On Thu, 2015-08-27 at 14:41 +0200, Hannes Reinecke wrote:
> The port group needs to be a separate structure as several
> LUNs might belong to the same group.
>
> Signed-off-by: Hannes Reinecke <hare@xxxxxxx>
> ---
> drivers/scsi/device_handler/scsi_dh_alua.c | 211 +++++++++++++++++++----------
> 1 file changed, 139 insertions(+), 72 deletions(-)
>
> diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c b/drivers/scsi/device_handler/scsi_dh_alua.c
> index ef4363a..d1010dd 100644
> --- a/drivers/scsi/device_handler/scsi_dh_alua.c
> +++ b/drivers/scsi/device_handler/scsi_dh_alua.c
> @@ -64,9 +64,13 @@
> #define ALUA_OPTIMIZE_STPG 1
> #define ALUA_RTPG_EXT_HDR_UNSUPP 2
>
> -struct alua_dh_data {
> +static LIST_HEAD(port_group_list);
> +static DEFINE_SPINLOCK(port_group_lock);
> +
> +struct alua_port_group {
> + struct kref kref;
> + struct list_head node;
> int group_id;
> - int rel_port;
> int tpgs;
> int state;
> int pref;
> @@ -75,6 +79,12 @@ struct alua_dh_data {
> unsigned char *buff;
> int bufflen;
> unsigned char transition_tmo;
> +};
> +
> +struct alua_dh_data {
> + struct alua_port_group *pg;
> + int rel_port;
> + int tpgs;
> struct scsi_device *sdev;
> activate_complete callback_fn;
> void *callback_data;
> @@ -86,21 +96,35 @@ struct alua_dh_data {
> static char print_alua_state(int);
> static int alua_check_sense(struct scsi_device *, struct scsi_sense_hdr *);
>
> -static int realloc_buffer(struct alua_dh_data *h, unsigned len)
> +static int realloc_buffer(struct alua_port_group *pg, unsigned len)
> {
> - if (h->buff && h->buff != h->inq)
> - kfree(h->buff);
> + if (pg->buff && pg->buff != pg->inq)
> + kfree(pg->buff);
>
> - h->buff = kmalloc(len, GFP_NOIO);
> - if (!h->buff) {
> - h->buff = h->inq;
> - h->bufflen = ALUA_INQUIRY_SIZE;
> + pg->buff = kmalloc(len, GFP_NOIO);
> + if (!pg->buff) {
> + pg->buff = pg->inq;
> + pg->bufflen = ALUA_INQUIRY_SIZE;
> return 1;
> }
> - h->bufflen = len;
> + pg->bufflen = len;
> return 0;
> }
>
> +static void release_port_group(struct kref *kref)
> +{
> + struct alua_port_group *pg;
> +
> + pg = container_of(kref, struct alua_port_group, kref);
> + printk(KERN_WARNING "alua: release port group %d\n", pg->group_id);
> + spin_lock(&port_group_lock);
> + list_del(&pg->node);
> + spin_unlock(&port_group_lock);
> + if (pg->buff && pg->inq != pg->buff)
> + kfree(pg->buff);
> + kfree(pg);
> +}
> +
> /*
> * submit_rtpg - Issue a REPORT TARGET GROUP STATES command
> * @sdev: sdev the command should be sent to
> @@ -225,6 +249,8 @@ static int alua_check_tpgs(struct scsi_device *sdev, struct alua_dh_data *h)
> static int alua_check_vpd(struct scsi_device *sdev, struct alua_dh_data *h)
> {
> unsigned char *d;
> + int group_id = -1;
> + struct alua_port_group *pg = NULL;
>
> if (!sdev->vpd_pg83)
> return SCSI_DH_DEV_UNSUPP;
> @@ -241,7 +267,7 @@ static int alua_check_vpd(struct scsi_device *sdev, struct alua_dh_data *h)
> break;
> case 0x5:
> /* Target port group */
> - h->group_id = get_unaligned_be16(&d[6]);
> + group_id = get_unaligned_be16(&d[6]);
> break;
> default:
> break;
> @@ -249,7 +275,7 @@ static int alua_check_vpd(struct scsi_device *sdev, struct alua_dh_data *h)
> d += d[3] + 4;
> }
>
> - if (h->group_id == -1) {
> + if (group_id == -1) {
> /*
> * Internal error; TPGS supported but required
> * VPD identification descriptors not present.
