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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>
This commit is contained in:
parent
1be2956d30
commit
d0c8b259f8
4 changed files with 48 additions and 11 deletions
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@ -772,6 +772,12 @@ int se_dev_set_emulate_write_cache(struct se_device *dev, int flag)
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pr_err("emulate_write_cache not supported for pSCSI\n");
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pr_err("emulate_write_cache not supported for pSCSI\n");
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return -EINVAL;
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return -EINVAL;
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}
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}
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if (dev->transport->get_write_cache) {
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pr_warn("emulate_write_cache cannot be changed when underlying"
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" HW reports WriteCacheEnabled, ignoring request\n");
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return 0;
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}
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dev->dev_attrib.emulate_write_cache = flag;
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dev->dev_attrib.emulate_write_cache = flag;
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pr_debug("dev[%p]: SE Device WRITE_CACHE_EMULATION flag: %d\n",
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pr_debug("dev[%p]: SE Device WRITE_CACHE_EMULATION flag: %d\n",
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dev, dev->dev_attrib.emulate_write_cache);
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dev, dev->dev_attrib.emulate_write_cache);
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@ -154,6 +154,7 @@ static int iblock_configure_device(struct se_device *dev)
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if (blk_queue_nonrot(q))
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if (blk_queue_nonrot(q))
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dev->dev_attrib.is_nonrot = 1;
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dev->dev_attrib.is_nonrot = 1;
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return 0;
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return 0;
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out_free_bioset:
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out_free_bioset:
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@ -654,20 +655,24 @@ iblock_execute_rw(struct se_cmd *cmd)
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u32 sg_num = sgl_nents;
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u32 sg_num = sgl_nents;
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sector_t block_lba;
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sector_t block_lba;
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unsigned bio_cnt;
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unsigned bio_cnt;
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int rw;
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int rw = 0;
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int i;
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int i;
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if (data_direction == DMA_TO_DEVICE) {
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if (data_direction == DMA_TO_DEVICE) {
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struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
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struct request_queue *q = bdev_get_queue(ib_dev->ibd_bd);
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/*
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/*
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* Force data to disk if we pretend to not have a volatile
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* Force writethrough using WRITE_FUA if a volatile write cache
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* write cache, or the initiator set the Force Unit Access bit.
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* is not enabled, or if initiator set the Force Unit Access bit.
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*/
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*/
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if (dev->dev_attrib.emulate_write_cache == 0 ||
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if (q->flush_flags & REQ_FUA) {
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(dev->dev_attrib.emulate_fua_write > 0 &&
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if (cmd->se_cmd_flags & SCF_FUA)
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(cmd->se_cmd_flags & SCF_FUA)))
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rw = WRITE_FUA;
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rw = WRITE_FUA;
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else
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else if (!(q->flush_flags & REQ_FLUSH))
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rw = WRITE_FUA;
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} else {
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rw = WRITE;
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rw = WRITE;
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}
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} else {
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} else {
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rw = READ;
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rw = READ;
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}
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}
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@ -774,6 +779,15 @@ iblock_parse_cdb(struct se_cmd *cmd)
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return sbc_parse_cdb(cmd, &iblock_sbc_ops);
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return sbc_parse_cdb(cmd, &iblock_sbc_ops);
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}
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}
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bool iblock_get_write_cache(struct se_device *dev)
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{
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struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
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struct block_device *bd = ib_dev->ibd_bd;
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struct request_queue *q = bdev_get_queue(bd);
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return q->flush_flags & REQ_FLUSH;
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}
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static struct se_subsystem_api iblock_template = {
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static struct se_subsystem_api iblock_template = {
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.name = "iblock",
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.name = "iblock",
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.inquiry_prod = "IBLOCK",
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.inquiry_prod = "IBLOCK",
