diff options
| author | Nicholas Bellinger <nab@linux-iscsi.org> | 2013-01-29 22:10:06 -0800 |
|---|---|---|
| committer | Nicholas Bellinger <nab@linux-iscsi.org> | 2013-02-13 11:27:51 -0800 |
| commit | d0c8b259f8970d39354c1966853363345d401330 (patch) | |
| tree | e6739094ba5db9ca88038f0e047e83e82bf21088 /drivers/target/target_core_device.c | |
| parent | 1be2956d30b2b6200ebb26ffb758ed3c8071303c (diff) | |
| download | linux-d0c8b259f8970d39354c1966853363345d401330.tar.bz2 | |
target/iblock: Use backend REQ_FLUSH hint for WriteCacheEnabled status
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>
Diffstat (limited to 'drivers/target/target_core_device.c')
| -rw-r--r-- | drivers/target/target_core_device.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/drivers/target/target_core_device.c b/drivers/target/target_core_device.c index f2aa7543d20a..d10cbed23472 100644 --- a/drivers/target/target_core_device.c +++ b/drivers/target/target_core_device.c @@ -772,6 +772,12 @@ int se_dev_set_emulate_write_cache(struct se_device *dev, int flag) pr_err("emulate_write_cache not supported for pSCSI\n"); return -EINVAL; } + if (dev->transport->get_write_cache) { + pr_warn("emulate_write_cache cannot be changed when underlying" + " HW reports WriteCacheEnabled, ignoring request\n"); + return 0; + } + dev->dev_attrib.emulate_write_cache = flag; pr_debug("dev[%p]: SE Device WRITE_CACHE_EMULATION flag: %d\n", dev, dev->dev_attrib.emulate_write_cache); |