> @@ -258,15 +284,33 @@ static int alua_check_vpd(struct scsi_device *sdev, struct alua_dh_data *h)
> sdev_printk(KERN_INFO, sdev,
> "%s: No target port descriptors found\n",
> ALUA_DH_NAME);
> - h->state = TPGS_STATE_OPTIMIZED;
> h->tpgs = TPGS_MODE_NONE;
> return SCSI_DH_DEV_UNSUPP;
> }
> sdev_printk(KERN_INFO, sdev,
> "%s: port group %02x rel port %02x\n",
> - ALUA_DH_NAME, h->group_id, h->rel_port);
> + ALUA_DH_NAME, group_id, h->rel_port);
>
> - return 0;
> + pg = kzalloc(sizeof(struct alua_port_group), GFP_KERNEL);
> + if (!pg) {
> + sdev_printk(KERN_WARNING, sdev,
> + "%s: kzalloc port group failed\n",
> + ALUA_DH_NAME);
> + /* Temporary failure, bypass */
> + return SCSI_DH_DEV_TEMP_BUSY;
> + }
> + pg->group_id = group_id;
> + pg->buff = pg->inq;
> + pg->bufflen = ALUA_INQUIRY_SIZE;
> + pg->tpgs = h->tpgs;
> + pg->state = TPGS_STATE_OPTIMIZED;
> + kref_init(&pg->kref);
> + spin_lock(&port_group_lock);
> + list_add(&pg->node, &port_group_list);
> + h->pg = pg;
> + spin_unlock(&port_group_lock);
> +
> + return SCSI_DH_OK;
> }
>
> static char print_alua_state(int state)
> @@ -377,7 +421,7 @@ static int alua_check_sense(struct scsi_device *sdev,
> * Returns SCSI_DH_DEV_OFFLINED if the path is
> * found to be unusable.
> */
> -static int alua_rtpg(struct scsi_device *sdev, struct alua_dh_data *h, int wait_for_transition)
> +static int alua_rtpg(struct scsi_device *sdev, struct alua_port_group *pg, int wait_for_transition)
> {
> struct scsi_sense_hdr sense_hdr;
> int len, k, off, valid_states = 0;
> @@ -387,13 +431,14 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_dh_data *h, int wait_
> unsigned int tpg_desc_tbl_off;
> unsigned char orig_transition_tmo;
>
> - if (!h->transition_tmo)
> + if (!pg->transition_tmo)
> expiry = round_jiffies_up(jiffies + ALUA_FAILOVER_TIMEOUT * HZ);
> else
> - expiry = round_jiffies_up(jiffies + h->transition_tmo * HZ);
> + expiry = round_jiffies_up(jiffies + pg->transition_tmo * HZ);
>
> retry:
> - retval = submit_rtpg(sdev, h->buff, h->bufflen, &sense_hdr, h->flags);
> + retval = submit_rtpg(sdev, pg->buff, pg->bufflen,
> + &sense_hdr, pg->flags);
>
> if (retval) {
> if (!scsi_sense_valid(&sense_hdr)) {
> @@ -415,10 +460,10 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_dh_data *h, int wait_
> * The retry without rtpg_ext_hdr_req set
> * handles this.
