_ioctl.c
@@ -30,6 +30,13 @@
#define MAX_BUF PAGE_SIZE
+static inline int sdev_early_check(struct scsi_device *sdev)
+{
+ if (!sdev || sdev->sdev_state == SDEV_DEL
+ || sdev->sdev_state > SDEV_QUIESCE)
+ return -ENXIO;
+ return 0;
+}
/**
* ioctl_probe -- return host identification
* @host: host to identify
@@ -91,6 +98,10 @@ static int ioctl_internal_command(struct scsi_device *sdev, char *cmd,
int result;
struct scsi_sense_hdr sshdr;
+ result = sdev_early_check(sdev);
+ if (result)
+ return result;
+
SCSI_LOG_IOCTL(1, printk("Trying ioctl with scsi command %d\n", *cmd));
result = scsi_execute_req(sdev, cmd, DMA_NONE, NULL, 0,
@@ -194,10 +205,11 @@ static int scsi_ioctl_get_pci(struct scsi_device *sdev, void __user *arg)
int scsi_ioctl(struct scsi_device *sdev, int cmd, void __user *arg)
{
char scsi_cmd[MAX_COMMAND_SIZE];
+ int result;
- /* No idea how this happens.... */
- if (!sdev)
- return -ENXIO;
+ result = sdev_early_check(sdev);
+ if (result)
+ return result;
/*
* If we are in the middle of error recovery, don't let anyone
@@ -288,6 +300,10 @@ int scsi_nonblockable_ioctl(struct scsi_device *sdev, int cmd,
{
int val, result;
+ result = sdev_early_check(sdev);
+ if (result)
+ return result;
+
/* The first set of iocts may be executed even if we're doing
* error processing, as long as the device was opened
* non-blocking */
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