[SCSI] sym2: Fix build when spinlock debugging is enabled

When spinlock debugging is turned on, a struct completion grows beyond the
size allowed for the scsi_pointer.  So move the struct completion back onto
the stack.  The additional memory barriers are to keep us from completing
a random piece of kernel stack if the command happens to complete after
the error handling has finished.

Signed-off-by: Matthew Wilcox <matthew@wil.cx>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

1 files changed, 12 insertions, 8 deletions

diff --git a/drivers/scsi/sym53c8xx_2/sym_glue.c b/drivers/scsi/sym53c8xx_2/sym_glue.c
index 2c4e5f1e7a9..9c83b4d39a2 100644
--- a/drivers/scsi/sym53c8xx_2/sym_glue.c
+++ b/drivers/scsi/sym53c8xx_2/sym_glue.c
@@ -140,11 +140,11 @@ static struct scsi_transport_template *sym2_transport_template = NULL;
  *  Driver private area in the SCSI command structure.
  */
 struct sym_ucmd {               /* Override the SCSI pointer structure */
-        struct completion done;
-        void (*old_done)(struct scsi_cmnd *);
-        dma_addr_t data_mapping;
-        int to_do;
-        u_char data_mapped; /* corresponds to data_mapping above */
+        dma_addr_t      data_mapping;
+        unsigned char   data_mapped;
+        unsigned char   to_do;                  /* For error handling */
+        void (*old_done)(struct scsi_cmnd *);   /* For error handling */
+        struct completion *eh_done;             /* For error handling */
 };
 
 #define SYM_UCMD_PTR(cmd)  ((struct sym_ucmd *)(&(cmd)->SCp))
@@ -713,7 +713,7 @@ static void sym_eh_done(struct scsi_cmnd *cmd)
         cmd->scsi_done = ucmd->old_done;
 
         if (ucmd->to_do == SYM_EH_DO_WAIT)
-                complete(&ucmd->done);
+                complete(ucmd->eh_done);
 }
 
 /*
@@ -728,6 +728,7 @@ static int sym_eh_handler(int op, char *opname, struct scsi_cmnd *cmd)
         SYM_QUEHEAD *qp;
         int to_do = SYM_EH_DO_IGNORE;
         int sts = -1;
+        struct completion eh_done;
 
         dev_warn(&cmd->device->sdev_gendev, "%s operation started.\n", opname);
 
@@ -742,8 +743,10 @@ static int sym_eh_handler(int op, char *opname, struct scsi_cmnd *cmd)
         }
 
         if (to_do == SYM_EH_DO_WAIT) {
-                init_completion(&ucmd->done);
+                init_completion(&eh_done);
                 ucmd->old_done = cmd->scsi_done;
+                ucmd->eh_done = &eh_done;
+                wmb();
                 cmd->scsi_done = sym_eh_done;
         }
 
@@ -779,8 +782,9 @@ static int sym_eh_handler(int op, char *opname, struct scsi_cmnd *cmd)
         spin_unlock_irq(host->host_lock);
 
         if (to_do == SYM_EH_DO_WAIT) {
-                if (!wait_for_completion_timeout(&ucmd->done, 5*HZ)) {
+                if (!wait_for_completion_timeout(&eh_done, 5*HZ)) {
                         ucmd->to_do = SYM_EH_DO_IGNORE;
+                        wmb();
                         sts = -2;
                 }
         }