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@ -790,6 +804,7 @@ static struct se_subsystem_api iblock_template = {
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.show_configfs_dev_params = iblock_show_configfs_dev_params,
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.show_configfs_dev_params = iblock_show_configfs_dev_params,
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.get_device_type = sbc_get_device_type,
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.get_device_type = sbc_get_device_type,
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.get_blocks = iblock_get_blocks,
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.get_blocks = iblock_get_blocks,
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.get_write_cache = iblock_get_write_cache,
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};
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};
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static int __init iblock_module_init(void)
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static int __init iblock_module_init(void)
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@ -407,16 +407,31 @@ spc_emulate_evpd_83(struct se_cmd *cmd, unsigned char *buf)
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}
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}
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EXPORT_SYMBOL(spc_emulate_evpd_83);
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EXPORT_SYMBOL(spc_emulate_evpd_83);
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static bool
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spc_check_dev_wce(struct se_device *dev)
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{
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bool wce = false;
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if (dev->transport->get_write_cache)
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wce = dev->transport->get_write_cache(dev);
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else if (dev->dev_attrib.emulate_write_cache > 0)
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wce = true;
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return wce;
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}
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/* Extended INQUIRY Data VPD Page */
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/* Extended INQUIRY Data VPD Page */
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static sense_reason_t
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static sense_reason_t
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spc_emulate_evpd_86(struct se_cmd *cmd, unsigned char *buf)
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spc_emulate_evpd_86(struct se_cmd *cmd, unsigned char *buf)
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{
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{
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struct se_device *dev = cmd->se_dev;
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buf[3] = 0x3c;
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buf[3] = 0x3c;
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/* Set HEADSUP, ORDSUP, SIMPSUP */
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/* Set HEADSUP, ORDSUP, SIMPSUP */
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buf[5] = 0x07;
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buf[5] = 0x07;
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/* If WriteCache emulation is enabled, set V_SUP */
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/* If WriteCache emulation is enabled, set V_SUP */
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if (cmd->se_dev->dev_attrib.emulate_write_cache > 0)
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if (spc_check_dev_wce(dev))
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buf[6] = 0x01;
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buf[6] = 0x01;
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return 0;
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return 0;
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}
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}
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@ -766,7 +781,7 @@ static int spc_modesense_caching(struct se_device *dev, u8 pc, u8 *p)
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if (pc == 1)
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if (pc == 1)
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goto out;
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goto out;
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if (dev->dev_attrib.emulate_write_cache > 0)
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if (spc_check_dev_wce(dev))
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p[2] = 0x04; /* Write Cache Enable */
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p[2] = 0x04; /* Write Cache Enable */
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p[12] = 0x20; /* Disabled Read Ahead */
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p[12] = 0x20; /* Disabled Read Ahead */
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@ -878,7 +893,7 @@ static sense_reason_t spc_emulate_modesense(struct se_cmd *cmd)
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(cmd->se_deve->lun_flags & TRANSPORT_LUNFLAGS_READ_ONLY)))
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(cmd->se_deve->lun_flags & TRANSPORT_LUNFLAGS_READ_ONLY)))
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spc_modesense_write_protect(&buf[length], type);
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spc_modesense_write_protect(&buf[length], type);
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if ((dev->dev_attrib.emulate_write_cache > 0) &&
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if ((spc_check_dev_wce(dev)) &&
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(dev->dev_attrib.emulate_fua_write > 0))
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(dev->dev_attrib.emulate_fua_write > 0))
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spc_modesense_dpofua(&buf[length], type);
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spc_modesense_dpofua(&buf[length], type);
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@ -35,6 +35,7 @@ struct se_subsystem_api {
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u32 (*get_device_type)(struct se_device *);
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u32 (*get_device_type)(struct se_device *);
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sector_t (*get_blocks)(struct se_device *);
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sector_t (*get_blocks)(struct se_device *);
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unsigned char *(*get_sense_buffer)(struct se_cmd *);
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unsigned char *(*get_sense_buffer)(struct se_cmd *);
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bool (*get_write_cache)(struct se_device *);
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};
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};
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struct sbc_ops {
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struct sbc_ops {
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