Re: [PATCH V3] scsi: core: put LLD module refcnt after SCSI device is released
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: 2021-10-05 13:35:43
On Thu, Sep 30, 2021 at 08:44:15PM +0800, Ming Lei wrote:
SCSI host release is triggered when SCSI device is freed, and we have to make sure that LLD module won't be unloaded before SCSI host instance is released because shost->hostt is required in host release handler. So make sure to put LLD module refcnt after SCSI device is released.
What is a "LLD"?
quoted hunk ↗ jump to hunk
Fix one kernel panic of 'BUG: unable to handle page fault for address' reported by Changhui and Yi. Reported-by: Changhui Zhong <redacted> Reported-by: Yi Zhang <redacted> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Ming Lei <redacted> --- drivers/scsi/scsi.c | 4 +++- drivers/scsi/scsi_sysfs.c | 12 ++++++++++++ include/scsi/scsi_device.h | 1 + 3 files changed, 16 insertions(+), 1 deletion(-)diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c index b241f9e3885c..291ecc33b1fe 100644 --- a/drivers/scsi/scsi.c +++ b/drivers/scsi/scsi.c@@ -553,8 +553,10 @@ EXPORT_SYMBOL(scsi_device_get); */ void scsi_device_put(struct scsi_device *sdev) { - module_put(sdev->host->hostt->module); + struct module *mod = sdev->host->hostt->module; + put_device(&sdev->sdev_gendev); + module_put(mod); } EXPORT_SYMBOL(scsi_device_put);diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c index 86793259e541..9ada26814011 100644 --- a/drivers/scsi/scsi_sysfs.c +++ b/drivers/scsi/scsi_sysfs.c@@ -449,9 +449,16 @@ static void scsi_device_dev_release_usercontext(struct work_struct *work) struct scsi_vpd *vpd_pg80 = NULL, *vpd_pg83 = NULL; struct scsi_vpd *vpd_pg0 = NULL, *vpd_pg89 = NULL; unsigned long flags; + struct module *mod; + bool put_mod = false; sdev = container_of(work, struct scsi_device, ew.work); + if (sdev->put_lld_mod_ref) {
Why do you need this flag at all? Shouldn't you just always grab/release the module? Why would you not want to? thanks, greg k-h