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Commit 9bc6548f authored by Christophe Vu-Brugier's avatar Christophe Vu-Brugier Committed by Nicholas Bellinger
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target: do not reject FUA CDBs when write cache is enabled but emulate_write_cache is 0 



A check that rejects a CDB with FUA bit set if no write cache is
emulated was added by the following commit:

  fde9f50f target: Add sanity checks for DPO/FUA bit usage

The condition is as follows:

  if (!dev->dev_attrib.emulate_fua_write ||
      !dev->dev_attrib.emulate_write_cache)

However, this check is wrong if the backend device supports WCE but
"emulate_write_cache" is disabled.

This patch uses se_dev_check_wce() (previously named
spc_check_dev_wce) to invoke transport->get_write_cache() if the
device has a write cache or check the "emulate_write_cache" attribute
otherwise.

Reported-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarChristophe Vu-Brugier <cvubrugier@fastmail.fm>
Signed-off-by: default avatarNicholas Bellinger <nab@linux-iscsi.org>
parent 5f7da044

drivers/target/target_core_device.c

+12 −0
Original line number Diff line number Diff line
@@ -650,6 +650,18 @@ static u32 se_dev_align_max_sectors(u32 max_sectors, u32 block_size) 
	return aligned_max_sectors;

}



bool se_dev_check_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;

}



int se_dev_set_max_unmap_lba_count(

	struct se_device *dev,

	u32 max_unmap_lba_count)

drivers/target/target_core_sbc.c

+1 −2
Original line number Diff line number Diff line
@@ -708,8 +708,7 @@ sbc_check_dpofua(struct se_device *dev, struct se_cmd *cmd, unsigned char *cdb) 
		}

	}

	if (cdb[1] & 0x8) {

		if (!dev->dev_attrib.emulate_fua_write ||

		    !dev->dev_attrib.emulate_write_cache) {

		if (!dev->dev_attrib.emulate_fua_write || !se_dev_check_wce(dev)) {

			pr_err("Got CDB: 0x%02x with FUA bit set, but device"

			       " does not advertise support for FUA write\n",

			       cdb[0]);

drivers/target/target_core_spc.c

+3 −16
Original line number Diff line number Diff line
@@ -454,19 +454,6 @@ spc_emulate_evpd_83(struct se_cmd *cmd, unsigned char *buf) 
}

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)
@@ -490,7 +477,7 @@ spc_emulate_evpd_86(struct se_cmd *cmd, unsigned char *buf) 
	buf[5] = 0x07;



	/* If WriteCache emulation is enabled, set V_SUP */

	if (spc_check_dev_wce(dev))

	if (se_dev_check_wce(dev))

		buf[6] = 0x01;

	/* If an LBA map is present set R_SUP */

	spin_lock(&cmd->se_dev->t10_alua.lba_map_lock);
@@ -897,7 +884,7 @@ static int spc_modesense_caching(struct se_cmd *cmd, u8 pc, u8 *p) 
	if (pc == 1)

		goto out;



	if (spc_check_dev_wce(dev))

	if (se_dev_check_wce(dev))

		p[2] = 0x04; /* Write Cache Enable */

	p[12] = 0x20; /* Disabled Read Ahead */
@@ -1009,7 +996,7 @@ 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 ((spc_check_dev_wce(dev)) &&

	if ((se_dev_check_wce(dev)) &&

	    (dev->dev_attrib.emulate_fua_write > 0))

		spc_modesense_dpofua(&buf[length], type);

include/target/target_core_backend.h

+1 −0
Original line number Diff line number Diff line
@@ -111,6 +111,7 @@ void array_free(void *array, int n); 
void	target_core_setup_sub_cits(struct se_subsystem_api *);



/* attribute helpers from target_core_device.c for backend drivers */

bool	se_dev_check_wce(struct se_device *);

int	se_dev_set_max_unmap_lba_count(struct se_device *, u32);

int	se_dev_set_max_unmap_block_desc_count(struct se_device *, u32);

int	se_dev_set_unmap_granularity(struct se_device *, u32);