scsi_dh_alua: allocate RTPG buffer separately

The RTPG buffer will only evaluated within alua_rtpg(),
so we can allocate it locally there and avoid having to
put it into the global structure.

Reviewed-by: Ewan Milne <emilne@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c b/drivers/scsi/device_handler/scsi_dh_alua.c
index 73df60e..af5acc1 100644 (file)
--- a/drivers/scsi/device_handler/scsi_dh_alua.c
+++ b/drivers/scsi/device_handler/scsi_dh_alua.c
@@ -56,7 +56,7 @@
 #define TPGS_MODE_IMPLICIT             0x1
 #define TPGS_MODE_EXPLICIT             0x2
 
-#define ALUA_INQUIRY_SIZE              36
+#define ALUA_RTPG_SIZE                 128
 #define ALUA_FAILOVER_TIMEOUT          60
 #define ALUA_FAILOVER_RETRIES          5
 
@@ -71,9 +71,6 @@ struct alua_dh_data {
        int                     state;
        int                     pref;
        unsigned                flags; /* used for optimizing STPG */
-       unsigned char           inq[ALUA_INQUIRY_SIZE];
-       unsigned char           *buff;
-       int                     bufflen;
        unsigned char           transition_tmo;
        struct scsi_device      *sdev;
        activate_complete       callback_fn;
@@ -85,21 +82,6 @@ struct alua_dh_data {
 
 static char print_alua_state(int);
 
-static int realloc_buffer(struct alua_dh_data *h, unsigned len)
-{
-       if (h->buff && h->buff != h->inq)
-               kfree(h->buff);
-
-       h->buff = kmalloc(len, GFP_NOIO);
-       if (!h->buff) {
-               h->buff = h->inq;
-               h->bufflen = ALUA_INQUIRY_SIZE;
-               return 1;
-       }
-       h->bufflen = len;
-       return 0;
-}
-
 /*
  * submit_rtpg - Issue a REPORT TARGET GROUP STATES command
  * @sdev: sdev the command should be sent to
@@ -333,8 +315,8 @@ static int alua_check_sense(struct scsi_device *sdev,
 static int alua_rtpg(struct scsi_device *sdev, struct alua_dh_data *h, int wait_for_transition)
 {
        struct scsi_sense_hdr sense_hdr;
-       int len, k, off, valid_states = 0;
-       unsigned char *ucp;
+       int len, k, off, valid_states = 0, bufflen = ALUA_RTPG_SIZE;
+       unsigned char *ucp, *buff;
        unsigned err, retval;
        unsigned long expiry, interval = 0;
        unsigned int tpg_desc_tbl_off;
@@ -345,14 +327,19 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_dh_data *h, int wait_
        else
                expiry = round_jiffies_up(jiffies + h->transition_tmo * HZ);
 
+       buff = kzalloc(bufflen, GFP_KERNEL);
+       if (!buff)
+               return SCSI_DH_DEV_TEMP_BUSY;
+
  retry:
-       retval = submit_rtpg(sdev, h->buff, h->bufflen, &sense_hdr, h->flags);
+       retval = submit_rtpg(sdev, buff, bufflen, &sense_hdr, h->flags);
 
        if (retval) {
                if (!scsi_sense_valid(&sense_hdr)) {
                        sdev_printk(KERN_INFO, sdev,
                                    "%s: rtpg failed, result %d\n",
                                    ALUA_DH_NAME, retval);
+                       kfree(buff);
                        if (driver_byte(retval) == DRIVER_ERROR)
                                return SCSI_DH_DEV_TEMP_BUSY;
                        return SCSI_DH_IO;
@@ -390,14 +377,18 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_dh_data *h, int wait_
                sdev_printk(KERN_ERR, sdev, "%s: rtpg failed\n",
                            ALUA_DH_NAME);
                scsi_print_sense_hdr(sdev, ALUA_DH_NAME, &sense_hdr);
+               kfree(buff);
                return SCSI_DH_IO;
        }
 
-       len = get_unaligned_be32(&h->buff[0]) + 4;
+       len = get_unaligned_be32(&buff[0]) + 4;
 
-       if (len > h->bufflen) {
+       if (len > bufflen) {
                /* Resubmit with the correct length */
-               if (realloc_buffer(h, len)) {
+               kfree(buff);
+               bufflen = len;
+               buff = kmalloc(bufflen, GFP_KERNEL);
+               if (!buff) {
                        sdev_printk(KERN_WARNING, sdev,
                                    "%s: kmalloc buffer failed\n",__func__);
                        /* Temporary failure, bypass */
@@ -407,24 +398,25 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_dh_data *h, int wait_
        }
 
        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];
+       if ((buff[4] & RTPG_FMT_MASK) == RTPG_FMT_EXT_HDR && buff[5] != 0)
+               h->transition_tmo = buff[5];
        else
                h->transition_tmo = ALUA_FAILOVER_TIMEOUT;
 
-       if (wait_for_transition && (orig_transition_tmo != h->transition_tmo)) {
+       if (wait_for_transition &&
+           (orig_transition_tmo != h->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;
        }
 
-       if ((h->buff[4] & RTPG_FMT_MASK) == RTPG_FMT_EXT_HDR)
+       if ((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 = buff + tpg_desc_tbl_off;
             k < len;
             k += off, ucp += off) {
 
@@ -474,6 +466,7 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_dh_data *h, int wait_
                err = SCSI_DH_OK;
                break;
        }
+       kfree(buff);
        return err;
 }
 
@@ -668,8 +661,6 @@ static int alua_bus_attach(struct scsi_device *sdev)
        h->state = TPGS_STATE_OPTIMIZED;
        h->group_id = -1;
        h->rel_port = -1;
-       h->buff = h->inq;
-       h->bufflen = ALUA_INQUIRY_SIZE;
        h->sdev = sdev;
 
        err = alua_initialize(sdev, h);
@@ -691,8 +682,6 @@ 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);
        sdev->handler_data = NULL;
        kfree(h);
 }