[PATCH] sd: Reduce log level to KERN_NOTICE for missing caching mode page

[PATCH] sd: Reduce log level to KERN_NOTICE for missing caching mode page

[Alain Kalker]

Reduce the lernel log level to KERN_NOTICE for messages related
to a missing caching mode page.

Reasons why I think this change is justified:
- The condition is non-fatal; the existing workaround assumes
  a write through cache. Although this reduces write performance,
  it doesn't limit functionality in any way.
- The current log level suggests that immediate action is
  required, however, as it is a hardware limitation, there is
  nothing much the user can do about it besides replacing the
  affected hardware.
- The current situation breaks quiet boot (kernel commandline
  parameter 'quiet'), and may trip log monitoring software
  unneccessarily, either on every boot or whenever an affected
  external device is plugged in.

Signed-off-by: Alain Kalker <a.c.kalker@gmail.com>
---
 drivers/scsi/sd.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index efcbcd1..5f0f6c6 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -2442,7 +2442,7 @@ sd_read_cache_type(struct scsi_disk *sdkp, unsigned char *buffer)
 			}
 		}
 
-		sd_first_printk(KERN_ERR, sdkp, "No Caching mode page found\n");
+		sd_first_printk(KERN_NOTICE, sdkp, "No Caching mode page found\n");
 		goto defaults;
 
 	Page_found:
@@ -2489,7 +2489,7 @@ defaults:
 				"Assuming drive cache: write back\n");
 		sdkp->WCE = 1;
 	} else {
-		sd_first_printk(KERN_ERR, sdkp,
+		sd_first_printk(KERN_NOTICE, sdkp,
 				"Assuming drive cache: write through\n");
 		sdkp->WCE = 0;
 	}
-- 
2.0.0

Re: [PATCH] sd: Reduce log level to KERN_NOTICE for missing caching mode page

[Alain Kalker]

On 06/02/2014 12:46 PM, Alain Kalker wrote:
> Reduce the lernel log level to KERN_NOTICE for messages related
> to a missing caching mode page.
>
> Reasons why I think this change is justified:
> - The condition is non-fatal; the existing workaround assumes
>    a write through cache. Although this reduces write performance,
>    it doesn't limit functionality in any way.
> - The current log level suggests that immediate action is
>    required, however, as it is a hardware limitation, there is
>    nothing much the user can do about it besides replacing the
>    affected hardware.
whoops, confused that one with KERN_ALERT, sorry about that.

Will reword, rebase and repost.
> - The current situation breaks quiet boot (kernel commandline
>    parameter 'quiet'), and may trip log monitoring software
>    unneccessarily, either on every boot or whenever an affected
>    external device is plugged in.
>
> Signed-off-by: Alain Kalker <a.c.kalker@gmail.com>

[PATCH V2] sd: Reduce log level to KERN_NOTICE for missing caching mode page

[Alain Kalker]

Reduce the lernel log level to KERN_NOTICE for messages related
to a missing caching mode page.

Reasons why I think this change is justified:
- The condition is not an error; the existing workaround of assuming
  a write through cache doesn't limit functionality in any way.
- It doesn't warrant a warning either: as it is most likely
  a hardware limitation, there is little that an ordinary user can do
  about it besides replacing the affected hardware.
  Making it a warning would still break quiet boot (kernel commandline
  parameter 'quiet'), and may still trip log monitoring software
  unneccessarily, either on every boot or whenever an affected
  external device is plugged in.
- It should be a notice, for it is a normal but significant condition,
  as it may impact write performance. This would bring it on par with
  the log messages in the same function.

Signed-off-by: Alain Kalker <a.c.kalker@gmail.com>
---
 drivers/scsi/sd.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index efcbcd1..5f0f6c6 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -2442,7 +2442,7 @@ sd_read_cache_type(struct scsi_disk *sdkp, unsigned char *buffer)
 			}
 		}
 
-		sd_first_printk(KERN_ERR, sdkp, "No Caching mode page found\n");
+		sd_first_printk(KERN_NOTICE, sdkp, "No Caching mode page found\n");
 		goto defaults;
 
 	Page_found:
@@ -2489,7 +2489,7 @@ defaults:
 				"Assuming drive cache: write back\n");
 		sdkp->WCE = 1;
 	} else {
-		sd_first_printk(KERN_ERR, sdkp,
+		sd_first_printk(KERN_NOTICE, sdkp,
 				"Assuming drive cache: write through\n");
 		sdkp->WCE = 0;
 	}
-- 
2.0.0