> */
> - if (!(h->flags & ALUA_RTPG_EXT_HDR_UNSUPP) &&
> + if (!(pg->flags & ALUA_RTPG_EXT_HDR_UNSUPP) &&
> sense_hdr.sense_key == ILLEGAL_REQUEST &&
> sense_hdr.asc == 0x24 && sense_hdr.ascq == 0) {
> - h->flags |= ALUA_RTPG_EXT_HDR_UNSUPP;
> + pg->flags |= ALUA_RTPG_EXT_HDR_UNSUPP;
> goto retry;
> }
>
> @@ -435,11 +480,11 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_dh_data *h, int wait_
> return SCSI_DH_IO;
> }
>
> - len = get_unaligned_be32(&h->buff[0]) + 4;
> + len = get_unaligned_be32(&pg->buff[0]) + 4;
>
> - if (len > h->bufflen) {
> + if (len > pg->bufflen) {
> /* Resubmit with the correct length */
> - if (realloc_buffer(h, len)) {
> + if (realloc_buffer(pg, len)) {
> sdev_printk(KERN_WARNING, sdev,
> "%s: kmalloc buffer failed\n",__func__);
> /* Temporary failure, bypass */
> @@ -448,31 +493,33 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_dh_data *h, int wait_
> goto retry;
> }
>
> - orig_transition_tmo = h->transition_tmo;
> - if ((h->buff[4] & RTPG_FMT_MASK) == RTPG_FMT_EXT_HDR && h->buff[5] != 0)
> - h->transition_tmo = h->buff[5];
> + orig_transition_tmo = pg->transition_tmo;
> + if ((pg->buff[4] & RTPG_FMT_MASK) == RTPG_FMT_EXT_HDR &&
> + pg->buff[5] != 0)
> + pg->transition_tmo = pg->buff[5];
> else
> - h->transition_tmo = ALUA_FAILOVER_TIMEOUT;
> + pg->transition_tmo = ALUA_FAILOVER_TIMEOUT;
>
> - if (wait_for_transition && (orig_transition_tmo != h->transition_tmo)) {
> + if (wait_for_transition &&
> + (orig_transition_tmo != pg->transition_tmo)) {
> sdev_printk(KERN_INFO, sdev,
> "%s: transition timeout set to %d seconds\n",
> - ALUA_DH_NAME, h->transition_tmo);
> - expiry = jiffies + h->transition_tmo * HZ;
> + ALUA_DH_NAME, pg->transition_tmo);
> + expiry = jiffies + pg->transition_tmo * HZ;
> }
>
> - if ((h->buff[4] & RTPG_FMT_MASK) == RTPG_FMT_EXT_HDR)
> + if ((pg->buff[4] & RTPG_FMT_MASK) == RTPG_FMT_EXT_HDR)
> tpg_desc_tbl_off = 8;
> else
> tpg_desc_tbl_off = 4;
>
> - for (k = tpg_desc_tbl_off, ucp = h->buff + tpg_desc_tbl_off;
> + for (k = tpg_desc_tbl_off, ucp = pg->buff + tpg_desc_tbl_off;
> k < len;
> k += off, ucp += off) {
>
> - if (h->group_id == get_unaligned_be16(&ucp[2])) {
> - h->state = ucp[0] & 0x0f;
> - h->pref = ucp[0] >> 7;
> + if (pg->group_id == get_unaligned_be16(&ucp[2])) {
> + pg->state = ucp[0] & 0x0f;
> + pg->pref = ucp[0] >> 7;
> valid_states = ucp[1];
> }
> off = 8 + (ucp[7] * 4);
> @@ -480,8 +527,8 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_dh_data *h, int wait_
>
> sdev_printk(KERN_INFO, sdev,
> "%s: port group %02x state %c %s supports %c%c%c%c%c%c%c\n",
> - ALUA_DH_NAME, h->group_id, print_alua_state(h->state),
> - h->pref ? "preferred" : "non-preferred",
> + ALUA_DH_NAME, pg->group_id, print_alua_state(pg->state),
> + pg->pref ? "preferred" : "non-preferred",
> valid_states&TPGS_SUPPORT_TRANSITION?'T':'t',
> valid_states&TPGS_SUPPORT_OFFLINE?'O':'o',
> valid_states&TPGS_SUPPORT_LBA_DEPENDENT?'L':'l',
> @@ -490,7 +537,7 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_dh_data *h, int wait_
> valid_states&TPGS_SUPPORT_NONOPTIMIZED?'N':'n',
> valid_states&TPGS_SUPPORT_OPTIMIZED?'A':'a');
>
> - switch (h->state) {
> + switch (pg->state) {
> case TPGS_STATE_TRANSITIONING:
> if (wait_for_transition) {
> if (time_before(jiffies, expiry)) {
> @@ -505,7 +552,7 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_dh_data *h, int wait_
> }
>
> /* Transitioning time exceeded, set port to standby */
> - h->state = TPGS_STATE_STANDBY;
> + pg->state = TPGS_STATE_STANDBY;
> break;
> case TPGS_STATE_OFFLINE:
> /* Path unusable */
> @@ -526,22 +573,22 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_dh_data *h, int wait_
> * response. Returns SCSI_DH_RETRY per default to trigger
> * a re-evaluation of the target group state.
