lk/linux-kernel-test
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

target/iblock: Use backend REQ_FLUSH hint for WriteCacheEnabled status

Browse Source 
This patch allows IBLOCK to check block hints in request_queue->flush_flags
when reporting current backend device WriteCacheEnabled status to a remote
SCSI initiator port.

This is done via a se_subsystem_api->get_write_cache() call instead of a
backend se_device creation time flag, as we expect REQ_FLUSH bits to possibly
change from an underlying blk_queue_flush() by the SCSI disk driver, or
internal raw struct block_device driver usage.

Also go ahead and update iblock_execute_rw() bio I/O path code to use
REQ_FLUSH + REQ_FUA hints when determining WRITE_FUA usage, and make SPC
emulation code use a spc_check_dev_wce() helper to handle both types of
cases for virtual backend subsystem drivers.

(asias: Drop unnecessary comparsion operators)

Reported-by: majianpeng <majianpeng@gmail.com>
Cc: majianpeng <majianpeng@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: James Bottomley <JBottomley@Parallels.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
This commit is contained in:
Nicholas Bellinger
2013-01-29 22:10:06 -08:00
parent 1be2956d30
commit d0c8b259f8
4 changed files with 48 additions and 11 deletions
Download Patch File Download Diff File Expand all files Collapse all files

21
drivers/target/target_core_spc.c
View File

@@ -407,16 +407,31 @@ check_scsi_name:
}
EXPORT_SYMBOL(spc_emulate_evpd_83);
static bool
spc_check_dev_wce(struct se_device *dev)
{
bool wce = false;
if (dev->transport->get_write_cache)
wce = dev->transport->get_write_cache(dev);
else if (dev->dev_attrib.emulate_write_cache > 0)
wce = true;
return wce;
}
/* Extended INQUIRY Data VPD Page */
static sense_reason_t
spc_emulate_evpd_86(struct se_cmd *cmd, unsigned char *buf)
{
struct se_device *dev = cmd->se_dev;
buf[3] = 0x3c;
/* Set HEADSUP, ORDSUP, SIMPSUP */
buf[5] = 0x07;
/* If WriteCache emulation is enabled, set V_SUP */
if (cmd->se_dev->dev_attrib.emulate_write_cache > 0)
if (spc_check_dev_wce(dev))
buf[6] = 0x01;
return 0;
}
@@ -766,7 +781,7 @@ static int spc_modesense_caching(struct se_device *dev, u8 pc, u8 *p)
if (pc == 1)
goto out;
if (dev->dev_attrib.emulate_write_cache > 0)
if (spc_check_dev_wce(dev))
p[2] = 0x04; /* Write Cache Enable */
p[12] = 0x20; /* Disabled Read Ahead */
@@ -878,7 +893,7 @@ static sense_reason_t spc_emulate_modesense(struct se_cmd *cmd)
(cmd->se_deve->lun_flags & TRANSPORT_LUNFLAGS_READ_ONLY)))
spc_modesense_write_protect(&buf[length], type);
if ((dev->dev_attrib.emulate_write_cache > 0) &&
if ((spc_check_dev_wce(dev)) &&
(dev->dev_attrib.emulate_fua_write > 0))
spc_modesense_dpofua(&buf[length], type);