[PATCH v2 6/7] scsi_debug: protect device access with atomic_rw lock

Akinobu Mita
2014-01-19T13:52:04Z

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.mita@gmail.com>
Cc: "James E.J. Bottomley" <JBottomley@parallels.com>
Cc: Douglas Gilbert <dgilbert@interlog.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: linux-scsi@vger.kernel.org
---
New patch from this version

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