> */
> -static unsigned alua_stpg(struct scsi_device *sdev, struct alua_dh_data *h)
> +static unsigned alua_stpg(struct scsi_device *sdev, struct alua_port_group *pg)
> {
> int retval;
> struct scsi_sense_hdr sense_hdr;
>
> - if (!(h->tpgs & TPGS_MODE_EXPLICIT)) {
> + if (!(pg->tpgs & TPGS_MODE_EXPLICIT)) {
> /* Only implicit ALUA supported, retry */
> return SCSI_DH_RETRY;
> }
> - switch (h->state) {
> + switch (pg->state) {
> case TPGS_STATE_OPTIMIZED:
> return SCSI_DH_OK;
> case TPGS_STATE_NONOPTIMIZED:
> - if ((h->flags & ALUA_OPTIMIZE_STPG) &&
> - !h->pref &&
> - (h->tpgs & TPGS_MODE_IMPLICIT))
> + if ((pg->flags & ALUA_OPTIMIZE_STPG) &&
> + !pg->pref &&
> + (pg->tpgs & TPGS_MODE_IMPLICIT))
> return SCSI_DH_OK;
> break;
> case TPGS_STATE_STANDBY:
> @@ -555,13 +602,13 @@ static unsigned alua_stpg(struct scsi_device *sdev, struct alua_dh_data *h)
> default:
> sdev_printk(KERN_INFO, sdev,
> "%s: stpg failed, unhandled TPGS state %d",
> - ALUA_DH_NAME, h->state);
> + ALUA_DH_NAME, pg->state);
> return SCSI_DH_NOSYS;
> break;
> }
> /* Set state to transitioning */
> - h->state = TPGS_STATE_TRANSITIONING;
> - retval = submit_stpg(sdev, h->group_id, &sense_hdr);
> + pg->state = TPGS_STATE_TRANSITIONING;
> + retval = submit_stpg(sdev, pg->group_id, &sense_hdr);
>
> if (retval) {
> if (!scsi_sense_valid(&sense_hdr)) {
> @@ -571,7 +618,7 @@ static unsigned alua_stpg(struct scsi_device *sdev, struct alua_dh_data *h)
> if (driver_byte(retval) == DRIVER_ERROR)
> return SCSI_DH_DEV_TEMP_BUSY;
> } else {
> - sdev_printk(KERN_INFO, h->sdev, "%s: stpg failed\n",
> + sdev_printk(KERN_INFO, sdev, "%s: stpg failed\n",
> ALUA_DH_NAME);
> scsi_print_sense_hdr(sdev, ALUA_DH_NAME, &sense_hdr);
> }
> @@ -596,13 +643,12 @@ static int alua_initialize(struct scsi_device *sdev, struct alua_dh_data *h)
> goto out;
>
> err = alua_check_vpd(sdev, h);
> - if (err != SCSI_DH_OK)
> - goto out;
> -
> - err = alua_rtpg(sdev, h, 0);
> - if (err != SCSI_DH_OK)
> + if (err != SCSI_DH_OK || !h->pg)
> goto out;
>
> + kref_get(&h->pg->kref);
> + err = alua_rtpg(sdev, h->pg, 0);
> + kref_put(&h->pg->kref, release_port_group);
> out:
> return err;
> }
> @@ -618,6 +664,7 @@ out:
> static int alua_set_params(struct scsi_device *sdev, const char *params)
> {
> struct alua_dh_data *h = sdev->handler_data;
> + struct alua_port_group *pg = NULL;
> unsigned int optimize = 0, argc;
> const char *p = params;
> int result = SCSI_DH_OK;
> @@ -630,10 +677,18 @@ static int alua_set_params(struct scsi_device *sdev, const char *params)
> if ((sscanf(p, "%u", &optimize) != 1) || (optimize > 1))
> return -EINVAL;
>
> + rcu_read_lock();
> + pg = rcu_dereference(h->pg);
> + if (!pg) {
> + rcu_read_unlock();
> + return -ENXIO;
> + }
> +
> if (optimize)
> - h->flags |= ALUA_OPTIMIZE_STPG;
> + pg->flags |= ALUA_OPTIMIZE_STPG;
> else
> - h->flags &= ~ALUA_OPTIMIZE_STPG;
> + pg->flags |= ~ALUA_OPTIMIZE_STPG;
