linux-kernel - [PATCH 3/3] sr: Remove in_interrupt() usage in sr_init

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Date:   Fri,  4 Dec 2020 17:48:50 +0100
From:   Sebastian Andrzej Siewior <bigeasy@...utronix.de>
To:     linux-scsi@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     Jens Axboe <axboe@...nel.dk>,
        "James E.J. Bottomley" <jejb@...ux.ibm.com>,
        "Martin K. Petersen" <martin.petersen@...cle.com>,
        "Ahmed S . Darwish" <a.darwish@...utronix.de>,
        Thomas Gleixner <tglx@...utronix.de>,
        Sebastian Andrzej Siewior <bigeasy@...utronix.de>
Subject: [PATCH 3/3] sr: Remove in_interrupt() usage in sr_init_command().

The in_interrupt() check in sr_init_command() is a leftover from the
past, pre v2.3.16 era to be exact. Back then the ioctl() was served by
`sr' itself and sector size changes by CDROMREADMODE2 (as noted in the
comment) were accounted within sr's data structures which allowed a
"lazy" reset so it could be skipped on the next request and reset back
to the default value once the device node was closed or before a command
from the blockqueue was issued.

This does not work like that anymore. The CDROMREADMODE2 is served by
cdrom's mmc_ioctl() function which may change the sector size but the
`sr' driver does not learn about it and so its ->sector_size is not
updated.
The ioctl() resets the changed sector size back to 2048.
sr_read_sector() also resets the sector size back to the default once it
is done.

Remove the conditional sector size update from sr_init_command() and
sr_release() because it is not needed.

Link: https://lkml.kernel.org/r/20201204164803.ovwurzs3257em2rp@linutronix.de
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
---
This change makes also ide-cd providing the last non-empty
cdrom_device_info::release callback.

 drivers/scsi/sr.c | 17 -----------------
 1 file changed, 17 deletions(-)

diff --git a/drivers/scsi/sr.c b/drivers/scsi/sr.c
index fd4b582110b29..e4633b84c556a 100644
--- a/drivers/scsi/sr.c
+++ b/drivers/scsi/sr.c
@@ -416,19 +416,7 @@ static blk_status_t sr_init_command(struct scsi_cmnd *SCpnt)
 		goto out;
 	}

-	/*
-	 * we do lazy blocksize switching (when reading XA sectors,
-	 * see CDROMREADMODE2 ioctl) 
-	 */
 	s_size = cd->device->sector_size;
-	if (s_size > 2048) {
-		if (!in_interrupt())
-			sr_set_blocklength(cd, 2048);
-		else
-			scmd_printk(KERN_INFO, SCpnt,
-				    "can't switch blocksize: in interrupt\n");
-	}
-
 	if (s_size != 512 && s_size != 1024 && s_size != 2048) {
 		scmd_printk(KERN_ERR, SCpnt, "bad sector size %d\n", s_size);
 		goto out;
@@ -701,11 +689,6 @@ static int sr_open(struct cdrom_device_info *cdi, int purpose)

 static void sr_release(struct cdrom_device_info *cdi)
 {
-	struct scsi_cd *cd = cdi->handle;
-
-	if (cd->device->sector_size > 2048)
-		sr_set_blocklength(cd, 2048);
-
 }

 static int sr_probe(struct device *dev)
-- 
2.29.2