[PATCH v3 6/7] scsi_debug: protect device access with atomic_rw lock

[Akinobu Mita]

This change ensures that concurrent device access including ramdisk
storage, protection info, and provisioning map by read, write, and
unmap commands are protected with atomic_rw spinlock.

Signed-off-by: Akinobu Mita <akinobu.m...@gmail.com>
Reviewed-by: Douglas Gilbert <dgilb...@interlog.com>
Reviewed-by: Martin K. Petersen <martin.peter...@oracle.com>
Cc: "James E.J. Bottomley" <jbottom...@parallels.com>
Cc: Douglas Gilbert <dgilb...@interlog.com>
Cc: "Martin K. Petersen" <martin.peter...@oracle.com>
Cc: linux-scsi@vger.kernel.org
---
 drivers/scsi/scsi_debug.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c
index 004b985..0bb1d49c 100644
--- a/drivers/scsi/scsi_debug.c
+++ b/drivers/scsi/scsi_debug.c
@@ -1888,17 +1888,19 @@ static int resp_read(struct scsi_cmnd *SCpnt, unsigned 
long long lba,
                return check_condition_result;
        }
 
+       read_lock_irqsave(&atomic_rw, iflags);
+
        /* DIX + T10 DIF */
        if (scsi_debug_dix && scsi_prot_sg_count(SCpnt)) {
                int prot_ret = prot_verify_read(SCpnt, lba, num, ei_lba);
 
                if (prot_ret) {
+                       read_unlock_irqrestore(&atomic_rw, iflags);
                        mk_sense_buffer(devip, ABORTED_COMMAND, 0x10, prot_ret);
                        return illegal_condition_result;
                }
        }
 
-       read_lock_irqsave(&atomic_rw, iflags);
        ret = do_device_access(SCpnt, devip, lba, num, 0);
        read_unlock_irqrestore(&atomic_rw, iflags);
        if (ret == -1)
@@ -2098,17 +2100,19 @@ static int resp_write(struct scsi_cmnd *SCpnt, unsigned 
long long lba,
        if (ret)
                return ret;
 
+       write_lock_irqsave(&atomic_rw, iflags);
+
        /* DIX + T10 DIF */
        if (scsi_debug_dix && scsi_prot_sg_count(SCpnt)) {
                int prot_ret = prot_verify_write(SCpnt, lba, num, ei_lba);
 
                if (prot_ret) {
+                       write_unlock_irqrestore(&atomic_rw, iflags);
                        mk_sense_buffer(devip, ILLEGAL_REQUEST, 0x10, prot_ret);
                        return illegal_condition_result;
                }
        }
 
-       write_lock_irqsave(&atomic_rw, iflags);
        ret = do_device_access(SCpnt, devip, lba, num, 1);
        if (scsi_debug_lbp())
                map_region(lba, num);
@@ -2187,6 +2191,7 @@ static int resp_unmap(struct scsi_cmnd * scmd, struct 
sdebug_dev_info * devip)
        struct unmap_block_desc *desc;
        unsigned int i, payload_len, descriptors;
        int ret;
+       unsigned long iflags;
 
        ret = check_readiness(scmd, 1, devip);
        if (ret)
@@ -2208,6 +2213,8 @@ static int resp_unmap(struct scsi_cmnd * scmd, struct 
sdebug_dev_info * devip)
 
        desc = (void *)&buf[8];
 
+       write_lock_irqsave(&atomic_rw, iflags);
+
        for (i = 0 ; i < descriptors ; i++) {
                unsigned long long lba = get_unaligned_be64(&desc[i].lba);
                unsigned int num = get_unaligned_be32(&desc[i].blocks);
@@ -2222,6 +2229,7 @@ static int resp_unmap(struct scsi_cmnd * scmd, struct 
sdebug_dev_info * devip)
        ret = 0;
 
 out:
+       write_unlock_irqrestore(&atomic_rw, iflags);
        kfree(buf);
 
        return ret;
-- 
1.8.3.2

--
To unsubscribe from this list: send the line "unsubscribe linux-scsi" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html