> + rcu_read_unlock();
>
> return result;
> }
> @@ -658,16 +713,23 @@ static int alua_activate(struct scsi_device *sdev,
> struct alua_dh_data *h = sdev->handler_data;
> int err = SCSI_DH_OK;
>
> - err = alua_rtpg(sdev, h, 1);
> - if (err != SCSI_DH_OK)
> + if (!h->pg)
> goto out;
>
> + kref_get(&h->pg->kref);
> +
> if (optimize_stpg)
> - h->flags |= ALUA_OPTIMIZE_STPG;
> + h->pg->flags |= ALUA_OPTIMIZE_STPG;
>
> - err = alua_stpg(sdev, h);
> + err = alua_rtpg(sdev, h->pg, 1);
> + if (err != SCSI_DH_OK) {
> + kref_put(&h->pg->kref, release_port_group);
> + goto out;
> + }
> + err = alua_stpg(sdev, h->pg);
> if (err == SCSI_DH_RETRY)
> - err = alua_rtpg(sdev, h, 1);
> + err = alua_rtpg(sdev, h->pg, 1);
> + kref_put(&h->pg->kref, release_port_group);
> out:
> if (fn)
> fn(data, err);
> @@ -683,13 +745,19 @@ out:
> static int alua_prep_fn(struct scsi_device *sdev, struct request *req)
> {
> struct alua_dh_data *h = sdev->handler_data;
> + int state;
> int ret = BLKPREP_OK;
>
> - if (h->state == TPGS_STATE_TRANSITIONING)
> + if (!h->pg)
> + return ret;
> + kref_get(&h->pg->kref);
> + state = h->pg->state;
> + kref_put(&h->pg->kref, release_port_group);
> + if (state == TPGS_STATE_TRANSITIONING)
> ret = BLKPREP_DEFER;
> - else if (h->state != TPGS_STATE_OPTIMIZED &&
> - h->state != TPGS_STATE_NONOPTIMIZED &&
> - h->state != TPGS_STATE_LBA_DEPENDENT) {
> + else if (state != TPGS_STATE_OPTIMIZED &&
> + state != TPGS_STATE_NONOPTIMIZED &&
> + state != TPGS_STATE_LBA_DEPENDENT) {
> ret = BLKPREP_KILL;
> req->cmd_flags |= REQ_QUIET;
> }
> @@ -710,11 +778,8 @@ static int alua_bus_attach(struct scsi_device *sdev)
> if (!h)
> return -ENOMEM;
> h->tpgs = TPGS_MODE_UNINITIALIZED;
> - h->state = TPGS_STATE_OPTIMIZED;
> - h->group_id = -1;
> + h->pg = NULL;
> h->rel_port = -1;
> - h->buff = h->inq;
> - h->bufflen = ALUA_INQUIRY_SIZE;
> h->sdev = sdev;
>
> err = alua_initialize(sdev, h);
> @@ -736,8 +801,10 @@ static void alua_bus_detach(struct scsi_device *sdev)
> {
> struct alua_dh_data *h = sdev->handler_data;
>
> - if (h->buff && h->inq != h->buff)
> - kfree(h->buff);
> + if (h->pg) {
> + kref_put(&h->pg->kref, release_port_group);
> + h->pg = NULL;
> + }
> sdev->handler_data = NULL;
> kfree(h);
> }
#include <linux/rcupdate.h> and RCU write side locking is not added until patch 19/23.
This patch uses rcu_read_lock()/rcu_read_unlock()/rcu_dereference() and should have
the #include added.
Note: lookup of existing alua_port_group object is not added until patch 17/23.
Note that in alua_check_vpd(), returning SCSI_DH_DEV_TEMP_BUSY if kmalloc() or pg
or alloc_ordered_workqueue() fails will cause alua_bus_attach to fail with -EINVAL.
i.e. "temp busy" will not get retried so this is kind of misleading.
Reviewed-by: Ewan D. Milne <emilne@xxxxxxxxxx>
--
To unsubscribe from this list: send the line "unsubscribe linux-scsi" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
